Glyceraldehyde 3-phosphate Dehydrogenase Gene Research Articles

GAPDH Gene Family in Populus deltoides: Genome-Wide Identification, Structural Analysis, and Expression Analysis Under Drought Stress.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an enzyme widely involved in glycolysis in animal cells and in non-metabolic processes, including apoptosis and the regulation of gene expression. GAPDH is a ubiquitous protein that plays a pivotal role in plant metabolism and handling of stress responses. However, its function in plant stress resistance remains unknown. Identification and systematic analysis of the GAPDH family in Populus deltoides (P. deltoides) have not been performed. Bioinformatics methods were used to analyze the physicochemical characteristics, structural characteristics, phylogenetic relationships, gene structure, motif analysis, and expression of GAPDH gene family members in P. deltoides. We identified 12 GAPDH members in P. deltoides. Five types of PdGAPDH were identified: GAPA, GAPB, GAPC1, GAPC2, and GAPCp. PdGAPDH genes were differentially expressed in leaves, stems, and roots of 1-year-old poplar seedlings. PdGAPDH gene transcripts showed that PdGAPDH2 and PdGAPDH4 were highly expressed in the leaves. In the roots, seven genes-PdGAPDH01, PdGAPDH05, PdGAPDH06, PdGAPDH07, PdGAPDH08, PdGAPDH09, and PdGAPDH12-showed significantly high expression levels. PdGAPDH02, PdGAPDH03, PdGAPDH04, and PdGAPDH11 showed decreased expression under drought conditions and recovered after re-watering. These results lay the foundation for further studies on the drought stress mechanisms of P. deltoides.

First Report of Leaf Spot Caused by Alternaria alternata on Artemisia stolonifera (Maxim) Komar. in China.

Artemisia stolonifera (Maxim.) Komar., also known as the 'elite of Artemisia', is currently widely planted in Jiangxi, Hubei, and other provinces in China. Since April 2023, a leaf spot on Ar. stolonifera was observed in the total cultivation area of 33.33 ha in Zhangshu City, Jiangxi Province. The incidence was 50% to 60%. Small irregular blackish-brown spots first appeared on the leaves, some with chlorotic margins, which later joined into clumps. In severe cases, the leaves were completely necrotic, seriously affected the growth and quality of Ar. stolonifera. Small pieces (3 to 4 mm) were excised from the necrotic borders of 20 typical symptomatic infected leaves, disinfected with 2.5% sodium hypochlorite solution for 3 min, rinsed five times with sterile water, and placed on potato dextrose agar (PDA) medium, incubated at 25℃ for 5 days. 15 purified isolates with similar morphological characteristics were obtained by transferring hyphal tips (isolation frequency of 75%). The colonies on PDA initially were white, and then became olive green with a white rim. After 10 days of culture on potato carrot agar medium (PCA), the conidia were septate, light brown in color, with dimensions ranging from 10.82 to 30.59 × 7.12 to 11.97 μm (n=50). The culture and morphological characteristics corresponded to Alternaria spp. (Simmons 2007), and the representative isolates JNC01 and JNC02 were used for further identification. To further identify the isolates, the RNA polymerase II second largest subunit (RPB2), internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Alternaria major allergen (Alt a1), translation elongation factor 1-alpha (TEF-α) and histone 3 (HIS3) were amplified using primers RPB2-5F2/RPB2-7CR, ITS1/ITS4, gpd1/gpd2, Alt a1-F/Alt a1-R , EF1-728F/EF1-986R and H3-1a/1b, respectively (Glass and Donaldson 1995; Lawrence et al. 2013; Berbee et al. 1999; Hong et al. 2005). The subsequent sequences were deposited in GenBank (accession nos. PP101993 and PQ458469; PP350760 and PQ45545; PP409573 and PQ474679; PP746506 and PQ474680; PP375820 and PQ458468; PQ001738 and PQ458467 for JNCO1 and JNC02 respectively. NCBI BLASTn sequence analysis revealed that all sequences, except for HIS3 had 100% homology with those of the Al. alternata strain CBS 612.72 (RPB2: KP124777.1, ITS: KP124308.1, GAPDH: KP124165.1, Alt a1: KP123861.1, TEF-α: KP125084.1), meanwhile, HIS3 had 100% identity with the Al. alternata strain MRY1 (MK210171.1). Phylogenetic trees, constructed using concatenated sequences based on ITS, GAPDH, Alt a1, TEF and RPB2 genes, as well as one built solely with HIS3, both placed JNC01 and JNC02 in the Al. alternata clade with high confidence. To test pathogenicity, about 5 mL of conidia suspension (1×106 conidia/mL) of JNC01 was sprayed on five 1-year-old healthy seedlings, while five seedlings were sprayed with sterile distilled water as a control. All plants were covered with plastic bags and placed in a greenhouse at 25 ± 2℃. After 7 days, brown spots, some with chlorotic margins, were observed, similar to those observed in the field. The controls remained symptom-free. The pathogens reisolated from the diseased tissue were again identified as Al. alternata by both morphological and molecular identification based on ITS and HIS3. This study is the first report of Al. alternata causing leaf spot on Ar. stolonifera in China and provides vital information on the pathogen for further diagnosis and management of the disease.

Anthracnose Caused by Colletotrichum spaethianum on Polygonatum odoratum var. pluriflorum in Korea.

Polygonatum odoratum var. pluriflorum (Miq.) Ohwi (Asparagaceae), commonly known as Lesser Solomon's seal, is a perennial herbaceous plant widely distributed in the temperate regions of the Northern Hemisphere. It is known for tea and contains various pharmacologically active compounds (Chang et al. 2007). In September 2021, previously unseen anthracnose was encountered on Polygonatum odoratum var. pluriflorum in Chuncheon (37°45'07''N; 127°47'45''E) and Wanju (35°38'47''N; 127°31'16''E), Korea, with a disease incidence of 20 to 30% of the inspected plants. The disease symptoms begin with leaf yellowing (chlorosis) along the margins, progressing toward the central part of the leaf. As the disease progressed, brown necrotic lesions developed, covered with small, dark dots, indicating the presence of conidiomata of Colletotrichum. The disease often led to leaf blight, resulting in concentric lesions of a periodic and concentric arrangement of conidiomata, forming circular patterns within the affected tissue. It expanded rapidly during the rainy season producing water-soaked lesions but nearly slowed down during the dry season, leaving the plant with a ragged appearance. Monoconidial isolates were obtained from five fresh samples collected in Wanju, of which a representative isolate was deposited in the Korean Agricultural Culture Collection (KACC410442), and the dried specimen was housed at the herbarium of Jeonbuk National University (JBNU0135). Morphological characteristics of the fungus were examined with fresh and naturally infected leaves. Setae (n = 30) were dark brown to nearly blackish, 45 to 172 um long, 4.1 to 6.1 µm wide at the base, and becoming narrower upwards, apex pointed, 2 to 4-septate. Conidia were 1-celled, sometimes uniseptate before germination, slightly curved, with an acute or rounded apex and a more or less truncate base, and 11.4 to 23.2 × 3.1 to 4.2 µm. Appressoria were single or in groups, dark brown, lobate, irregularly shaped, and 6.0 to 11.9 × 7.0 to 14.8 µm. Two-week-old colonies grown on PDA at 25 ℃ reached 30-35 mm in diam., initially white, turning gray with age, with cottony aerial mycelia. These morphological characteristics were in good agreement with those of C. spaethianum (Damm et al. 2009; Liu et al. 2020). To confirm the morphology-based determination, genomic DNA was extracted from KACC410442, and multi-loci sequences of the internal transcribed spacer region (ITS) rDNA, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), actin (actA), chitin synthase (CHS1), histone (HIS3) and tubulin (TUB2) genes were determined, as outlined by Cannon et al. (2012) and Damm et al. (2009). The resulting sequences obtained in this study were registered to GenBank (PP739190 for ITS, PP741985 for GAPDH, PP741986 for actA, PP741987 for CHS1, PP741988 for HIS3, and PP741989 for TUB2) and compared with other sequences on GenBank using the BLASTn search tool. The results showed 100% identity to other C. spaethianum sequences (e.g., MT611068 for ITS, MN400659 for actA, OP965007 for CHS1, OR060963 for GAPDH, PP480643 for HIS3, and OQ613727 for TUB2). In a maximum parsimony tree, the Korean isolate formed a well-supported clade (100% bootstrap value) with reference sequences of C. spaethianum. Pathogenicity was tested by spraying a conidial suspension (1×104 conidia/ml) from a two-week-old culture onto ten leaves of three potted plants, without wounding. Ten water-sprayed leaves were served as controls. The plants were maintained in a dew chamber and later moved to a greenhouse at 25 to 30 °C. After two weeks, all inoculated plants developed anthracnose symptoms, while the control plants remained symptomless. The fungus isolated from the inoculated plants was morphologically identical to that initially observed, fulfilling Koch's postulates. C. spaethianum has been known on various plant species, but mostly on the Asparagaceae, including Anemarrhena (Okorley et al. 2019), Hosta (Damm et al. 2009; Cheon and Jeon 2016), and Polygonatum (Liu et al. 2020; Ma et al. 2021). To our knowledge, this is the first report of anthracnose caused by C. spaethianum on P. odoratum var. pluriflorum in Korea, highlighting the continuous need for disease management and control in the cultivation of this plant.

A Comparison of GAPDH and ACTB As Internal Control for Gene Expression Studies in Different Cancer Cell Lines

Housekeeping genes are used as internal controls to normalize the expression of target genes in gene expression studies. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and Actin beta (ACTB) are frequently preferred as housekeeping genes in gene expression studies. Due to the general alterations in the gene expression pattern in cancer cases, the selection of the appropriate housekeeping genes for these studies are challenging. In this study, we aimed to analyze the expression of the well-known housekeeping genes GAPDH and ACTB in 6 different cancer cell lines. Furthermore, the relative gene expression of the selected target gene (Tissue inhibitor of metalloproteinases 2-TIMP2) was normalized separately using GAPDH and ACTB and the obtained results were compared with each other. Finally, the stability of GAPDH and ACTB was analyzed using the in-silico tool, Bestkeeper. As a result of the study, it is found that the expression of GAPDH and ACTB were significantly different in the Jurkat (p< 0.01), MOLT4 (p< 0.05), REH (p< 0.001) and HT29 (p< 0.001) cell lines. Based on this finding, significantly different relative target gene expression values were obtained in different cell lines depending on whether the selected housekeeping gene was GAPDH or ACTB. In addition, GAPDH was found to show less variation among the samples used in all cell lines and more stability based on Bestkeeper analysis. These results support that the appropriate housekeeping gene selection, especially in cancer cell lines, may be an effective factor in obtaining accurate results for the studies in the field provide guidance to researchers. Keywords: Cancer cell lines, Gene expression, Housekeeping genes, GAPDH, ACTB

First report of wheat leaf spot disease caused by Curvularia inaequalis in China.

Wheat (Triticum aestivum) is an economically important crop widely cultivated in China. In August 2022, brown oval leaf spots with yellow halos were observed on approximately 10% wheat seedlings over an area of about 1 hectare in Xining City, Qinghai Province, which adversely affected wheat growth and production. Six diseased leaves were collected from the field in Huangyuan county (101°69' E, 37°04' N). The 0.5 cm × 0.5 cm pieces were cut from the border between healthy and diseased regions of the sampled leaves, surface sterilized for 10 s in 75% ethanol, followed by a 1% NaClO for 90 s, and rinsed three times with distilled sterile water. The pieces of leaf tissue were dried with sterile tissue, and plated on potato dextrose agar (PDA) amended with streptomycin (0.02 g/L) and ampicillin sulfate (0.05 g/L) to eliminate bacterial contamination. The dishes were placed in an incubator at 25°C for 72 h in dark. Three isolates, WGC201, WGC202 and WGC203, were obtained by a single-spore culture method. Fungal colonies on PDA media were dark green (Fig. 1A and 1B). Conidiophores were septate and geniculate terminals, while conidia exhibited straight or slightly curved forms with four transverse septa, the central cell being notably longer and wider than the others. The size of such conidia were 27.34 µm to 40.62 µm× 11.61 µm to 15.97 µm (number = 50) (av. 32.71 µm× 13.11 µm) (Fig. 1C and 1D) (Moubasher et al. 2010). The internal transcribed spacer (ITS) region of nuclear ribosomal DNA and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene were amplified and sequenced using universal primers ITS1/ITS4 and GPDF/GPDR (White et al. 1990; Berbee et al. 1999). DNA sequences were deposited into the NCBI database (ITS, PP789629, PP801333, and PP801574; GAPDH, PP849124, PP849125, and PP849126). Phylogenetic analysis with a neighbor-joining method based on the concatenated sequences of ITS and GAPDH genes showed that the three isolates clustered within a C. inaequalis branch (Fig. 2). Based on morphological and molecular identification, the fungal isolates were identified as C. inaequalis. The pathogenicity test was conducted in a greenhouse at 25°C using a spore suspension method and three isolates were used. Conidia were produced on PDA media (25℃) for 14 days. Plates were washed with sterilized distilled water and filtered with cheese cloth. Conidial suspension was adjusted to a concentration of 1×107 conidia/mL. Fifteen healthy seedlings of a wheat cultivar Xiaoyan-6 at a 3-4 leaf stage were inoculated by evenly spraying a 100mL spore suspension. Plants inoculated with sterile water served as a control. All plants were covered with plastic bags for 3 days. At 7 days after inoculation, all pathogen-inoculated plants showed similar symptoms (brown leaf oval spots with yellow halos) with those observed in the field, while all plants inoculated with sterile water showed no symptoms (Fig. 1E and 1F). The pathogen was reisolated from the symptomatic leaves and proved to be C. inaequalis. Morphological, molecular and pathogenic results indicated that C. inaequalis is the pathogen causing wheat leaf disease in China. The results are consistent with a previous report in Azerbaijan (Özer et al. 2020). To our knowledge, this is the first report of C. inaequalis causing spot disease on wheat in China. The occurrence, spread and economic importance to different wheat cultivars of the emerging disease in China will be further investigated and evaluated.

Genome-Wide Characterization of Glyceraldehyde-3-Phosphate Dehydrogenase Genes and Their Expression Profile under Drought Stress in Quercus rubra.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is crucial in plant metabolism and responses to various abiotic stresses. In the glycolysis pathway, glyceraldehyde-3-phosphate (G3P) is oxidized to 1,3-bisphosphate glycerate (1,3-BPG) through the catalytic action of GAPDH. However, the GAPDH gene family in Quercus rubra has been minimally researched. In this study, we identified 13 GAPDH-encoding genes in Q. rubra through a bioinformatics analysis of genomic data. Evolutionary studies suggest that these QrGAPDH genes are closely related to those in Glycine max and Triticum aestivum. We conducted a comprehensive whole-genome study, which included predictions of subcellular localization, gene structure analysis, protein motif identification, chromosomal placement, and analysis of cis-acting regions. We also examined the expression of GAPDH proteins and genes in various tissues of Q. rubra and under drought stress. The results indicated diverse expression patterns across different tissues and differential expression under drought conditions. Notably, the expression of Qurub.02G290300.1, Qurub.10G209800.1, and Qrub.M241600.1 significantly increased in the leaf, stem, and root tissues under drought stress. This study provides a systematic analysis of QrGAPDH genes, suggesting their pivotal roles in the drought stress response of trees.

First Report of Colletotrichum fioriniae Causing Anthracnose on Persimmon in China.

Persimmons (Diospyros kaki Thunb.) have a longstanding history of cultivation in China. Both aesthetically pleasing and edible, they often symbolize a sweet and fulfilling life. During the summer of 2022, a severe outbreak of anthracnose was observed on the lower leaves of persimmon trees in the National Field Genebank for Persimmon (NFGP), located in Yangling, Shaanxi, China (34°17'42.80″ N, 108°04'08.21″ E). The estimated incidence rate of this disease within the NFGP was approximately 30%. The typical symptoms of the disease included the presence of irregular lesions on leaves, and oval sunken lesions on infected fruit. Under high humidity conditions, pink sticky substances appeared in the affected areas. The presence of numerous lesions led to softening and detachment of persimmon fruit. To identify the causal pathogen, 5 × 5mm samples of the diseased leaves were collected from the interface between the infected and healthy leaves. The leaves were disinfected with 70% alcohol for 20 s, followed by rinsing with sterile water. Subsequently, the leaves were immersed in 1% NaClO for 2 to 3 minutes, rinsed with sterile water three times, dried using sterile absorbent paper, and the leaf samples were then transferred onto potato dextrose agar (PDA) medium, and cultured in 25°C incubators. Once the colony reached a certain size, small pieces of hyphae were extracted from edge and transferred for purification and repeated three times. After being cultured on PDA for 7 days, the colony showed a white spongy surface with a pink-orange center. The conidia displayed a fusiform shape and were transparent, measuring 4.58 to 6.53 μm × 9.27 to 13.11 μm (n=50). The isolates share morphological similarities with Colletotrichum fioriniae. The representative isolate HY-7 was selected for molecular identification. The internal transcribed spacers (ITS) region, chitin synthase (CHS-1), actin (ACT), beta-tubulin 2 (TUB2), and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene were amplified using ITS1/4 (White et al. 1990), CHS-79F/CHS-345R (Carbone & Kohn, 1999), ACT512F/ACT (Carbone & Kohn, 1999), T1/BT2B (Glass & Donaldson 1995, O'Donnell et al., 1997), and GDF/GDR (Templeton et al. 1992), respectively. The generated sequences were deposited at GenBank under accession numbers OR878056 (ITS), OR766019 (CHS-1), OR766021(TUB2), OR766018 (ACT) and OR766020 (GAPDH). BLAST analysis revealed the sequences were 100% identical to C. fioriniae (MH865005 for ITS, JQ948953 for CHS-1, JQ949613 for ACT, JQ949943 for TUB2 and JQ948622 for GAPDH). The morphological characteristics and molecular analyses of the isolate matched the description of C. fioriniae. To fulfill Koch's postulates, the twigs and leaves of 'Fupingjianshi' in four different directions were inoculated without wounding in the field, and 10 healthy fruits were selected for wound inoculation. The concentration of conidia used for inoculation was about 1 × 106 conidia/ml, and sterilized water was used as control. The experiment was replicated three times under the same conditions. One week after inoculation, characteristic symptoms resembling those observed on the leaves of primary diseased persimmon trees appeared on the leaves and fruits. No symptoms were observed on the leaves, twigs and fruits in the control treatment. The pathogen from the artificially infected leaves and fruits were reisolated and identified as C. fiorinae based on morphological and molecular characteristics. Persimmon anthracnose is a common disease in regions where the fruit is grown, to the best of our knowledge, this is the first documented occurrence of C. fioriniae-induced anthracnose on persimmons in China, which should be paid more attentions. This report will help identify disease symptoms in the field and provides a basis for determining the occurrence, distribution, and control of C. fioriniae on persimmon leaves and fruits.

The Relationship Between GAPDH Gene Polymorphism and Risk of Acute Coronary Syndrome in South Indians with Type 2 Diabetes Mellitus.

As glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is one of the regulators of carbonyl stress, a pathogenic mechanism for diabetic complications like acute coronary syndrome (ACS), the study aimed to investigate the relationship between GAPDH gene polymorphism, GAPDH activity in red blood cell (RBC), methylglyoxal (MG) levels in plasma and ACS risk in South Indians with type 2 diabetes mellitus (T2DM). This study comprised 150 T2DM with ACS as cases and 150 T2DM without ACS as controls. The GAPDH rs1136666, rs1060620 and rs1060619 gene polymorphisms were identified by TaqMan probe assays. The RBC GAPDH activity and plasma MG levels were estimated. Cases had significantly higher plasma MG levels and lower RBC GAPDH activity than controls (P < 0.001). The distribution of rs1060620 or rs1060619 alleles and genotypes significantly differed between groups. The rs1060620 AG (OR 0.55; 95% CI 0.33-0.92; P = 0.022) or rs1060619 CT (OR 0.51; 95% CI 0.31-0.83; P = 0.007) genotype was associated with reduced ACS risk, confirmed in the over-dominant genetic model. Haplotype analyses revealed that the GAT and CGC haplotypes were associated with increased (OR 28.37; 95% CI 3.82-210.49; P = 8.51 × 10-7) and decreased (OR 0.45; 95% CI 0.24-0.86; P = 0.014) ACS risk in T2DM patients, respectively. Lower GAPDH activity was observed in the TT and CT genotypes compared to the CC genotype of rs1060619 (P < 0.001). This work established that the GAPDH rs1060620 or rs1060619 gene polymorphisms are associated with ACS risk in South Indians with T2DM.

Designing A Novel Primer Set for GAPDH Gene to Enhance Taxonomic and Phylogenetic Studies of Golovinomyces Species

Golovinomyces (Erysiphaceae, Ascomycota) is an obligate plant pathogenic group causing powdery mildew on diverse angiosperm plants, including economically significant crops. Despite advancements in the taxonomy and phylogeny of Golovinomyces species using ribosomal DNA markers (ITS and LSU), several taxonomic issues remain unresolved. Previously, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene, which exhibits higher nucleotide variation, has been proposed as an additional marker for powdery mildew species. In this study, we designed a new primer set (GoGPD-F and GoGPD-R) to improve the PCR success and efficiency of the GAPDH gene across various Golovinomyces species and dried herbarium specimens. The primers were successful in amplifying and sequencing the GAPDH gene in sixteen Golovinomyces species, including six species not previously registered in GenBank and two undescribed species. This development is a significant contribution to future research on the identification, taxonomy, and phylogeny of Golovinomyces species, offering a more robust tool for resolving existing taxonomic issues.

Identification and validation of reference genes for gene expression study using Quantitative Real-Time PCR in shallot (Allium cepa L. Aggregatum group) based on bulb development phase

Abstract. Sulistyaningsih E, Sawitri WD, Handayani VDS, Wicaksono AW, Silalahi CM, Murti RH. 2024. Identification and validation of reference genes for gene expression study using Quantitative Real-Time PCR in shallot (Allium cepa L. Aggregatum group) based on bulb development phase. Biodiversitas 25: 2645-2651. Shallot (Allium cepa L. Aggregatum group) is cultivated vegetatively using bulbs (produce many bulbs) and generatively using TSS (True Seed of Shallot) which tends to produce single bulbs. Bulb aggregation is influenced by activity of genes and the gene expression could be analyzed using quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). The qRT-PCR analysis requires reference gene data (housekeeping gene) as a comparison gene against our target gene. This study aimed to select and validate three housekeeping genes in shallot as an initial study for qRT-PCR analysis. The research flow began with the preparation of shallot 'TukTuk' leaves and bulb samples in bulb formation from bulb initial phase to mature phase. Furthermore, a specific primer design based on actin, tubulin, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene sequences were obtained from gene bank data. The results showed that the actin, tubulin, and GAPDH genes were successfully amplified and the products were 142 bp, 116 bp, and 136 bp in size, respectively and the genes were expressed almost constantly in leaves and bulbs in all phases of bulb formation. The tubulin gene had the potential as a reference gene for qRT-PCR analysis in shallot with the most consistently expressed.

First Report of Alternaria alternata Causing Leaf Spot on Catalpa bungei in China.

Catalpa bungei originates from China. It is fast-growing and possesses a vertically aligned trunk, rendering it a commendable construction material and a significant economic species. In July 2022, a serious leaf spot occurred in the LanLake farm (surveyed area of about 700 acres) in Nanyang (33°3'23" N, 112°28'50" E), Henan Province, China. The incidence rate of leaf disease reached 54% (n=100). The disease initially manifested as irregular round spots with a yellowish-brown hue, subsequently extending in all directions. Later, the lesion periphery exhibited a darkening effect, leading to yellowing. Twenty diseased leaves were randomly collected and cut into small pieces at the interfaces between infected and healthy tissues. The tissues were sterilized in a solution of 75% ethanol and 1% NaClO for 30 seconds and 1 minute, respectively. After rinsing in sterile water, the pieces were placed on potato dextrose agar (PDA) plates and incubated at 25°C for 5 days. A total of 29 purified fungal strains were acquired, exhibiting comparable phenotypes in terms of morphological characteristics. Three strains (QS1-1, QS1-2, and QS1-3) were isolated for subsequent investigations. The colony exhibited abundant aerial mycelium with shades ranging from dark green to grey-brown on the reverse side. To analyze the morphological characteristics of conidia, potato carrot agar (PCA) was used as the culture medium and incubated at 25°C with a 12-hour light/dark cycle. Conidia were obclavate or spheroidal, dark brown, with 3 to 5 transverse septa, and 1 to 4 longitudinal septa, measuring 12.4 to 36.7 × 4.4 to 9.0 μm (n=100), with conical beak lengths ranging from 0 to 4.3 μm. These morphological traits suggested that the pathogen shares similarities with the Alternaria species. The rDNA internal transcribed spacer (ITS), translation elongation factor 1-alpha gene (tef1), glyceraldehyde 3-phosphate dehydrogenase gene (gapdh), and RNA polymerase II second largest subunit (rpb2) were amplified for further molecular identification. The resultant sequences were submitted to GenBank with the following accession numbers: OR733559, OR742124, OR761873 (ITS), OR939796, OR939797, OR939798 (tef1), OR939801, OR939802, OR939803 (gapdh), and PP054846, PP054847, PP054848 (rpb2). A Phylogenetic tree was constructed of combined genes (ITS, tef1, gapdh, and rpb2) of sequences, alongside the sequences of the type strains by the neighbor-joining method. The three strains formed a clade with the strains CBS 121456 of Alternaria alternata in phylogenetic trees, being separated from other Alternaria spp. The morphological features and molecular analyses supported the strains as members of Alternaria alternata (Woudenberg et al. 2015). To validate pathogenicity, a conidial suspension (106 conidia ml-1) of all three strains was inoculated onto three healthy leaves of five seedlings, with 50 μl of inoculum absorbed with cotton balls. Another group of five plants received sterile water as a control. All plants were incubated in a climate chamber at 28°C and 90% relative humidity. Four days post-inoculation, lesions resembling natural phenomena were observed, whereas control plants showed no symptoms. Subsequent reisolation produced cultures that were morphologically and molecularly identical to the original strains, fulfilling Koch's postulates. Stem canker of C. bungei caused by Phytophthora nicotianae has been reported in China (Chang et al. 2022). This is the first report of A. alternata causing leaf spots on C. bungei in China. Further research is required on management options to control this disease and the host range still needs to be clarified for accurate disease management.

First Report of Anthracnose Caused by Colletotrichum spaethianum on Hosta longipes in Korea.

Hosta longipes (Franch. & Sav.) Matsum. (Asparagaceae) is a perennial, herbaceous plant, native to Japan and Korea (Lee et al. 2021). In Korea, the plant is used as an edible vegetable and ornamental (Kang and Ju 2015). During 2021-2022, anthracnose symptoms were observed on leaves of H. longipes with over 70% disease incidence in Wanju-gun (35°38'47''N; 127°31'16''E) and Jangsu-gun (35°35'31''N; 127°30'03''E) in Jeollabuk-do, Korea. The disease initially appeared on old leaves, gradually spreading to young ones. The symptoms were characterized as yellow to white discoloration on the upper leaf surface with black necrotic tissue in the center of the lesion. Three H. longipes samples with anthracnose symptoms were collected. From each, a monoconidial isolate was obtained and then deposited in the Korea Agricultural Culture Collection (accession Nos. KACC 410038, 410391, and 410443). The dried specimens were housed at the herbarium of Jeonbuk National University (JBNU0129, 0137) and Korea University (KUS-F33379). Conidiomata was acervular, 65 to 80 × 56 to 70 µm in diam. Setae were dark brown, 2 to 4-septate, 63 to 161 µm long, being formed on a pale brown cushion. Conidia were hyaline, smooth-walled, aseptate, slightly curved, base truncate, 3.9 to 5.1 × 17 to 23 µm. The appressoria were solitary, olivaceous-brown, ovoid or irregularly shaped. Two-week-old colonies grown on PDA at 25 ℃ were 20-25 mm in diameter, initially white, then turned gray with age, with cottony aerial mycelium. The morphological and cultural characteristics of the fungus were consistent with those of Colletotrichum spaethianum (Allesch.) Damm, P.F. Cannon & Crous (Damm et al. 2012). To confirm morphology-based identification, the nucleotide sequences of the internal transcribed spacer (ITS) rDNA region, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), actin (actA), chitin synthase (CHS1), histone (HIS3) and tubulin (TUB2) genes were determined for KACC410443, as outlined by Cannon et al. (2012) and Damm et al. (2009). The resulting sequences were submitted into GenBank (PP000829 for ITS, PP133094 for GAPDH, PP083418 for actA, PP133091 for CHS1, PP133097 for HIS3, and PP133099 for TUB2) and compared with reference sequences in GenBank using BLASTn search tool. The results showed a 100% match with C. spaethianum (MT611068), C. incanum (MN880260) and C. truncatum (EF016303) for ITS, and 100% with C. spaethianum for GAPDH (MH370513), actA (MH045677), CHS1 (MH370520), HIS3 (MH985161), and TUB (MH456884). Pathogenicity was tested by inoculating conidial suspension (1 ×104 cfu/ml) of three-week-old fungal colonies of the isolate KACC410443 onto leaves of three healthy potted plants. Prior to inoculation, leaves were deliberately wounded by pinpricking with a sterilized needle. Two wounded but non-inoculated plants served as controls. Plants were maintained in a greenhouse at 25 to 30 °C. Inoculated plants developed anthracnose symptoms after eight days, while the control plants remained symptomless. The fungus isolated from the inoculated plants was morphologically identical to that observed initially, fulfilling Koch's postulates. To our knowledge, there is no previous record of C. spaethianum on H. longipes, although C. spaethianum has been reported to infect another species, H. plantaginea (Cheon and Jeon 2016). This is the first report of this fungus on H. longipes in Korea (KSPP 2024) and globally (Farr and Rossman 2024). The anthracnose on this ornamental plant can be considered a new severe threat to planting strategies in gardens.

First Report of White Mold Caused by Sclerotinia sclerotiorum on Echeveria gigantea in Mexico.

Echeveria gigantea, native of Mexico (Reyes et al. 2011), holds economic importance as it is marketed as a potted plant and cut flower due to its drought-tolerant capabilities and aesthetic appeal. In September 2023, a field sampling was conducted at the Research Center in Horticulture and Native Plants (18°55'56.6" N, 98°24'01.5" W) of UPAEP University. Echeveria gigantea cv. Quilpalli plants with white mold symptoms were found in an area of 0.5 ha, with an incidence of 40% and severity of 50% on severely affected stems. The symptoms included chlorosis of older foliage, necrosis at the base of the stem, and soft rot with abundant white to gray mycelium and abundant production of irregular sclerotia resulting in wilted plants. The fungus was isolated from 30 symptomatic plants. Sclerotia were collected, sterilized in 3% NaOCl, rinsed with sterile distilled water (SDW), and plated on Potato Dextrose Agar (PDA) with sterile forceps. Subsequently, a dissecting needle was used to place fragments of mycelium directly on PDA. Plates were incubated at 23 °C in darkness. A total of 30 isolates were obtained using the hyphal-tip method, one from each diseased plant (15 isolates from sclerotia and 15 from mycelium). After 6 days, colonies had fast-growing, dense, cottony-white aerial mycelium forming irregular sclerotia of 3.67 ± 1.13 mm (n=100). Each Petri dish produced 32.47 ± 7.5 sclerotia (n=30), after 12 days. The sclerotia were initially white and gradually turned black. The isolates were tentatively identified as Sclerotinia sclerotiorum based on morphological characteristics (Saharan and Mehta 2008). Two isolates were selected for molecular identification. Genomic DNA was extracted using the CTAB protocol. The ITS region and the glyceraldehyde 3-phosphate dehydrogenase (G3PDH) gene were sequenced for two randomly selected isolates (White et al. 1990; Staats et al. 2005). The ITS and G3PDH sequences of the SsEg9 isolate were deposited in GenBank (ITS-OR816006; G3PDH-OR879212). BLAST analysis of the partial ITS (510 bp) and G3PDH (915 bp) sequences showed 100% and 99.78% similarity to S. sclerotiorum isolates (GenBank: MT101751 and MW082601). Pathogenicity was confirmed by inoculating 30 120-day-old E. gigantea cv. Quilpalli plants grown in pots with sterile soil. Ten sclerotia were deposited at the base of the stem, 10 mm below the soil surface. As control treatment, SDW was applied to 10 plants. The plants were placed in a greenhouse at 23 °C and 90% relative humidity. After 16 days, all inoculated plants displayed symptoms similar to those observed in the field. Control plants did not display any symptoms. The fungus was reisolated from the inoculated stems, fulfilling Koch's postulates. The pathogenicity tests were repeated three times. Recently S. sclerotiorum has been reported causing white mold on cabbage in the state of Puebla, Mexico (Terrones-Salgado et al. 2023). To the best of our knowledge, this is the first report of S. sclerotiorum causing white mold on E. gigantea in Mexico. Information about diseases affecting this plant is very limited, so this research is crucial for designing integrated management strategies and preventing spread to other production areas.

Identification and validation of stable reference genes for RT-qPCR analyses of Kobresia littledalei seedlings

BackgroundKobreisa littledalei, belonging to the Cyperaceae family is the first Kobresia species with a reference genome and the most dominant species in Qinghai-Tibet Plateau alpine meadows. It has several resistance genes which could be used to breed improved crop varieties. Reverse Transcription Quantitative Real-Time Polymerase Chain Reaction (RT-qPCR) is a popular and accurate gene expression analysis method. Its reliability depends on the expression levels of reference genes, which vary by species, tissues and environments. However, K.littledalei lacks a stable and normalized reference gene for RT-qPCR analysis.ResultsThe stability of 13 potential reference genes was tested and the stable reference genes were selected for RT-qPCR normalization for the expression analysis in the different tissues of K. littledalei under two abiotic stresses (salt and drought) and two hormonal treatments (abscisic acid (ABA) and gibberellin (GA)). Five algorithms were used to assess the stability of putative reference genes. The results showed a variation amongst the methods, and the same reference genes showed tissue expression differences under the same conditions. The stability of combining two reference genes was better than a single one. The expression levels of ACTIN were stable in leaves and stems under normal conditions, in leaves under drought stress and in roots under ABA treatment. The expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression was stable in the roots under the control conditions and salt stress and in stems exposed to drought stress. Expression levels of superoxide dismutase (SOD) were stable in stems of ABA-treated plants and in the roots under drought stress. Moreover, RPL6 expression was stable in the leaves and stems under salt stress and in the stems of the GA-treated plants. EF1-alpha expression was stable in leaves under ABA and GA treatments. The expression levels of 28 S were stable in the roots under GA treatment. In general, ACTIN and GAPDH could be employed as housekeeping genes for K. littledalei under different treatments.ConclusionThis study identified the best RT-qPCR reference genes for different K. littledalei tissues under five experimental conditions. ACTIN and GAPDH genes can be employed as the ideal housekeeping genes for expression analysis under different conditions. This is the first study to investigate the stable reference genes for normalized gene expression analysis of K. littledalei under different conditions. The results could aid molecular biology and gene function research on Kobresia and other related species.

First Report of Gray Mold Caused by Botrytis cinerea on Dragon Fruit (Hylocereus undatus) in Mexico.

The dragon fruit is native of Mexico, and Puebla is the third-largest producing state (SIAP 2023). In June 2023, field sampling was conducted in El Paraíso, Atlixco (18° 49' 5.275" N, 98° 26' 52.353" W), Puebla, Mexico. The mean temperature and relative humidity were 20 °C and 75% for seven consecutive days. Dragon fruits cv. 'Delight' close to harvest with gray mold symptoms were found in a commercial area of 2 ha, with an incidence of 35 to 40% and an estimated severity of 75% on infected fruit. The symptoms included necrosis at the apex, which later spread throughout the fruit, along with a soft, black rot covered in abundant mycelium and sporulation. The fungus was isolated from 40 symptomatic fruits by disinfesting pieces of necrotic tissue with 3% NaClO for one minute, rinsing with sterile distilled water (SDW), plating on Petri dishes with potato dextrose agar, and incubating at 25 °C in the dark. One isolate was obtained from each diseased fruit by the hyphal-tip method. The colonies were initially white with a growth rate of 1.15-1.32 cm per day and turned gray after 10 days; the mycelium was dense and aerial. Spherical and irregular sclerotia were formed, measuring 0.9-1.4 × 0.6-1.1 mm (n = 100). Each Petri dish produced 56-278 sclerotia (n = 40) after 11 days; these were initially white and gradually turned dark brown. Brown to olive conidiophores were straight, septate, and branched, measuring 1075-1520 × 10-21 μm, with elliptical hyaline to light brown conidia of 6.6-11.5 × 5-8.1 μm (n=100). The isolates were tentatively identified as Botrytis cinerea based on morphological characteristics (Ellis 1971). Two representative isolates were chosen for molecular identification and genomic DNA was extracted by the CTAB protocol. The ITS region and the heat shock protein (HSP60), RNA polymerase binding II (RPB2) and glyceraldehyde 3-phosphate dehydrogenase (G3PDH) genes were sequenced (White et al. 1990; Staats et al. 2005). The sequences of a representative isolate (BcPh5) were deposited in GenBank (ITS-OR582337; HSP60-OR636622; RPB2-OR636623; and G3PDH-OR636621). BLAST analysis of the partial sequences of ITS (479 bp), HSP60 (1006 bp), RPB2 (1126 bp), and G3PDH (907 bp) showed 100% similarity to B. cinerea isolates (GenBank: KM840848, MH796663, MK919495, MF480679). Phylogenetic analysis confirmed that BcPh5 clustered with B. cinerea strains. Pathogenicity was confirmed by inoculating the non-wounded surface of 20 detached dragon fruits cv. 'Delight' using the BcPh5 isolate by depositing 20 μl of a 105 conidia/ml suspension with a sterile syringe. The fruits were placed on the rim of a plastic container and inserted in a moisture box with 2 cm of water at the bottom. The box was covered with a plastic sheet to maintain humidity. Control fruits were inoculated with SDW. The inoculated fruits became covered with abundant white to gray mycelium, and soft rot developed within eight days, while no symptoms were observed on the controls. The fungus was re-isolated from the inoculated fruits as described above, fulfilling Koch's postulates. The pathogenicity tests were repeated three times. Gray mold caused by B. cinerea was also recently reported in Mexico on pomegranate (Hernández et al. 2023) and rose apple (Isodoro et al. 2023). As far as we know, this is the first report of B. cinerea causing gray mold on dragon fruit in Mexico. This research is essential for designing integrated management strategies against gray mold on dragon fruits.

First Report of Alternaria Leaf Spot Caused by Alternaria alternata on Ulmus parvifolia in Jiangsu, China.

Ulmus parvifolia Jacq. is an important tree with ornamental value, which is widely planted in Hebei and southern regions of China. In September 2022, a leaf spot symptom was observed on about approximately 20% U. parvifolia seedlings growing a tree farm (20000 m2) of Jiangsu Academy of Forestry (118°45'57.30″E, 31°51'27. 94″N). Gray to black spots appeared on leaves of seedlings. Five diseased leaves were collected from five different seedlings. The pieces were excised from the margins between healthy and diseased tissues, surface sterilized in 75% ethanol for 30 s and then in 1.5% NaClO for 90 s, rinsed three times in sterilized distilled water, plated on potato dextrose agar (PDA) and incubated at 25℃ in the darkness. Pure cultures were obtained by monosporic isolation. Six isolates with identical morphological features and the internal transcribed spacer (ITS) sequences were obtained (the isolate rate of 67%), and identified as Alternaria sp. A representative isolate, LY-1-1 was used for the further study. The colony of LY-1-1, growing on PDA was cotton-like and brown in color with gray-white aerial hyphae on their surfaces, and its reverse was dark grey. The conidia were ovate to pear-shaped, brown in color, with 1 to 4 transverse septa and 0 to 1 longitudinal septa, parietal cells extending into the beak, and measured 7.1 to 12.5×3.8 to 7.1 µm (n=35). These characteristics were consistent with the description of Alternaria sp. (Simmons 2007). The regions of ITS, large subunit ribosomal RNA (LSU), small subunit ribosomal RNA (SSU), anonymous region OPA10-2 genomic sequence (OPA10-2), Alternaria 1 major allergen (Alta1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1-alpha (TEF1) genes (GenBank Accession No. OR047916, OR051904, OR047919, OR061065, OR061063, OR061064, and OR061062, respectively) were amplified (White et al. 1990; Woudenberg et al. 2015) and sequenced. These obtained sequences showed 99.86-100% similarity to the ITS (514/515 bp) of A. alternata isolate SPM-2 (OR378581), LSU (801/801 bp) of isolate B9 (OR366492), SSU (1019/1020 bp) of strain LSU0766 (MT000349), OPA10-2 (632/633 bp) of strain 19-1 (MN185000), Alta1 (470/470 bp) of strain CMML21-73 (OQ831518), GAPDH (177/177 bp) of isolate CS36-3 (KY814638), and TEF1 (240/240 bp) of isolate SY-6 (OP980553). A neighbor-joining phylogenetic tree was generated by combining all sequenced loci in MEGA7. The isolate LY-1-1 clustered in the A. alternata clade with 98% bootstrap support. Three 3-month-old U. parvifolia seedlings were wounded with a sterile needle and inoculated with 20 μL conidia suspension (1×106 spores/mL) on the left sides of leaves. Inoculation on the right side with 20 µL of sterile water was treated as a control. All inoculated plants were incubated in a greenhouse at 25℃, 80% relative humidity, and a 12-h light/dark cycle. The experiment was repeated three times. After 5 days of inoculation, typical gray to black spots were found on the left sides of all inoculated leaves, and the control did not have any leaf spot symptoms. Subsequently, the same fungus was reisolated and identified based on morphological and molecular traits, fulfilling Koch's postulates. The A. alternata has been reported to cause leaf spot on pecan (Wu et al. 2020), fruit spot on olive (Alam et al. 2019) and fruit rot on lychee (Alam et al. 2017). However, there are no other reports of A. alternata on U. parvifolia in the world. Thus, this study provides an important reference for the biology, epidemiology of A. alternata.

First Report of Leaf Spot on Taraxacum mongolicum Caused by Alternaria solani in China.

Taraxacum mongolicum is a perennial herbaceous plant in the family Asteraceae, with a high edible and medicinal value and is widely planted in China. In August 2022, leaf spots were found on T. mongolicum in Tianjiazhai Town, Xining City, Qinghai Province, China (36°27'17.65″N, 101°47'19.65E, elevation: 2,408 m). The plants exhibited round or irregular brown spots, and the centers of some of the spots were gray (Fig. S1A). An investigation was performed over a hectare area, and the incidence of leaf spot reached 15%-30%, seriously affecting the quality and yield of T. mongolicum. Eleven T. mongolicum leaf spot samples were collected. To isolate the pathogenic fungus, approximately 0.5 cm×0.5 cm pieces of tissues were obtained using sterile scissors from the junction of infected and healthy tissues. The symptomatic leaves were surface-disinfected with 3% NaClO for 1.5 min and washed three times with sterile water. The disinfected pieces were dried and placed on water agar plates in an incubator for 2 days at 25°C. Subsequently, the leaf surface exhibited conidiophores and conidia. Eleven isolates were obtained by single spore isolation. The sparse aerial mycelia were dark grey to black brown in color on potato dextrose agar (PDA) (Fig. S2A), and produced dark, multi-septate conidia with 7-11 transverse septa and 1-2 longitudinal septa (Fig. S2C). Conidia with one or two beaks were long-ovoid, with an average length and width of 103.4 × 21.2 μm, and 80.7 × 3.9 μm of the beaks. One hundred and ten conidia were measured. The identification of 11 isolates was confirmed by multilocus sequence analyses of the internal transcribed spacer of ribosomal DNA (rDNA ITS) (White et al. 1990), and the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (Xu et al. 2022), actin (ACT) (Yang et al. 2020), histone 3 (HIS3) (Zheng et al. 2015), translation elongation factor 1-α (TEF1-α) (Carbone. 1999), and the second largest subunit of RNA polymerase II (RPB2) (Liu et al. 1999) genes. The sequences of all the isolates were deposited in Genbank (NCBI Accession Nos. ITS: OR105029-OR105039, ACT: OR135220-OR135230, GAPDH: OR135231-OR135241, HIS3: OR122992-OR123002, TEF1-α: PP055972-PP055982, and RPB2: PP055983-PP055993), and the sequence similarity of ITS, ACT, GAPDH, HIS3，TEF1-α and RPB2 were 100%, 98%, 100%, 99%, 100%, and 99% to the sequences of Alternaria solani, respectively. Combined sequences of ITS, GAPDH, TEF1-α, and RPB2 genes were concatenated and a maximum parsimony tree was constructed with PAUP* v. 4.0 alpha. The results indicated that 11 isolates were clustered together with A. solani (Fig. S2D). Therefore, 11 isolates were identified as A. solani based on their morphological and molecular characteristics. Eleven isolates were inoculated on their host to perform Koch's postulates. The isolates were grown on PDA for six days. Healthy one month old T. mongolicum seedlings were planted in 10 cm flowerpots (Fig. S1B) or the seedlings were moved to Petri dish (Fig. S1C), and their leaves were inoculated with 5 mL of hyphae suspension by smearing method. In addition, seedlings of the same age were treated with sterile water to serve as the control. The inoculated seedlings were moved into an artificial climatic box at 25℃, relative humidity was 70%, with 12 h light/12 h dark condition. Totally 80 seedlings were inoculated with isolates and 15 were used as the control. After 7 days, similar symptoms were observed on the plants inoculated with isolates, while control plants did not produce symptoms. The assays were conducted three times. Furthermore, isolates were re-isolated from the symptomatic leaves, and the colonial morphology was the same as the original isolates (Fig S2 A and B). The recovered isolates were identified as A. solani by amplifying and sequencing a portion of the HIS3 gene. Alternaria solani has been previously reported to cause early blight of potato and other Solanum crops (van der Waals et al. 2004; Zheng et al. 2015). To our knowledge, this is the first report of A. solani causing leaf spot of T. mongolicum in China. This disease must be considered in management practices, and our finding provided a basis for disease prevention and management.

First Report of Sclerotinia Rot Caused by Sclerotinia sclerotiorum on Artemisia capillaris in China.

Artemisia capillaris (Asteraceae) is an annual herb found in ˃10 provinces in China. It is cultivated on ˃670 ha, with annual production around 2,500 tons. Its shoot is used in traditional Chinese medicine (Liu et al. 2021). From April to May 2023, Sclerotinia rot symptoms were seen at the Institute of Medicinal Plant Development (40.04°N, 116.28°E), Beijing, China. Disease incidence was up to 10% in the field through investigation of 300 plants. Initial symptoms were irregular tan-brown lesions (0.5 to 5.0 mm) that expended to circumferential necrosis on the roots and basal stem, aerial mycelia and sclerotia were developed on them. The leaves and stem tips were withered and droopy in severe cases. Twelve symptomatic primary roots of 12 plants from two sites were cut into 5 × 5 mm pieces, surface sterilized with 75% ethanol for 30 s and 5% NaClO for 60 s, rinsed with distilled water for three times, dried with sterile filter paper, put on potato dextrose agar (PDA), and incubated at 25°C in the dark for 2 days. Two Sclerotinia-like isolates were obtained using the hyphaltip method. White aerial mycelia were sparse and appressed for isolate YC1-3 and dense for isolate YC1-7. After incubated at 25°C in the dark for 15 days, 10 to 25 sclerotia were developed near the colony margin. Sclerotia of isolate YC1-3 were 1.0 to 3.9 × 1.2 to 4.5 (mean 1.8 × 2.2) mm (n = 60), ovoid or arc-shaped. Sclerotia of isolate YC1-7 were 1.5 to 3.4 × 2.7 to 9.2 (mean 2.3 × 4.3) mm (n = 60), ovoid, dumbbell shaped or curved. The isolates were identified as Sclerotinia sclerotiorum based on morphology (Maas 1998). To further identify the pathogens, molecular identification was performed with isolates YC1-3 and YC1-7. DNA of the two isolates were extracted by the cetyltrimethylammonium bromide (CTAB) method. Polymerase chain reaction was performed with primers ITS1/ITS4 for the internal transcribed spacer (ITS) region (Choi et al. 2020; White et al. 1990) and primers G3PDHfor/G3PDHrev for the glyceraldehyde 3-phosphate dehydrogenase (G3PDH) gene (Garfinkel. 2021). BLAST search analysis revealed that the ITS sequence (GenBank OR229758 and OR229762) was ≥99% similar to S. sclerotiorum (MN099281, MZ379265, KX781301, etc.), and the G3PDH sequence (OR778388 and OR761975) was too (MZ493894, JQ036048, OQ790148, etc.). Phylogenetic trees were computed with ITS and G3PDH sequences using the Maximum Likelihood in MEGA 11. Nine two-month-old seedlings of A. capillaris were used to test pathogenicity. The epidermis layer of each primary root was slightly wounded (2 × 2 mm, 1 mm deep) using a sterile dissecting blade. Three plants were inoculated with mycelial plugs (5 mm in diameter) of YC1-3 and YC1-7 that cultured on PDA for 7 days. Control plants were inoculated with sterile PDA plugs. All seedlings were then incubated at 25oC and 90% relative humidity. After isolate YC1-7 inoculation 3 days and isolate YC1-3 inoculation 5 days, inoculated roots had symptoms like those in the field, controls had no symptoms. S. sclerotiorum was consistently re-isolated from diseased roots, fulfilling Koch's postulates. Diseases caused by S. sclerotiorum have been reported threatens several important economical crops (Marin and Peres 2020; Guan et al. 2022). To our knowledge, this is the first report of S. sclerotiorum causes Sclerotinia rot on A. capillaris. To avoid of significant economic losses, it is urgent to establish an effective disease-management strategy.

First Report of Colletotrichum gloeosporioides Causing Anthracnose on Peanut in Chongqing, China.

In July 2022, dieback and discoloration were detected on infected stems of peanut in Qijiang District of Chongqing (106.56°E,29.41°N), China, with an incidence up to 5%. These peanut stems had disease symptoms typical of anthracnose with irregular gray-brown spots with dark brown edges, sunken, and necrotic. High temperature and high humidity were favorable for the growth of the pathogen. To isolate the pathogen, we collected 10 typical infected peanuts and cut one piece from each of symptomatic stems, surface sterilized with 0.5% NaClO for 1 min, and 75% ethanol for 30 s, then rinsed three times with sterile distilled water and dried on sterilized filter paper. These pieces were incubated on potato dextrose agar (PDA) at 25°C in the dark. Pure cultures were obtained from hyphal tips of each colony. It was found that isolates with the same colony morphology were isolated from each infected stem. A representative isolate (L7) was used for morphological characterization, molecular analysis, phylogenetic analysis, and pathogenicity tests. The colonies appeared white to gray, with white margins and aerial hyphae, and the reverse of the colonies was gray to brown. Conidia were cylindrical, aseptate, with obtuse to slightly rounded ends, 13.4 to 18.8 × 4.2 to 5.8 μm (n=50). Morphological characteristics were generally consistent with those of Colletotrichum gloeosporioides species complex (Cannon et al., 2012). For molecular identification, genomic DNA was extracted using a CTAB method and partial sequences of β-tubulin (TUB2), actin (ACT) genes, chitin synthase (CHS) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes were amplified and sequenced using primers T1/T2, ACT-512F/ACT-783R, CHS-79F/CHS-345R, and GDF1/GDR1, respectively (Damm et al., 2012; Dowling et al., 2020). Using the BLAST, TUB2, ACT, CHS and GAPDH gene sequences (GenBank accession No. OR714793, OP168707, OP168708 and OR714794, respectively) were100% (429 bp out of 429 bp), 99.22% (256 bp out of 258 bp), 99.64% (276 bp out of 277 bp) and 100% (253 bp out of 253 bp) identical to C. gloeosporioides CBS:112999 (JQ005587, JQ005500, JQ005326, and JQ005239), respectively. Using Neighbor-Joining algorithm, phylogenetic analysis was conducted based on the concatenated sequences of published TUB2, ACT, CHS and GAPDH genes. The identified isolate (L7) was closely related to C. gloeosporioides. To evaluate pathogenicity, the stems of ten peanut (Zhonghua12) seedlings (2 weeks) were wounded with a sterile toothpick and mycelial plugs (5 mm in diameter) or 20 μl of conidial suspension (105/ml) were inoculated. Non-colonized agar plugs or 20 μl of sterile distilled water were treated as control. After inoculation, the peanuts were kept in a moist chamber at 28°C with 80% humidity in the dark for 24 h, and subsequently transferred to the moist chamber with 12 h light and darkness cycle for 6 days, similar symptoms were observed on all inoculated peanuts. Controls remained asymptomatic. C. gloeosporioides was reisolated from the diseased stems and confirmed using morphological features and sequence analysis of TUB2, ACT, CHS and GAPDH. Anthracnose caused by C. truncatum and C. fructicola has been reported on peanut leaves in China (Gong et al., 2023; Yu et al., 2019). To our knowledge, this is the first report of anthracnose on peanut stem caused by C. gloeosporioides in Chongqing. Our report will provide crucial information for studying on epidemiology and management of this disease.

First Report of White Mold Caused by Sclerotinia sclerotiorum on Cabbage in Mexico.

The state of Puebla is the main producer of cabbage (Brassica oleracea var. capitata) in Mexico, with an area of approximately 1,858 ha (SIAP 2023). In April 2023, a field sampling was conducted in the San Luis Ajajalpan, Tecali de Herrera (18°55.57'N, 97°55.607'W), Puebla, Mexico. The average temperature was 24°C and the relative humidity was 95% for five consecutive days. Cabbage plants cv. 'American Taki San Juan' close to harvest, with head rot symptoms were found in a commercial area of approximately 3 ha, at an estimated incidence of 35 to 45%. More than 70% of the leaves were symptomatic on severely affected plants. Typical symptoms included chlorosis of older foliage, soft rot with abundant white to gray mycelium, and abundant production of large and irregularly-shaped sclerotia. The fungus was isolated from 30 symptomatic plants. Sclerotia were collected from symptomatic heads, surface sterilized in 3% NaOCl, rinsed twice with sterile distilled water, and plated on Potato Dextrose Agar (PDA) with sterile forceps. Subsequently, a dissecting needle was used to place fragments of mycelium directly on PDA. Plates were placed in an incubator at 25°C in the dark. A total of 30 representative isolates were obtained by the hyphal-tip method, one from each diseased plant (15 isolates from sclerotia and 15 from mycelial fragments). After 8 days, colonies had fast-growing, dense, cottony-white aerial mycelium forming irregular sclerotia of 3.75 ± 0.8 mm (mean ± standard deviation, n=100). Each Petri dish produced 14-25 sclerotia (mean = 18, n = 50), after 10 days. The sclerotia were initially white and gradually turned black. The isolates were identified as Sclerotinia sclerotiorum based on morphological characteristics (Saharan and Mehta 2008). Two representative isolates were chosen for molecular identification, and genomic DNA was extracted by a CTAB protocol. The ITS region and the glyceraldehyde 3-phosphate dehydrogenase (G3PDH) gene were sequenced for two isolates (White et al. 1990; Staats et al. 2005). The ITS and G3PDH sequences of a representative isolate (SsC.1) were deposited in the GenBank (ITS- OR286628; G3PDH- OR333495). BLAST analysis of the partial sequences ITS (509 bp) and G3PDH (915 bp) showed 100% similarity to S. sclerotiorum isolates (GenBank: MT436756.1 and OQ790148). Pathogenicity was confirmed by inoculating 10 detached cabbage heads of 'American Taki San Juan', using the SsC.1 isolate, according to Sanogo et al. (2015). Heads were placed on the rim of a plastic container and inserted in a moisture box with 2 cm of water on its bottom. The box was covered with a plastic sheet to maintain humidity. The control plants were inoculated with a plug of noncolonized PDA. The inoculated cabbages were covered with white to gray mycelia and abundant sclerotia within 10 days, whereas no symptoms were observed on non-inoculated controls. The fungus was re-isolated from the inoculated cabbages as described above, fulfilling Koch's postulates. The pathogenicity tests were repeated three times. White mold caused by S. sclerotiorum on Brussels sprouts was recently reported in Mexico (Ayvar-Serna et al. 2023). In 2015, S. sclerotiorum was reported on cabbage in New Mexico, causing head rot (Sanogo et al. 2015). To our knowledge, this is the first report of S. sclerotiorum causing white mold on cabbage in Mexico. This research is essential for designing management strategies and preventing spread to other production areas.