Leaf Pieces Research Articles

First report of Alternaria leaf spot caused by Alternaria brassicae on broccoli in North Carolina, United States.

In September 2023, broccoli (Brassica oleracea var. italica) 'Sweet Bunch' plants on an organic farm in Buncombe County, North Carolina (NC), displayed symptoms of Alternaria leaf spot. Disease affected 10 to 20% of leaf area on all (approximately 30) plants. Lesions were dark brown with chlorotic halos, irregular in shape, and ≤3 cm in diameter. Leaf samples were incubated in a humidity chamber for 24 h, and the pathogen was putatively identified as Alternaria brassicae based on conidial morphology (Rimmer et al. 2007; Supplemental Fig. 1). Leaf pieces (2 x 2 mm) spanning lesion edges were surface-disinfested (1% sodium hypochlorite solution) for 1 min, rinsed in sterile distilled water, embedded in potato dextrose agar, and incubated at 22°C with a 12-h photoperiod. A pure culture was obtained by transferring a hyphal tip onto 20% V8 juice agar and incubated as above. After 10 d, colonies consisted of concentric zones of white to brown mycelia with white, aerial mycelia. Within 7 d, conidia measuring 80 to 150 µm long with 0 to 3 longitudinal septa, 6 to 15 transverse septa, and a long beak were observed, and the isolate was putatively identified as A. brassicae (Rimmer et al. 2007). To confirm identification, DNA was extracted from mycelia and subjected to PCR using primers to amplify a portion of the internal transcribed spacer of rDNA (ITS: ITS1/ITS4) (White et al. 1990), the transcription elongation factor-1 (tef1: EF1-728F/EF1-986R) (Carbone and Kohn 1999), and the glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH: gpd1/gpd2) (Berbee et al. 1999). Amplicons were sequenced at Eton Bioscience (Durham, NC) and subjected to BLAST analysis in NCBI GenBank. Sequences matched (99.5 to 100% identity) A. brassicae CBS 116528 accessions KC584185 (ITS), KC584641 (tef1), and KC584102 (GAPDH) (Woudenberg et al. 2013). All sequences were deposited in NCBI GenBank (accessions PP584506, PP584507, PP584508). To confirm pathogenicity on broccoli and kale (B. oleracea var. sabellica), 5-week-old plants of broccoli 'Sweet Bunch', 'Eastern Crown', and 'Green Magic' and kale 'Winterbor', 'Darkibor', and 'Oldenbor' grown in 10-cm-diameter pots were separated by crop type and arranged in four randomized complete blocks by cultivar. Each block contained single-plant replicates of each cultivar that were either inoculated or non-inoculated. Conidia of A. brassicae obtained from 10-d-old cultures (3.5 x 103 conidia/ml) were sprayed onto each inoculated plant until run-off. Non-inoculated plants were sprayed with distilled water. Plants were incubated in a humidity chamber alternated with ambient greenhouse conditions every 48 h for 10 d, with average greenhouse temperatures ranging from 15 to 28°C. The experiment was conducted twice. Dark brown to gray lesions measuring 1 to 3 mm in diameter were observed on leaves of all inoculated plants within 5 d of inoculation (Supplemental Fig. 2), and non-inoculated plants remained healthy. On broccoli plants, lesions expanded in concentric rings, and sporulation of the pathogen was observed on leaf tissue and petioles 10 d after inoculation. Lesions remained small (< 3 mm) on kale plants, and sporulation was not observed. Alternaria brassicae was re-isolated from leaf tissue of all inoculated cultivars using methods described above. Pathogen identity was confirmed via colony and conidial morphology. The larger impact of A. brassicae on brassicas is unknown, but finding this less common Alternaria species in the eastern United States could have implications for host resistance development and fungicide efficacy (Nieto-Lopez et al. 2023).

First report of Trichoderma roseum causing tea leaf rot in China.

Tea (Camellia sinensis) is consumed worldwide for its numerous benefits and China lead the world production. In March 2023, leaf spots were observed on approximately 10% of tea plants in a 50-ha commercial tea plantation in Menghai (21°46'13"N, 100°30'6"E), Yunnan, China. Initial symptoms appeared as small spots, which progressively expanded and spread over the entire leaf surface. Subsequently, pale pink mold layers developed from the lesions (Fig. S1). To isolate the pathogen, small leaf pieces (3 × 3 mm) were cut from the margins of the lesions, sterilized with 75% ethanol for 30 sec and 0.5% NaClO for another 30 sec, and rinsed three times with sterile water. The pieces were placed on acidified potato dextrose agar (PDA) plates and incubated in darkness at 28°C. A total of 15 fungal isolates with identical morphologies were collected. The colonies appeared pale pink with white mycelia initially then turned orange-pink at the center and light white at the edges. After 10-15 days, exhibiting a powdery texture and concentric rings with uniform edges. Conidia were found at the apex peduncle and were inverted pear-shaped or oval, either non-septate (15.3 ± 2 × 7.8 ± 1.8 μm in size, n = 60) or septate, with a slightly constricted spore base featuring papillary projecvtions (14.8 ± 1.5 × 7.4 ± 0.7 μm in size, n = 60). The morphology closely resembled Trichoderma roseum (Oh et al. 2014). To confirm the species, the strain CYB5 was selected for identification by sequencing the ribosomal internal transcribed spacer (ITS) and large subunit (LSU) genes using polymerase chain reaction (PCR) (White et al.1990). The ITS (GenBank accession OR889657) and LSU (PQ270526) gene sequences exhibited 98% similarity with the Trichoderma roseum sequence KP317992 from NCBI database. A phylogenetic tree was constructed using MEGA 11 (Felsenstein 1981) based on the concatenated sequences (ITS and LSU) of the strain CYB5 and reference strains (Fig. S2). The analysis confirmed that CYB5 is T. roseum (Inácio et al. 2011). Pathogenicity tests were conducted on detached healthy tea leaves placed on wet filter paper in petri dishes. Micro-wounds were made on leaves using a sterilized needle, followed by inoculation with a 6-mm plug of CYB5. Control leaves were inoculates with fungus-free agar disks. The dishes were incubated at 25°C in the dark for 7 days. The leaves inoculated with CYB5 developed reddish brown to dark brown lesions around the inoculated sites, while control leaves remained asymptomatic. The fungus was reisolated from the lesion, and the isolates were morphologically identical to the original cultures. A second pathogenicity test was conducted on potted tea plants of the cultivar 'Yunkang No. 10.' Three plants scratched with a needle and three non-wounded plants were inoculated by spraying 20 ml of a spore suspension (105 spores/ml) of CYB5. Plants sprayed with sterile water served as controls. All plants were maintained in a growth chamber at 28°C, and 70% relative humidity. The lesions developed three days post-inoculation, and typical symptoms appeared after 10 days on spore-inoculated plants only. T. roseum was reisolated and reidentified based on the morphology and molecular analyses, thus fulfilling Koch's postulates. To our best knowledge, this is the first report of T. roseum causing tea leaf rot in China.

First Report of Leaf Blight of Syringa oblata Caused by Botryosphaeria dothidea in China.

As an important landscaping plant, Syringa oblata is widely planted in northern China with high ornamental, medicinal, and edible value (Men et al. 2023). In September 2023, a new leaf blight disease on S. oblata was observed in Tianjin (39.0916°N, 117.1019°E), China. The onset of foliar symptoms was marked by the appearance of yellow-brown spots that originated from the tip and margin, subsequently evolving into irregularly shaped brown lesions. Finally, the lesions are distributed throughout the leaf surface, causing the leaf to wilt and seriously affecting photosynthesis. To identify the pathogen responsible for leaf blight of S. oblata, symptomatic leaves were collected and cut into square leaf blocks with a size of 0.3 cm², which were sterilized by immersion in 75% ethanol for 60 s and 5% NaClO for 30 s, and rinsed three times with sterile distilled water. The sterilized leaf pieces were then placed on potato dextrose agar (PDA) and incubated at 25 °C for 3-5 days. The peripheral hyphae of the fungal colony which developed from the infected tissues were isolated onto PDA plates. The fungal cultures on PDA plates were used for morphological observation and identification of the fungus. Colonies of B. dothidea on PDA medium were initially off-white, batting-shaped and gradually grayish-black. Aerial hyphae were well developed and could reach the tip of the petri dish. To induce sporulation, the hyphae were picked into medium containing sterilized pine needles. Conidia were found on pine needles after 30 d of incubation at 25°C. Conidia were hyaline, unicellular, oblong to spindle-shaped, and 17.5-23.0 µm in size × 6.1-8.5 µm(n=50). Based on these characteristics, the isolates were preliminarily identified as B. dothidea (Phillips et al. 2005). To provide additional evidence for the classification of the isolate, genomic DNA was extracted from the isolates of B. dothidea and used for Polymerase Chain Reaction (PCR). The internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GPDH), and actin (ACT) were amplified with the primer pairs ITS1/ITS4, GDP1/GDP2, and ACT-512F/ACT-783R, respectively (Jiang et al. 2022). A BLAST search of sequences showed the ITS, GPDH, and ACT sequences had >99% identity with homologous sequences from B. dothidea isolates Bb158-4(HQ392696.1), PPO-46523(MG761771.1), and CMW7779 (AY972117.1), respectively. Phylogenetic analysis determined that the isolate was in the same clade position as B. dothidea, which confirmed the above morphological identification. To assess pathogenicity, the fungal cakes (6 mm diameter) were obtained from the edge of a fresh colony (cultured on a PDA plate for 7 days) using a sterile perforator. Ten surface-sterilized leaves of healthy S. oblata with uniform growth condition were collected and inoculated with fungal cakes after wounding. Ten leaves were inoculated with sterile PDA medium blocks as control. The test was repeated three times. All leaves were kept at 25°C and sterile H2O was sprayed daily to keep leaves surface moist. After five days, all vaccination sites showed lesions similar to those of the S. oblata diseased leaves in the field, while the controls were asymptomatic. B. dothidea was reisolated from symptomatic tissues, thus fulfilling Koch's postulates. B. dothidea is a member of Botryosphaeriaceae. Currently, B. dothidea infection of Syringa spp. plants has not been reported. However, in China, it has been reported to cause stem rot on Forsythia suspense (He et al. 2022) and leaf dieback on sweet osmanthus (Ling et al. 2010), demonstrating that B. dothidea can infect Oleaceae species. This study found that S. oblata could be infected by B. dothidea. To the best of our knowledge, this is the first report of B. dothidea causing leaf blight on S. oblata in China. Identifying the pathogen of S. oblata leaf blight is essential for the prevention and management of disease associated with S. oblata.

THE PERSPECTIVITIES OF MICRICLONAL PROPAGATION OF ACER PLATANOIDES L. CRIMSON KING (ACEARCEAE JUSS.)

Clonal micropropagation – massive asexual propagation of plants from cell and tissue culture; the resulting plants are genetically identical to the original copy. The conservation of plants by tissue culture methods is of great interest and will probably become even more common in the future. The advantages of this method are numerous, but we find it most important that the initiation of cultivation requires only a single plant, a seed or a single explant (apex, meristem, bud, piece of leaf, stem etc.), thus, the available plant specimens (which can be only a few) will not be affected by harvesting them from their habitat. The state program “Developing of the scientific basis for the sustainable reproduction of valuable specimens of the botanical garden collection in in vitro culture” is being conducted in the laboratory of biotechnology of the Tashkent Botanical Garden of the Institute of Botany, Academy of Sciences of the Republic of Uzbekistan, directed at microclonal propagation of many valuable species presented in a single copy, as well as species in demand in urban greening programs. Acer platanoides L. Crimson King variety (Acearceae Juss.) is a deciduous, slow-growing tree, reaching 15 m with age. The crown shape is wide-round and even. The leaves are large, 5-7 lobed, deep purple, and do not change color throughout the growing season. The trunk is smooth, dark in color, with clearly defined longitudinal grooves. Because of its graceful shape, the Crimson King variety is extremely popular. It is actively planted in city yards, parks, and roadsides. Suitable for landscaping. Within this state program the protocol of microclonal propagation of A. platanoides Crimson King variety has been developed to propagate this species for Botanical Garden collection as well as for greening programs. Solutions of sodium hypochloride (4-6%), hydrogen peroxide (2-15%), silver nitrate (0.01%), Tween20, ethanol (70%), and some other sterilizing agents were tested for developing a protocol for sterilization of maple explants. “Belizna” solution, “Domestos” sterilizing soap, fungicides difenoconazole, mancoseb and metalaxyl, fludioxonil, propiconazole, antibiotics streptomycin, amoxicillin, gentamicin, and etc. were also implemented for explants sterilization. As a result of the studies, it was determined that the most optimal source of explants are branches with apical (10% regeneration) and lateral (100% regeneration) buds of the annual shoot of A. platanoides Crimson King variety. Plant growth environment is important in the success of in vitro propagation. Thus, explants obtained from trees growing in the arid areas of massive Kuylyuk in Tashkent, were characterized by low viability and a high degree of infection with fungal diseases in comparison with explants obtained from trees growing in Hastimom Square in Tashkent, where trees are watered daily. We found two ways of in vitro propagation of A. platanoides L. variety Crimson King: 1. With the use of microcuttings. 2. Indirect organogenesis with induction of callus. The best way for A. platanoides L. variety Crimson King became indirect organogenesis trough induction of the callus in the WPM - Wood Propagation Media, hormone free or with 6- benzilaminopurine in the media. The duration of the developing of a plant usually takes 6-9 months.

Analisis Gaya Bahasa dalam Puisi “Hatiku Selembar Daun” Karya Sapardi Djoko Damono

This research is an analysis of the language style contained in the poem “Hatiku Selembar Daun” by Sapardi Djoko Damono. The purpose of the research is to describe the language style used by the author. Poetry as a type of literary work is formed due to the presence of building blocks, one of which is language style (majas). This research uses qualitative research methods. The research source is primary data with literature study data collection techniques. The results of the study show that the majas that the author tends to use in his poem entitled “My Heart is a Piece of Leaf” are comparative majas including personification, hyperbole, and metaphor with the results in the first stanza using the personification language style, the second stanza the hyperbole language style, and the third stanza the metaphor language style

First Report of Exserohilum rostratum Causing Brown Spot on Spartina alterniflora in China.

Spartina alterniflora Loisel, a perennial grass, has become an invasive species in China's coastal wetlands (Zhang et al. 2018). In July 2021, brown spot symptoms were observed on S. alterniflora in a coastal wetland (21°45'48″N, 108°44'00″E) in Beihai City, Guangxi Province, China. The disease affected approximately 50% of the plants in the surveyed area (0.2 ha) and was also observed in other regions of Beihai. It caused brown lesions with a gray or whitish center on the leaves and stems of S. alterniflora. As the disease developed, it ultimately led to leaf shedding and plant death. To isolate the causal agent, 18 fragments (~ 5 mm) from six symptomatic plants (3 leaf pieces per plant) were surface sterilized with 1% NaOCl solution for 2 min and rinsed three times with sterilized water. Subsequently, the tissues were placed on potato dextrose agar (PDA) medium supplemented with chloramphenicol (0.1 g/liter) and incubated at 28°C for three days. The hyphal tips were transferred onto fresh PDA to obtain pure cultures. A total of 25 isolates were obtained, 20 of which shared similar morphologies, while the remaining five exhibited distinct morphological characteristics and were non-pathogenic to S. alterniflora. Three isolates (MC16.1.3, MC16.6.2, and MC16.8.3) were randomly selected from the 20 for further investigation. The colonies on PDA were flat with dense aerial mycelia. The colony margins were entire, light brown in the centre, white to grey at the margin; reverse dark brown in the centre, gray at the margin. Conidia were straight to slightly curved, light olive-brown to dark olive-brown, septate, measured 33.5 to 79.1 μm × 10.4 to 18.7 μm (average 52.9 × 14.4 μm, n = 100), with a distinctly protruding hilum swelled from the basal cell. For molecular identification, the genomic DNA was extracted from mycelium on PDA using the CTAB method (Guo et al. 2000). The internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and translation elongation factor 1 alpha (TEF1-α) genes were amplified and sequenced with the primer pairs ITS1/ITS4 (White et al. 1990), GPD1/GPD2 (Berbee et al. 1999), and EF1-983/EF1-2218 (Rehner et al. 2005), respectively. A BLAST analysis revealed that the ITS (OR516787-9), GAPDH (OR523686-8), and TEF-α (OR523683-5) had 99.1 to 99.7% identity with those of E. rostratum strains BRIP 11417 (LT837836, LT882553, and LT896656) and CBS 128061 (KT265240, LT715900, and LT896658) (Hernández-Restrepo et al. 2018). Based on the concatenated sequences, a phylogenetic tree generated by PhyloSuite software (Zhang et al., 2020) through Bayesian inference (BI) and Maximum Likelihood (ML) methods placed the isolates within E. rostratum. These morphological characteristics and molecular analyses confirmed the pathogen as E. rostratum (Hernández-Restrepo et al. 2018; Kaboré et al. 2022). To confirm pathogenicity, a conidial water suspension (~ 1 × 106 conidia/ml) of each of the three strains was inoculated on nine healthy S. alterniflora plants that had been grown for six months. Control plants were treated with sterile water. All plants were then enclosed in plastic bags and incubated in a greenhouse at 28°C. Six days after inoculation, the plants exhibited symptoms similar to those observed in nature. The control plants developed no symptoms. These experiments were replicated three times with similar results. To fulfill Koch's postulates, E. rostratum was consistently re-isolated from symptomatic tissue and confirmed by morphology and sequencing, whereas no fungus was isolated from the control plants. In recent years, S. alterniflora has posed a serious threat to the indigenous biodiversity of wetland ecosystems (Zhang et al. 2018). To our knowledge, this is the first report of E. rostratum causing brown spot on S. alterniflora worldwide.

First report of large-berry coffee (Coffea liberica) anthracnose caused by Colletotrichum kahawae in China.

Large-berry coffee (Coffea liberica) is one of the three cultivated coffee species and a precious breeding germplasm in China (Yan et al, 2019). Anthracnose is a damaging epidemic disease on coffee worldwide (Mohammed et al. 2015). Between June and September 2022, anthracnose was observed on coffee plants in Puer area, Yunnan, China and disease incidence (% plants diseased) of 8.5%-28.2% was recorded in the field. The disease symptoms were observed at all growth stages. Lesions on leaves were circular or oval, with a white to gray central zone outlined by a brown margin and surrounded by a chlorotic halo, Φ5.1-18.5 mm; some lesions extended and coalesced later to form large, blighted areas, leading to complete leaf senescence, defoliation and bare blighted branches on heavily infected trees. The spots on coffee berries were oval or fusiform, sunken and brown-black; diseased berries became gray-black and dried-out but remained on the tree. Leaves with typical anthracnose lesions were collected from fields in Simao ( 22.07°E,100.98°N) to isolate the pathogen. Leaf pieces (5×5mm) from the lesion margin were cut, surface-sterilized with 75% ethanol and 2% NaClO, and cultured on PDA at 25°C. Three isolates with the same colony morphology were obtained by hyphal tip purification. Detached and intact leaves of 6-month coffee seedlings were inoculated with Φ5mm mycelial discs of the isolates. Anthracnose lesions developed on the inoculated leaves, with all 3 isolates, 7d after incubation in a growth chamber (25°C, > 90% RH and lighting 8 h/d at 11000 lux). Pathogens with the same colony morphology as those of the original isolates were re-isolated from the infected tissues of inoculated leaves, thus fulfilling Koch's Postulates. The ITS sequence (PP550861) for the isolate was PCR-amplified and Blast-n analyses showed 100 % (554/554bp) identity to Colletotrichum kahawae LWTJ01; so they were the same population and coded as KFTJ02. The actin (ACT), calmodulin(CAL), glyceraldehydes-3-phosphate dehydrogenase (GAPHD) and histone 3 (HIS3) genes (Qiu et al. 2020) were amplified from one of KFTJ02 isolates, sequenced and deposited in NCBI GenBank (OR842543, OR842544, OR842545 & OR842546). A phylogenetic tree was generated based on the concatenated sequences of the four genes and those of related Colletotrichum spp. using MEGA 6.0 and KFTJ02 clustered in the same clade with C. kahawae IMI319418 on the tree (Bootstrap sup.=88%). When cultured at 25°C on PDA for 7 days, its colonies were near round or ovoid, gray-white, contoured, Φ73.2-80.1 (76.2±2.3)mm or growth rate 10.2-11.1(8.1) mm/d (n=10). The hyphae were hyaline, septated, branching at near right angles. Conidial masses formed 14 days after incubation. The conidia were elliptical, hyaline, monocellular, 10.2-15.5 (12.7±1.06)×3.8-5.2 (4.3±0.52) µm (n=50). The appressoria were black-brown, oval or irregular, 7.8-9.3 (8.5±0.81)μm (n= 50). These morphological characteristics were consistent with those of C. kahawae (Bridge et al, 2008). Therefore, KFTJ02 was identified as C. kahawae, which has been found to infect Camellia oleifera, Areca catechu and Ficus microcarpa (Wei et al, 2023; Zhang et al, 2020; Lin 2023). The coffee berry disease pathogen (C. kahawae) is a quarantine species which has not been recorded and so it is first reported on coffee crops in China. Results of the present study provide important references for further studies on this disease.

First Report of Neofusicoccum parvum causing leaf spot on Camellia japonica in China.

Camellia japonica is an important garden landscape plant in southern China. In April 2022, leaf spot symptoms were observed at the camellia garden of Jiaying University (24°32'83″N, 17 116°12'31″E) in Meizhou city, Guangdong Province, China. The initial symptoms were grayish brown spots on the leaves, as the disease progressed, the lesions were enlarged and affected the whole leaf and eventually led to the loss of its ornamental value. The disease incidence was above 15%. Leaf pieces (5 × 5 mm) from 3 diseased Camellia leaves were sterilized in 75% ethanol for 1 min, then in 1% NaOCl for 1 min; and rinsed three times with sterile water. Leaf pieces were inoculated on potato dextrose agar (PDA) medium and incubated at 25 °C. Three days later, fungal colonies initially showed a white aerial mycelium, turning gray after 5 days, and dark gray after 7 days of incubation. Conidia were single-celled, hyaline, ellipsoidal and without septa. Dimensions of conidia (n≥50) were 14.27 to 20.65 × 4.28 to 6.56 μm. The morphological characteristics matched the genus Neofusicoccum (Pavlic et al. 2009). For molecular identification, the rDNA internal transcribed spacer (ITS1, 5.8S and ITS2) region, translation elongation factor 1-alpha (tef1-α), and beta-tubulin (tub2) of a representative isolate SC6-2 were amplified using the primer pairs ITS1/ITS4, EF1/EF2 and BT2a/-BT2b, respectively (Golzar and Burgess，2011). The sequences obtained were deposited in GenBank (accession nos. PP064173, PP479650 and PP082457 for ITS, tef1-α and tub2, respectively). Nucleotide BLAST analysis showed a 99.81% homology with N. parvum (519/520 bp, OQ509869; 519/520 bp, KF294003; 518/519 bp KF293989) for ITS, 100% homology with N. parvum (398/398 bp, MN318108; 398/398 bp, MK294085; 398/398 bp, MH936021) for tub2, and >99% homology with N. parvum (259/259 bp, 100%, MW390561; 263/265 bp, 99.25%，MN175952; 263/265 bp, 99.25%, MK781982) for tef1-α. The combined phylogenetic analyses (ITS, tef1-α, and tub2) showed that the sequence of the tested isolate and the corresponding sequence of N. parvum (CMW9081, SHSJ1-2) in GenBank grouped in the same branch of the phylogenetic tree. Based on morphological characters, DNA sequencing, and the phylogenetic tree, it can be determined that the pathogen was Neofusicoccum parvum. Inoculation on Camellia leaves was performed to confirm pathogenicity. Nine healthy camellia leaves were pin-pricked with a sterile needle and inoculated with mycelial plugs of isolate SC6-2. Nine other healthy leaves were pin-pricked and inoculated with noncolonized PDA plugs as control leaves. The inoculated leaves were maintained on water agar solid medium at 25°C. To keep a high-humidity environment the inoculation sites were covered by moistened cotton for 2 days. The experiment was repeated three times. Five days after inoculation, all the inoculated leaves showed similar symptoms to those observed in the field, whereas control leaves were asymptomatic for 6 days. The fungal isolates recovered from inoculated leaves were morphologically identical to the N. parvum isolates originally recovered from symptomatic leaves collected in the field, fulfilling Koch's postulates. Neofusicoccum parvum is an aggressive pathogen that causes severe disease on important tree and woody species (Liddle et al. 2019). It has been reported that N. parvum can infect the leaves and branches of grapes (Otoya-Martinez et al. 2023), dieback on Camellia japonica (Pintos, et al. 2012), Brazilian pepperwood (Bertetti et al. 2022), mango (Giancarlo et al. 2023) and other plants. To our knowledge, this is the first report of N. parvum causing leaf spot on Camellia japonica in China.

First Report of Bacterial Leaf Streak of Rice Caused by Pantoea ananatis in Guangdong Province, China.

Rice (Oryza sativa L.) is a crucial staple crop worldwide, and bacterial diseases are among the primary factors affecting rice yield. In late October 2022, bacterial leaf streak disease was observed on the leaves of the rice variety Meixiangzhan 2 across multiple fields (approximately 130 hm2) in Leizhou City, Guangdong Province, China. The incidence rate was up to 30% in each field. Infected rice leaves exhibited distinctive symptoms at the boundary between diseased and healthy tissue, featuring dark green to yellow-brown streaks, while most of the leaf margin exhibited symptoms of either leaf edge or sheath rot. Disease progression from the leaf tip inwards revealed gray-white or dehydrated lesions with a bluish-gray color. Some leaves exhibited wrinkling at the edges, and severe symptoms at the leaf tip resembled those of bacterial leaf blight in rice. Ten leaves were collected from 10 infected rice plants in three distinct fields, and leaf pieces at the border of diseased and healthy areas were surface disinfected with 75% anhydrous ethanol for 60 seconds, rinsed three times with sterile water, and then soaked in sterile water for 8 hours. The obtained bacterial suspension was diluted at a ratio of 1: 106, and 100 μL of the diluted samples were plated on Potato Dextrose Agar (PDA) plates. After incubation at 28°C for 48 hours, the yellow bacterial colonies that appeared, were purified on PDA plates. To confirm the bacterial species, the amplification of genes gyrB, leuS, rpoB, and 16S rDNA was performed on six randomly selected isolates from the three different fields using the primers 27F/1492R, gyrB-F/R, leuS-F/R and rpoB-F/R, as reported by Yu et al (2022), respectively. PCR products were sequenced. All six isolates had identical sequences for all genes sequenced.The gene sequences of 16S rDNA (960 bp), gyrB (953 bp), leuS (733 bp), and rpoB (877 bp) for LZ1, were deposited in the NCBI database under accession numbers PP048830 , PP068625 , PP068626, and PP068627, respectively. These sequences were subsequently compared using BLASTn tool against the NCBI nr/nt database. The 16S rDNA, gyrB, leuS, and rpoB of LZ1 showed similarities of 99.90%, 99.16%, 99.73%, and 99.89%, with the corresponding sequences of P. ananatis TZ39 (GenBank accession numbers MZ800600.1 for 16S rDNA, and CP081342.1 for gyrB, leuS and rpoB ). MLSA analysis using concatenated sequences of gyrB, leuS, and rpoB genes indicated that the isolated strain LZ1 belongs to P. ananatis. In the tillering stage of rice varieties Meixiangzhan 2 and Huahangyuzhan, P. ananatis LZ1 was inoculated at a concentration of 108 CFU/mL using the leaf-cutting method, with sterile water used as a control (Toh et al., 2019). After 14 days of bacterial inoculation, the inoculated leaves gradually became necrotic, changing from light green to brown showing identical symptoms as those in the field, while the control plants remained symptom-free. Subsequent 16S rDNA, gyrB, leuS and rpoB gene sequencing results further confirmed the identity of the pathogen as P. ananatis, thereby fulfilling Koch's postulates. Previous reports have already identified P. ananatis as the pathogen causing rice bacterial leaf streak (Kini et al., 2017; Arayaskul et al., 2019; Yu et al., 2022; Lu et al., 2022; Luna et al., 2023; Yuan et al., 2023). This is the first report of rice bacterial leaf streak caused by P. ananatis in Guangdong Province, China, laying the foundation for future research to establish strategies for the prevention and control of this disease.

First report of Diaporthe eres causing leaf spot on Rosa roxburghii Tratt in Guizhou Province, China.

Rosa roxburghii Tratt is a plant from the Rosaceae family whose fruits are rich in vitamins, dietary fiber, flavonoids, phenolic acids, and other active components (Jiang, et al. 2024). In July 2023, about R. roxburghii 500 plants were investigated in a field of 6000 m2 in Guiding County (107°14'E, 26°45'N), Guizhou province, China, and the results showed a leaf spot incidence of s 20 to 30%. . The affected leaves had irregular, black lesions with a clear blackish brown boundary and faint black conidiomata in a brown center. Fifteen symptomatic leaves were collected from 10 plants washed with sterile distilled water, and 5 × 5 mm pieces of the infected tissues were cut. After surface sterilization for30 s with 75% ethanol, 2 min with 3% NaOCl, three washes in sterilized distilled water, the leaf pieces were dried and placed on potato dextrose agar (PDA) and incubated at 25℃ for 5 days. Three isolates (H3-Y-1-1, H3-Y-1-2, H3-Y-1-3) with identical morphology were obtained, and the isolate H3-Y-1-1was selected for further study. The colonies on PDA exhibited irregular growth patterns, with white felty aerial mycelium on the upper surface, and white mycelium on the lower surface. Conidiomata were irregularly distributed over the agar surface. The isolate H3-Y-1-1 produced darkly pigmented pycnidia on PDA after 30 days and oozed milky mucilaginous drops. The fungus produced two types of conidia, α and β. Regular α conidia were 4.74 - 5.96 × 1.52 - 2.24 μm (n = 50), hyaline, elongated, biguttulate and non-septate. Beta conidia were 20.13 - 25.74 × 0.86 - 1.29 μm (n = 50), aseptate, hyaline, smooth, spindle shaped, slightly curved to bent. The morphological features were consistent with the description of Diaporthe eres (Pereira, et al. 2022). The pathogen was confirmed to be D. eres by amplification and sequencing of the internal transcribed spacer region (ITS), the partial β-tubulin (TUB), the partial translation elongation factor 1-alpha (TEF) genes using primers ITS1/ITS4, Bt-2a/Bt-2b, EF1-728F/EF1-986R, respectively. Sequences from PCR amplification were deposited in GenBank with accession numbers PP411998 (ITS), PP502153 (TUB), PP502156 (TEF). BLAST searches of the sequences revealed (96%) (500/523nt), 97% (479/494 nt) and 99% (334/338 nt) homology with those of D. eres CBS 138594 from GenBank (OM698848, OM752196 and OM752197), respectively. Phylogenetic analysis using maximum-likelihood and Bayesian methods placed the isolate H3-Y-1-1 in a well-supported cluster with D. eres CBS 101742. The pathogen was thus identified as D. eres based on the morphological characterization and molecular analyses (Feng, et al. 2013; Tao, et al. 2020). To assess its pathogenicity, healthy R. roxburghii potted plants were inoculated with H3-Y-1-1 spore suspensions. Symptomatic leaves mirroring field symptoms were observed after XX days of incubations at XX°C, while control plants exhibited no symptoms. Diaporthe eres was consistently reisolated from the infected leaves showing brown irregular or round lesions at the initial stage of the disease, expanding and become more irregular over time ultimately causing leaf curling and plant death. To our knowledge, this is the first report of leaf spot on R. roxburghii caused by D. eres in China. The disease may become a serious threat to fruit of R. roxburghii production in China. Therefore, detection of this pathogen is very important to ensure timely disease management.

First Report of Nigrospora sphaerica causing Leaf Spot on Rhododendron simsii in China.

Rhododendron simsii (indoor azalea) is widely cultivated for its high ornamental value (Xu et al. 2021). In April to May 2023, a leaf spot disease occurred in a field study at the Baili Azalea Forest Area (27°12'N, 105°48'E), Guizhou Province, China. About 500 plants were investigated, and the results showed that the incidence of leaf spot was 20 ~ 30%. To study this disease, 10 plants showing severe symptoms were collected. Initially, the symptoms were round or irregularly shaped brown spots (1 to 10 mm). With time, the spots enlarged and merged. Symptomatic leaves were washed with sterile distilled water, and 5 × 5 mm pieces of the infected tissues were removed. After surface sterilization (30 s with 75% ethanol, 2 min with 3% NaOCl, then washed three times with sterilized distilled water), the leaf pieces were dried and placed on potato dextrose agar (PDA) and incubated at 25℃ for 5 days. Fungal colonies developed from leaf tissues, and the germinated spores were transferred onto PDA for further purification and morphological observation. Three isolates (GUBJ23, GUBJ24, and GUBJ12) with similar morphology were obtained from five affected leaves. The representative strain GUBJ23 was selected for further study. On PDA the mycelium was initially white but with sporulation turned gray and then black. Black, single-celled conidia, spherical to sub-spherical, from 11.80 to 21.39 × 13.38 to 21.83 μm (n = 50) in diameter were borne singly on hyaline vesicles at the tips of conidiophores. These morphological characteristics were similar to those of Nigrospora sphaerica (Wang et al. 2017). To confirm the identification, primer pairs for the internal transcribed spacer (ITS) region (ITS5/ITS4), β-tubulin (TUB2) (Bt-2a/Bt-2b), and the translation elongation factor 1-alpha (TEF1-α) (EF1-728F/EF1-986R), were used for PCR amplification of DNA from strain GUBJ23 (Carbone and Kohn 1999; Glass et al. 1995; White et al. 1990). The resulting sequences were deposited in GenBank with accession numbers OR818025 (ITS), OR835150 (TUB2), and OR835147 (TEF1-α). BLAST searches of the sequences revealed 99.80% identity (503/504 bp) of the ITS sequence, 100.00% identity (395/395 bp) of the TUB2 sequence, and 100.00% identity of the TEF1-α sequence (241/241 bp) with N. sphaerica LC7294 (accessions KX985932, KY019602, and KY019397, respectively.) Based on a combined dataset of ITS, TEF1-α, and TUB2 sequences, a phylogenetic tree was constructed using the maximum likelihood method and confirmed that isolates GUBJ23, GUBJ24, and GUBJ12 were N. sphaerica (Wang et al. 2017). Leaves of three healthy R. simsii plants were spray-inoculated with a spore suspension (105 conidia/mL), and an additional three plants were sprayed with sterile water. These plants were incubated at 25℃ in 75% relative humidity. After 5 to 7 days of inoculation, 0.5 to 1.8 mm spots appeared on the leaves. At 10 to 14 days after inoculation, grayish brown, semicircular or irregular lesions appeared on the leaves, usually with a diameter of 0.8 to 3 mm. The symptoms were like symptoms seen on naturally infected leaves, while the control leaves remained asymptomatic. The pathogen was re-isolated from diseased leaves and identified by morphological characterization and molecular analyses (ITS, TUB and TEF1-α), and the reisolated pathogen was identical to N. sphaerica. Thus completing Koch's postulates. According to previous research, N. sphaerica is a widely distributed phytopathogenic fungus that has a wide host range (Wang et al. 2017). This study is the first to identify N. sphaerica as the cause of leaf spot disease in R. simsii. Given the popularity of R. simsii as a pot plant and landscape shrub in Asia and othr regions, the occurrence of leaf spot disease seriously affects its ornamental and economic value. Therefore, it is crucial to establish and implement effective disease management practices to reduce impact of the disease.

First Report of Paramyrothecium breviseta Causing Target Spot on Amorphophallus muelleri in Yunnan, China.

Amorphophallus muelleri is an Araceae plant with perennial tuber, widely used in food, pharmaceutical and chemical industry due to its richness in glucomannan. In April 2022, an outbreak of a target spot on A. muelleri plantlets was observed in a nursery in Ruili, Yunnan, China. The leafstalks of the diseased plantlets in the nursery turned brown and decayed (Fig.1 A-B), then gradually some water-soaked spots on the true leaves developed along the veins (Fig.1 A). Subquencely, the spots on the true leaves turned dark green to white-grayish in the center, which formed light to dark brown concentric rings with a target-like appearance surrounded by a yellow halo (Fig.1 C). When the temperature was 20-34℃ and the relatively humidity was 25-80%, dark-green to black sporodochia with white hypha appeared on the lower and upper leaf surfaces. Finally, 5-8% of the plants surveyed on 800 m2 of one-year-old plantlets in the nursery showed the symptoms and some plants with infected leafstalks would be death. Similar symptoms were also observed on about 10% of the transplanted plants surveyed on 12000 m2 (1.2 ha) of two-year-old plantlets in the field. Five diseased leaves from five distinct plantlets in the nursery were collected for pathogen isolation. Leaf pieces(5 x 5 mm) were cut from the edge of necrotic lesions, and surface-sterilized with 2.5% sodium hypochlorite for 1 min, 75% ethanol for 30 s, then rinsed 5 times by sterilized distilled water, finally put the leaf pieces on sterilized filter paper for 3-5 minutes to dry them and transferred onto potato dextrose agar (PDA) in petri dishes at 25℃ for three days. Five pure cultures identical to colony and conidial characteristics were isolated from five individual plants. The representative pure culture (M1) was grayish-white and circular colonies were 7.50 cm in diamter after 15 days at 25℃, with dark green concentric rings of sporodochia, the dorsal view of the colonies were yellowish. Conidia were aseptate, smooth, cylindrical, 5.00-6.25 (5.71) x 1.25-1.67 (1.63) µm (n = 20) rounded at both ends. A spore suspension (1 x 106 spores/ml) was prepared by harvesting spores from 15-day-old cultures grown in the dark at 25℃, then a thirty-ml of spore suspension was sprayed on the healthy leaves of 10 two-year-old plantlets. Thirty-ml of sterile water was sprayed on the healthy leaves of another 10 seedlings and used as the control. All seedlings were placed in a nursery at 20 to 34℃ and a relative humidity of 25 to 80%. Similar symptoms (Fig.1 D-F) to those observed in the nursery and field developed on all the 10 seedlings inoculated with M1 after two days, but not on the control leaves. The pathogenicity tests were repeated for three times. Fungal cultures reisolated from the infected leaves were identical to the original colonies and conidia, completing Koch's postulates. The internal transcribed spacer (ITS, primers ITS1 and ITS4) region of ribosomal DNA (OQ553785), calmodulin (cmdA, primers CAL-228F and CAL2Rd)(OQ559103), RNA polymerase II second largest subunit (rpb2, primers RPB2-5F2 and RPB2-7cR) (OQ559104) and β-tubulin (tub2, primers Bt2a and Bt2b) (OQ559105) of M1 had 100%, 98.52%, 98.98% and 98.98% identity with the sequences of Paramyrothecium breviseta CBS544.75 (KU846289 for ITS, KU846262 for cmdA, KU846351 for rpb2, and KU846406 for tub2), respectively. In the phylogenic tree based on ITS, cmdA, rpb2 and tub2 gene sequences, the pure culture M1 clustered with P. breviseta CBS544.75, SDBR-CMU387, DRL4 and DRL3, which has been reported as the pathogen of leaf spot of Coffea arabica in China, C. canephora in China and Thailand (Wu et al. 2021; Withee et al. 2022). Molecular and morphological observations showed the pure culture M1 were P. breviseta (Withee et al. 2022), in addition the disease was named as target spot dueing to the typical target symptom on the leaves. To our knowledge, this is the first report of P. breviseta on A. muelleri from Yunnan, China, as well as worldwide. This disease can caused serious economic losses of A. muelleri dueing to that it can result 5-8% death of the plants in the nursery.

First Report of Chocolate Spot Caused by Botrytis eucalypti on Faba bean in China.

Faba bean (Vicia faba) is one of the characteristic economic crops in Qinghai Province of China, which has multiple uses as grain, vegetable, fodder, fertilizer and medicine. Chocolate spot is a critical disease of faba bean in the world, and it is widely spread in all production areas of Qinghai. In August 2021, a severe occurrence of chocolate spot was found in a faba bean field in Xunhua County, Qinghai Province (35°52'N, 102°22'E, alt. 1890m). All plants in the field were affected by this disease. A voucher specimen was deposited in the Herbarium of Plant Pathology, College of Agricultural and Forestry Sciences at Qinghai University under accession No. PY015. The pathogen infected the leaves and stems, causing small irregular red spots to appear, which later coalesce into larger spots and faded green lesions appear around the spots. Diseased leaf pieces 5 mm2 were surface sterilized with 75% ethyl alcohol for 30s, 1.2% NaOCl for 30s, and rinsed three times with sterile water. They were then plated on potato dextrose agar (PDA) at 22℃ for 10 days in the dark. Fungal colonies are initially white, then gray, and have produced spores by 5 days. Conidia are clusters, ellipsoidal or ovoid, 9-14 × 6-9 μm. The conidiophore is straight, terminally enlarged, septate, 300-1500 μm long, 8-13 μm wide. No sclerotia were observed during culture. DNA of the strain PY015 was extracted by CTAB method. Molecular identification was first performed using the universal region of ITS (ITS1/ITS4). The PCR product was sequenced, the sequence was deposited in GenBank under the accession number OR739575. The results showed 100% similarity to Botrytis spp. (KX301016, MT250940, LC519322) in BLAST search. Molecular characterization was continued using five specific primer pairs: RPB2 (DNA-dependent RNA polymerase subunit II, RPB2-5F/RPB2-7cR), NEP1 and NEP2 (necrosis and ethylene-inducing proteins, NEP1for/ NEP1revB and NEP2forD/NEP2revD), HSP60 (heat-shock protein 60, HSP60for/HSP60rev), G3PDH (glyceraldehyde-3-phosphate dehydrogenase, G3PDHfor/G3PDHrev). The sequences of PY015 were deposited in GenBank (accession numbers: OR731179, OR731180, OR731181, OR731182, OR731183), and all five sequences showed 100% similarity to Botrytis eucalypti YZU171088 (accession numbers: MH614610 MH614611, MH614612, MH614613 MH614614). A phylogenetic tree based on these five genes was constructed using Mega7.0 (1000 bootstrap replicates, neighbor-joining method), and PY015 was placed in the same clade as YZU171088 with 100% bootstrap values. Morphological and molecular biological results confirmed that isolate PY015 was B. eucalypti. To fulfill Koch's postulates, the spore suspension (2 × 105 conidia/ml) was sprayed on healthy faba bean (Yun-122) plants at the 10-leaf stage, while an equal amount of sterile distilled water was applied to controls. After 7 days, the inoculated plants showed symptoms consistent with field infection and B. eucalypti was re-isolated using the same protocol, while the control remained asymptomatic. The pathogenicity test was repeated twice. The same isolates were recovered from symptomatic leaves and identified by NEP1 sequence. B. eucalypti was morphologically and molecularly identical to the original isolates, completing Koch's postulates. Currently, Botrytis fabae, Botrytis fabiopsis, and Botrytis cinerea are the main pathogens of chocolate spot on faba bean that have been identified and reported nationally and internationally. B. eucalypti is a new species discovered from eucalyptus in southern China in 2016, and its current hosts are only eucalyptus and citrus. To our knowledge, the present study is the first report of chocolate spot caused by B. eucalypti on faba bean in China.

First report of Sclerotium hydrophilum causing leaf spot on Brasenia schreberi in central China.

Brasenia schreberi, commonly known as watershield and referred to as 'Chun Cai' in Chinese, is a worldwide aquatic vegetable. It has long been regarded as health- promoting vegetable due to production of mucilage in young shoots, and thus has gained popularity in China. In September 2022, a leaf spot disease was observed at the National Aquatic Vegetable Germplasm Resource Nursery located in Wuhan, Hubei province, China. The disease occurred on watershield leaves. It started with the formation of leaf spots surrounded by halos.These spots ranged in color from yellow to brown and in diameter from 1 to 10 mm. Subsequently, the smaller spots merged, ultimately causing the entire leaves to turn black. Small brown- to black-colored sclerotia were produced on the underside of the diseased leaves. Disease incidence was 30% on average, and yield loss was approximately 15% on average. To isolate the pathogen, leaf tissues at the disease-healthy border area were excised into 5 × 5 mm pieces, these segments were immersed in 75% ethanol for 30 s, followed by immersion in 0.5% sodium hypochlorite for 30 s, and then rinsed twice in sterile water. After air-drying, the leaf pieces were incubated on potato dextrose agar (PDA) in darkness at 28°C for 3 d. Mycelia from the leaf pieces were transferred to new PDA plates for purification, three sclerotia-forming fungal isolates (Whcc-1, Whcc-3, Whcc-4) were finally obtained. They were incubated on PDA at 28°C for 4 to 14 d for observation of colony morphology. At 4 d after incubation (DAI), they grew rapidly with the average growth rate of 2.2 cm/d and formed colonies with whitish substrate mycelia and well-developed aerial mycelia and small white to light brown-colored sclerotia. At 10 to 14 DAI, the sclerotia gradually turned to black, 0.2 to 0.4 mm in diameter (0.26 mm on average, n = 50). These morphological characteristics matched description of Sclerotium hydrophilum (Bashyal et al. 2021). Molecular identification was done to further clarify the species identity of this fungus. Genomic DNA was extracted from isolates Whcc-1, Whcc-3, and Whcc-4. The internal transcribed spacer region of the ribosomal DNA (ITS-5.8S rDNA) and the small subunit ribosomal RNA gene (ssrRNA) were amplified using universal primers ITS1/ITS4 and NS1/NS6, as described by White et al. (1990). Sequence analysis revealed a high degree of similarity between the ITS-5.8S rDNA sequences from Whcc-1, Whcc-3, and Whcc-4 (GenBank Acc. No. OP782030, PP035994, and PP035995, respectively) and those of S. hydrophilum strain CBS201.27 (GenBank Acc. No. FJ231396), with similarities of 99.25%, 99.4%, and 99.25%, respectively. The ssrRNA sequences from Whcc-1, Whcc-3, and Whcc-4 (GenBank Acc. No. PP238401, PP261342 and PP261345) were found to be identical, displaying 100% similarity to the ssrRNA sequences of S. hydrophilum strain ZH11 (GenBank Acc. No. KC354147). Based on both morphological and molecular evidence, it can be inferred that Whcc-1, Whcc-3, and Whcc-4 belong to the species S. hydrophilum. Pathogenicity tests were conducted by inoculation of the mycelial agar plugs of Whcc-1, Whcc-3 or agar plugs of fresh PDA (control) on floating leaves of two watershield plants, 4 leaves (replicates) for each treatment. After inoculation, the treated leaves were sealed in plastic bags to maintain humidity, and grown under natural conditions (18°C to 28°C, with 8 hours of light daily). At 7 DAI, while control leaves remained healthy, the leaves inoculated with Whcc-1 and Whcc-3 leaves formed yellow- to brown-colored spots similar to those observed in the field surveys. S. hydrophilum was re-isolated from the leaf spots, thus verifing Koch's postulates. S. hydrophilum has a wide host range, infecting at least 19 genera of plants, including common rice and wild rice (Johnson et al. 1976), and water lily (Kernkamp et al. 1977). Moreover, it has been reported to infect rice in China (Punter et al. 1984; Zhong et al. 2018). To our knowledge, this is the first report of S. hydrophilum on watershield leaves in central China.

Silver Nanoparticles as Catalysts of Foeniculum vulgare L. Callus Formation and Its Content of Vitamins and some Fatty Acids.

Plants are a precious resource of a wide range of secondary metabolites, that are benefitted as flavours, pharmaceuticals, colours, colognes, food additives and also biopesticides. The current study tested the impact of silver nanoparticles (AgNPs) on Foeniculum vulgare. Foeniculum vulgare seeds were surface sterilized, Vital leaf pieces are grown on MS media including diverse mixtures of plant growth regulators, the special effects of AgNPs plus PGRs on callus propagation were evaluated, and separated compounds of fatty acid and vitamins were identified. Outcomes revealed that several intensities of AgNPs expressively influenced the callus propagation and significantly raised the callus biomass with combination including the plant growth regulators. Highest fresh (7.32 g.L-1) biomass addition of callus was remarked on the media elevated in vitro at 20 ppm AgNPs combined with (2 mg.L-1 2,4-D) and results noted that the callus appeared compact and greenish in colour with 40 ppm AgNPs in combination with (2 mg.L-1 2,4-D). The results elucidated the amplification of the value of both fatty acids (stearic acid (47.85 %), oleic acid (189.28 %), Linoleic (6.34 %) and Linolenic (0.83 %)), and vitamins (Vitamin E (8.99 U.mg-1) and vitamin A (27.19 U.mg-1) by using MS + 2,4-D (2 mg.L-1) + AgNPs (20ppm). Application of a combination of AgNPs along with PGRs led to callus proliferation in Foeniculum vulgare L. In vitro. But, the unaccompanied use of AgNPs was originate inductive in the biosynthesis of greater quantities of special fatty acids and vitamin metabolites.

First Report of Anthracnose on Ilex cornuta Caused by Colletotrichum aenigma in China

Ilex cornuta (Aquifoliaceae) is a dark green evergreen shrub with glossy leaves that is widely distributed in China and East Asia and used as an ornamental and medicinal plant. In March 2022, typical symptoms of anthracnose were observed on I. cornuta leaves (with approximately 30% of leaves affected) in Jiangxi Academy of Forestry, Nanchang city, Jiangxi Province, China. The early symptoms were light brown spots on the edge or tip of the leaves. The spots gradually expanded to ovoid-shaped lesions and eventually become necrotic, dry, and gray with a dark brown margins. To isolate the pathogen, ten symptomatic leaves were randomly collected, the edges between diseased area and healthy area were cut into small pieces (4×4 mm), surface sterilized by dipping in 70% ethanol for 30 s and 1% sodium hypochlorite (NaClO) for 30 s, and then washed three times with sterile distilled water. Leaf pieces were then placed on potato dextrose agar (PDA) plates at 28℃ in the dark. Subsequently, six isolates were obtained using the single-spore method, five of them were similar in morphological characteristics. Colonies grown on PDA for 7 days were 75-85 mm in diameter, and were cottony, dense, and pale white on the surface and white to grayish-green on the reverse side. Conidia were single-celled, transparent and subcylindrical to clavate. The contents of the conidia were granular and 15.63–20.63 × 5.63–7.50 μm in size (=17.78 ± 1.41× 6.50 ± 0.55 μm, n = 40). The species was also identified by analysis of the internal transcribed spacer (ITS) region, actin (ACT), glyceradehyde-3-phosphate dehydrogenase (GAPDH) and β-tubulin (TUB2), calmodulin (CAL), glutamine gynthetase (GS), DNA Lyase (APN2), intergenic spacer and partial mating type (ApMat) genes using ITS4/ITS5, ACT-512F/ACT-783R, GDF/GDR, T1/Bt2b, CL1C/CL2C, GSF/GSR, ColDL-F3/CgDL-R1 and CgDL-F6/CgMAT1F2 primers, respectively (Weir, et al. 2012; Maharachchikumbura, et al. 2014; Khodadadi, et al. 2020). The sequences were deposited in GenBank (Accession Nos. OQ600619, OQ603370, OQ603373, OQ603379, OQ974177, OQ974176, OQ974178, and OQ974175). BLASTN analysis in GenBank showed that these genes exhibited 100% similarity to the sequences of Colletotrichum aenigma (MT476812, MN525817, MN525878, MN525904, MN525836, KX620296, and MN338281) and 99% similarity to the sequence of Colletotrichum sp. strain (MT071110). Concatenated sequences of these eight genes and Colletotrichum species sequences from GenBank were then used to construct a phylogenetic tree by using the maximum likelihood method in IQtree V1.5.6. Isolate JFRL 03-1005 was grouped into a clade with C. aenigma with a high bootstrap value. Thus, the isolate was identified as C. aenigma based on morphological and molecular data. To verify Koch's postulates, pathogenicity was tested on 2-year-old healthy potted plants of I. cornuta. Ten disinfected leaves were wounded with a sterile scalpel, and then inoculated with 10 μl of conidial suspension (1 × 106 conidia/ml) from isolate JFRL 03-1005. The control leaves were inoculated with 10 μl of sterile water. Then, the potted plants were incubated at 28°C with a 12 h photoperiod and 80% humidity. After 10 days, distinct spots appeared on all inoculated leaves, whereas control leaves remained asymptotic. C. aenigma was reisolated from the spots and identified by sequencing the ITS, ACT, GAPDH, TUB2, CAL, GS, APN2 and ApMat genes. Previous studies reported that C. aenigma can caused anthracnose on the leaves of various cash crops in China, such as apple, tree peonies, mulberry, and walnut (Wang et al. 2020; Zhang et al. 2021; Wang et al. 2022; Zhu et al. 2022). To the best of our knowledge, this is the first report of C. aenigma causing anthracnose on I. cornuta in China, this report further confirmed that C. aenigma has a wide range of hosts in nature. the anthracnose on I. cornuta caused by C. aenigma has seriously affected its ornamental value. Therefore, more attention should be paid to this disease and appropriate control strategies should be formulated.

First Report of Calonectria montana Causing Leaf Spot on Ligularia fischeri in China.

Ligularia fischeri (Ledeb.) is a perennial herbal plant of Compositae that is cultivated commercially in China as a medicinal, ornamental, and edible plant. Leaf spots were observed in 2-year-old L. fischeri in Benxi County of northeast China, in August 2021. Irregular reddish brown spots ranging from 3 to 11 mm were observed on infected leaves, and each leaf had dozens of spots (Fig. 1). As the disease progressed, the diseased spots withered and the centers fell out, and multiple lesions merge into large diseased spots, causing leaf wilting. The roots and stem bases were not infected during the reproductive stage. More than 37% of the plants in a 18 ha field were infected in 2021. The ten diseased leaves were collected and cut into small (3-5 mm) pieces, which were surface-disinfested by immersing into 1% NaOCl for 2 min and rinsing with sterile distilled water three times. The leaf pieces were then placed on acidified potato dextrose agar (PDA) in petri plates and incubated in the dark at 25°C. Twenty isolates with the same morphological characteristics were obtained. Isolates were further purified by starting a new colony for each isolate from a single spore collected from water agar. Isolate TYTW7 was randomly selected for identification and pathogenicity testing. It grew rapidly and produced profuse aerial mycelia with a carmine red underside. The conidiophores had many fertile branches and formed an elongated stipe with a sphaeropedunculate vesicle at the tip. The one-septate conidia were cylindrical and almost straight with parallel walls and rounded ends. Their sizes ranged from 30.35 to 51.76 × 2.93 to 5.01 μm (n = 100) and the pathogens were initially identified as Calonectria sp. (Crous 2002; Crous et al. 2004; Lombard et al. 2015, 2016). Further confirmation of the identification was determined according to published method (Liu and Chen 2017; Shao and Li 2021). The partial gene regions including the translation elongation factor 1-alpha (GenBank accession no. OP290551), histone H3 (OP290552), calmodulin (OP290553) and β-tubulin (OP290554) were obtained, and BLAST searches showed 99-100% homology with the ex-type culture CERC 8952 (MF527049, MF527065, MF527081 and MF527107) and phylogenetic analysis combining all loci revealed that the isolate TYTW7 and the type strain of Ca. montana clustered in one group (Fig. 2). Based on morphological characteristics and phylogenetic analysis, isolate TYTW7 was identified as Ca. Montana. Healthy 2-year-old plants were used for the pathogenicity test. A spore suspension (1×105 spores/mL water) was used to inoculate three host plants; sterile water was sprayed on the same number plants serving as a control. The experiment was repeated three times. All plants were incubated at 27±2°C (12h photoperiod) and were evaluated after seven days. The inoculated plants showed lesions on the leaf surface, similar to those in the field, and the control remained symptomless. The pathogens were successfully reisolated and identified by sequencing, and no pathogens were isolated from symptomless control plants. To our knowledge, this is the first report of Ca. montana causing L. fischeri leaf spot. The disease poses a threat to the production and more control strategies are needed on management options to minimize losses.

First Report of Leaf Spots Caused by Pestalotiopsis nanjingensis on Photinia × fraseri in China

Photinia × fraseri Dress, belonging to the Rosaceae family, is widely cultivated as an ornamental plant in China. In July 2022, the leaf spot symptoms were observed on over thirty P. × fraseri plants in an approximately 2-hectare park in Xinjian District, Nanchang City, Jiangxi Province, China (28°43′02″ N, 115°44′01″ E), with a disease incidences of roughly 10% . At first, small, grayish-white lesions appeared on the leaf edges, later expanding into 2 to 10 mm circular or irregular spots. These spots turned grayish-white to brown, with dark brown margins. Eventually, some lesions’ centers dried and died. For fungal isolation, ten symptomatic leaves were randomly collected. The edges between the diseased and healthy tissues were cut into small pieces (4 × 4 mm). These pieces were then surface-sterilized by dipping in 70% ethanol for 30 s and 1% NaClO for 30 s. Subsequently, they were rinsed three times with sterile distilled water. Leaf pieces were then transferred to potato dextrose agar (PDA) medium and incubated at 25 °C for 3–4 days. Eight isolates with similar colony morphology were collected from diseased leaves. Colonies of this fungus on PDA were nearly round, white, and had sparse aerial mycelium on the surface with black, gregarious conidiomata. The conidia were nearly cylindrical, smooth, hyaline, and 4-septate, measuring 16.7 to 24.3 × 4.2 to 6.6 µm (mean 20.9 × 5.3 µm, n=50). The three middle cells were smooth, doliiform, and brown, with concolorous septa that were darker than the rest of the cell. They measured 11.8 to 17.0 µm long (mean 14.1 µm, n=50). The basal and apical cells were triangular and transparent. The basal cells had a mean length of 4.7 µm and were equipped with a basal appendage, while the apical cells had two appendages with a mean length of 17.7 µm(n=50). The characteristics of these isolates match those of Pestalotiopsis species (Maharachchikumbura et al. 2014). To identify them accurately, three representative isolates, namely JFRL 03-161, JFRL 03-162, and JFRL 03-226, were selected for further analysis. The internal transcriptional spacer (ITS) region, β-tubulin (TUB2) and translation elongation factor 1-alpha (TEF1-α) gene were amplified and sequenced using primers ITS1/ITS4 (White et al. 1990), BT2a/BT2b (Glass and Donaldson 1995), and EF1-526F/EF1-1567R (Maharachchikumbura et al. 2012), respectively. All sequences (ITS: OR342044-OR342046, TUB2: OR343299-OR343301, and TEF1-α: OR343302-OR343304) were deposited in GenBank. A BLASTn homology search revealed 99-100% identity to Pestalotiopsis nanjingensis CSUFTCC16 (ex-type). The sequences included ITS (OK493602, 486/486 nucleotides), TUB2 (OK562377, 438/439 nucleotides), and TEF1-α (OK507972, 478/478 nucleotides). The maximum likelihood analyses were performed for the combined ITS, TUB2 and TEF1-α data sets using IQtree web server (Trifinopoulos et al. 2016). The resulting phylogenetic tree demonstrated a strong association: the three isolates clustered tightly with P. nanjingensis forming a clade with robust 99% bootstrap support. This clustering, consistent with both morphological and molecular characteristics, confirmed the identity of the fungus as P. nanjingensis. To evaluate its pathogenicity, we obtained 3-year-old P. × fraseri ‘Red Robin’ plants, which were purchased then potted in a controlled climate chamber. We surface sterilized six healthy leaves of P. × fraseri with 70% ethanol and created wounds using a sterile needle. Subsequently, we inoculated a 50 μL conidial suspension (1 × 106 conidia/mL) of the isolate JFRL 03-161 on these wounded leaves. In parallel, another six leaves from P. × fraseri were inoculated with sterile distilled water, serving as the control group. All potted plants were incubated under conditions of 26 °C and 80% humidity. After seven days, all leaves inoculated with isolate JFRL 03-161 displayed symptoms similar to those observed in the field, whereas the control leaves remained unaffected. To fulfill Koch’s postulates, we re-isolated P. nanjingensis plants from the symptomatic leaves and identified it based on morphological and molecular characteristics. It has been reported that two species of Pestalotiopsis, namely P. microspora and P. trachicarpicola can caused damage to the leaves of P. × fraseri in China (Xu et al. 2022; Zhu et al. 2021). However, to our best knowledge, this is the first report on leaf spot caused by P. nanjingensis on P. × fraseri in China. Therefore, it is necessary to pay more attention to the leaf spot disease of P. × fraseri caused by Pestalotiopsis species and develop appropriate control strategies.

First Report of Apiospora arundinis Causing Leaf Spot on Polygonatum cyrtonema Hua in China.

Polygonatum cyrtonema Hua, which is a perennial herb of Liliaceae, can be used as clinical Chinese medicine for treating diabetes and asthma. It is widely cultivated in China, with 700 ha planted in Tonggu County, Jiangxi province (Chen et al. 2022). In June 2022, leaf spot symptoms were observed on P. cyrtonema in Tonggu county (28°71'42″N, 114°56'19″E), and the disease incidence was estimated to be above 35%. In the early stages of infection, small brown spots appear on the edge or tip of the leaves. As the lesion matures, the spots gradually expand to form wedge-shaped or elliptic to irregular lesions with brown edges and yellow halos. To identify the pathogen species, leaf pieces (5 × 5 mm) from the lesion borders were surface sterilized in 75% ethanol for 30 s, followed by 2% NaClO for 2 min, then rinsed with sterile distilled water for 3 times and dried with sterile filter paper. The tissues were placed on potato dextrose agar (PDA) and incubated at 25°C. Pure cultures were obtained by monosporic isolation, and the representative isolates, HJYB2-1, HJYB2-2 were used for morphological studies and phylogenetic analyses. Colonies on PDA of the two isolates were white with fluffy aerial mycelia. The hyphae were smooth, hyaline, and branched. The conidiophores were hyaline or pale brown and produced conidiogenous cells. The conidiogenous cells were pale brown, smooth, and ampulliform, 5.8-11.7 × 3.0-4.9 μm (n=50). The conidia were brown, smooth, and ellipsoidal to spherical, 4.7-7.3 × 2.3-4.5 μm (n=50). Morphological features were similar to Apiospora arundinis species complex (Crous et al. 2013, Pintos et al. 2021). For molecular identification, the ITS, TUB2 and TEF 1-α genes were amplified with the primer pairs ITS1/ITS4, T1/Bt-2b and EF1-728F/EF-2 (White et al. 1990), respectively. The generated sequences were deposited in GenBank with accession numbers OR229623, OR229624 (ITS), OR260104, OR260105 (TUB2), and OR290789, OR290790 (TEF1-α). Maximum likelihood and Bayesian posterior probability analyses using IQtree v. 1.6.8 and Mr. Bayes v. 3.2.6 with the concatenated sequences placed HJYB2-1 and HJYB2-2 in the clade of A. arundinis. The two isolates were identified as A. arundinis based on morphological and multilocus phylogenetic analyses. For pathogenicity testing, healthy leaves of six P. cyrtonema plants (five leaves each, n=30) in the field were pin-pricked with a sterile needle and inoculated with 100 µL spore suspension on the wound (1×106 conidia per mL). Healthy leaves of another three P. cyrtonema plants (five leaves each, n=15) in the field were pin-pricked with a sterile needle, inoculated with sterile distilled water and served as the control. All the inoculated leaves were covered with plastic bags to keep a high-humidity environment with a temperature of about 28℃. The test was repeated three times. More than 90% of inoculated leaves showed similar symptoms to those observed in the field, whereas control leaves were asymptomatic for 7 days. Apiospora arundinis was reisolated from the leaf lesions on the inoculated plants. No pathogenic fungus was isolated from the control leaves. A. arundinis has been reported causing disease on Camellia sinensis (Thangaraj et al. 2019), Prunus persica (Ji et al. 2020), Saccharum officinarum (Liao et al. 2022) but has not previously been reported causing disease on P. cyrtonema. To our knowledge, this is the first report that A. arundinis can cause leaf spot on P. cyrtonema in China. Our result should help with future monitoring and control of this disease.

First Report of Pantoea agglomerans Causing Leaf Blight on Schisandra chinensis in China.

Schisandra chinensis (Turcz.) Baill is a perennial liana, which is widely cultivated and used in China. In August 2022, Schisandra chinensis leaves with small light brown spots were found on plants growing in Fusong (127°28'E, 42°33'N) of China. There was 15% disease incidence and 50% disease severity of Schisandra chinensis in 2-ha fields of S. chinensis. As the disease progressed, the spots become darker and form round or irregular concentric circles. Leaves with brown spot symptoms were collected from the field. Leaf pieces (5 mm × 5 mm) were excised from lesion margins, surface disinfected with 75% ethanol for 1 min, followed by 1.5% sodium hypochlorite for 3 min, and incubated on Luria Bertani (LB) solid medium at 28°C for 24 hours. Eight cultures were isolated, and representative single colony (XWWZH) was selected from the pure cultures according to colony characteristics for observation The purified colonies were round, yellow, and slimy, cells were straight rod-shaped (0.40 to 0.52 × 1.12 to 1.69 µm) were observed. The isolate was Gram negative. It was positive for methyl red reaction, lysine decarboxylase reaction, gelatin hydrolysis reactionand sucrose utilization. It was negative for indole reaction and produced H2S. The bacterium was preliminarily identified as Pantoea agglomerans based on morphological and biochemical tests (Baird et al. 2007). The 16S rDNA and a portion of rpoB of strain XWWZH were amplified and sequenced. The sequences were submitted to GenBank. (Accession OP763753 and OQ813505, respectively). Phylogenetic trees were constructed based on the 16S rDNA and rpoB gene sequences. The sequences of strain XWWZH clustered with strains P. agglomerans deposited in GenBank. The pathogenicity was verified with non-wounded S. chinensis seedlings by punching holes with sterile needles and injecting a solution of 1 × 108 CFU/ml solution. Sterile ddH2O was injected in the control experiment. The inoculated seedlings were incubated in a greenhouse at 25°C with a relative humidity of 65 to 70%. Five to eight days after inoculation, inoculated leaves, exhibited symptoms which were morphologically identical to those of the originally infected leaves whereas control plants remained asymptomatic. The pathogenicity assays were repeated twice with the same results. The re-isolated pathogen had the same morphology and DNA sequences as the original isolate obtained from the field samples, completing Koch's postulates. Strains of P. agglomerans have been reported to severely infect many plants (Ren et al.2008; Lee et al. 2010; Yang et al. 2011; Guo et al. 2019; Gao et al, 2022), but to the best of our knowledge, this is the first report of a strain of P. agglomerans causing leaf blight on Schisandra chinensis in China. The identification of leaf blight caused by P. agglomerans will enable farmers to prevent and manage it ahead of time to reduce losses.