Plant disease最新文献

{"title":"<i>Ganoderma adspersum</i>, the Cause of Extensive Wood Decay of Almond Trees in California Orchards.","authors":"Daisy Ahumada, Andrew 'Bob' Johnson, Felipe E S Cortez, Phoebe E Gordon, Catherine Mae Culumber, David Rizzo","doi":"10.1094/PDIS-03-24-0631-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-24-0631-RE","url":null,"abstract":"<p><p>Ganoderma adspersum, previously unreported in North America, was identified as the primary causal agent of root and butt rot-related failure in almond trees in California's Central Valley. This disease has been observed over approximately 340 km in California and in orchards spanning 5 to 20+ years old. The most common sign is reddish-brown basidiomata that develop at the base of the trees in the later stages of the disease. Ganoderma adspersum was isolated from the decayed wood of failed trees with the peach rootstock cultivar Nemaguard®. Rootstocks were inoculated with G. adspersum in a greenhouse setting and decay similar to naturally infected trees developed. The pathogen was reisolated from the inoculated plants, confirming pathogenicity.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459001","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":"The fermentation broth of <i>Streptomyces noursei</i> strain S86 as a potential biocontrol product for Fusarium crown rot of wheat.","authors":"Jing Wang, Chunli Xu, Wenqing Xiao, Miaomiao Wang, Xue Han, Yang Sun, Beibei Ge","doi":"10.1094/PDIS-10-24-2109-RE","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2109-RE","url":null,"abstract":"<p><p>Fusarium crown rot of wheat, caused by Fusarium pseudograminearum, significantly affects the yield and quality of wheat worldwide. Here, Streptomyces noursei strain S86 (herein referred to as S86), was evaluated for its biocontrol efficacy and biochemical characteristics. Strain S86 was found to secrete cellulase, amylase and other enzymes. Whole genome sequencing and LC-MS analyses confirmed that S86 could produce toyocamycin, nystatin, anisomycin, natamycin, and other antimicrobial metabolites. The fermentation broth of S86 inhibited the growth of F. pseudograminearum and had broad-spectrum inhibitory activity against Rhizoctonia cerealis, Cochliobolus sativus, Fusarium graminearum, and Gaeumannomyces graminis var. graminis. A greenhouse experiment demonstrated that wheat seeds coated with S86 fermentation broth showed better control efficiency against Fusarium crown rot (68.33%), which was 22.63% higher than direct root irrigation with the S86 fermentation broth. These results indicate that S86 fermentation products have the potential to be developed as biological controls of Fusarium crown rot disease in the field.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459046","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>Ralstonia pesudosolanacearum</i> Causing Bacterial Wilt of <i>Canna edulis</i> in China.","authors":"Jia Lin Qiu, KeJing Lin, YiFan Zhang, Xue Qing Cai","doi":"10.1094/PDIS-10-24-2174-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2174-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Canna edulis is a perennial herb, belonging to the Canna, Cannaceae. Native to South America and the West Indies, it was introduced into China in the 1950s, and widely planted in China (Liu et al, 2013). The planting area of C. edulis was about 20 hm2 in Datian town, Taining county, Sanming city, Fujian Province, China, and a new bacterial disease of Canna was found in July 2022, the disease incidence was about 20% in the field. The apical or middle leaves of the affected plants initially showed withering symptoms during the daytime and recovered at night. As the disease progressed, the whole plant withered, but the leaves' color remained green. Blackening and rotting of the roots and basal stem tissues were observed, leading to plant death (Figure S1). The transverse section of the basal stem or roots showed that the vascular tissues became brown, and when compressed, a milky whitish ooze could be observed. Eight bacterial strains (B1-B8) were isolated and purified from six diseased plants on nutrient agar medium (NA) by streak plate method. The pathogenicity of the isolated strains was tested by wounding inoculation on roots, that is, first, we cut off the roots of healthy Canna seedlings with a sterile knife (avoiding lumpy roots), and then watered 50 mL bacterial solution at a concentration of 3×108 CFU·mL-1 per seedling, took sterile water as a negative control, inoculated three plants with each bacterial strain, and repeated three times. The results indicated that the Canna seedlings wilted on the 6th day and began to die on the 14th day after inoculation, the symptoms were consistent with those in the field. The water treatment produced no symptoms. The bacterial strains whose colony morphology was similar to those of test strains were re-isolated on NA medium from inoculated plants, in which the colonies were irregular, milky-white with the production of sticky substances and strong motility. So, Koch's rule proved all the test strains as the causal pathogens of bacterial disease. The physiological and biochemical assays of eight bacterial strains were consistent with those of the control strains, R. pseudosolanacearum RS-5 and FQRS1. The 16S rDNA gene was amplified with the universal primer 27F/1492R (Lane, 1991), and the phylogenetic tree showed that the tested strains clustered with R. pseudoslanacearum (Figure S2A), indicating the test strains to be R. pseudoslanacearum. All the test bacteria could obtain two specific bands (280-bp and144-bp) by PCR amplification with composite primers [Nmult21:1F, Nmult21:2F, Nmult23:AF, Nmult22:InF, Nmult22:RR] (Fegan and Prior, 2005), and the bacterial strains could be identified as phylotype I (Asia group). In addition, the bacteria could use lactose, maltose, cellobiose, mannitol, sorbitol and dulcitol, according to the classification standard of Ralstonia biovar by Hayward (1964), the test bacterial strains could be identified as biovar III. PCR amplification of the endoglucanase gene (egl","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459008","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":"Thermotherapy via aerated steam is an effective alternative for non-chemical management of cryptic infection of strawberry by <i>Colletotrichum acutatum</i>.","authors":"Marcus Vinicius Marin, Nan-Yi Wang, Bill W Turechek, Natalia A Peres","doi":"10.1094/PDIS-03-24-0700-RE","DOIUrl":"https://doi.org/10.1094/PDIS-03-24-0700-RE","url":null,"abstract":"<p><p>Annual strawberry production in Florida is threatened by anthracnose, caused by <i>Colletotrichum acutatum</i>. This disease is often transmitted through quiescently infected transplants from strawberry nurseries. Managing anthracnose has become even more difficult in both nursery and fruit production fields since the rise of strains resistant to <i>QoI</i> fungicides. In this study, thermotherapy was evaluated as a potential alternative to manage the disease by reducing inoculum in plant stock. Initial laboratory assessments demonstrated that the germination of <i>C. acutatum</i> spores was entirely suppressed upon exposure to 44°C for 120 min, 48°C for 10 min, or 52°C for 5 min. Conversely, a minor proportion of <i>C. acutatum</i> spores (less than 10%) sustained viability, even after being subjected to 40°C for 240 min. Heat treatment of strawberry transplants at 44°C for 240 min, with or without a preheating step (37°C for 1 h), via aerated steam, significantly reduced the colonization of petioles by <i>C. acutatum</i>. Early season harvest data from field trials showed that heat-treated plants, with or without a pre-heating phase, had considerably lower fruit disease incidence and higher yield than the nontreated controls. These findings suggest that heat treatment via aerated steam might be a viable means to decrease C. acutatum inoculum in strawberry transplants, thereby reducing anthracnose in fruit-producing areas.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459051","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>Rhizoctonia solani</i> AG 5 causing stem lesion and root necrosis of mint in Idaho.","authors":"Christian J R Cumagun, Benjamin B Wood, Joshua Rosnow, James Warwick Woodhall","doi":"10.1094/PDIS-10-24-2154-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2154-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;In August 2023, disease symptoms were noted on mint plants (Mentha arvensis) in two southwest Idaho fields with 10 to 30% of the plants exhibiting dark brown stem lesions and root necrosis. To identify the causal agent, isolations from symptomatic tissue were conducted. The surface of the disease material was treated with sodium hypochlorite (0.6%) for 1 minute and washed three times using sterile water. Approximately 2 mm³ tissue sections were cultured on water agar supplemented with 0.02% penicillin and 0.08% streptomycin and incubated at room temperature for 3-5 days. Fungal colonies were tentatively identified as Rhizoctonia from right-angle branching and septate hyphal structures, slight constriction and septum near the branch base. Single hyphal tips were transferred to potato dextrose agar (PDA) and grown at room temperature. Approximately five isolates with a consistent macromorphology were observed. These isolates had light brown mycelia and produced 1-10 mm light brown to dark irregularly shaped sclerotia after a month at ambient temperature with no exposure to continuous light. A representative isolate, designated 23D360 was selected for sequencing and pathogenicity testing. Isolate 23D360 mycelia were removed with a scalpel after 7 days of growth for DNA extraction (Synergy Kit, OPS Diagnostics, N.J., USA) and sequencing of the rDNA internal transcribed spacer (ITS) region and translation elongation factor 1α (tef1α) (Sharon et al. 2008). For ITS a 693 bp amplicon was generated and the sequence was submitted to GenBank (Accession PQ068734). NCBI-BLAST indicated this sequence was 100% identical to an isolate previously identified as R. solani AG 5 (Accession MW999177). For tef1α a 708 bp amplicon was generated and the sequence was submitted to Genbank (Accession PV021964). This tef1α sequence also had a 100% identical match to a previously characterized R. solani AG 5 strain (Accession OP832176). Final confirmation of 23D360 was done using an AG 5 specific real-time PCR assay which targets the beta-tubulin gene (Budge et al. 2009). Pathogenicity testing was performed twice on thirteen 1-week-old mint transplants cultivar 'Black Mitcham Scottish' grown in premium potting compost (Scotts) in greenhouse conditions (30°C, 12h daylight). Barley seeds soaked in water overnight were autoclaved twice, inoculated with a mycelial plug of isolate 23D360 and incubated for 2 weeks at ambient room temperature (25°C). Barley seed inoculum (5 g) was placed around each transplant at the root and stem convergence point. Thirteen 1-week-old transplants were mock-inoculated with autoclaved barley seeds as a control. Approximately 23% damping-off incidence was observed on inoculated transplants five days post-inoculation, while control transplants remained healthy. At 21 days post-inoculation, plants were assessed for visible stem lesions and root necrosis. The incidence of stem lesions occurred on 80% of seedlings, with all transplants with stem les","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459012","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":"Pythium Root Rot of Wheat is not Suppressed by Indigenous 2,4-Diacetylphloroglucinol-Producing Pseudomonads in Take-All Decline Soils.","authors":"Raul Allende-Molar, Tim Paulitz, Linda Thomashow, Olga Mavrodi, David Michael Weller","doi":"10.1094/PDIS-09-24-2041-RE","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-2041-RE","url":null,"abstract":"<p><p>Take-all, caused by <i>Gaeumannomyces tritici</i> and Pythium root rot, caused by a complex of <i>Pythium</i> spp., are important diseases of wheat in Washington state, USA, and they often occur on the same plant. During wheat monoculture, a natural biocontrol of take-all known as take-all decline (TAD) develops from a buildup in the rhizosphere of 2,4-diacetylphloroglucinol (DAPG)-producing pseudomonads belonging to the <i>Pseudomonas fluorescens</i> complex. To determine if TAD also suppresses Pythium root rot, wheat seedlings were grown in two TAD soils and their homologous non-cropped virgin (conducive) soils amended with inoculum of <i>Pythium abappressorium</i>, <i>P</i>. (<i>Globisporangium</i>) <i>irregulare</i> group I, <i>P</i>. (<i>Globisporangium</i>) <i>irregulare</i> group IV or <i>P</i>. (<i>Globisporangium</i>) <i>ultimum</i>. TAD soils alone or mixed 1:9 with pasteurized conducive soil did not consistently reduce symptoms of Pythium root rot as compared to their homologous virgin (conducive) soils. In TAD and conducive soils, plant height, length of the first true leaf, number of root tips, and root lengths were similar. Wheat grown in <i>Pythium</i>-infested and non-infested TAD soils supported rhizosphere populations of DAPG-producing pseudomonads above 10⁷ CFU g^-1 of root. Mycelial growth of the <i>Pythium</i> spp. was inhibited in vitro by both DAPG-producers and synthetic DAPG. However, concentrations of DAPG required to inhibit mycelial growth of the <i>Pythium</i> spp. ranged from 15 to 30 µg mL^-1, which is 5-10 times greater than the dose reported to inhibit the take-all pathogen. In conclusion, Washington TAD soils do not suppress Pythium root rot of wheat.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459036","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":"Early-season predictions of aerial spores to enhance infection model efficacy for Cercospora leaf spot management in sugarbeet.","authors":"Alexandra P Hernandez, Chris Bloomingdale, Sarah Ruth, Erica Cushnie, Cheryl Trueman, Linda Hanson, Jaime F Willbur","doi":"10.1094/PDIS-10-24-2153-RE","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2153-RE","url":null,"abstract":"<p><p><i>Cercospora beticola</i> causes one of the most destructive foliar diseases of sugarbeet in many growing regions. Management of Cercospora leaf spot (CLS) relies heavily on timely and repeated fungicide applications. Current treatment initiation is often supported by models predicting conditions favorable for infection; however, these models lack information of <i>C. beticola</i> presence and abundance. Burkard volumetric mechanical samplers and highly CLS-susceptible sentinel beets (biological samplers) were used to assess early-season aerial <i>C. beticola</i> conidia from sugarbeet fields in Michigan and in Ontario, Canada from 2019-2022. In initial correlation and logistic regression analyses (n=449), duration of leaf wetness, air temperature, and wind speed were found to predict the risk of elevated <i>Cercospora</i> spore concentrations with 67.9% accuracy. In 2022 and 2023, a select model and a limited set of action thresholds, in addition to the BEETcast model, were tested for fungicide application timing. When CLS pressure was high, extending the interval between applications showed reduced management of CLS (<i>P</i> < 0.001), sugar percentage, and RWS (<i>P</i> < 0.05) compared to the grower standard. Model-based programs integrating canopy closure information resulted in CLS, yield, and sugar metrics comparable to the grower standard despite one less fungicide application. In additional training analysis (n=402), an ensemble model included leaf wetness, air temperature, relative humidity, and wind speed variables with a testing accuracy of 73.2% (n=101). Based on model development, refinement, and validation, assessment of elevated early-season <i>C. beticola</i> presence and abundance has potential to improve application timing and efficacy for preventative CLS management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143459004","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>Fusarium commune</i> causing damping off and wilt in <i>Cannabis sativa</i> (L.) in Pennsylvania.","authors":"Eden Stephania Blit, Sydney Gerstenberg, Richard N Philbrook, Jeremy Warren","doi":"10.1094/PDIS-10-24-2067-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2067-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Cannabis sativa is a crop prescribed for medical use in Pennsylvania, with an estimated state revenue of $1.5 billion dollars in 2023 (Cannabis Benchmarks, 2024). In August of 2023, mature Cannabis sativa plants at an indoor facility (102m2) in Chambersburg, PA, were observed with wilted yellowing leaves, browning stems/roots, and withering. Of the 490 plants at the facility, 70% displayed the described symptoms, likely exposed to the pathogen through the site's irrigation system. Cultivar \"BDC\" displayed the most severe symptoms; root samples from 3 soil-grown, mature, symptomatic \"BDC\" plants were harvested for testing. In a laminar flow hood, roots were surface sterilized with 3% sodium hypochlorite for 5 minutes, rinsed with sterile deionized water, cut into 1cm long with a heat-sterilized scalpel, and embedded into Potato Dextrose Agar (PDA) plates. After 2-3 days of incubation at 27°C, a fast-growing fungus with violet aerial mycelium and burgundy-colored bottom surface grew from all root segments. When plated on SNA, the mycelium was hyaline with some white aerial growth. The culture's morphology was consistent with Fusarium spp. (Mirghasempour SA, et al, 2022 & Yin, et al, 2022). DNA was extracted using Quick DNA Fungi/Bacterial Kit (Zymo Research Irvine, CA, USA). PCR was performed to amplify fungal RNAP II with RPB2 5f2F/7cR primers (Donnell et al., 2015 & O'Donnell et al., 2022) and TEF1 using primers Fa6/Ra7, followed by nested primers Fa/Ra (Karlsson et al., 2015). Amplicons were Sanger sequenced, trimmed, and compared to known sequences using BLAST. Amplicons from the isolates showed 100% identity to Fusarium commune accessions MH822055 (658bp/658bp) and MZ513475 (1778bp/1778bp) (Skovgaard, O'Donnell et Nirenberg). Consensus sequences were deposited in GenBank with accession numbers PP844864 (TEF1) and PP844863 (RPB2). PDA culture isolated from roots was diced and transferred to 500mL of V8 broth. A negative control was prepared using sterile PDA. The broths were placed on a shaker and incubated at 150 rpm and 27°C for 48 hours. Light microscopy revealed mycelial growth, microconidia and macroconidia in the inoculated suspension, as described in Chen, D et al (2023). Growth was absent in the control broth. To test Koch's postulates, each broth was diluted to 1L and 30 rockwool cubes (150 cm3) were soaked in the broths: 15 in the inoculated, 15 in the control. The stems of 30 unrooted \"BDC\" C. sativa cuttings were dipped in rooting gel (Clonex, Growth Technology, Somerset, UK) and embedded into the cubes. Cuttings were grown indoors, at 27°C for 14 days under LED lights with an 18-hour photoperiod. Inoculated cuttings displayed wilting/yellowing leaves, browning stem bases, and white mold growing on stems. Control cuttings had no disease symptoms and rooted successfully. Stem samples from 2 infected and 2 control cuttings were plated as previously described. After 48 hours at 27C, mycelial growth was observed from stems of infe","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143441340","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>Agroathelia rolfsii</i> Causing Southern Blight of <i>Alocasia</i> in Florida.","authors":"Marcus Vinicius Marin, Caitlin Sollazzo, Teresa E Seijo, Natalia A Peres","doi":"10.1094/PDIS-11-24-2473-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2473-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Alocasia 'Calidora' (NCSU, 2025), known as upright elephant ear, is an ornamental plant grown for its large, glossy leaves and architectural value. In September 2023, diseased Alocasia 'Calidora' plants were submitted by a commercial grower from Highlands County, FL, to the Diagnostic Clinic at the University of Florida's Gulf Coast Research and Education Center. The grower reported about 10% disease incidence in a field of about 3 ha with an estimated 30,000 plants. The plants, initially propagated from tissue-cultured starters and established in the greenhouse, were transplanted to the field. About three months after planting, symptoms including stunted growth, yellowing leaves, and bulb rot were observed, which were accompanied by dense white mycelia and sclerotia. Symptomatic tissues excised from infected bulbs were disinfested in a 10% bleach solution for 90s, rinsed twice with sterile water, and plated on a general isolation medium (Amiri et al. 2018). Plates were kept at 25°C and a 12-h photoperiod. A fungus producing white mycelia with round sclerotia which resembled those of Agroathelia rolfsii (Redhead and Mullineux, 2023) was consistently isolated in 28 out of 30 isolations . Three isolates were obtained by hyphal-tip of isolations from different tissue pieces. For morphological characterization, the same medium and conditions described above were used, 6 plates per isolate, and experiments were repeated once. Colonies had rapid growth, with an average daily radial growth of 7.2 ± 0.28 mm, covering the 100-mm diameter plate within 5 days. Abundant sclerotia (most spherical) were formed, initially white maturing to tan/dark brown. Mature sclerotia measured 1.4 ± 0.1 mm in diameter (n = 50). Ten-day cultures produced 556 to 2,032 sclerotia/plate (aver. = 1,379 ± 105). Clamp connections were observed. The internal transcribed spacer region (ITS; primers ITS1/ITS4, White et al. 1990), large subunit ribosomal ribonucleic acid (LSU; primers LROR/LR5, Vilgalys and Hester, 1990), and the alpha subunit of the elongation factor (EF-1α; primers EF595F/EF1160R, Kauserud and Schumacher, 2001) were sequenced and deposited in GenBank [accession nos.: PQ436344 to PQ436346 (ITS), PQ428904 to PQ428906 (LSU), PQ441996 to PQ441998 (EF-1α)]. BLASTn searches revealed isolates were 100% identical to an isolate of A. rolfsii (AFTOL-ID 664 = CBS 745.84; Paul et al., 2017) in ITS (DQ484062, 596/596 nt), LSU (AY635773, 1431/1431 nt), and EF-1α (GU187681, 1068/1068 nt) sequences. One isolate was selected to carry out pathogenicity assays in the greenhouse (aver. temperature = 26℃; ranging from 22 ̶ 28℃). Alocasia 'Calidora' plants (5 per inoculated and non-inoculated control treatments) were transplanted into 1-liter pots with 100 sclerotia from 10-day cultures placed on the surface of the potting soil. Control plants were not inoculated. Plants were drip irrigated three times a day (10 seconds per cycle). The trial was repeated once. At 12 weeks, ~80% of i","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143449734","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>Botrytis cinerea</i> Causing Leaf Spot on <i>Tinospora sagittata</i> in China.","authors":"Gaolei Cai, Yang Zhou, Mingqing Han, Han Zhang, Siru Yang, Zhongxin Lu, Pinghua Wu, Zunwei Ke","doi":"10.1094/PDIS-06-24-1186-PDN","DOIUrl":"10.1094/PDIS-06-24-1186-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Tinospora sagittata (Oliv.) Gagnep. (Tinosporeae) has been used in traditional Chinese medicine in the Chinese pharmacopoeia. In October of 2023, a leaf spot on T. sagittata with incidence of about thirty percent was observed in an herbal nursery at Yunyang District of Shiyan City, Hubei province in China (110°49' 28''E, 32°46'14''N). Initial symptoms included irregular chlorosis, necrotic lesions and grey mold layer with dark brown borders appearing on the leaf tips and margins. After 10 days or so, the lesions spread to cover the entire leaf, with further development leading to leaf desiccation and death. For isolating the pathogens, 6 leaves with disease symptoms were randomly collected and 12 pieces (5mm2) including the diseased and healthy tissues were firstly sterilized with 75% ethanol, then were sterilized with sodium hypochlorite. After rinsing with sterile water three times, samples were plated onto potato dextrose agar (PDA) at 25°C in the dark for 7 days. Twelve isolates (TSJG1-12) with similar morphology were obtained after 7 days, from which TSJG2 was selected as a representative isolate for further study. The initial colony was gray white, and the mycelium grew vigorously. In the later stage, black irregular sclerotia started to form after 10 day incubation on PDA media. Conidia were 7.24-14.36×6.10-10.42 μm (n=50), hyaline, ovoid or ellipsoid in shape. The strain TSJG2 was tentatively identified as Botrytis cinerea based on the morphological characteristics (Ellis 1971). Genomic DNA was extracted from its mycelia, using a commercial DNA extraction kit (Tsingke Biotechnology Co., Ltd, Wuhan, China). Four genes encoding the internal transcribed spacer region of rDNA (ITS), β-tubulin (TUB2), heat shock protein (HSP60), RNA polymerase subunit II second largest subunit (RPB2) were amplified specific primers ITS1/ITS4, bt2a/bt2b, HSP60-F/HSP60-R and RPB2-F/RPB2-R respectively (Aktaruzzaman et al., 2022; Lu et al., 2023). The sequences were generated and deposited into GenBank with accession numbers PP425840 (527bp), PP471570 (430bp), PP476363 (1031bp), PP442152 (1224bp) for ITS, TUB2, HSP60 and RPB2. The sequences showed 99-100% similarity to the reference strain of Botrytis cinerea (ITS TUB, HSP60 and RPB2 sequence accession numbers MT495453.1, ON238899.1, MF468109.1 and MH479932.1, respectively). Based on morphological and molecular features, the strain TSJG2 was identified as Botrytis cinerea. The suspension with a concentration of 1x106 spores/mL was inoculated on 10 unwounded 1-year-old leaves of T. sagittata. Sterile water was inoculated on 10 healthy plant leaves as control. All treated plants were placed in a greenhouse at of 22℃with high humidity 75%. All inoculated leaves showed chlorosis and black-brown necrotic lesions on leaves after 5 days, whereas control leaves were asymptomatic. Pathogens were reisolated from the diseased leaves and identified as B. cinerea based on its morphological and molecular characteristics,","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468790","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}