Brown Lesions Research Articles

First report of Calonectria ilicicola causing red crown rot of soybean in Indiana.

Soybean (Glycine max [L.] Merr.) samples from commercial fields in Decatur and Spencer counties, Indiana were submitted to the Purdue Plant and Pest Diagnostic Lab in August to October 2022. Plants exhibited whole-leaf to interveinal chlorosis of the foliage, red to dark brown external lesions on the crown spreading from the soil-line upward, and severe root rot. In the fields, patches of diseased plants were observed, with greater than 50% of the plants affected and yield loss up to 50%. Orange to red perithecia were present on the exterior of symptomatic stem tissue and ranged in size from 329 to 433 × 232 to 306 µm (n = 10). Stems were surface sterilized in 10% Clorox (0.825% NaOCl) for 1 min, then rinsed with sterile distilled water and dried. In a laminar flow hood, sections of symptomatic stem tissue were plated on using quarter-strength potato dextrose agar (QPDA) and incubated under fluorescent lights on a 12-hr light/dark cycle at 20°C. After 6 days, fungal colonies with fluffy aerial hyphae, which were white near the colony margins and orange to burnt-red near their center, grew uniformly from the stem tissue plated. Elongate, cylindrical hyaline conidia with zero to three septations measuring 45.5 to 73.8 × 4.4 to 6.7 µm (n = 22) grew in clusters from symptomatic stem tissue within the plate. Perithecia developed after 14 days. Falcate, hyaline ascospores with one to two septa measuring 29.4 to 54.7 × 4.6 to 6.8 (n = 23) µm developed within the perithecia. Calonectria ilicicola Boedijn & Reitsma was confirmed based on morphological characteristics (Padgett et al. 2015). Isolate PPDL 22-01457B was used for DNA extraction using the ZR Fungal/Bacterial DNA Miniprep kit (Zymo Research, Irvine, CA). The internal transcriber region (ITS), actin (ACT) and β-tubulin (TUB2) genes were amplified (Carbone and Kohn 1999; Glass and Donaldson 1995; O'Donnell and Cigelnik 1997; White et al. 1990). Amplicons were sent for Sanger sequencing (Genewiz, Inc., South Plainfield, NJ), submitted to Genbank, and assigned accession numbers ITS: OQ932995, Actin: OR484986, and β-tubulin: OR546281. Sequences were analyzed using the NCBI BLASTn tool with results showing 99.5 to 100% identical to C. ilicicola (GenBank accessions LC500063, OQ303403, CP085825, respectively). To perform Koch's Postulates, 90 soybean seeds (CP3620E) were planted in potting media (Berger, Saint-Modeste, Quebec, Canada) in a seed flat with 45 of the plants used as controls and grown under grow lights for 16hr light/8hr dark at 20℃. Individual seedling crowns were inoculated 3 days post-emergence with a 5 to 10 ml spore and hyphal suspension that was scraped from the surface of a 14-day old QPDA culture after adding 300 mL deionized (DI) to each plate grown at 20 to 22°C. The control plants received sterile-DI water. Plants were covered in a plastic bag for 72 h. Plant stems were sprayed with sterile-DI water once a day for seven days. Symptoms were observed after four days, but significant crown rot and lesions developed after two weeks before wilting and dying. Calonectria iliciola was isolated uniformly from symptomatic plants and identified morphologically. Control plants showed no symptoms. Inoculations were repeated 3 times with similar results. As of fall 2023, red crown rot has been confirmed in Adams and Rush counties in Indiana. Red crown rot has been confirmed in several Midwest states (Kleczewski et al. 2019, Neves et al. 2023), but the extent of its distribution and disease management strategies are still limited.

First Report of Colletotrichum fructicola Causing Anthracnosis on Glycine max in Brazil

Brazil is the largest producer of soybean [Glycine max (L.) Merrill], cultivated in diverse environments and systems. This scenario can contribute to emergence of new diseases or increase the severity of secondary diseases. In March 2023, elliptical to circular, brownish lesions, 5.2–6.1 cm length and 1.1–1.5 cm width, with salmon-colored masses of conidia in the center of the lesions, were observed on the stems of soybean cultivar ‘CZ 16B17 IPRO’, in the municipality of Campos Novos, Santa Catarina, Brazil (27º25'19''S and 51º14'14''05W). The presence of 210–355 μm length and 210–232 μm width acervuli was rare, with arrows larger than the mass of conidia (Figure S1). Fragments of the infected tissues were cut, disinfected and placed in Petri dishes containing Potato Dextrose Agar (PDA) or V8-agar medium and maintained at 23 ± 2ºC and a photoperiod of 12 h dark–light cycle. After 13 days, the development of grayish-white colonies was observed on both culture media, with the formation of a mass of septate hyaline, oblong, cylindrical conidia, 13.3–15.3 µm length and 2.9–3.5 µm width, with obtuse ends. One pure monosporic isolate was selected, isolate CF1. The presence of sexual structures was observed on PDA after 13 days and in V8 after 15–20 days. Perithecia were dark brown and globose, either immersed in the culture medium or on the surface between the mycelia. Inside of perithecia, unitunicate, clavate, and cymbiform asci, 39.1–61.0 μm length and 9.6–11.7 μm width were observed, containing eight spindle-shaped and slightly curved ascospores with rounded tips 13.8–18.3 μm length and 3.0–4.2 μm width (Figure S1). Pathogenicity tests were performed on young soybean plants at V1 phenological growth stage in four repetitions. PDA disks, 7mm in diameter, with growth mycelium were placed on stems while using uninfected PDA disks as a control. Plants were incubated in a chamber at 25 ± 2°C and 90% relative humidity. Anthracnose lesions were observed only on the stems of the inoculated plants. The same pattern of symptoms was observed on the stems, and the fungus were reisolated on PDA. The colony and morphological characteristics were identical to the previously isolated fungus. For molecular characterization, the growth mycelia were collected, macerated in liquid nitrogen, and DNA was extracted using the method Doyle and Doyle (1990) with CTAB. End-point PCR was performed using the GoTaq® Flexi DNA Polymerase (Promega, USA) and the primers, ITS-1F/ITS-4, T1/Bt2b, CL1C/CL2C, GDF/GDR, and SODglo2-F/SODglo2-R (Weir et al. 2012) for the amplification of internal transcribed spacer (ITS), β-tubulin (TUB2), calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and superoxide dismutase (SOD), respectively. Amplified fragments were sequenced and compared with the available sequences in the Genbank (www.ncbi.nlm.nih.gov/genbank/). The sequences of all five-genes (Accession numbers OR883777, OR891749, OR891750, OR891751 and OR891752, respectively) of the isolate CF1 characterized in this study showed 99% nucleotide identities whith the stand isolate ICMP 18581 of Colletotrichum fructicola. A phylogenetic tree was constructed in MEGA X (Kumar et al. 2021), containing the amplified and concatenated sequences and representative species from the Colletotrichum gloeosporioides complex. The isolate grouped only with C. fructicola clade, confirming the identity of the fungus (Figure S2). To our knowledge, this is the first study reporting the infection of C. fructicola in soybeans in Brazil, which has already been reported in China (Xu et al. 2023).

First Report of Penicillium oxalicum Causing Leaf Blight on 'Hongyang' Kiwifruit in China.

In September 2022, leaf blight symptoms (Fig. 1) were detected on six-year-old kiwi trees (Actinidia chinensis cv. 'Hongyang') in Xuzhou municipality (117.29º E, 34.23º N), Jiangsu Province. Early-stage disease symptoms included light brown necrotic lesions of irregular shape ranging in length from 0.2 to 2.4 cm, which turned into leaf blight after approximately 2 weeks. Those symptoms were similar to those previously reported during a Pestalotiopsis sp. infection on kiwi trees in Turkey (Karakaya 2001). Approximately 20% of the leaves from 300 trees examined in one kiwi orchard, 3000 m2 in size, showed the disease symptoms. Ten leading edges of symptomatic leaves were sterilized with 2% sodium hypochlorite for 1 min, rinsed twice with sterile ddH2O and cultured at 26ºC for 3 days on PDA medium containing 50 µg/ml chloramphenicol. The fungal colonies were collected, and the single spore isolation method was used to obtain four isolates. The obtained isolates showed white aerial mycelia that turned greyish after 2 days of cultivation on PDA medium at 26ºC. ITS (OR054113, OR054153-OR054155), TUB2 (OR060951-OR060953, OR249978), and CMD (OR255947-OR255950) genes were amplified using the ITS1/ITS4, BT2a/BT2b and CMD5/CMD6 primers, respectively (Visagie et al. 2014a). The obtained ITS, TUB2, and CMD sequences shared 99.81%-100%, 96.72%-96.96%, and 90.17%-92.58% homology compared to the ex-type strain P. oxalicum CBS 219.30 (MH855125, KF296462, and KF296367), while the obtained ITS and TUB2 sequences showed 99.62%-99.81%, and 96.46%-96.72% identity compared to the representative strain P. oxalicum DTO 179B9 (KJ775647 and KJ775140) (Visagie et al. 2014b). The sequences obtained also showed high homology compared to P. oxalicum HP7-1 (ITS: 99.81%-100% homology; TUB2: 98.98%-99.38% homology; CMD: 94.71%-95.10% homology) (Li et al. 2022). A molecular phylogenetic tree was constructed using MEGA X with representative Penicillium strains retrieved from GenBank (Fig. 2). Microscope observations revealed the presence of curved septate hyphae. Conidia were colorless, unicellular, and ellipsoidal (5-8 μm in length; > 2000 observations), whereas conidiophores were mainly monoverticillate (approximately 20% of the conidiophores were biverticillate) (50-70 μm in length; 43 observations) and contained cylindrical phialides (13-15 μm in length). These findings are consistent with P. oxalicum morphology (Wu et al. 2022; Zheng et al. 2023). The pathogenicity of the four isolates was screened using healthy non-detached 'Hongyang' kiwi leaves. Fifteen leaves from five different two-month-old trees were used for each isolate, with three repetitions. For inoculation, a 10 mL solution containing 1 × 106 spores/mL was sprayed on the leaves. Sterilized water was used in the control experiment, which was carried out using fifteen leaves from five different two-month-old trees, with three repetitions. Inoculated trees were stored at 26ºC and 60% relative humidity for 2 days. All the infected leaves had necrotic lesions and leaf blight symptoms comparable to those found in the field, but the control leaves had no lesions. The pathogen was recovered, and its identity was confirmed by ITS sequencing and morphology analysis, fulfilling Koch's postulates. P. oxalicum is a common cause of blue mould in postharvest fruits (Tang et al. 2020). P. oxalicum has been recently reported as the causal agent of leaf spot in pineapple (Wu et al. 2022; Zheng et al. 2023), and leaf blight on maize (Han et al. 2023). Although Alternaria sp., Glomerella cingulate, Pestalotiopsis sp., Phomopsis sp., and Phoma sp. were previously isolated from kiwi leaves with blight symptoms (Kim et al. 2017), this is the first report of P. oxalicum causing leaf blight on kiwi trees worldwide. P. oxalicum is a well-known source of mycotoxins, such as secalonic acid (Otero et al. 2020), indicating that its presence in kiwifruit orchards may pose a significant risk to human health. The discovery of this hazardous pathogen in kiwi trees must drive the development of management strategies. Kiwifruit is an important dietary source of vitamins, fiber, folate, and potassium, and China is the major producer of kiwifruit, with more than 1.2 million metric tons harvested in 2021. This report will help to generate a better understanding of the pathogens affecting kiwifruit orchards in China.

First Report of Panicle Wilting on Rice (Oryza sativa L.) Caused by Fusarium kyushuense in Heilongjiang Province, China.

Heilongjiang is the largest rice-producing province in China, with annual yield of 28.9 million tons cultivated on 3.8 million hectares (Liu et al. 2021). During field surveys from July to August (2021-2022), symptoms of wilting were observed on rice panicles across Baoqing county (46.32°N, 132.20°E), Shuangyashan city, Heilongjiang province, China. Disease incidence ranged from 10 to 35%, and yield losses were estimated to be 5 to 20% over 7 surveyed fields of 18.5 ha in total. Initially, infected panicles exhibited carmine to brownish spots at the flowering and early grain-filling stages, which gradually merged into large and irregular lesions and spread to the entire panicle surface. Eventually, panicles became wilting and decayed at the ripening stage. To identify the etiological agent, thirty-five symptomatic panicles were collected randomly from 35 plants at different positions in 7 fields. The fragments (approximately 3 mm2) were dissected from margins of individual lesions, surface-disinfested with 70% ethanol for 30 s followed by 2% sodium hypochlorite for 2 min, and rinsed three times in sterilized water. The pieces were then dried and placed onto half-strength potato dextrose agar (PDA) supplemented with 50 μg/mL of streptomycin sulfate. After incubation at 28°C for 4 days, nineteen cultures were obtained and purified using the single-spore isolation method. On PDA plates, the colonies produced fluffy and cottony aerial mycelia and were white to yellowish with deep-yellow to red-brown pigments. The microconidia were hyaline, elliptical or clavate, zero to one septum, measuring 6.3 to 19.2 × 2.6 to 5.1 μm in size (n = 50). On carnation leaf agar (CLA), the macroconidia were thick-walled, falcate to almost straight, three to five septa, apical cell hooked to tapering, basal cell foot-shaped, measuring 27.4 to 47.8 × 3.6 to 5.4 μm in size (n = 50). No chlamydospore was observed. The internal transcribed spacer (ITS) region of ribosomal RNA, translation elongation factor (TEF-1α) gene, and β-tubulin (β-TUB) gene were amplified and sequenced using primers ITS1/ITS4 (White et al. 1990), EF1/EF2 (O'Donnell 2000), and T1/T22 (O'Donnell and Cigelnik 1997) from three representative isolates (PJ58, PJ69 and PJ83), respectively. The obtained sequences were deposited in GenBank (accession nos. ON527509, OQ772202 and OQ777725 for ITS; ON573222, OQ784926 and OQ784927 for TEF-1α; ON573223, OQ784928 and OQ784929 for β-TUB, respectively). BLASTn analysis revealed 99.8 to 100% homology with the corresponding sequences of Fusarium kyushuense (MH892849 for ITS, AB674297 for TEF-1α, and GQ915442 for β-TUB, respectively) in GenBank. Maximum likelihood phylogeny based on the concatenated sequences of ITS, TEF-1α and β-TUB grouped three representative isolates in the F. kyushuense clade. Combined with the morphological and molecular characteristics, the fungus was identified to be F. kyushuense. Pathogenicity of the three isolates of F. kyushuense was evaluated on a susceptible rice cultivar Nanjing 46 at the booting stage. The upper part of a healthy panicle was inoculated by injecting 2 ml of a conidial suspension (1 × 106 spore/ml) obtained from a 7-day-old PDA culture of each isolate. The negative control was treated with sterile distilled water. The experiment was performed thrice with ten replicated plants for each treatment. All plants were placed in a humid chamber at 25°C with a 12-h photoperiod and 80% relative humidity. Twenty days after inoculation, it was found that the inoculated panicles showed typical reddish to brownish lesions, whereas control plants remained symptomless. Pathogens were reisolated from the artificially inoculated panicles and confirmed by morphological and molecular tests, fulfilling Koch's postulates. In recent years, this species has been associated with stalk rot and ear rot of maize (Cao et al. 2021; Wang et al. 2014) and wilt of tobacco (Wang et al. 2013). Also, it was mentioned as a producer of mycotoxins, especially trichothecenes and HT-2 toxin (Varga et al. 2016). To our knowledge, this is the first report of F. kyushuense causing panicle wilting on rice in China. The appropriate control strategies should be made to reduce the risk of disease due to food security concerns and potential threats to rice production.

Occurrence of Fusarium fujikuroi Causing Fusarium Wilt on Carthusian Pink in China.

Carthusian pink (Dianthus carthusianorum) is native to Europe and is widely grown in China for landscaping. In September 2022, wilting symptoms of carthusian pink were found in Xixia City (33°18'31″ N, 111°29'45″ E), Henan Province, China, with a disease incidence of 65%. Approximately 100 plants were surveyed on the landscaping lawns of the park. Initial symptoms were yellow to brown lesions on the base of stems and leaves. Later, the lesions spread throughout the plants, turning leaves yellow, and leading to root and leaf rot. Eventually, the plants shriveled and died (Figure S1a). Thirty diseased tissues isolated from the roots and leaves were cut into 5×5 mm pieces, which were surface sterilized with 75% ethanol solution for 30 seconds and 1% NaClO solution for 1 minute, rinsed three times in sterilized water, placed on potato dextrose agar (PDA) plates supplemented with 50 μg ml-1 streptomycin, and incubated at 28°C for five days. A total of 25 purified fungal strains with similar phenotypic features were obtained. Three representative strains named OSZ-P1, OSZ-P2, and OSZ-P3 were selected for identification. Fungal colonies developed an abundant aerial mycelium, initially white, which subsequently developed red to purple pigments (Figure S1b). Macroconidia were slender, straight, and measured 12.74 to 49.39 × 2.07 to 4.39 μm (n=50), with two to five septa. Microconidia were clavate and measured 6.31 to 11.61 × 2.15 to 4.02 μm (n=50) (Figure S1c). These morphological characteristics were consistent with Fusarium spp.. The rDNA internal transcribed spacer (ITS), β-tubulin gene (tub2), translation elongation factor 1-alpha gene (tef1), calmodulin (cmdA), RNA polymerase largest subunit (rpb1), and RNA polymerase II second largest subunit (rpb2) were amplified with primers ITS1/ITS4, BT-2a/BT-2b, EF1/EF2, CL1/CL2A, Fa/G2R, and 5F2/7Cr, respectively, for further identification (Yilmaz et al. 2021, O'Donnell et al. 2022). ITS (OQ726389, OQ726390, OQ726391), tub2 (OQ730191, OQ789645, OQ789646), tef1 (OR088904, OR088905, OR088906), cmdA (OR133730, OR133731, OR133732), rpb1 (OR088907, OR088908, OR133729), and rpb2 (OR133733, OR133734, OR133735) nucleotide sequences of the strains OSZ-P1, OSZ-P2, and OSZ-P3 were submitted to GenBank. BLASTn analysis of OSZ-P1 sequences exhibited 99 to 100% similarity with Fusarium fujikuroi sequences (strains Augusto2, I1.3, and CSV1) CP023096, CP023108, CP023084 of cmdA, CP023089, CP023077 of rpb1, and CP023093, CP023105, CP023081 of rpb2. A Phylogenetic tree was constructed of combined genes (tub2, tef1, cmdA, rpb1, rpb2) of sequences, alongside the sequences of the type strains by the neighbor-joining method. The three strains formed a clade with the type strains CBS257.52 and Augusto2 of F. fujikuroi in phylogenetic trees, being clearly separated from other Fusarium spp. (Figure S2). The morphological features and molecular analyses supported the strains as members of F. fujikuroi. To verify the pathogenicity, aboveground parts of the plants of five healthy six-month-old potted plants were sprayed with 100 µl of conidial suspension per pot (106 conidia ml-1), and five similar plants were sprayed with sterilized water as a control. All plants were placed in a climate incubator at 28°C and 90% relative humidity. Seven days after inoculation, withered and yellowed lesions were observed, similar to the natural lesions (Figure S1e). No symptoms were observed on the control plants. The whole pathogenicity tests were performed thrice. Reisolation resulted in cultures that were morphologically and molecularly identical to the original isolates, fulfilling Koch's postulates. Fusarium wilt disease has been reported on other plants of the genus Dianthus. Vascular wilt on Dianthus caryophyllus (carnation) caused by Fusarium oxysporum is the most destructive disease of carnation crops worldwide (Ardila et al. 2014). Fusarium acuminatum causing Dianthus chinensis root rot and foliage blight has recently been reported in Nanjing, China (Xu et al. 2022). To our knowledge, this is the first report of F. fujikuroi causing Fusarium wilt on carthusian pink worldwide. The host range of F. fujikuroi still needs to be clarified for accurate disease management in the selection of plant species for landscape.

First report of stem gray blight on Hylocereus megalanthus and Hylocereus polyrhizus caused by Diaporthe arecae in Brazil.

In November 2021, stem gray blight symptoms were seen on two dragon fruit (pitaya) species (Hylocereus megalanthus and H. polyrhizus) in an orchard with 100% disease incidence in Fortaleza, Ceará, Brazil (3°44'24.5"S 38°34'30.8"W). The symptoms were initially yellowish to dark brown lesions, and as the symptoms progressed, the lesions turned grayish with small black pycnidia in the center. Isolation was carried out by disinfecting small pieces of the symptomatic stems in 70% ethanol for 1 min, followed by 1% NaOCl for 1 min, and then rinsed three times with sterile distilled water. Excess water was removed using sterile filter paper. Then the stem fragments were placed on PDA media. Colonies produced small black pycnidia with conidia and some were sterile after 68 days of incubation. Two monosporic isolates were obtained from the colonies: UFCM 0708 from H. megalanthus and the UFCM 0710 from H. polyrhizus, which were used for pathogenicity test, morphological and molecular identification. The colony on PDA was smoke gray with aerial mycelium and the reverse was smoke grey to dark grey. The α-conidia from UFCM 0708 and UFCM 0710 were hyaline, aseptate and fusiform and measured 6.4 to 9.7 (8.0) x 1.2 to 2.4 (1.7) µm and 6 to 13.1 (8.2) x 1.7 to 2.4 (2.0) µm, respectively. The β-conidia from UFCM 0708 and UFCM 0710 were hyaline, aseptate and filiform and measured 15 to 22.5 (18.8) x 0.6 to 1.7 (1.0) µm, and 17.2 to 27.5 (22.3) x 0.5 to 1.0 (0.8) µm (n=30), respectively. This morphology placed the isolates as Diaporthe sp. (Udayanga et al. 2012). For further confirmation, genomic DNA was extracted from the isolates (UFCM 0708 and UFCM 0710), and beta-tubulin (TUB2) and translation elongation factor 1-alpha (TEF1) gene fragments were amplified. BLASTn search results with isolates TEF1 and TUB2 sequences varied from 98.58% to 99.52% identity to the ex-type sequence of Diaporthe arecae (CBS 161.64). Phylogenetic analysis of concatenated sequences alignment carried out using the Maxinum-likelihood and Bayesian Inference analysis placed the isolates within D. arecae clade with 86% bootstrap and 0.99 posterior probabilities support. The sequences obtained in this study were deposited in GenBank (TEF1: OP534720 and OP534722; TUB2: OP534717 and OP534719). The isolates were confirmed as D. arecae based on molecular analysis and morphological characteristics (Gomes et al. 2013). Koch's postulates were completed as described by Karim et al. (2019) through the inoculation of six stems of each dragon fruit (pitaya) species. The stems were wounded by removing a 5 mm diameter disc and after that they were inoculated with a 5 mm diameter mycelial plug from 5 days old PDA plates. PDA plugs were used as control. Each stem was covered with a plastic bag and sterilized water was added into the sterilized filter paper to maintain humidity. The bags were kept in a room at day and night temperature of 25 ± 2 °C. The same symptoms seen in the field appeared on the stems 21 days after inoculation. The control stems remained symptomless. Diaporthe arecae have been reported on H. polyrhizus in Malaysia (Huda-Shakirah et al. 2021). To our knowledge, this is the first report of D. arecae on H. megalanthus and H. polyrhizus in Brazil.

First Report of Calonectria ilicicola causing Leaf spot on Camellia sinensis in Yunnan province, China.

Tea (Camellia sinensis (L.) Kuntze) is among the most significant industrial crops due to its distinctive fragrance and flavor generated (Bag et al. 2022). From October to December in 2021, a leaf spot disease affected the quality and yield of tea (C. sinensis var. assamica cv. Yunkang 10), in Pu'er (100.57°E, 22.45°N), Yunnan province, China. Based on the survey, the incidence was approximately 15% in a plantation of 4500 m2 (2050 tea trees approximately). The symptoms on leaves were regular circular, dark brown lesions with black conidiomata in gray centers. Twenty symptomatic leaves were collected from 10 trees. After rinsing and surface sterilization (75% ethanol for 30 s and 3% NaClO for 90 s, rinsed 3 times with sterile distilled water), diseased tissues (5 × 5 mm) were cut at the junction of infected and healthy site and placed on potato dextrose agar (PDA) (3 pieces per plate) and incubated in the dark at 28℃ for 5 days (Mao et al. 2023). Three single-spore isolates 6a-H-1, 6a-H-2 and 6a-H-3 were obtained, which showed identical in morphology and molecular analysis. Therefore, the targeted isolate 6a-H-2 was used for further study. Fungal colonies were white, then gradually turning into goose yellow (Fig.2. A-C). Chlamydospores were dark brown and oval (Fig.2. G). Asci produced after 30 days approximately, were orange-red, nearly spherical, rough-surface, and measured as 470 µm ± 11.68 µm (n = 50) (Fig.2. H). Ascospores were released from the asci orifice (Fig.2. I) which were hyaline, fusoid with rounded ends, straight to slightly curved, two septate, slightly constricted at the septum, and ranged from 48.77 ± 2.76 µm × 6.22 ± 0.41 µm (n = 50) (Fig.2. D-F). Macroconidia were cylindrical (Fig.2. J), rounded at both ends, straight, with an average length of 63.5 ± 0.31 μm × 2.62 ± 0.03 μm without septa (n=50) (Fig.2. M-O). Stipe extension terminated in sphaero-pedunculate vesicles (Fig.2. K-L). The morphological features were consistent with the descriptions of Calonectria ilicicola (Pei et al. 2015; Polizzi et al. 2012). The pathogen was confirmed to be C. ilicicola by amplification and sequencing of the histone (HIS3), translation elongation factor 1-alpha (TEF1) and calmodulin (CAL) genes using primers H3-3F/H3-3R, EF1-728F/EF1-986R and CAL-228F/CAL-2Rd, respectively (Crous et al. 2004). The sequences of PCR products were deposited in GenBank with accession numbers OR188222 (HIS3), OR188223 (TEF1) and OR188221 (CAL). BLAST searches of the obtained sequences revealed 99.22% (510/514 nucleotides), 98.37% (241/245 nucleotides) and 99.58% (472/474 nucleotides) homology with those of C. ilicicola (CBS 190.50) in GenBank (AY725676, AY725726 and AY725764), respectively. Phylogenetic analysis (MEGA 7.0) using the Maximum Likelihood method placed the isolate 6a-H-2 in a well-supported cluster with C. ilicicola. The pathogenicity of 6a-H-2 was tested through a pot assay. Five healthy plants had their leaves scratched with a sterilized needle, then inoculated by spraying 20 mL of spore suspension (105 spores mL-1) of 6a-H-2. Five additional tea plants sprayed with sterile distilled water served as controls. All plants were placed in a growth chamber at 28℃, with 70% relative humidity. The symptoms developed on all inoculated leaves but not on the control leaves. The lesions were first visible 72 h after inoculation, and typical lesions similar to those observed on field plants appeared after 10 days. The same fungus was reisolated and identified based on the morphology and molecular analyses (HIS3, TEF1 and CAL) from the infected leaves but not from the non-inoculated leaves. To our knowledge, this is the first report of leaf spot on tea caused by C. ilicicola in China. This study provides valuable information for the identification and control of the leaf spot on tea.

First Report of Cercospora Leaf Spot Caused by Cercospora cf. flagellaris on Lonicera japonica Thunb. in Henan, China.

Honeysuckle flower (Lonicera japonica Thunb.) is a traditional Chinese medicinal plant. It is perennial and widely cultivated in China, Japan and Korea. From late August to October in 2021 and 2022, leaf spots symptoms were observed on L. japonica in different planting fields in Yuzhou, Yuanyang and Fenqiu districts, Henan province, China. The disease incidence was above 85% which reduce photosynthesis. Early disease symptoms appeared as small, circular to elliptical, brown spots on the leaves and later the lesions (1 to 5 mm × 1 to 4 mm) slowly developed yellow haloes. The different brown lesions seldom merge and form larger irregular lesions. Small fragments (3 to 5 mm) of leave tissue were excised from the lesion margins and surface-sterilized in 3% NaClO for 3 min, followed by three washes with sterile distilled water, and then placed on potato dextrose agar (PDA) and incubated at 25°C in the dark for 5 days. A total number of 8 cultures were obtained and purified by single-spore subcultures on PDA for morphological identification. The colonies on PDA were whitish to gray, with cottony aerial mycelium. Conidiophores were fasciculate, olivaceous brown, straight or geniculate, uniform in width, multiseptate, and ranged from 290 to 700 μm (560 μm on average, n = 20). Conidia were hyaline, slightly curved or straight, needle shaped, truncate at the base, and terminal at the tip, 3 to 17-septate, and measuring 150 to 240 μm (180 μm on average, n = 20). The morphological features were consistent with Cercospora cf. flagellaris Ellis & G. Martin (Groenewald et al. 2013). The genomic DNA was extracted using CTAB method. The nuclear ribosomal internal transcribed spacer region (ITS), portions of the actin (ACT), histone H3 (HIS3), and translation elongation factor 1-α (TEF1) genes were amplified using primers ITS1/ITS4 (Groenewald et al. 2013), ACT-512F/ACT-783R (Carbone and Kohn 1999), CYLH3F/CYLH3R (Crous et al. 2006), and EF1-728F/EF1-986R (Carbone and Kohn 1999). The resulting 537-bp ITS, 226-bp ACT, 410-bp HIS3, and 306-bp TEF1 sequences of isolate JDJ002 were deposited in GenBank (accession nos. OR492367, OR548247, OR548248 and OR548248, respectively). Sequence analysis revealed that ITS, ACT, HIS3 and TEF1α sequences exhibited ≥99% of identity with the ITS (KP896013), ACT(KP895965), HIS3(MK991295) and TEF1 (MN180408) sequences of C. cf. flagellaris, respectively. A pathogenicity test was conducted on healthy of L. japonica leaves. The healthy leaves pricked from L. japonica plants, rinsed in autoclaved distilled water three times and dried with distilled filter paper. Then twelve healthy leave were inoculated with a mycelial plug (0.4 cm diameter) harvested from the periphery of two week-old colony. As negative control, leaves inoculated with PDA medium plugs. Inoculated leaves were covered with plastic bags to maintain high relative humidity and incubated at 25°C in growth chamber. After 7 days, the inoculated leaves showed symptoms identical to those observed in the field under natural conditions, whereas negative control remained symptom-free. Re-isolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was C. cf. flagellaris. Pathogenicity tests were repeated three times by the same methods with the same results. To our knowledge, this is the first report of C. cf. flagellaris except Cercospora rhamni Fack., Alternaria alternata, Corynespora cassiicola or Phomopsis sp. causing leave spots on L. japonica in China.

First report of leaf blight disease caused by Aspergillus welwitschiae on Persicaria lapathifolia var. salicifolia in China.

Persicaria lapathifolia var. salicifolia (Sibth.) Miyabe, has long been extensively utilized in traditional medicine for its significant medical values (Seimandi et al, 2021). Despite its extensive use, the leaf blight disease of this plant has never been documented in China. However, in September 2023, the symptoms of leaf blight disease were observed on P. lapathifolia var. salicifolia on the campus of Zhejiang Normal University (29°8'3″ N, 119°37'47″ E), Zhejiang province, China. The disease incidence was 40% on the 50 plants surveyed, according to the field survey. The progression of leaf pathogenesis is mainly divided into three stages. Early symptoms manifested as the light yellow spots on the edges or tips of the leaves, which subsequently developed into brown or yellow irregular lesions and eventually led to the curling and wilting leaves. Thus, the leaf tissues (5 × 5 mm) from the border of diseased and healthy areas were surface-sterilized in 1% sodium hypochlorite for 3 min, followed by 75% ethanol for 30 s, and rinsed three times with sterile water. After drying on sterile filter paper, the leaf tissues were put on PDA medium and cultured at 25°C for 3 days. Seven purified fungal isolates were obtained, and one representative strain was selected for further identification. After that, the isolate was identified by the combination of morphological studies and molecular analysis. The fungi exhibited rapid growth on PDA, attaining a diameter of 80 to 85 mm in 5 days. The colonies were black with a yellow margin, and the reverse sides were light yellow and partly colorless. Moreover, the conidia were brown to black, smooth to slightly rough, measuring 3.2 to 3.8 μm (n = 30) in diameter, with radiated conidial heads and expanded ampulliform phialides under the optical microscope. Therefore, the isolate's characteristics were consistent with the descriptions of Aspergillus welwitschiae (Bres.) Henn. (Gherbawy et al, 2021). To further identify the isolate, the internal transcribed spacer (ITS) region (Gardeset al, 1993) and the second largest RNA polymerase subunit (RPB2) (Liu et al, 1999) were employed for phylogenetic analysis. The obtained sequences were despot in GenBank (Acc. Nos. OR797058 for ITS, OR797058 for RPB2, respectively), and exhibited a high degree of sequence homology to A. welwitschiae (MK450815, MK450818, LC179911, and LC000572), with 99% to 100% identity. Besides, multilocus phylogenetic analysis showed that the isolate gathered into one clade with A. welwitschiae. Based on the integrated morphological and molecular results, the isolate was determined to be A. welwitschiae. Six healthy 1-year-old P. lapathifolia var. salicifolia were used to verify Koch's postulates. Three leaves were wounded with sterile pins and inoculated with the conidial suspension (107 conidia/mL) of isolates, while plants inoculated with sterile water were used as controls. After sealing with plastic wrap for 24 hours, the plants were cultivated at 25 °C and 85% relative humidity. Necrotic lesions were observed on leaves 10 days after inoculation, while the control leaves remained asymptomatic. The fungi were re-isolated from the diseased leaves and identified as the original ones through morphological and molecular identification, confirming Koch's postulates. While A. welwitschiae has been reported to cause the rot disease of Sisal Bole in Brazil (Duarte et al, 2018) and maize ear in Serbia (Nikolic et al., 2023), to our knowledge, this study marks the first report of A. welwitschiae causing leaf blight on P. lapathifolia var. salicifolia in China, extending the host range to A. welwitschiae.

First Report of Pantoea anthophila Causing Shoot Dieback Disease of Ceylon Ironwood (Mesua ferrea) in Malaysia

Ceylon ironwood (Mesua ferrea Linn.) or Penaga lilin is one of Asia's most popular tropical herbal plants, including Malaysia (Sharma et al., 2017). The trees are cultivated for their aesthetic value and pharmacological properties, especially as traditional remedies for asthma, dermatopathy, inflammation, and rheumatic conditions (Adib et al., 2019). In August 2022, a disease survey was conducted on Ceylon ironwood trees ranging from 5 to 12 years old in Botanical Park, Putrajaya, Malaysia, with 80% exhibiting shoot dieback disease of the 15 trees exhibiting shoot dieback disease. Symptoms include irregular, water-soaked with brown lesions on young leaves and shoots, where the small lesion coalesced and formed broad necrotic regions, subsequently causing dieback and gradual defoliation. Three infected shoots were collected from each tree, excised into small pieces (10 to 20 mm), immersed with 75% ethanol for 3 min, washed with 2% NaOCl solution for 1 min, and rinsed twice for 1 min in sterilized distilled water. A 10 µl aliquot of the sample suspension was streaked onto nutrient agar (NA) and incubated for 24 h to 48 h at 35 °C. A total of 15 isolates with similar morphology were obtained, and each isolate was re-streaked three times to obtain pure colonies that were round, smooth, with irregular edges, and produced yellow pigment in culture. All isolates were Gram-negative, negative for indole production, and utilized glucose, maltose, trehalose, sucrose, D-lactose, and pectin. Three representative isolates (C001, C002, and C003) with similar morphology were selected for further characterization. The total genomic DNA of all isolates was extracted from overnight cultures using Geneaid™ DNA Isolation Kit (Geneaid Biotech Ltd., Taiwan). PCR amplification of 16S rDNA (Zhou et al., 2015) and species-specific infB (Brady et al., 2008) genes was performed, and each of the ~1500 bp and ~900 bp amplicons were sequenced. BLASTn and phylogenetic analyses revealed all isolates were 100% identical to Pantoea anthophila (P. anthophila) LGM 2558 strains (Accession Nos. NR_116749 and NR_116113) for the 16S rDNA gene. They were 99% identical to P. anthophila CL1 strain (Accession Number CP110473) for infB gene. These sequences were later deposited in the GenBank (Accession Nos. OQ772233, OQ772234, and OQ772235 for 16S rDNA gene, and OQ803527, OQ803528, and OQ803529 for infB gene). For the pathogenicity test, healthy Ceylon ironwood seedlings' shoots were inoculated with 10 mL of each isolate suspension (1 x 108 CFU/ml) by spraying the inoculum on the young shoots using a sterilized spray bottle. Control seedlings were inoculated with sterile water. The inoculated shoots were covered with a sealed plastic bag to maintain the moisture and were kept in the greenhouse with temperatures ranging from 26 to 35 °C. The experiments were repeated twice, with three replicates for each treatment. Inoculated shoots showed dieback symptoms like natural infection, including irregular, water-soaked, and brown lesions on leaves and young shoots at 10 days post-inoculation. Control seedlings remained asymptomatic. The pathogen was re-isolated and identified via sequencing of the 16S rDNA and infB genes, thus fulfilling Koch’s postulates. Previously, P. anthophila has been reported to cause soft rot in wampee plants in China (Zhou et al., 2015) and leaf blight of cotton in Pakistan (Tufail et al., 2020). To our knowledge, this is the first report of P. anthophila causing shoot dieback disease of Ceylon ironwood trees in Malaysia. Plant disease management strategies need to be established to reduce losses due to P. anthophila infection since the pathogen could limit Ceylon ironwood tree production in Malaysia.

Comprehensive insights into sorghum (Sorghum bicolor) defense mechanisms unveiled: Plant growth-promoting rhizobacteria in combating Burkholderia-induced bacterial leaf stripe disease

Sorghum, a vital cereal crop with significant importance in traditional human health systems, faces severe challenges from biotic stresses. This study aimed to assess the morpho-physiological variations and plant growth promoting rhizobacteria (PGPR)-induced defense mechanisms in sorghum against Burkholderia sp. infection, a well-known cause of bacterial leaf stripe disease. Also, the alterations in the leaf protein band profile of sorghum exposed to Burkholderia infection were assessed via 2-D gel electrophoresis wherein the disappearance of protein bands in diseased leaf tissues was recorded. The selected PGPR, A. chroococcum Beijerinck 1901 (MCC 2351), B. megaterium (MCC 2336), and P. fluorescens (NAIMCC B-00,340), secreted hydrogen cyanide and ammonia, and produced lytic enzymes, cellulase and amylase. When tested in-planta, Burkholderia sp., applied as a foliar spray, more profoundly impacted the growth as compared to seed coat application, resulting in significant reductions in root dry biomass, whole plant length, and total chlorophyll content by 93.9, 73.4 and 53.8 %, respectively, compared to disease-free control. Visible symptoms of bacterial leaf stripe disease like brown discoloration and necrotic lesions were observed in infected sorghum plants. Furthermore, the level of phytochemicals, proline, and malondialdehyde and antioxidants, CAT and SOD, in foliage declined significantly by 46.4, 70.2, 20.7, and 16.9 %, respectively, following inoculation with Bacillus applied as a seed coat. Additionally, Burkholderia-infected plants exhibited cellular damage, mainly in leaf tissues, as revealed by SEM and CLSM. Interestingly, the PGPR inoculation substantially enhanced the measured growth parameters of sorghum while reducing the levels of phytochemicals and antioxidants. These findings suggest that A. chroococcum, B. megaterium, and P. fluorescens, possessing biocontrol activity, can be employed as a profitable, environment and pocket-friendly approach for managing plant diseases and promoting the production of sorghum under biotic stress, thereby sufficing the human food demands.

Morphological characterization, phylogeny and pathogenesis of Setophoma terrestris causing corky and pink roots of tomato (Solanum lycopersicum) in Sinaloa, Mexico

Tomato (Solanum lycopersicum) is one of Mexico’s main crops. In the years 2017 and 2018, symptoms of corky and pink roots were observed with an incidence of 10 to 20% in Culiacan, Sinaloa, Mexico. In the foliage, plants presented a generalized chlorosis, with stunted growth and senescence in the leaves. In the roots, brown and pink lesions were formed, as well as a corky texture. The objective of this study was to morphologically and molecularly characterize fungal isolates associated to corky and pink root in tomato orchards in Culiacan, Sinaloa, as well as to evaluate their pathogenicity. Monoconidial isolates were obtained and they were identified as Setophoma terrestris, based on their morphological characteristics. To confirm the identity, the area of the internal transcribed spacers (ITS) of the rDNA was amplified and sequenced, along with a fragment of the gene 28S of the rRNA (LSU). Using the sequences obtained, a phylogenetic tree was created using the Bayesian Inference and it was found that the sequences were grouped with the ex–type sequences of Setophoma terrestris. The pathogenicity of the isolates was verified by inoculating mycelial discs into the root of 10 one-month-old tomato seedlings. The roots of the seedlings inoculated with PDA discs without mycelium served as a control. Thirty days after inoculation, corky and pink root symptoms appeared, whereas the roots of control plants remained healthy. According to the morphological characterization, the molecular identification and the pathogenicity tests, Setophoma terrestris was confirmed to be the causal agent of corky and pink root in agricultural tomato orchards in Culiacan, Sinaloa.

First Report of Leaf Spot Disease on Pineapple Caused by Fusarium solani in China.

Pineapple (Ananas comosus) is an economically important tropical fruit in Guangdong Province, China. The plants were seriously infected with a year-round leaf spot disease. During September to November 2022, the leaf spot disease of pineapple was found in Xuwen city and Zhanjiang city of Guangdong Province. A disease survey of 1 ha revealed that pineapple was affected at an incidence ranging from 30% to 50%. The disease caused economic loss to control plant diseases with chemicals. The initial symptoms were observed after 1 month of planting in October and included yellow spot and developed brown necrotic lesions. The leaves of pineapples showed symptoms of Large brown necrotic lesions appear on leaves especially on the tip of basal leaves. The diseased leaves were collected and surface-disinfested in 1% NaClO for 2-3 m, rinsed with sterilized water, air dried, placed on potato dextrose agar (PDA) medium, and incubated for 3 to 5 days at 28°C. Two isolates (PLF1 and PLF2) were collected and purified using the single-spore method. Colonies developing on PDA were in a circle with abundant white, densely fluffy aerial mycelium, pale to colorless after 3 d and pale orange 5-15 d later. Cultures of the isolates produced macroconidia which were falcate, 1-3-septate, hyaline, 18.2-43.4×4.8-6.8 µm(n=50). Cultures of the isolate also produced large amount of conidia which were hyaline, oblong, no septate, 5.2-10.6×2.7-5.2 µm (n=50). These characteristics were consistent with the description of Fusarium sp. (Chitrampalam et al. 2018). For molecular identification, the genomic DNA of the 2 isolates was extracted. The fragments of internal transcribed spacer (ITS), translation elongation factor 1α (EF1α) and β-tubulin were amplified and sequened using the primer pairs of ITS4/ITS5, EF1/EF2 (O'Donnell et al. 2008) and T1/T2 (O'Donnell et al. 1997). These sequences were deposited in GenBank (OR501466, OR501467 for the ITS; OR499874, OR499875 for elongation factor; OR499876, OR499877 for β-tubulin). Phylogenetic trees were constructed in MAGA 11 using the Maximum likelihood (ML) method based on the concatenated sequences of ITS, EF1α, and Tublin (Figure 1). The 2 isolates were grouped with F. solani A01-1 (GCA_027945525.1) with a bootstrap value of 100 in the phylogenetic tree. The morphology and multi-gene phylogenetic analysis indicated that the new isolates are F. solani. The 2 isolates were selected for pathogenicity tests to fulfill Koch's postulates. Six plants at seven- to ten-leaf stage were inoculated with each isolate separately. Three sites of each leaf were wounded with a sterile needle and covered with a piece of cotton drenched with 200 µl spore suspension (107 spores/ml) from each isolate cultured in PD medium. Leaves inoculated with PD medium served as negative controls. Inoculated plants were placed in an incubator at 28°C, and 80% humidity under a 12-h light/dark cycle for 7 days. After 7 days of incubation, necrotic spots were observed in all the inoculated plants except the negative control. The pathogenicity tests were conducted three times with similar results. The strains were then reisolated from the lesions and found to be Fusarium solani as those of the inoculum. F．ananatum， F. guttiforme and F. subglutinans have been reported to infect all parts of pineapplefusariosis disease (Jacobs et al. 2010; Stępień et al. 2013; Ventura et al. 1993). To our knowledge, this is the first report of fusariosis on Pineapple caused by F. solani. Identification of F. solani as a disease agent on pineapple will assist in disease management for this important fruit tree.

First report of Diplodia bulgarica causing black canker on apple in California.

California is the sixth largest apple-producing state in the United States with a production that reached 4,654 ha in 2021. During the late winter of 2023, black canker symptoms were observed on branches of 'Gravenstein' apple (Malus domestica) in two commercial orchards in Sonoma County, California. The prevalence of symptomatic trees ranged from 10 to 30%. External symptoms included charcoal looking-cankers with the bark peeling off from the primary and secondary branches. Internally, cankers were dark brown in color with a hard consistency. Pycnidia were observed on the surface of older cankers. Fungal isolations were performed from disinfected (70% ethanol, 30 s) symptomatic branch samples (n = 15). Small wood pieces (5 mm length) were taken from the margin of diseased and healthy tissues, and placed on potato dextrose agar acidified with 92% lactic acid at 0.5 mL per liter (APDA). Plates were incubated at room temperature (20-22 °C) for 7 days. Colonies of Botryosphaeriaceae species (Phillips et al. 2013) (n = 12) were consistently recovered and pure cultures were obtained by transferring a single hyphal tip onto fresh APDA. Colonies were light gray with irregular margins. To induce pycnidia formation, two isolates (UCD11350 and UCD11351) were grown on pistachio leaf agar for 21 days. Conidia (n = 50) were thick-walled and ovoid in shape, initially hyaline, then turned pale brown and dark brown at maturity, and some of them became 1-septate, ranging from 18.9 to 24.0 (21.9) × 11.5 to 14.7 (13.4) µm. Isolates were identified by sequencing a partial region of the beta-tubulin (tub2) gene using the primers Bt2a/Bt2b (Glass and Donaldson 1995). BLAST searches on NCBI GenBank revealed 99.5 % identity with the Diplodia bulgarica ex-type (CBS 1245254). To confirm the identity, the rRNA internal transcribed spacer (ITS) and the translation elongation factor 1-alpha (tef1) were also sequenced using ITS5/ITS4 (White et al. 1990), and EF1-688F/EF1-1251R (Alves et al. 2008), respectively. A maximum parsimony multi-locus phylogenetic analysis clustered Californian isolates with reference strains of D. bulgarica. Sequences were deposited in GenBank (nos. OR631209 to OR631210, OR637361 to OR637362, OR637363 to OR637364 for ITS, tub2, and tef1, respectively). Pathogenicity tests were conducted on 2 to 3-year-old branches (n = 5) of over 20-year-old trees by inserting a 5-mm segment of a toothpick, completely colonized with each of the two isolates mentioned above, into a 1-mm-diameter hole made with a sterile drill bit. The same number of branches where mock inoculated with a non-colonized toothpick as negative control. The experiment was performed twice. After ten weeks, inoculations resulted in dark brown necrotic lesions that ranged from 54.0 to 59.8 mm in length. Negative controls remained asymptomatic. Koch's postulates were fulfilled by successfully recovering the isolates from the lesion margins, which were confirmed by morphology. Diplodia bulgarica was first described affecting M. sylvestris in Bulgaria (Phillips et al. 2012), and then detected on M. domestica causing cankers in Iran (Abdollahzadeh 2015), India (Nabi et al. 2020), Germany (Hinrichs-Berger al. 2021) and Türkiye (Eken 2021). The pathogen was also identified causing postharvest fruit rot (Eken 2022). To our knowledge, this is the first report of D. bulgarica causing branch canker on apple in California, which provides important information for developing detection and control strategies.

First Report of Fusarium verticillioides causing Stem Blight of Schizonepeta tenuifolia in China.

Schizonepeta tenuifolia is an important medicinal plant in China. Over 10000 ha of S. tenuifolia is cultivated in the country annually. However, fungal diseases are a major limiting factor in S. tenuifolia production. In 2022, 50 ha in several S. tenuifolia fields in Hebei province were observed to be severely affected by a disease causing a yield loss of 30%. Results from field surveys suggested an epidemic during seedlings stages that affected S. tenuifolia stems, causing irregularly watery brown lesions. Lesions ranged from 1.5 to 2 × 2.5 to 3 cm. To isolate the causal agent, tissue was removed from the border of lesions and surface sterilized in 75% ethanol for 30 sec and 0.1% HgCl2 for 1 min, then rinsed three times with steriled distilled water(SDW), plated on potato dextrose agar(PDA) at 25℃, and incubated in the dark for 7 days. Five putative isolates of the genus Fusarium were hyphal-tipped on new PDA plates. Isolates were cultured on synthetic low-nutrient agar(SNA) with a ~ 1 × 2-cm strip of sterile filter paper on the agar surface(Nirenberg 1976). Cultures were incubated for 7 to 10 days at 20℃ in dark conditions. When sporulation was observed, agar blocks were mounted on a microscopic slide with a drop of lactophenol cotton blue and examined at 400×. Colonies grew rapidly with abundant pink to violet aerial hyphae. Sporodochia formed on the agar, and the aerial conidiophores branched sparsely, often alternately or oppositely, terminating with up to three verticillate phialides. Microconidia produced on polyphialides and aggregating in heads were unicellular, ovoidal or ellipsoidal, 4.4 to 17 × 1.5 to 4.5 μm. Macroconidia were abundant, falcate to straight, three to five septate, with a distinct foot cell, 27 to 73 × 3.1 to 5.6 μm. Based on morphological characteristics, isolates were tentatively identified as F. verticillioides(A1-Hatmi et al. 2016; Guarro 2013). Pathogenicity tests were performed by injection inoculation of 0.1 mL of conidial suspensions(1×106 conidia/mL) into three S. tenuifolia stems using a disposable needle and syringe. Distilled water was injected into three mock controls. Inoculated plants were placed in a greenhouse at 32 to 34℃ and 95% relative humidity. Typical lesions were observed 7 days after inoculation, except in the control samples. Each treatment was replicated three times. The suspected pathogen was consistently reisolated from diseased tissue according to Koch's postulates, and was found to be morphologically similar to F. verticillioides. Preliminary morphological identification of the pathogen was further confirmed by using genomic DNA extracted from the mycelia of a 7-day-old culture grown on PDA at 25℃. The translation elongation factor 1-α gene(TEF1) was amplified(O'Donnell et al. 1998) and the TEF region(Genbank Accession No. OR105502) was sequenced by Sangon Biotech Co., Ltd.(Shanghai, China) and displayed 100% nucleotide similarity with rDNA-TEF of F. verticillioides(JF740717) separately after a BLASTn search in Genbank. Based on the symptoms, fungal morphology, TEF sequence, and pathogenicity testing, this fungus was identified as F. verticillioides. to our knowledge, this is the first report of F. verticillioides infecting S. tenuifolia in China. This report will promote further research of F. verticillioides on this host and lead to better understanding of disease prevalence, extent of damage, and possible management options.

First report of Diaporthe eres causing leaf spot on Rhododendron latoucheae Franch. in China.

Rhododendron latoucheae Franch. is an evergreen shrub with charming fragrance and large and abundant flowers that make it highly attractive as an ornamental species. The species is distribution in southwest China covers several different habitats and environments (Zhang, et al. 2022). From May to July in 2023, symptoms of leaf spot were observed on R. latoucheae over a wide portion of the Baili Azalea Forest Area (27°10' to 27°20'N, 105°04' to 106°04'E), Guizhou Province, China. About 500 plants were surveyed, and the incidence of leaf spot on R. latoucheae leaves was 12%, significantly reducing their ornamental and economic value. The affected leaves had irregular, grey white lesions with a clear blackish brown boundary and faint black conidiomata in a brown center. To isolate the pathogen, 15 symptomatic leaves were collected from 10 plants. A few black dots were picked from the lesions with a sterilized needle, plated on water agar, and incubated at 25°C for 24 h to observe spore germination (Choi et al. 1999). Then the germinated spores were transferred onto PDA for further purification and morphological observation. Three single-spore isolates (GULJ1-L7, GULJ1-L8, and GULJ1-L9) identical in morphology were obtained. The isolate GULJ 1-L7 was used for further study. Colonies on PDA irregular grew white felty aerial mycelium, becoming white felted aerial mycelium in the centre and grey-brown mycelium at the marginal area on the upper surface, while the lower surface presents alternating white, tan and taupe. Colony with conidiomata irregularly distributed over agar surface. In the representative isolate, darkly pigmented pycnidia (flask-shaped) were produced over the colony surface on PDA after about 30 days, and oozed milky or yellowish mucilaginous drops. The fungus produced two types of conidia, α and β. Regular α conidia were 5.15-10.29 × 1.54-3.33 μm (n = 50), hyaline, elongated, biguttulate and non-septate. Beta conidia were 20.34-31.91 × 1.01-1.90 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 and the calmodulin (CAL) using primers ITS1/ITS4, Bt-2a/Bt-2b, EF1-728F/EF1-986R, and CAL-228F/CAL-737R, respectively (Tao et al. 2020). Sequences from PCR amplification were deposited in GenBank with accession numbers OR740563 (ITS), OR754301 (TUB), OR754298 (TEF), and OR754295 (CAL) respectively. BLAST searches of the sequences revealed 99.07% (533/538 nt), 100% (490/490 nt), 99.69% (317/318 nt) and 98.95% (376/380 nt) homology with those of D. eres AR5193T from GenBank (KJ210529.1, KJ420799.1, KJ210550.1 and KJ434999.1), respectively. Phylogenetic analysis (MEGA 7.0) using the maximum-likelihood method placed the isolate GULJ1-L7 in a well-supported cluster with D. eres CBS 138694T. The pathogen was thus identified as D. eres based on the morphological characterization and molecular analyses (Feng, et al. 2013; Tao, et al. 2020). The pathogenicity of GULJ1-L7 was tested through a pot assay. Due to the difficulty of artificial planting wild R. latoucheae, we conducted a pot essay to detect the pathogenicity of GULJ1-L7 using a closely related Rhododendron delavayi Franch. Ten healthy R. delavayi plants were scratched with a sterilized needle (0.45 mm in diameter) on three leaves per plant. Plants were inoculated by spraying α and β spore mixture suspension (106 spores ml-1) of GULJ1-L7 onto leaves until runoff, and the control leaves were sprayed with sterile water. The plants were maintained at 25°C and 75% relative humidity in a growth chamber. The pathogenicity test was repeated three times. After 14 days, the treated leaves developed brown lesions similar to those in the field, whereas the control had no symptoms. The same fungus was reisolated from the infected leaves and identified based on a morphological characterization and molecular analyses. These results fulfilled Koch's postulates. To our knowledge, this is the first report of leaf spot on R. latoucheae caused by D. eres in China. The fungal pathogen identification will provide valuable information for prevention and management of leaf spot disease associated with R. latoucheae.

Pelvic pain symptoms and endometriosis characteristics in relation to oxidative stress among adolescents and adults with and without surgically-confirmed endometriosis.

Background: While the majority of reproductive-aged females will experience pelvic pain during their lives, biological mechanisms underlying pelvic pain are not well understood. We investigated associations between pelvic pain symptoms and oxidative stress among people with and without surgically-confirmed endometriosis. Methods: Using an enzyme-linked immunosorbent assay, we measured 8-Hydroxy-2'-deoxyguanosine (8-OHdG) in urine samples and corrected for creatinine levels in 434 surgically-confirmed endometriosis participants compared to 605 participants never diagnosed with endometriosis. At enrollment, participants reported details of their pelvic pain symptoms. Linear regression was used to compute geometric mean (GM) creatinine-corrected 8-OHdG levels with 95% confidence intervals (CI) among all participants and those with and without endometriosis separately, adjusting for potential confounders. Interactions by surgically-confirmed endometriosis status were tested by Wald statistics. Results: No trends in 8-OHdG were observed among those with or without endometriosis for severity or frequency of dysmenorrhea, acyclic pelvic pain, dyspareunia or pain with bowel movements. Among endometriosis participants, lower 8-OHdG levels were observed for participants with any white, blue/black, or brown lesions (GM=76.7 versus 82.9 ng/mg; p=0.10), which was primarily driven by lower levels of 8-OHdG for any blue/black lesions (GM=72.8 versus 81.6 ng/mg; p=0.05). Conclusion: While no associations were observed between 8-OHdG and pelvic pain symptoms, future research is needed to assess how other pathways of oxidative damage, e.g. through proteins or lipids, may affect endometriosis-associated symptoms. Additionally, further research is needed to understand differences in oxidative stress among endometriosis lesion sub-phenotypes.

First Report of Lasiodiplodia pseudotheobromae Causing Necrosis and Canker Disease on Pear Tree in China.

Pear ispopularamongpeople, which is an important pillar industry in China. In March of 2023, dark brown necrotic lesions were discovered on the trunks of Pyrus pyrofolia cv. Osmanthus pear in orchard, Liuzhou City, Guangxi Zhuang Autonomous Region. In August, field investigation and sample collection were conducted in orchard. Forty pear trees were selected for symptomatic observation, which of 21 had lesions ranging from 10 to 24 per tree, and 19 with 1 to 8 lesions, respectively. To isolate the pathogen, small tissue pieces of 3 diseased pear trunk samples were disinfected with 75% ethanol for 1 minute, rinsed with sterile water, and dried with filter paper. The tissue pieces were placed on potato dextrose agar (PDA) plates and cultured in a dark incubator at 25℃. Six isolates with the similar morphology were obtained. One of the six isolates was randomly selected as the representative strain and named as GX-3. Mycelium grows with an average rate of 4.26 cm/d. The hypha is highly aerial, and is initially white and then turns black. Subsequently, pycnidia formed and secreted black mucus on the PDA medium after 28 days. The immature conidia were ellipsoid, colorless, hyaline, and unicellular, mostly becoming brown bicellular with longitudinal stripes at maturity. The conidial size was 22.5 to 32.6×12.1 to 19.7μm, and the average size was 28.4±2.3×16.7±2.0 μm (n=50), respectively. GX-3 colony morphology was consistent with that of Lasiodiplodia pseudotheobromae (Alves et al.2008). For molecular identification, the internal transcribed spacer of rDNA (ITS), translation elongation factor 1-α (TEF1-α), and β-tubulin regions were amplified using the primers ITS1/4, EF1-728F/986R, and Bt2a/Bt2b, respectively (White et al.1990; Carbone and Kohn 1999; Glass and Donaldson 1995). The obtained sequences of GX-3 were deposited in NCBI with Accession numbers OR655421, OR661231, and OR661230, respectively. The sequences of ITS, TEF1-α, and β-tubulin from GX-3 are 99.44%、99.67% and 99.78% identities with those of L. pseudotheobromae CBS 447.62, respectively. The phylogenetic analysis was performed by maximum likelihood method, revealing that GX-3 is closely clustered with the isolates of L. pseudotheobromae. Therefore, the GX-3 strain was identified as L. pseudotheobromae. GX-3wasfurtheranalyzedforitspathogenicityonpear. Firstly, the GX-3 mycelium plugs and spraying spore suspension with the concentration of 1×107 conidia/ml were applied on the stems of 4-month-old healthy birch-leaf pear (Pyrus betulifolia Bunge) potted seedlings by acupuncture needle method, meanwhile PDA and sterile waterwere usedascontrols. After 3 days of inoculation, stem surface of the birch-leaf pear exhibited dark brown lesions with slight surface depression, obvious dryness, and canker symptoms, while the control treatment showed no symptoms. The GX-3 was also inoculated on in vitro branches of 'Hosui', 'Hongxiangsu', 'Bodoqing' and 'Xuehua', showing dark brown canker lesions. The same pathogen can be successfully isolated from diseased stems and branches but not from the controls, which accomplishes Koch's postulates. L. pseudotheobromae has been widely reported that it can cause rot and canker on apple, walnut, hackberry, and so on (Xue et al. 2019; Wang et al. 2023; Liang et al. 2020). This is the first report of necrosis and canker disease caused by L. pseudotheobromae on pear in China, which is a potential threat to pear industry.

P18 Giant Periocular Juvenile Xanthogranulomas Treated with Trametinib

Abstract Juvenile Xanthogranuloma (JXG), the commonest type of non-Langerhans cell histiocytosis, is regarded as a benign self-limiting condition of infancy, characterised by asymptomatic yellow brown papulonodular lesions, usually confined to the skin but occasionally affecting the eyes or internal organs. Skin lesions characteristically regress spontaneously within 3-6 years. We describe an unusually aggressive cutaneous presentation requiring input from paediatric oncology. A 6 year old boy presented with extensive soft yellowish papules, plaques and nodules particularly around the eyes but also over the chest and leg. Biopsy confirmed the clinical diagnosis of JXG. The lesions enlarged progressively with new lesions appearing, causing significant distortion of the upper and lower eyelids with reduced ability to open the eyes, discomfort and distress. Treatment was started with topical steroids, progressing to intralesional and systemic steroids, but with minimal effect. In view of the severity, vinblastine and subsequently cytarabine were added, again with limited benefit. The periocular lesions were surgically debulked and he was commenced on Trametinib (a MEK inhibitor) with a good response. Now aged 9 years, and the patient displayed a favourable clinical response after 3 months of being on Trametinib. JXG rarely requires treatment, but there is no recognised therapy for the occasional problematic lesions. In this case trametinib was effective and well-tolerated. The efficacy of trametinib in histiocytosis has been attributed to the presence of activating BRAF and MAP2K1 mutations. Genetic analysis of JXG may guide future therapies.

First Report of Fusarium ipomoeae Causing leaf rot on Hosta plantaginea in China.

Hosta plantaginea is an important horticultural plant with ornamental value and is widely cultivated in China. Since April 2022, leaf rot has been observed in the H. plantaginea plants in Wanzhou District, Chongqing City, China (31º14'58"N, 108º53'25"E), the initial symptom is a yellow and brown lesion on the edge of the leaf, in the late stage, brown blighted tissue caused leaves to curl and abscise. Ten typical diseased leaves were collected, the margins of infected tissues were cut into small pieces (5×5 mm) and were sterilized in 75% Ethanol for 30 s, 3% sodium hypochlorite for 3 min, rinsed three times with sterile water, then dried on sterile filter paper and placed to potato dextrose agar (PDA) medium at 25℃for 4 days. Thirteen isolates with morphological characteristics similar to those of Fusarium spp. (Nelson et al. 1983) were recovered. These isolates had white, pink and yellowish mycelia, two isolates produced irregular colonies, and remaining isolates showed round. Two of each type were selected for intensive study (yz2, yz11, yz9 and yz17). The colony of yz2 reached 62 mm in diameter on PDA medium after seven days, macroconidia were elongated sickle-shaped, 3-5 septa, and 12.92 to 21.49 × 3.42 to 5.90 μm in size, microconidia were oval and measured 5.69 to 12.95 × 3.41 to 9.80 μm in size, conidiophores were whorled and branched, yz9 attained 74 mm in diameter after nine days, macroconidia were curved sickle-shaped and apex cell acuminate, 26.9 to 57.2 × 2.4 to 7.1 μm, 3-5 septa. The microconidia were fusiform, 17.8 to 28.8 × 11.2 to 14.5 μm. Conidiophores variable in length. Genomic DNA was extracted from 7-day-old aerial mycelia of four strains (yz2, yz9, yz11 and yz17). The internal transcribed spacer (ITS) region (White et al. 1990), translation elongation factor (EF-1α) (Cao et al. 2014) and partial RNA polymerase second largest subunit (RPB2) (Wang et al. 2019) gene regions were amplified and multilocus phylogenetic analysis was conducted, their sequences were deposited in NCBI Genbank with the following accession numbers: the strains of yz2 and yz11 with OQ829372 and OR236201 for ITS, OQ848594 and OR282462 for EF-1α, OR492296 and OR492297 for RPB2; yz9 and yz17 with OQ829383 and OR236222 for ITS, OQ848595 and OR282463 for EF-1α, OR492295 and OR492298 for RPB2. The ModelFinder was used to select the best-fit model in PhyloSuite v1.2.2, the Bayesian Inference method (BI) analysis was used to estimate the system relationship, yz9 and yz17 were identified as Fusarium ipomoeae, yz2 and yz11 were identified as Fusarium tricinctum. To verify Koch's postulates, 8 healthy plants of H. plantaginea (two-year-old) grown were rinsed with sterile water, after 5 leaves per plant were stabbed with a sterilized needle, 4 plants were inoculated with conidial suspension (1×106 conidia mL-1), other plants injected with sterile water as control, then placed in a greenhouse maintained with 95% relative humidity at 25 ± 1°C. The symptoms on the leaves were similar to field after inoculation for 7 days, whereas all control leaves remained healthy. The same pathogen was re-isolated and re-identified based on multilocus phylogenetic analysis, fulfilling Koch's postulates. To our knowledge, this is the first report of F. ipomoeae causing leaf rot on H. plantaginea in China. In addition, F. ipomoeae was reported to cause leaf spot in Peanut (Xu et al. 2021), and F. tricinctum can cause fruit rot on navel orange in China (Yang et al. 2023). H. plantaginea as a horticultural plant is popular with some people, but it has long been threatened by Fusarium.spp. The finding can provide a theoretical basis for control leaf rot on H. plantaginea.