Plant disease最新文献

{"title":"Development of a quantitative PCR method to detect the bacterial gall pathogen <i>Pseudomonas amygdali</i> pv. <i>loropetali</i> from loropetalum plant materials.","authors":"Jiayuan Jia, Kenneth Leep, Kate Phillips, Emma Willis, Lindsey Robinson, Wes Phillips, Quentin D Read, Warren Copes, Shien Lu","doi":"10.1094/PDIS-11-23-2533-SR","DOIUrl":"https://doi.org/10.1094/PDIS-11-23-2533-SR","url":null,"abstract":"<p><p>Bacterial gall caused by Pseudomonas amygdali pv. loropetali (PAL) is a prevalent problem on Loropetalum chinense shrubs in commercial plant nurseries. A method was developed to reliably detect PAL on the surface of loropetalum twigs. A whole genome analysis resulted in the identification of a locus encoding an AraC regulator that is specific to PAL. A pair of primers and a TaqMan probe were designed based on a 71-base pair sequence in this locus. Positive results of PCR amplification were obtained with genomic DNA samples from all PAL strains but not from those of other Pseudomonas species, Agrobacterium tumefaciens, or Burkholderia contaminans. Melting curve analysis demonstrated that all PAL PCR products shared the same melting temperature of 79°C. TaqMan-based qPCR analysis of the serially diluted genomic DNA from PAL strain AAC exhibited a strong linear response for regressed cycle threshold (Ct) and logarithm copy values (Adjusted R2 = 0.9944) with a high amplification efficiency (E = 1.96), while the linear response (Adjusted R2 = 0.8885) for PAL genomic DNA extracted from serially diluted bacterial cell suspension had a reduction in detection sensitivity. The limits of detection and quantification of PAL from the spiked plant twigs (diameter × length = ~0.45 × 2.45 cm) were 873 and 14,724 cells, respectively, using a modified Promega Wizard extraction protocol. These limits of the qPCR method, while restrictive, still allow a practical detection of PAL strains associated with plant tissue that can be utilized in epidemiological studies to develop disease management options.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128041","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":"Determining the causal agents of Alternaria leaf blight and head rot affecting broccoli in the Eastern United States.","authors":"Roy L Davis, Daniel Guillermo Cerritos Garcia, Amelia G Martin, Michael F Fenton, Karan Patel, Carlos Saint-Preux, Mychele Batista da Silva, Hirut Betaw, Edgar Humberto Nieto-López, Steve Rideout, David Langston, Christine Anne Hoepting, Christine D Smart, Bhabesh Dutta, Sydney Everhart","doi":"10.1094/PDIS-01-25-0117-SR","DOIUrl":"https://doi.org/10.1094/PDIS-01-25-0117-SR","url":null,"abstract":"<p><p><i>Alternaria brassicicola</i> is the causal agent typically associated with Alternaria leaf blight and head rot (ABHR) disease in broccoli and related crops in the Eastern United States. Recently a new species, <i>A. japonica</i>, has been reported as causing disease in broccoli and other vegetables in this region. We conducted a multi-state pathogen survey during the growing seasons of 2022 and 2023 to assess the distribution and occurrence of <i>A. japonica</i> in relation to <i>A. brassicicola</i> in five broccoli-producing states. Our approach specifically targeted collection of broccoli leaves with lesions typical of ABHR within commercially grown fields managed using either organic or conventional approaches in Connecticut, Massachusetts, New York, Virginia, and Georgia. Only typical ABHR leaf lesions were selected for pathogen isolation and, subsequently, sequencing of the <i>Alternaria</i> major allergen a1 gene was used to identify <i>Alternaria</i> species. The predominant species isolated was <i>A. brassicicola</i> (88% in 2022 and 94% in 2023) and the second most common was <i>A. alternata</i> (12% in 2022 and 6% in 2023), which was obtained from fields in Connecticut and Massachusetts in 2022, and in Virginia in both years. <i>Alternaria japonica</i> was not found in either year. Symptoms of <i>A. alternata</i> were indistinguishable from <i>A. brassicicola</i>, as were colony morphologies. While <i>A. alternata</i> is considered a generalist and of little consequence for broccoli, it is considered a pathogen of significance on multiple crops (blueberry, citrus, pistachios), but there remains scant information on the disease etiology on broccoli. Therefore, we inoculated broccoli with <i>A. alternata</i> in controlled conditions in order to shed light on possible differences in infectivity of these species on broccoli. Results of our study showed that <i>A. alternata</i> is pathogenic on broccoli, capable of initiating infection and causing lesions typical of ABHR. This indicates that future disease surveys of ABHR should conclusively identify species of <i>Alternaria</i> that are causing disease. Additional research is needed to determine the significance of this finding in relation to yield impacts, epidemiology, fungicide resistance, and management recommendations.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127785","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":"Cryotherapy-based methods for virus and viroid eradication in horticultural plants.","authors":"Jingwei Li, Min-Rui Wang, Zhibo Hamborg, Dag-Ragnar Blystad, Gayle Volk, Jean Carlos Bettoni, QiaoChun Wang","doi":"10.1094/PDIS-02-25-0384-FE","DOIUrl":"https://doi.org/10.1094/PDIS-02-25-0384-FE","url":null,"abstract":"<p><p>Rapid population growth poses a major challenge to global food security. Promoting sustainable agricultural production is necessary to ensure the global food security. Horticultural plants are a high-valued part in agricultural production. Virus and viroid diseases have long been a key factor limiting the horticultural production. Cultivation and distribution of pathogen-free plants is currently the most efficient practice for managing virus and viroid diseases, and their spread in the landscape. Cryotherapy-based methods are recently developed novel biotechnologies for the efficient production of pathogen-free plants. This review outlines updated information on the development and advances in cryotherapy-based methods for efficiently eradicating viruses and viroids in horticultural plants. Mechanisms underlining cryotherapy-based methods for improved pathogen eradication are discussed, and suggestions for further studies are proposed.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144127664","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 Crown Rot Caused by <i>Fusarium nygamai</i> on Wheat in Kazakhstan.","authors":"Aidana Kharipzhanova, Göksel Özer, Tugba Bozoglu, Alma Kokhmetova, Vladimir Tsygankov, Yerlan Dutbayev","doi":"10.1094/PDIS-12-24-2561-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2561-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Fusarium crown rot impacts wheat, causing yield and quality losses in arid and semi-arid regions worldwide. During wheat disease surveys in July 2023, crown rot symptoms were observed (20% incidence) across Aktobe Agricultural Experimental Station experimental plots (50°17'02\"N, 57°09'14\"E), Aktobe, Kazakhstan, from which 20 symptomatic spring durum wheat (Triticum durum Desf.) plants were collected. Infected plants showed brown discoloration that extended from the crown to 2-3 cm up the stem bases, with lesions on the subcrown internode and primary roots. Severely affected plants showed stunted growth. The affected tissues were washed, surface sterilized with 1% NaClO for 2 min, rinsed three times with sterile distilled water, and placed on 1/5 strength PDA plates. After a 5-day incubation at 23°C in darkness, 38 colonies exhibiting Fusarium-like morphology were observed and single spore isolates were obtained from each colony on fresh PDA and SNA, following the protocol of Leslie and Summerell (2006). The partial TEF1 and RPB2 genes were amplified and sequenced using primers EF1/EF2 (O'Donnell et al. 1998) and 5f2/7cr (Reeb et al. 2004; Liu et al. 1999). BLASTn analysis against NCBI GenBank and Fusarium-ID databases revealed that the sequences of three isolates showed 100% nucleotide identity with Fusarium nygamai holotype strain NRRL 13488 (TEF1: AF160273; RPB2: EF470114). The TEF1 and RPB2 gene sequences from the isolate 986b were deposited in GenBank under Accession Nos. PQ366035 and PQ366036, respectively. All three isolates showed white to violet mycelium, with colonies developing a central greyish-orange or dark violet spore mass; macroconidia measured 30.75 ± 2.79 × 3.61 ± 0.48 μm (n=30) and were hyaline, 3-septate, slender, and falcate to almost straight; microconidia formed on SNA measured 11.45 ± 0.95 × 2.77 ± 0.52 μm (n=30) and were produced in short chains or false heads; chlamydospores were formed in 2-4 weeks, conforming to the description of F. nygamai by Leslie and Summerell (2006). The pathogenicity of three isolates was tested on a susceptible durum wheat variety, Kızıltan 91. Seeds were surface-sterilized in 1% NaClO, rinsed, and germinated on water-soaked filter paper for 3 days. Five uniform seedlings were planted in 9-cm pots containing a sterile peat-vermiculite-soil mixture (1:1:1, v/v/v), with three replicate pots per isolate. A 1-cm mycelial PDA disc was placed on each seed and covered with the substrate, while control seeds received sterile PDA discs. Pots were arranged in a completely randomized design and incubated at 23°C with a 12-hour photoperiod. Four weeks of post-inoculation, typical crown rot symptoms appeared on plants, and the pathogen was re-isolated. The identity of re-isolated fungi was confirmed through morphological examination and TEF1 gene sequencing, establishing causation and fulfilling Koch's postulates, while control plants remained healthy throughout the experiment with no fungal growth de","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144128193","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":"Comparison of rDNA-ITS Sequences, Vegetative Compatibility, Biological Characteristics, and Thifluzamide Sensitivity of <i>Rhizoctonia solani</i> AG-3 Potato Type, Tomato Type, and Tobacco Type Subgroup Isolates Collected from Potato and Tobacco in China.","authors":"Mengxiao Liu, Tianbo Liu, Yu Yang, Qian Li, Haiyan Mao, Xinchun Li, Fenglu Wang, Jingtao Zhao, Chong Zhang, Yuanhua Wu","doi":"10.1094/PDIS-07-24-1407-RE","DOIUrl":"10.1094/PDIS-07-24-1407-RE","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Potato black scurf and tobacco target spot are significant agricultural diseases primarily caused by &lt;i&gt;Rhizoctonia solani&lt;/i&gt; AG-3, which is further classified into potato type (PT), tomato type (TM), and tobacco type (TB) subgroups, with the naming of these subgroups originally indicating their respective infection hosts potato, tomato, and tobacco. This study determined the subgroup classification of 129 &lt;i&gt;R&lt;/i&gt;. &lt;i&gt;solani&lt;/i&gt; AG-3 isolates recovered from tobacco leaves exhibiting target spot disease in major tobacco-cultivating regions of China, as well as 80 &lt;i&gt;R&lt;/i&gt;. &lt;i&gt;solani&lt;/i&gt; AG-3 isolates obtained from potato stem cankers and tuber sclerotia in Liaoning, Jilin, and Heilongjiang provinces, and Inner Mongolia autonomous region of China. Sequence analysis of the internal transcribed spacer (ITS) regions revealed that all potato isolates belonged to the &lt;i&gt;R&lt;/i&gt;. &lt;i&gt;solani&lt;/i&gt; AG-3 PT subgroup, whereas the tobacco isolates were classified into TM and TB subgroups. Specifically, 51 strains from the northeast (Liaoning, Jilin, and Heilongjiang provinces) belonged to the TM subgroup, whereas the others belonged to the TB subgroup. Phylogenetic analysis indicated a closer relationship between AG-3 TM and AG-3 PT compared with AG-3 TB. Population genetic analysis highlighted distinct genetic variations among the subgroups, with the AG-3 TB subgroup isolates exhibiting fewer ITS1 variable sites and the AG-3 PT subgroup displaying a higher number of ITS2 variable sites. Furthermore, comparisons were made regarding macroscopic vegetative interactions, biological characteristics, pathogenicity to potato and tobacco, and susceptibility to thifluzamide among the three subgroups. The results indicated no macroscopic somatic interactions among the subgroups, with the highest frequency of somatic incompatibility observed within AG-3 PT, followed by AG-3 TM and AG-3 TB. Additionally, the three subgroups differed in colony color, sclerotium morphology, production time, and distribution location on potato dextrose agar medium, with AG-3 TM being the least likely to produce sclerotia. Regarding temperature, optimal growth conditions varied among the subgroups. Regarding pathogenicity, the AG-3 PT subgroup strains were more pathogenic on tobacco and potato stem bases compared with the AG-3 TB subgroup, whereas the AG-3 TB and TM subgroup strains were more pathogenic on leaves. Notably, AG-3 TM exhibited remarkable virulence toward both the stem base and leaves. The AG-3 PT subgroup strains exhibited the highest susceptibility to thifluzamide, with a susceptibility baseline of 0.037 ± 0.013 mg·liter&lt;sup&gt;-1&lt;/sup&gt;, followed by the AG-3 TM subgroup strains with a baseline of 0.111 ± 0.034 mg·liter&lt;sup&gt;-1&lt;/sup&gt; and the AG-3 TB subgroup strains with a baseline of 0.137 ± 0.035 mg·liter&lt;sup&gt;-1&lt;/sup&gt;. This study contributes to a deeper understanding of the biology and etiology of the three subgroups of &lt;i&gt;R&lt;/i&gt;. &lt;i&gt;solani&lt;/i&gt; AG-3, providing a valuable theor","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS07241407RE"},"PeriodicalIF":4.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142625742","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":"Development and Validation of a Mechanistic, Weather-Based Model for Walnut Blight Caused by <i>Xanthomonas arboricola</i> pv. <i>juglandis</i>.","authors":"Tao Ji, Tito Caffi, Giorgia Fedele, Ran Liu, Vittorio Rossi","doi":"10.1094/PDIS-09-24-1850-RE","DOIUrl":"10.1094/PDIS-09-24-1850-RE","url":null,"abstract":"<p><p>Walnut blight, caused by <i>Xanthomonas arboricola</i> pv. <i>juglandis</i> (<i>Xaj</i>), occurs worldwide in almost all areas where the Persian walnut (<i>Juglans regia</i>) is grown, causing significant reductions in nut yield via defoliation and fruit drop. The disease control relies on the calendar-based, repeated use of chemical bactericides, negatively impacting economic and environmental sustainability and potentially inducing <i>Xaj</i> resistance to chemicals. This study developed and validated a mechanistic model incorporating the main stages of the pathogen's life cycle and the influence of weather under orchard conditions to improve the scheduling of disease control interventions. The model can simulate (i) the mobilization of primary inoculum; (ii) the infection caused by bacteria; and (iii) the lesion formation and production of secondary inoculum. We evaluated the model against 21 independent walnut blight epidemics in Italy (9 epidemics on leaves in five orchards) and the United States (12 epidemics on fruit in six orchards). Overall, the model provided accurate predictions for both the occurrence and nonoccurrence of infection, with a precision and F1-score of 0.866 and 0.844, respectively. The model could accurately predict disease progression across the season, with a concordance correlation coefficient between observed and predicted disease severities of 0.951, a root mean square error of 0.069, and a coefficient of residual mass of 0.024. After further validation, the model can serve as a decision-making tool for the risk-based timing of chemical sprays in walnut blight management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS09241850RE"},"PeriodicalIF":4.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142688427","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":"Identification of a Reduced Rate Combination of a Plant Growth Inhibitor with a Plant Defense Inducer for the Management of the Shoot Blight Phase of Fire Blight.","authors":"Suzanne M Slack, Xiaochen Yuan, Cory A Outwater, George W Sundin","doi":"10.1094/PDIS-09-24-2008-RE","DOIUrl":"10.1094/PDIS-09-24-2008-RE","url":null,"abstract":"<p><p>The secondary shoot blight phase of fire blight is a critical component of disease epidemics in apples, pears, and other Rosaceae family plants with infection occurring at the tips of vigorously growing branches. Shoot blight infections are exacerbated in modern high-density apple plantings, where growers emphasize maximizing tree growth to recapture planting costs and increase yields of high-quality fruit. The overarching goal of this study was to develop new strategies for shoot blight management that do not impact the growth and yield of young apple trees. 'Gala' apple trees of various ages were inoculated with the fire blight pathogen <i>Erwinia amylovora</i>. Being treated with a combination of reduced rate mixtures of prohexadione calcium (ProCa; 6-12× rate reduction) with acibenzolar-<i>S</i>-methyl (ASM; 2× reduction) resulted in a significant decrease in shoot blight incidence and severity without significant impacts on branch growth. The systemic spread of <i>E. amylovora</i> was significantly reduced in trees sprayed with these lower-rate mixtures. Comparable rates of either treatment alone were not as effective in reducing lesion length. A transcriptomic analysis revealed a synergistic effect in which the expression of marker genes associated with systemic acquired resistance was higher in apple trees sprayed with the low-rate mixture of ProCa + ASM than with either compound alone. We conclude that the combination of ProCa + ASM at reduced rates is an effective treatment for the shoot blight phase of fire blight without impacting horticultural practices associated with high-density apple production.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS09242008RE"},"PeriodicalIF":4.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142716840","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":"<i>Fusarium</i> and <i>Neocosmospora</i> Species Associated with the Decline of <i>Metasequoia glyptostroboides</i> in China.","authors":"Duan-Chong Liu, Wen-Xia Zhao, Jian-Ping Xia, San-Shan Cai, Wen-Xia Huai, Ru-Bin Zhang, Bin Li, Hua-Lan Peng, Shi-Jun Zhang","doi":"10.1094/PDIS-01-24-0201-RE","DOIUrl":"10.1094/PDIS-01-24-0201-RE","url":null,"abstract":"<p><p>During surveys conducted in 2020, severe symptoms associated with death and decline were observed on more than 30-year-old <i>Metasequoia glyptostroboides</i> (Chinese redwood) trees in the shelter forests along the Yangtze River in Jingzhou City, Hubei Province, China. A previous study showed that <i>Phytophthora acerina</i> was one of the causal agents of the decline of the Chinese redwood. In this study, a total of 147 fungal isolates were obtained from the diseased roots and xylem of trunks of declining <i>M</i>. <i>glyptostroboides</i> trees. Through morphology and multilocus phylogenetic analysis, these isolates were identified as eight species belonging to the genera <i>Fusarium</i> and <i>Neocosmospora</i>, including <i>F. fujikuroi</i>, <i>F. irregulare</i>, <i>F. odoratissimum</i>, <i>F. reticulatum</i>, <i>N. falciformis</i>, <i>N. keratoplastica</i>, <i>N. solani</i>, and <i>N. tonkinensis</i>. Single inoculation and coinoculation with <i>P. acerina</i> assays of these <i>Fusarium</i> and <i>Neocosmospora</i> species were then performed to test pathogenicity on 3-year-old seedlings of <i>M. glyptostroboides</i>. Lesions (i.e., on seedling stems) caused by species of the genera <i>Neocosmospora</i> and <i>Fusarium</i> were smaller than those caused by <i>P. acerina</i>. Coinoculation of <i>F. fujikuroi</i> and <i>P. acerina</i>, as well as the coinoculation of <i>F. reticulatum</i> and <i>P. acerina</i>, caused larger lesions than inoculation with <i>P. acerina</i> alone. All these species of <i>Fusarium</i> and <i>Neocosmospora</i> were shown to have the potential to be pathogenic to <i>M. glyptostroboides</i>. This study provided evidence that the decline of <i>M. glyptostroboides</i> in Jingzhou is a disease complex.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS01240201RE"},"PeriodicalIF":4.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142505814","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 of Fludioxonil-Resistant Strains of <i>Colletotrichum gloeosporioides</i> from Eastern China.","authors":"Jin Wang, Zhihui Zhang, Dongya Shi, Shuping Chu, Yingying Cao, Huanhuan Zheng, Fengjie Li, Hongyu Ma, Changjun Chen","doi":"10.1094/PDIS-08-24-1763-RE","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1763-RE","url":null,"abstract":"<p><p>Ripe rot caused by <i>Colletotrichum</i> spp. poses a devastating threat to the grape industry worldwide. <i>C. gloeosporioides</i> is the main pathogen of grape ripe rot in eastern China. Fludioxonil has been used extensively to control disease on grape in China for more than 20 years. However, it remains unclear whether the strains of <i>C. gloeosporioides</i> in Chinese vineyards are resistant to fludioxonil. Of the 68 <i>C. gloeosporioides</i> isolates collected from the commercial vineyards during 2016 to 2018, 52 showed low resistance to fludioxonil (Flu^LR) with a resistance frequency of 76.47%. To further characterize strains with moderate or high resistance to fludioxonil, six induced highly fludioxonil-resistant (Flu^IHR) mutants were obtained by repetitive exposure to fludioxonil in vitro. In comparison with the fludioxonil-sensitive (Flu^S) isolates, most of the low fludioxonil-resistant (Flu^LR) and Flu^IHR strains hardly exhibited biological fitness penalty based on mycelial growth, sporulation, and virulence. Analysis of EC₅₀ values of several fungicides showed a strong correlation between fludioxonil and procymidone but no correlation between fludioxonil and fluazinam or prochloraz. Sequence alignment of CgOs-1 indicated that amino acid substitutions in Flu^IHR strains could be categorized into three Flu-resistant genotypes, CgOs-1^T50A, CgOs-1^T50A&A300T, and CgOs-1^T50A&T654K, while no amino acid substitutions were found in CgOs-1 from the Flu^LR or Flu^S isolates. To our knowledge, this is a detailed report characterizing fludioxonil-resistant strains of <i>C. gloeosporioides</i> selected from commercial vineyards and laboratories, which will provide a valuable reference for the control of grape ripe rot.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS08241763RE"},"PeriodicalIF":4.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144120569","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":"Outbreak of Cucumber Mosaic Virus Subgroup IB in Pepper from the Espelette Area (Basque Country, Southwestern France) and First Report of Five Taxa as Natural Hosts of CMV.","authors":"Jonathan Gaudin, Sylvain Piry, Catherine Wipf-Scheibel, Marion Szadkowski, Cecile Desbiez, Elodie Nguyen, Paul Dumeaux, Karine Berthier, Alexandra Schoeny, Gregory Girardot, Judith Hirsch, Eric Verdin, Elise Lepage, Patrick Gognalons, Claire Troulet, Benoît Moury, Loup Rimbaud","doi":"10.1094/PDIS-07-24-1553-SC","DOIUrl":"10.1094/PDIS-07-24-1553-SC","url":null,"abstract":"<p><p>To better understand the emergence of cucumber mosaic virus (CMV) in the protected designation of origin of Espelette pepper (southwestern France), more than 7,300 samples were collected in and around 36 pepper fields in 2021 and 2022 and diagnosed using ELISA, RT-PCR, and partial Sanger sequencing of viral RNAs. This allowed the identification of five new host genera or species among the natural hosts of CMV: <i>Arum italicum</i>, <i>Cerastium glomeratum</i>, <i>Hyacinthoides</i> sp., <i>Lysimachia arvensis</i>, and <i>Trifolium incarnatum</i>. A CMV variant belonging to subgroup IB and presenting a low molecular diversity was highly prevalent in the pepper crops (78% of the pepper samples) as well as in naturally growing plants (8% of the non-pepper samples) within the fields. CMV isolates from group II were detected in a single pepper plant as well as in <i>Hyacinthoides</i> sp. (three samples), <i>Capsella bursa-pastoris</i> (two samples), and <i>Stachys arvensis</i> (one sample). To our knowledge, this is the second report of the occurrence of subgroup IB of CMV in France. Investigation of old pepper samples indicated that it has been present at least since 2009.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS07241553SC"},"PeriodicalIF":4.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786451","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}