Plant disease最新文献

{"title":"First report of <i>Ralstonia pseudosolanacearum</i> phylotype I sequevar 14 causing bacterial wilt on tomato (<i>Solanum lycopersicum</i>) and eggplant (<i>Solanum melongena</i>) in North Carolina, USA.","authors":"Prem Magar, Alejandra I Huerta, Gilles Cellier, Frank Louws, Tika Adhikari","doi":"10.1094/PDIS-11-24-2377-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2377-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Ralstonia solanacearum species complex (RSSC) consists of three species, including R. solanacearum, R. pseudosolanacearum, and R. syzygii. The K60-type strain of R. solanacearum was isolated from a wilted 'Marglobe' tomato in Raleigh, North Carolina (NC) in 1953 (Kelman 1954). It is classified as phylotype IIA, sequevar 7 (Prior and Fegan 2005). In July 2023, during a field visit in Eastern NC, patches of &gt;50 eggplant (Solanum melongena cv. Pingtung Oriental) and tomato (Solanum lycopersicum cv. Saybrook) plants showing wilt symptoms were observed in a 1 ha field. Two plants from each host were collected from this site and tested positive for bacterial streaming in sterile deionized water for 2 min. One plant from each host was used for bacterial isolation by plating a 10 μl aliquot of the resulting bacterial streaming suspension on triphenyl tetrazolium chloride (TZC) medium (Kelman 1954) and incubated at 28°C for 48 hr. Multiple fluidal white colonies with a pink center and irregularly round morphology reminiscent of strains in the RSSC were observed on all plates. Only one colony from each plant host, NG-RL and EP-RL from tomato and eggplant, respectively, was selected for molecular characterization. Neither strain amplified the 357 bp band and was not R. solanacearum Select Agent (Opina et al. 1997). Genomic DNA from both NG-RL and EP-RL generated the 280 bp and 144 bp bands and confirmed as R. pseudosolanacearum phylotype I using the RSSC multiplex PCR (Fegan and Prior 2005). To determine sequevar, the primers Endo-F/Endo-R (Poussier et al. 2000; Fegan and Prior 2005) were used to sequence the partial endoglucanase (egl) gene from EP-RL and NG-RL (GenBank accessions: PQ554799 and PQ554800). These sequences were compared to publicly available egl sequences from GenBank and Cellier et al. (2023). A maximum likelihood phylogenetic tree showed that both NG-RL and EP-RL clustered with reference strains PSS81, MLI71-15, and Zo4 with 100% identity, confirming NG-RL and EP-RL are R. pseudosolanacearum phylotype I sequevar 14. To fulfill Koch's postulates, NG-RL and EP-RL inoculant was prepared from 48 h cultures grown on TZC plates at 28°C. Plates were flooded with sterile deionized water and then transferred to a falcon tube, adjusting O.D. 600 to 0.2 (~1×108 CFU/ml). The roots of six-week-old eggplants (cv. Black Beauty) and tomatoes (cv. Bonny Best) were wounded by running a scalpel through the soil 2 cm from the stem. This was repeated on six plants for both NG-RL and EP-RL. Mock-inoculated plants treated with sterile deionized water (SDW) served as controls. Plants incubated at 28°C in the greenhouse showed bacterial wilt symptoms nine days post-inoculation. R. pseudosolanacearum phylotype I sequevar 14 was confirmed from all bacteria-inoculated plants using the multiplex PCR and egl sequencing methods described above. No symptoms or bacteria were isolated from SDW mock-inoculated plants. There have been no prior reports of R. pseudosolan","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543052","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 Alternanthera mosaic virus infecting <i>Pereskia aculeata</i> in Brazil.","authors":"Marcelo Eiras, Alexandre Chaves, Fernanda Padua Del Corona, Jandson José do Vale Guimarães, Vinicius Henrique Bello, Elliot W Kitajima, Pedro Luis Ramos-González","doi":"10.1094/PDIS-01-25-0057-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-01-25-0057-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Pereskia aculeata Miller is a climbing cactus, native to native to tropical areas of the Americas, whose leaves are used in cooking and folk medicine. Known as \"Barbados gooseberry\", \"leaf cactus\" and \"ora-pro-nóbis\" (OPN), it is considered an unconventional food plant, valued for its high protein and mineral content, offering sustainable healthy food options. In 2024, three OPN plants displaying ringspots, mosaic and leaf distortion were collected in a vegetable garden at the Instituto Biológico, São Paulo, Brazil. Elongated and flexuous particles were observed in negatively stained extracts from OPN symptomatic leaves under a transmission electron microscope (TEM). Ultrathin sections of these tissues revealed the presence of aggregates of elongated particles, presumably viral, and unknown crystalline structures in epidermal and mesophyll cells. RNA extracts were isolated using TRIzol® (ThermoFisher Scientific) and analyzed by high-throughput sequencing (HiSeq 2500 Technology, 2x150 nt paired-end reads, Illumina, San Diego, CA, USA). Bioinformatic analyses of the generated library (15.9 million row reads) revealed the complete genome (6,652 nucleotides, GenBank accession PQ650655) of an isolate of Alternanthera mosaic virus (AltMV, Potexvirus alternantherae) with a mean coverage of 14.000x. This Brazilian isolate, named AltMV_BR1, shared 94.7% nucleotide sequence identity with the genome of AltMV isolates detected in a phlox (Phlox stolonifera) plant identified in the state of Pennsylvania, USA (RefSeq NC_007731). For validation, RNA extracts from the original samples were tested by RT-PCR using primers (Potex5: 5'-CAYCARCARGCMAARTGAYGA-3'/ Potex1RC: 5'-TCAGTRTTDGCRTCRAARGT-3') designed to anneal in the RdRp gene of potexviruses (Van der Vlugt and Berendsen 2002). Amplified fragments (expected size of 735 bp) were sequenced (GenBank accession PQ811939) and the presence of the AltMV was confirmed. The host range of this isolate was evaluated by mechanical inoculation on several cactus species, including OPN, as well as indicator plant species previously described as hosts of AltMV. OPN plants showed mosaic and leaf distortion, whereas Pereskia grandifolia plants expressed local necrotic rings and systemic chlorotic rings. Dragon fruit (Hylocereus undatus) and orchid cactus (Epiphyllum sp.) plants were infected but remained asymptomatic. Necrotic local lesions were observed on Gomphrena globosa. Local chlorotic lesions were detected on Chenopodium amaranticolor and C. quinoa, which developed into systemic infections on plants of both species. Amaranthus viridis and Portulaca oleracea plants also developed infections, resulting in systemic chlorosis and leaf crinkling, respectively. The presence of the virus in these hosts, as well as in the original host, was confirmed with a specific polyclonal antiserum (kindly provided by Dr. J.E. Thomas, Queensland Horticulture Institute, Australia) against AltMV by PTA-ELISA and TEM through detection of","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543074","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 Brown Leaf Spot of Potato in South India.","authors":"Shajith Basha Jaffer, Parthiban V Kumaresan, Iruthayasamy Johnson, Sambasivam Periyannan, Muthusamy Karthikeyan","doi":"10.1094/PDIS-10-24-2065-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2065-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Potato (Solanum tuberosum L.), as one of the major food crops, is cultivated in both temperate and subtropical climatic regions worldwide. During the field survey conducted in December 2023, black to brown colored spots with dark brown to black margins were observed in the leaves of the potato cultivar Kufri Jyothi, grown annually to monitor pest and disease incidence at the Indian Council of Agricultural Research (ICAR) - Central Potato Research Institute (CPRI) Research Station, Ooty, Tamil Nadu, India (Latitude - 11.370796 N, Longitude - 76.664094 E, Elevation - 2110 m above mean sea level. As the disease progressed, the spots were scattered throughout the leaves and coalesced to form necrotic lesions. The disease incidence reached 40 - 45%, attributed by airborne inoculum spread. Tissues collected from the margin of the infected leaf (5 × 5 mm) were surface disinfected with 1% NaOCl for 1 min, 70% ethanol for 30 sec and rinsed with sterilized water for three consecutive times before incubation at 25 ± 1°C on the potato dextrose agar (PDA) medium for pathogen culturing. Five cultures were obtained through single spore isolation and denoted as PTAA-01 to PTAA-05. The colony morphology of all five isolates was identical, with a greyish-brown and black appearance on the upper and undersides of the Petri dishes. The mycelia were septate, light grey and had a geniculate brown conidiophore with a short conidial chain. Conidia were brown, short-beaked, obclavate to obpyriform in shape, one to six and zero to two transverse and oblique septa. The dimensions of the conidia (n = 50) are 18 - 53 x 9 - 14 (length × width) µm. Morphological characters of the pathogen were consistent with Alternaria alternata (Fr.) Keissl, described earlier by Simmons (2007). Genomic DNA was extracted from the representative isolate PTAA-01 using CTAB method (Murray and Thompson 1980). PCR was performed with primers ITS1 / ITS4 targeting internal transcribed spacer (ITS) sequence (White et al. 1990), gpd1/gpd2 for glyceraldehyde-3-phosphate dehydrogenase (GAPDH), PG3/PG2b for endopolygalacturonase (EndoPG), Alt a1F/Alt a1R for Alternaria major allergen gene and EF1-728F/EF1-986R for translation elongation factor (TEF) 1-α (Woudenberg et al. 2015). Amplified products were sequenced and deposited in NCBI GenBank with accession numbers; PP864706 (ITS), PP943430 (GAPDH), PP968830 (EndoPG), PQ031066 (Alt a1) and PQ031067 (TEF1-α) and all shared &gt; 99% identity with A. alternata (GenBank accession numbers: MN919390, KX226447, KP123997, OK040811, and MZ648042), respectively. A neighbour-joining phylogenetic tree was constructed based on concatenated sequences of ITS, GAPDH, EndoPG, Alt a1, and TEF1-α using MEGA 11, where PTAA-01 isolates formed a clade with the strain of CBS 916.96 of A. alternata. For pathogenicity test, the conidial suspension (106 spores/ml) prepared from 15 days old culture was spray inoculated on one-month-old potato cultivar Kufri Jyothi in triplicates ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543047","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":"Vascular Streak Dieback: A Novel Threat to Redbud and Other Woody Ornamental Production in the United States.","authors":"Prabha Liyanapathiranage, Farhat A Avin, John Bonkowski, Janna L Beckerman, Michael Munster, Denita Hadziabdic, Robert N Trigiano, Fulya Baysal-Gurel","doi":"10.1094/PDIS-04-24-0905-FE","DOIUrl":"10.1094/PDIS-04-24-0905-FE","url":null,"abstract":"<p><p>Eastern redbud (<i>Cercis canadensis</i> L.) is a popular and high-value woody ornamental plant native to the Eastern and South Central United States. In recent years, redbud production in the Southeastern United States has been greatly affected by a novel threat: vascular streak dieback (VSD). Infected plants exhibit a common set of symptoms, including leaf scorch, tip dieback, and vascular streaking that creates a marbled pattern in stem cross-section. Based on both conventional diagnosis and molecular identification, it has been found that the fungus <i>Ceratobasidium</i> sp. D.P. Rogers (<i>Csp</i>) is consistently associated with VSD-symptomatic eastern redbuds. However, the causal agent(s) of VSD has not yet been conclusively confirmed. Although eastern redbud has been the most frequently identified host tree, more than 25 other native plant genera have been confirmed to have VSD associated with <i>Csp</i>. The near-obligate nature of this fungus has made it challenging to culture, extract DNA, and conduct further studies to confirm its pathogenicity. This article highlights the emerging challenges of VSD, focusing on the following: (i) the recent history of VSD; (ii) the increasing importance of VSD to woody ornamental nursery production in the United States; (iii) the currently available protocols for isolating, culturing, storing, and maintaining the putative causal agent; (iv) the rapid molecular detection of <i>Csp</i>; (v) phylogenetic findings on the origin and relatedness of <i>Csp</i> to previously recorded diseases, especially VSD in cacao (<i>Theobroma cacao</i> L.); and (vi) preliminary results and observations from fungicide trials and cultivar screening in Tennessee. The article also outlines research needed to comprehensively understand VSD and accelerate the development of effective management strategies.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS04240905FE"},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141907401","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>Pectobacterium aroidearum</i> Causing Soft Rot on Pear Fruit in China.","authors":"Shangbo Jiang, Jin Zhang, Di Yang, Chan Juan Du, Yunfeng Ye, Lian Fu Pan, Gang Fu","doi":"10.1094/PDIS-10-24-2204-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2204-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Pear (Pyrus pyrifolia) is an economically important fruit and widely planted in China. In September 2023, soft rot disease was observed on more than 20% of pear fruits (cv. Jinghua) in a plantation of approximately 1.0 ha of Shilin County, Kunming City, Yunnan Province, China. The initial symptoms manifested as water-soaked lesions. Then, they rapidly expanded and covered the whole fruit, which was soft and necrotic. At severe stage, infected fruits turned brown and dropped prematurely. To isolate and identify the causal pathogen, two diseased fruits were collected and pieces of rotted fruit tissue were cut into small fragments (5×5 mm), disinfested in 75% ethanol (30 s) and 2% sodium hypochlorite (60 s), and rinsed three times with sterile distilled water. The sterilized sections were soaked in 2 ml of sterile water and shaken for 3 min in a vortex oscillator. The suspension was streaked on Luria-Bertani (LB) agar medium. After incubation at 28°C for 36 h, single colonies were restreaked three times to obtain purified isolations. Thirteen bacterial strains with similar morphology were isolated from different fruits (seven strains in one fruit and six in the other), and their colonies were yellowish white, round, and convex with smooth surfaces on the LB agar plates. Representative strains YNPA1 and YNPA2, isolated from different fruits, were selected for further analyses. The two strains were Gram-negative, tested negative for citrate and catalase, but positive for sucrose and glucose. The 16S rRNA gene of these strains (GenBank accession nos. PP917741, PP917742) was amplified using primer pair 27F/1492R and sequenced. BlastN searches revealed that the obtained sequences shared &gt;99% identity with Pectobacterium aroidearum type strain (GenBank accession no. NR_159926). A multilocus sequence analysis based on concatenated sequences of five housekeeping genes was conducted, of which gyrA (product sizes: 987bp, GenBank accession no. PP928290, PP928291), icdA (589bp, PP928292, PP928293), mdh (547bp, PP928288, PP928289), proA (734bp, PP928294, PP928295), and rpoS genes (892bp, PP928296, PP928297) was amplified, using primer pair gyrA1/gyrA4, icdA400F/icdA977R, mdh86F/mdh628R, proAF1/proAR1, rpoS1/rpoS2, respectively (Ma et al. 2007; Waleron et al. 2008). The reconstructed maximum likelihood tree (Tamura-Nei model; with 1,000 bootstrap replicates) showed that strains YNPA1 and YNPA2 clustered with strains of P. aroidearum. Pathogenicity tests were performed on three healthy pear fruits by injecting 10 μl of bacterial suspensions of P. aroidearum strains YNPA1 and YNPA2 (108 CFU/ml), respectively; another three healthy control pear fruits were injected with 10 μl of sterile water. All tested fruits were covered with plastic bags and incubated at 28°C and 80% humidity in a growth chamber. After 3 days, all inoculated pear fruits showed soft rot symptoms resembling those observed in the plantation, while control fruits remained symptom-free. Bacteri","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543050","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":"Chemical Management Strategies for Halo Blight of Hop and In Vitro Sensitivity of <i>Diaporthe humulicola</i> Populations to Various Fungicide Classes.","authors":"Ross J Hatlen, Mary K Hausbeck, Madeline J Anthony, Roger Sysak, Randy Smith, Timothy D Miles","doi":"10.1094/PDIS-08-24-1611-RE","DOIUrl":"10.1094/PDIS-08-24-1611-RE","url":null,"abstract":"<p><p>Halo blight of hop, caused by <i>Diaporthe humulicola</i>, has increased in eastern North America since 2018. When left untreated, the disease can cause yield loss ranging from 17 to 56%. Currently, there are no fungicides registered for use on halo blight of hop. From 2020 to 2022, field trials were conducted using 10 fungicides registered for use on powdery and downy mildew of hop to determine their efficacy against halo blight. To validate field results, the effective concentration of fungicide required for 50% growth inhibition (EC₅₀) value was determined for each active ingredient including flutriafol, tebuconazole + fluopyram, cyflufenamid, and trifloxystrobin + salicylhydroxamic acid (SHAM). Each fungicide tested had an EC₅₀ value less than 50 ppm. A discriminatory dose was used to test the sensitivity of 206 <i>D. humulicola</i> isolates collected from the eastern United States and Canada in a poison agar assay. Results showed that tebuconazole + fluopyram decreased the incidence and severity of halo blight in the field. Also, this fungicide combination had EC₅₀ values of 2.26 × 10^-1 ppm and significantly reduced the growth of most of the isolates tested. Trifloxystrobin + SHAM decreased the presence of halo blight in the field trial, but some isolates were less sensitive in discriminatory dose testing. Our results show that fungicides in FRAC groups 3, 7, and 11 were the most effective to control halo blight. Analyses of field trials showed a positive correlation between the severity of early-season downy mildew infections and late-season halo blight infections.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS08241611RE"},"PeriodicalIF":4.4,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142351916","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 of a Recombinase Polymerase Amplification Assay for Rapid Detection of the New Root-Lesion Nematode <i>Pratylenchus dakotaensis</i> on Soybean.","authors":"Roshan Dhakal, Intiaz Amin Chowdhury, Addison Plaisance, Guiping Yan","doi":"10.1094/PDIS-05-24-1133-RE","DOIUrl":"10.1094/PDIS-05-24-1133-RE","url":null,"abstract":"<p><p>Root-lesion nematodes, <i>Pratylenchus</i> spp., are reported to cause serious yield losses in various crops, including soybean. A new root-lesion nematode species was detected in 2015 in a soybean field in North Dakota (ND) and named <i>Pratylenchus dakotaensis</i> in 2021. Nematode detection and differentiation from other species are critical in management strategies. Thus, a recombinase polymerase amplification (RPA) assay was developed for rapid detection of this nematode from field soils under isothermal conditions. New primers and probes were designed from internal transcribed spacer-ribosomal DNA region of the nematode genome and tested for both specificity and sensitivity. The RPA assay was able to detect DNA from a single adult nematode at 39.5°C in 20 min using both TwistAmp Basic and Exo Kits. The specificity of the primers was initially confirmed through in silico analyses and followed by laboratory tests. The assay successfully amplified DNA from the target species, although no amplification occurred for other <i>Pratylenchus</i> spp. and non-<i>Pratylenchus</i> control species. Sensitivity testing with real-time RPA revealed its ability to detect DNA in dilutions equivalent to 1/32 of a single nematode from DNA extracted from inoculated sterile soil. To further validate the assay, it was tested with 19 field soil samples collected in ND. This assay amplified soil DNA extracts of all <i>P. dakotaensis</i>-infested field samples confirmed through conventional PCR. It did not amplify DNA from 13 other field soils infested with other <i>Pratylenchus</i> spp. This is the first report of RPA development for detecting a root-lesion nematode species. The RPA assay developed can help in the rapid detection of this nematode species for effective nematode management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS05241133RE"},"PeriodicalIF":4.4,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142351919","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 and Fungicide Sensitivity of <i>Colletotrichum</i> spp. from <i>Capsicum</i> Peppers in South Korea.","authors":"Yeong Ung Shin, Oliul Hassan, Taehyun Chang","doi":"10.1094/PDIS-07-24-1486-SR","DOIUrl":"10.1094/PDIS-07-24-1486-SR","url":null,"abstract":"<p><p><i>Capsicum</i> peppers, peppers from plants of the genus <i>Capsicum</i> (family Solanaceae), are widely cultivated in South Korea, where annual production was 92,756 tons in 2021, 54.4% higher than that of the previous year. Occurring throughout the production cycle, anthracnose is a major disease limiting commercial <i>Capsicum</i> pepper production worldwide, including in South Korea. This study investigates the diversity and pathogenicity of <i>Colletotrichum</i> species responsible for <i>Capsicum</i> pepper anthracnose in Gyeongbuk, South Korea, focusing on disease incidence and symptomatology in the field and the identification, morphological characteristics, pathogenicity, and fungicide sensitivity of the causative species. Disease incidence ranged from 30 to 50%, with samples categorized into three distinct symptom types, aiding accurate field diagnosis. Phylogenetic analysis classified 41 isolates into six species in the <i>C. acutatum</i>, <i>gloeosporioides</i>, and <i>truncatum</i> species complexes, revealing significant genetic diversity. Morphological characterization supported these identifications, providing a comprehensive profile. Pathogenicity tests confirmed that all identified species induced typical anthracnose lesions, with lesion size variations suggesting differential aggressiveness. Temperature significantly influenced mycelial growth, with optimal growth between 20 and 26°C and <i>C</i>. <i>truncatum</i> demonstrating high temperature tolerance. In vitro fungicide sensitivity tests showed variable responses, with tebuconazole being generally effective. These findings underscore the need for species-specific fungicide recommendations and highlight the importance of continuous monitoring of <i>Colletotrichum</i> species. Future research should explore the molecular mechanisms of pathogenicity, host specificity, and fungicide resistance, integrating these findings with breeding programs to develop resistant pepper varieties. This study provides critical insights for effective anthracnose management in pepper cultivation and future research directions.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS07241486SR"},"PeriodicalIF":4.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142351914","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":"Four antimicrobial compounds and ISR induction are involved in biocontrol of crown gall disease by the plant beneficial rhizobacterium <i>Bacillus velezensis</i> FZB42.","authors":"Xu Qin, Yueting Xiao, Qin Xiong, Wei-Liang Kong, Rainer Borriss, Zhaoliang Gao, Ben Fan","doi":"10.1094/PDIS-10-24-2085-RE","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2085-RE","url":null,"abstract":"<p><p>Crown gall disease (CGD), which is caused by the bacterium Agrobacterium, is a common plant disease that often results in significant economic losses. Biocontrol offers an environmentally friendly and sustainable method to control CGD. In this study, we investigated the biocontrol effect and mechanism of CGD in Japanese cherry trees by B. velezensis FZB42, a prototype strain of the plant growth promoting rhizobacteria (PGPR). We found that the B. velezensis FZB42 mutants unable to produce one or a combination of four antimicrobial compounds (surfactin, macrolactin, bacilysin, and difficidin) significantly reduced their inhibitory activities against A. tumefaciens XYT-58 and their ability of controlling the occurrence of CGD. Using the purified compounds, we further demonstrated that bacilysin and surfactin can inhibit the growth of XYT-58 in vitro. Inoculation with B. velezensis FZB42 significantly increased the expression of genes related to the jasmonic acid (JA), ethylene (ET), and salicylic acid (SA) pathways in cherry seedlings when they were infected with XYT-58. To our knowledge, this is the first report that bacilysin and difficidin can also suppress the growth of Agrobacterium. Furthermore, our results indicate that multiple antimicrobial compounds and induced systemic resistance (ISR) are involved in the biocontrol of CGD by B. velezensis. The mechanism elucidated here provides guidance for the development and application of this type of PGPR strain in the biocontrol of CGD.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143468794","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":"Yellow dwarf viruses: aphid transmission efficiency and cereal host range.","authors":"Narelle Nancarrow, Brendan Rodoni, Shu Kee Lam, Piotr Trębicki","doi":"10.1094/PDIS-11-24-2523-RE","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2523-RE","url":null,"abstract":"<p><p>Yellow dwarf viruses (YDVs) are transmitted by aphids and can significantly reduce grain yield in cereals worldwide. While barley yellow dwarf virus PAV (BYDV PAV) has long been present in Australia, the YDV species barley virus G (BVG) and barley yellow dwarf virus PAS (BYDV PAS) were reported for the first time more recently. Little data about the transmission and host range of BVG has been published worldwide, while epidemiological information about BVG and BYDV PAS in an Australian context is limited. Therefore, glasshouse experiments were conducted to examine the efficiency of the bird cherry-oat aphid (Rhopalosiphum padi), corn leaf aphid (<i>Rhopalosiphum maidis</i>), rose grain aphid (<i>Metopolophium dirhodum</i>) and Russian wheat aphid (<i>Diuraphis noxia</i>) to transmit BVG, BYDV PAS and BYDV PAV. BYDV PAS and BYDV PAV were transmitted at similar rates by each of the four aphid species. Although BVG was most efficiently transmitted by the corn leaf aphid, it was also transmitted, albeit less efficiently, by the bird cherry-oat aphid. Significantly, in our study, the corn leaf aphid transmitted BVG at a much higher rate (63%) using single-aphid inoculations than had previously been reported by others (7%). Varying levels of susceptibility were observed in host range experiments, and four additional BVG hosts were identified. Russian wheat aphid did not transmit any of the viruses examined. These results have implications for YDV management while also demonstrating the complexity and specificity of the relationships between YDVs, the aphids that transmit them and the plant hosts that they infect.</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":"143458527","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}