Plant disease最新文献

{"title":"Genomic Epidemiology of <i>Erwinia amylovora</i> Strains That Caused the Fire Blight Outbreak in Korea.","authors":"Ju Yeon Song, Seong-Jin Lee, Moon Nam, Jong-Ho Lee, Eun-Jin Choi, Ye Ram Cho, Boyoung Lee, Jihyun F Kim","doi":"10.1094/PDIS-11-24-2420-RE","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2420-RE","url":null,"abstract":"<p><p>Fire blight, a devastating bacterial disease affecting rosaceous plants such as apples and pears, is caused by <i>Erwinia amylovora</i>. The disease, known for its rapid spread and destructive potential, can lead to severe symptoms and often result in the death of infected plants. In Korea, the observation of <i>E. amylovora</i> was first recorded in 2015, and subsequent dissemination has been noted across the peninsula. We previously determined the genomic characteristics of five Korean <i>E. amylovora</i> strains isolated in 2015, demonstrating a close phylogenetic relationship to a North American lineage. Based on these results, we have now sequenced a collection of 92 <i>E. amylovora</i> genomes from various fire blight cases in Korea spanning from 2016 to 2018. Through the population genomic approach, we explored the genetic diversity among the isolates. Our comprehensive genomic assessment facilitated the reconstruction of phylogenetic relationships, the correlation of genetic and spatial distances, and the inference of the most recent common ancestor of Korean <i>E. amylovora</i>. We conclude that <i>E. amylovora</i> was introduced to Korea several years before the first disease outbreak. Genomic insights obtained from our investigation will be invaluable for understanding the genetic characteristics, geographic spread and evolutionary dynamics of Korean <i>E. amylovora</i>.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143053172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leveraging Artificial Intelligence to Develop a Decision-Support Tool for Visual Symptom Assessment of Grapevine Leafroll and Red Blotch Diseases.","authors":"Sarah Lewis MacDonald, Tom Shapland, Hannah G Fendell-Hummel, Malcolm B Hobbs, Jennifer K Rohrs, Monica L Cooper","doi":"10.1094/PDIS-09-24-2048-RE","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-2048-RE","url":null,"abstract":"<p><p>The timely detection of viral pathogens in vineyards is a critical aspect of management. Diagnostic methods can be labor-intensive and may require specialized training or facilities. The emergence of artificial intelligence (AI) has the potential to provide innovative solutions for disease detection but requires a significant volume of high-quality data as input. With that purpose, we partnered with wine grape growers to collect a robust dataset of verified images. We used those images to train an AI model and develop a handheld application as a decision-support tool for grapevine leafroll and red blotch diseases. The tool allows users to scan a grapevine canopy with a mobile device and view a confidence reading describing the likelihood that the imaged vine has visual symptoms consistent with leafroll, red blotch, or a healthy vine. The 86% accuracy under field conditions and generally positive user experience suggest there is potential for the trained use of AI as an investigative tool to quickly assess visual symptoms associated with these grapevine diseases.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143053174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating oomycete pathogen and community responses to chemical- and Slow Sand Filtration-based water treatment strategies to enable water recycling in nursery production systems.","authors":"Johanna Del Castillo Múnera, Justine Beaulieu, Neelam Redekar, Claudia Delgado, Joyce L Eberhart, Jennifer L Parke, Samantha Hasselhoff, Mengjun Hu, Cassandra L Swett","doi":"10.1094/PDIS-12-23-2738-RE","DOIUrl":"https://doi.org/10.1094/PDIS-12-23-2738-RE","url":null,"abstract":"<p><p>While recycling irrigation water can reduce water use constraints and costs in nurseries, adoption is hindered by the associated risk of recirculating and spreading waterborne pathogens. To enable regional water re-use, this study assessed oomycete re-circulation risks and recycled water treatment efficacy at organismal and community scales. In culture-based analysis of recycled pond water at two Mid-Atlantic nurseries across three years, diverse oomycetes (12+ species) were detected using culture-based analysis, with Phytopythium helicoides as the dominant species; MiSeq analysis detected eight of these species, plus 24 additional taxa. Oomycete contamination risk and detection abilities in recycled water was highest in fall and/or spring based on species richness (P = 0.001). Four species, Pythium oopapillum, Pythium aff. diclinum, Phytophthora cryptogea-complex and Phytopythium helicoides were pathogenic to seedlings (90% damping off) and mature chrysanthemum plants, causing decline in more plants than negative controls (P = 0.025)-these species thus represented the known pathogen targets for recaptured water treatment. Slow Sand Filtration (SSF) of recaptured water resulted in an 85% or greater reduction in oomycete recovery from baits across months, although detection in greenhouse water following treatment indicated re-introduction challenges. MiSeq analysis indicated that SSF altered relative species abundances, which decreased for two species and increased for three species, including one putative pathogen, post-SSF (P < 0.05). Chlorine treatment reduced recovery of oomycetes from baits by at least 75%, although diversity increased, as did relative abundance of several species including one putative pathogen (P < 0.05). Together these results indicate that SSF and chlorination have potential efficacy in enabling irrigation water recycling in nursery production, although system modifications are needed to improve treatment efficacy and prevent pathogen re-introduction post-treatment.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143053162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aggressiveness and phylogenetic relationship of <i>Fusarium oxysporum</i> associated with crown and root rot in pyrethrum plants.","authors":"Yuzhu Liu, Niloofar Vaghefi, Alexander Idnurm, Peter Kevin Ades, Paul William James Taylor","doi":"10.1094/PDIS-12-24-2609-SR","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2609-SR","url":null,"abstract":"<p><p>In Australia, pyrethrum (Tanacetum cinerariifolium) cultivation provides a significant portion of the global supply of natural insecticidal pyrethrins. However, crown and root rots, along with stunted plant growth and plant loss during winter, are significant issues affecting certain sites. Several isolates of the Fusarium oxysporum species complex (FOSC) have been identified as causal agents of crown and root rot in pyrethrum, highlighting these as key pathogens contributing to this decline. However, the genetic and pathogenic diversity of the FOSC impacting pyrethrum is unclear. This study isolated F. oxysporum consistently from symptomatic and asymptomatic field-grown pyrethrum plant tissues, identified through morphological and multigene phylogenetic analyses. Phylogenetic analyses of partial gene sequences of calmodulin (cmdA), RNA polymerase II second largest subunit (rpb2), translation elongation factor 1-alpha (tef1-α) and β-tubulin (tub2) resolved the placement of these isolates within the context of different published FOSC taxonomies and revealed notable genetic diversity among the isolates. Glasshouse experiments effectively reproduced the crown and root rot symptoms observed in field conditions, demonstrating a similar level of aggressiveness among F. oxysporum isolates from pyrethrum plants. The results indicate the importance of soil-borne disease management to reduce yield decline in pyrethrum fields and will help with the selection of aggressive isolates for resistance screening of pyrethrum varieties.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143053159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crop rotation effects on the population density of soybean soilborne pathogens under no-till cropping system.","authors":"Chuntao Yin, Nathan Lahr, Apurba Sutradhar, Shannon Osborne, R Michael Lehman, Sharon Schneider","doi":"10.1094/PDIS-09-24-1953-RE","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1953-RE","url":null,"abstract":"<p><p>Soilborne diseases are persistent problems in soybean production. Long-term crop rotation can contribute to soilborne disease management. However, the response of soilborne pathogens to crop rotation is inconsistent, and rotation efficacy is highly variable. Selection of proper crop plants and crop sequences for disease management is needed. In this research, the effects of crop rotation on soybean soilborne pathogens were evaluated in a long-term no-till crop rotation field trial in South Dakota. Five rotation treatments were evaluated in this field trial, including corn-soybean (CS; Zea mays L., <i>Glycine max</i> (L.) Merr.), corn-soybean-spring wheat-pea (CSSwP; wheat: <i>Triticum aestivum</i> L., pea: <i>Pisum sativum</i> subsp. <i>arvense</i> (L.) Asch.), corn-soybean-spring wheat-sunflower (CSSwSf; sunflower: <i>Helianthus annus</i> L.), corn-oat-winter wheat-soybean (COWwS; oat: <i>Avena sativa</i> L.), and corn-pea-winter wheat-soybean (CPWwS). Six soilborne pathogens that consistently threaten the United States soybean production were quantified in the field soils using quantitative PCR or egg extraction for soybean cyst nematode. Three soilborne pathogens, <i>Macrophomina phaseolina, Fusarium oxysporum,</i> and <i>Pythium irregulare</i>, were detected, whereas the population density of <i>F. graminearum</i> and <i>F. virguliforme</i> was not measurable in the soil samples. The number of soybean cyst nematode eggs or juveniles was zero or very low in all soil samples. Overall, crop rotation treatments affected the population density of three detected pathogens but varied by crop phase, year, and pathogen species. The population density of three detected pathogens was positively correlated with soil temperature but negatively correlated with soil volumetric water content. Notably, the CPWwS rotation treatment had a consistently lower M. phaseolina population compared with the other rotation treatments, regardless of crop phase and year. This study provided potential crop sequences that limit soilborne pathogen populations in the soil and may reduce disease incidence on the host crops.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143053160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization, Phylogenetic Analyses, and Pathogenicity of <i>Eutiarosporella dactylidis</i> on Sorghum in China.","authors":"Xiaojie Zhang, Linying Wang, Tianyu Yang, Shangli Shi, Cheng Guo","doi":"10.1094/PDIS-04-24-0831-RE","DOIUrl":"10.1094/PDIS-04-24-0831-RE","url":null,"abstract":"<p><p>Sorghum, the fifth-largest cereal crop globally and a C4 crop, mainly grows in arid and semiarid areas. In 2021 to 2023, a new foliar disease of sorghum occurred in China. The diseased leaves showed water-soaked symptoms in the leaf tip and margins, resulting in half- and full-leaf desiccation and necrosis, thus affecting plant photosynthesis. A total of 24 <i>Eutiarosporella</i> strains were isolated from symptomatic leaves. Based on morphological characteristics, multilocus phylogenetic analysis involving <i>ITS</i>, <i>LSU</i>, and <i>EF1-α</i> sequences, and the pathogenicity test, the pathogen of sorghum causing leaf blight in China was identified as <i>Eutiarosporella dactylidis</i>. The virulence of all <i>E. dactylidis</i> strains was evaluated using the spray-mycelium method. Different strains showed significantly different pathogenicities toward a susceptible cultivar, Longza 10, with disease indexes ranging from 23.76 to 60.37. This study first reported leaf blight of sorghum caused by <i>E. dactylidis</i> and named it \"Eutiarosporella leaf blight,\" which provides a theoretical basis for farmers in disease management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS04240831RE"},"PeriodicalIF":4.4,"publicationDate":"2025-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142293146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence of Rapid Infection of Four Sweetpotato Potyviruses in a Commercial Field in California.","authors":"Juliana Osse de Souza, Teresa M Erickson, C Scott Stoddard, Christie V Almeyda, Maher Al Rwahnih","doi":"10.1094/PDIS-06-24-1304-SC","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1304-SC","url":null,"abstract":"<p><p>Sweetpotato (<i>Ipomoea batatas</i> Lam.) is grown worldwide and is a staple food in many countries. One of the main constraints for sweetpotato production is cultivar decline, caused by the accumulation of viruses and subsequent losses of storage root yield and quality over years of vegetative propagation. Virus indexing using diagnostic molecular techniques is essential for the detection and identification of the major viruses to avoid cultivar decline, but little information is available on the fate of clean (virus-tested) plant materials after field propagation. In this study, cuttings of three sweetpotato cultivars (Beauregard, Bellevue, and Vermillion) were acquired from a clean propagative material program and planted in commercial field plots in Merced County, California, over multiple growing seasons. In 2021 and 2022, the phytosanitary status of storage roots from different generations of the materials were assessed by reverse transcription quantitative PCR (RT-qPCR) at harvest at the Foundation Plant Services, University of California, Davis. The results showed their rapid infection with four major potyviruses-sweet potato feathery mottle virus, sweet potato virus 2, sweet potato virus C, and sweet potato virus G-over the two seasons. The infection by two to four potyviruses was confirmed by RT-PCR, RT-qPCR, high-throughput sequencing, and biological indexing onto <i>Ipomoea setosa</i> plants for symptoms evaluation.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS06241304SC"},"PeriodicalIF":4.4,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143009631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Report of <i>Phytophthora inundata</i> causing crown rot on <i>Olea europaea</i> (Olive) in Pakistan.","authors":"Hafiz Husnain Nawaz, Muhammad Ali, Attiq Rehman, Muhammad Azhar Iqbal, Kashaf Nawaz, Muhammad Amjad","doi":"10.1094/PDIS-01-24-0052-PDN","DOIUrl":"10.1094/PDIS-01-24-0052-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Crown rot impacted olive plants (cv. Koroneiki) in an orchard in Chakwal, Punjab, Pakistan (32° N, 72° E), with a prevalence of 60%. Observable symptoms included leaf chlorosis, defoliation, wilting, and twig dieback in 6-8-year-old plants, ultimately resulting in their demise (Fig. 1 A, B). It was Initially observed in June 2020. In September 2020, 48 samples (3 root and 3 crown stem part sample per plant) of diseased olive plants were randomly chosen from the orchard for detailed analysis. Bark pieces from the diseases portion were sectioned into smaller pieces and placed on corn meal agar supplemented with PARP. The culture was maintained at 22°C in the dark. Within 4 days, coenocytic white fluffy mycelium emerged. Hyphae were subsequently transferred to carrot agar medium supplemented with beta-sitosterol. A total of 15 isolates were obtained and characterized, yet a particular two isolates consistently stood out. These isolates did not show sexual reproduction in culture (Ann 1988). Instead, they reproduced asexually through sporangia borne on aerial sporangiophores, originating directly from the internal mycelium. Each branch of the sporangiophore featured a sporangium at its tip, with sporangia varying in shape from pyriform to ellipsoid and being non-papillate and non-caducous (Fig. 2B, C, D). After morphological study, the isolates were identified as Phytophthora species and named BPK-01 and BPK-02. For the molecular identification, we amplified and sequenced their internal transcribed spacer and beta-tubulin regions using universal primer pairs ITS1 and ITS-4, as well as TUB-F and TUB-R primer pairs (Safaiefarahani et al. 2013). Sequences of 816 bp and 940 bp were obtained for the ITS and beta-tubulin regions, respectively. These sequences were deposited in NCBI GenBank, resulting in accession numbers OL423596 and OL423597 for the ITS region of BPK-01 and BPK-02, and OL771190 and OL771191 for the beta-tubulin region of BPK-01 and BPK-02, respectively. BLAST analysis revealed 99.88% identity (816bp out of 837bp) for ITS and 100% (940bp out of 940bp) for TUB between our isolate and P. inundata reference isolates (GenBank Accessions MK326518.1 and EF210202). Phylogenetic analysis using MEGA X software further confirmed the identity of the olive crown rot isolate as P. inundata, aligning it with reference isolates from various Phytophthora species (Fig. 3) (Tamura et al. 2013). The fungal isolates have been officially deposited as living cultures at the Barani Agricultural Research Institute's fungal culture collection center under the designations BAPI.3550 and BAPI.3551. The pathogenicity test involved inoculating isolated strains on 2.5-year-old olive trees. Each isolate was used to inoculate five Koroneiki plants, while five plants served as controls. Inoculation, performed on the stem, included surface disinfection, wounding, and placement of a mycelium plug, with all plants maintained in controlled conditions (25°C, 12h light). ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143009642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of a locus associated with susceptibility to esca in grapevine.","authors":"Guillaume Arnold, Emilce Prado, Vincent Dumas, Gisèle Butterlin, Éric Duchêne, Didier Merdinoglu, Komlan Avia","doi":"10.1094/PDIS-06-24-1258-RE","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1258-RE","url":null,"abstract":"<p><p>Esca is the most destructive and predominant of grapevine trunk disease. The chronic infections and vine mortality caused by esca syndrome leads to huge economic losses and threatens the sustainability of vineyards worldwide. Esca is caused by numerous wood-decay and wood-decay associated fungi, but its full etiology remains unclear due to the grapevine trunk disease complex, making effective control methods challenging. As differences in esca susceptibility have already been observed among grapevine varieties, we investigated the presence of genetic factors that can explain theses variations using a Riesling x Gewurztraminer progeny. Thanks to the destructive phenotyping of a 16-year-old vineyard plot, we discovered that the Gewurztraminer variety carries on chromosome 1 a locus linked to variations in trunk necrosis associated with esca, which we have named Esca Necrosis Susceptibility 1 (ENS1). Our study also suggests that there is a partial link between trunk vigor and necrosis due to esca. To our best knowledge, ENS1 is the first instance of genetic factor identified as involved in the limitation of necrosis associated to grapevine esca. While the identification of ENS1 alone may not provide a complete resolution of the issue, this discovery nonetheless represents a first step towards a genetic solution and paves the way for broader genetic investigations in the future.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143009525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First report of <i>Alternaria alternata</i> causing winged leaf dieback disease on <i>Rhus chinensis</i> in Yunnan Province, China.","authors":"Lianhao Wen, Yanjie Li, Ju Gu, Yu Zhang, Jingjing Chen, Ziqiang Wu, Yandi Wu, Chao Wang","doi":"10.1094/PDIS-11-24-2476-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2476-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Rhus chinensis, a deciduous tree of the genus Rhus (family Anacardiaceae), is widely cultivated in China for its medicinal, edible, and ornamental value (Zhang et al., 2022). In April 2022, symptoms of winged leaf dieback disease were observed at Southwest Forestry University in Kunming, Yunnan Province, China (E102°45'42.122″, N25°4'1.36″, H1951m). A plantation survey revealed that 82% of R. chinensis individuals had symptoms consistent with winged leaf dieback disease, representing the disease severity across the district. The early symptoms of the disease included small, irregular dark brown or black spots on the leaves, which progressively expanded into necrotic patches, leading to the withering and shedding of adjacent leaves. A total of 25 samples were collected from different R. chinensis individuals and winged leaves in the plantation at Southwest Forestry University, Kunming, with sampling conducted in April 2022. Fifteen fungal isolates with similar morphological characteristics were purified using the tissue isolation method described by Li et al (Li et al., 2019). Initially, the fungal colonies appeared white, later turned grey, and eventually became greyish-black. The conidia were light brown to brown, ovate to oblong-ellipsoid, and slightly constricted near some septa. They measured 12.4 to 41.8 µm in length and 6.1 to 14.2 µm in width, containing 1 to 7 transverse septa and 0 to 3 longitudinal septa. The conidiophores were straight or slightly curved, light brown to brown, and measured 13 to 30 by 1.5 to 6 µm. These morphological characteristics were consistent with descriptions of A. alternata (Zhang et al., 2023). For molecular identification, four representative fungal strains (RCM1, RCM2, RCM3, and RCM4) were selected. Multilocus analysis was conducted on five genes: internal transcribed spacer (ITS), 18S ribosomal RNA (SSU), 28S ribosomal RNA (LSU), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and translation elongation factor 1-alpha (EF1-α). The gene sequences were subjected to a BLAST search in NCBI, and the corresponding sequences were downloaded from the GenBank database. A phylogenetic tree was then constructed using MEGA11, employing the Maximum Likelihood method for multi-gene association analysis. The resulting sequences were deposited in GenBank with accession numbers: ITS (OR649186, OR649187, OR649188, OR649189), GAPDH (OR727018, OR727019, OR727020, OR723970), SSU (OR649193, OR649194, OR649195, OR649196), LSU (OR649198, OR649199, OR649200, OR649201), and EF1-α (OR683440, OR683441, OR727016, OR727017). Phylogenetic analysis grouped these isolates within the A. alternata clade, supported by a 99% bootstrap value. To verify Koch's postulates, a spore suspension of the pathogen (1.2×105 spores/ml) and distilled water were separately inoculated onto 20 three-year-old potted R. chinensis winged leaves, using the RCM1 isolate. The inoculated winged leaves were covered with cotton to maintain moisture. After 10 d","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143009641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}