Plant disease最新文献

{"title":"Genetic Diversity of Cotton Leafroll Dwarf Virus from the Southwestern United States and Its Implications for the Multi-Introduction Event Hypothesis and Future Evolution.","authors":"Connor Ferguson, Akhtar Ali","doi":"10.1094/PDIS-05-24-0952-SR","DOIUrl":"10.1094/PDIS-05-24-0952-SR","url":null,"abstract":"<p><p>Cotton leafroll dwarf virus (CLRDV) is a viral agent recently identified in the United States in 2017 in Alabama. Since its identification, CLRDV has spread to every cotton-growing state east of New Mexico. Oklahoma, Kansas, and Texas make up the westernmost border of reported CLRDV incidence, making monitoring of these states vital for proper control. Additionally, as the virus evolves, mutations that alter symptomology, such as mutations in the F-box-like motif in ORF0/P0, may occur and need to be monitored thoroughly during the growing seasons. Using high-throughput sequencing and PCR-derived Sanger sequencing, 4 CLRDV genomes and 21 P0 gene isolates were sequenced from Oklahoma, Kansas, and Texas from 2019 to 2021 to determine the genetic diversity among CLRDV isolates. Phylogenetic analyses of the complete genomes revealed seven clades, whereas ORF0 gene analyses resulted in large polytomic clusters. BEAST analyses of the 114 total P0 sequences from GenBank, downloaded before 2024, revealed a lower mean substitution rate than previously reported as well as an earlier root year (1914). In addition, using all available CLRDV genome sequences, 11 likely recombination events were determined. Examination of the P0 amino acid sequences revealed 13 mutations unique to the isolates collected in this study. Based on the phylogenetic and amino acid analyses, the CLRDV isolates from Texas (TX clade) may represent evidence for the multi-introduction event hypothesis into the United States. Additionally, based on our analyses in this study, we propose the Asian CLRDV isolates should be constituted as a potentially separate strain of CLRDV.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS05240952SR"},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141902607","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 Anthracnose on <i>Asparagus kiusianus</i> caused by <i>Colletotrichum</i> spp. in Japan.","authors":"Jingyi Wang, Masaru Matsumoto","doi":"10.1094/PDIS-10-24-2216-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2216-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Asparagus kiusianus Makino, a native and endangered wild plant of the asparagus genus, is endemic to Northern Kyushu's coastal area in Japan (Ito et al. 2011). In July 2022, symptoms of a disease characterized by stem browning and dark brown patches were observed on wild A. kiusianus plants along the Nijinomatsubara coast (33°26'45.24\"N 130°00'10.44\"E) in Saga Prefecture, Japan, with an incidence rate reaching 20%. Thirty symptomatic stem segments (approx. 1 cm) were collected for detailed examination. Samples were surface sterilized with 70% ethanol for 30 s, followed by immersion in 5% sodium hypochlorite for another 30 s. After three rinses in sterile water, they were placed on Potato Dextrose Agar (PDA) and incubated in the dark at 25°C for 7 days. Five representative isolates were identified based on morphology and named as AKW 22.207, AKW 22.208, AKW 22.212, AKW 22.302 and AKW 22.306. For AKW 22.207, AKW 22.208, and AKW 22.302, the colonies were flat and orange, with the center and surrounding areas displaying a black coloration. The conidia were slightly curved, hyaline, unicellular, aseptate, and fusiform with blunt ends, measuring 11.5 to 23.6 μm in length and 2.2 to 3.1 μm in width (n = 20). For AKW 22.212, the colony was fluffy and grayish-brown, with a dark brown reverse side. Extracellular pigment caused a reddish-brown discoloration in the PDA medium. The conidia were falcate, hyaline, unicellular, aseptate, and fusiform, tapering gradually to each end, measuring 17.6 to 24.4 μm in length and 1.8 to 3.0 μm in width (n = 20). For AKW 22.306, the colony initially appeared white, then developed gray aerial mycelium and produced yellow and black acervuli. The conidia were hyaline, unicellular, aseptate, and cylindrical in shape, measuring 13.7 to 17.8 μm in length and 3.8 to 5.3 μm in width (n = 20). Fungal DNA extraction was performed, using the DNeasy Plant Mini Kit (manufactured by QIAGEN). PCR amplification targeted the ITS, ACT, and GAPDH regions using the primers ITS1 / ITS4 (White et al. 1990), ACT-512F / ACT-783R (Carbone et al. 1999) and GDF / GDR (Templeton et al. 1992), respectively. The obtained sequences were deposited in GenBank (ITS, LC790306 to LC790310; ACT, LC790312 to LC790316; GAPDH, LC790317 to LC790321). A phylogenetic tree was constructed using RAxML 8.2.12 software, which identified one isolate as Colletotrichum fructicola (AKW 22.306), one as C. guizhouense (AKW 22.212), and three as C. liriopes (AKW 22.207, AKW 22.208 and AKW 22.302). Six healthy A. kiusianus plants were inoculated, five with different isolates and one as a control. Stems were washed, wounded, and inoculated with isolate discs, secured with bandages and parafilm. A sterile PDA disc was used for the control. Plants were incubated at 25°C under a 14-hour light/10-hour dark cycle. The experiment was repeated twice for reproducibility. After one week, stem browning occurred, and all Colletotrichum isolates were successfully re-isolated. The m","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142802038","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 postharvest fruit rot of sweet orange in Anhui province, China.","authors":"Zhiqiang Song, Chao Chen, Ting Yu, Yaqian Zhang, Hengsheng Wang, Decong Xu","doi":"10.1094/PDIS-08-24-1654-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1654-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;As an important cash crop, sweet orange (Citrus sinensis Osbeck cv. Newhall) is globally cherished by consumers for its health-promoting properties. March 2024, orange postharvest rot was found in three markets in Anqing, Anhui Province, China, with an incidence of 15% to 20%. The initial symptom was the appearance of small, light to dark brown spots on the surface of the fruit, which later expand and cause the fruit to rot. To isolate the pathogen, ten 5 × 5 mm pieces of symptomatic tissue from the infected oranges were surface sterilized in 1% Sodium hypochlorite for 60 s, rinsed three times with sterile water, and plated onto potato dextrose agar (PDA) at 25°C for 7 days. The pure culture was obtained by transferring single-spore isolates to fresh PDA medium. Ten isolates with similar morphological characteristics were isolated, and all of the colonies were dark brown with white margins and abundant aerial mycelium and sporulation. Conidia were pale to dark brown in chains or singly and were obclavate to obpyriform, measuring 5.6 to 28.0 × 4.7 to 16.3 μm (n = 30) with 1 to 5 transverse septa and 0 to 3 longitudinal septa. Their morphological characteristics were consistent with the description of Alternaria sp. (Simmons 2007). For molecular identification, we arbitrarily selected five isolates and named them CZ-1 to 5 for further investigation. The genomic DNA of CZ-1 to 5 was extracted, and the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (TEF1) gene, and partial sequence of the β-tubulin (TUB2) gene were amplified with primers ITS1/ITS4, TEF1-F/TEF1-R (Zhang et al. 2020), and T1/T2 (O'Donnell and Cigelnik 1997), respectively. Sequences of the three loci from the representative isolate CZ-1 were deposited in GenBank (PP911430, PP928092, and PQ040398) and shared 100% nucleotide identity with Alternaria alternata sequences FJ717733, MH708309, and MN175551, respectively. A phylogenetic analysis was conducted using MEGA11 based on concatenated sequences of the three sequences, indicating that the isolates were closely clustered with reference strains of A. alternata. To evaluate pathogenicity, six surface-sterilized orange fruit with or without wounding were inoculated with a 20-μl drop of spore suspension (1 × 106 conidia/ml) of the isolates CZ-1 and -2. Another six fruit treated with sterile water with and without wounding were used as controls. All fruit were incubated in an artificial climate chamber at 25°C and 70 to 80% relative humidity for 7 days. Light to dark brown necrotic lesions at the wound sites appeared similar to those observed in the fruit markets, whereas control and nonwounded fruit remained healthy. The pathogens were re-isolated from the infected fruit, fulfilling Koch's postulates. The fungal pathogen A. alternata is widely distributed across various host plant species globally and has been documented as a causal agent of postharvest rot in kiwifruit (Li et al. 2017) and sweet cherry","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142802009","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>Ralstonia solanacearum</i> Species Complex in Australia.","authors":"Jane D Ray, Bhuwaneshwariba Vala, Sharl Mintoff, Nandita Pathania, Stanley E Bellgard","doi":"10.1094/PDIS-03-24-0691-SR","DOIUrl":"10.1094/PDIS-03-24-0691-SR","url":null,"abstract":"<p><p>The <i>Ralstonia solanacearum</i> species complex (RSSC) causes vascular wilt of many crops and is considered one of the most destructive plant pathogenic bacteria worldwide. The species complex was recently resolved into a stable taxonomy of three species aligning with the previously determined phylotypes, namely <i>R. solanacearum</i> (phylotype II), <i>R. pseudosolanacearum</i> (phylotype I and III), and <i>R. syzygii</i> (phylotype IV). Knowing which <i>Ralstonia</i> species and subspecies are established in Australia is important to Australia's biosecurity and market access. The goal of this study was to analyze Australia's <i>Ralstonia</i> culture collections and to assign the isolates to the modern taxonomic groups. The results shed light on the identity, distribution, and pathogenicity of the <i>Ralstonia</i> strains in Australia. <i>Ralstonia solanacearum</i>, <i>R. pseudosolanacearum</i> phylotype I, and <i>R. syzygii</i> phylotype IV-11 are present in Australia but have limited geographic ranges. We identified two aberrant RSSC strains that have genetic similarity to <i>R. syzygii</i> based on sequevar analysis, but do not yield a phylotype IV multiplex PCR band, similar to the known aberrant strain ACH732. The aberrant strains may represent a novel species. Three new sequevars were determined, 72, 73, and 74. Several <i>Ralstonia</i> lineages remain undetected in Australia, providing evidence that they are absent. These include <i>R. pseudosolanacearum</i> phylotype III and the phylotype I mulberry infecting strains; <i>R. solanacearum</i> strains IIC and the Moko causing strains; and <i>R. syzygii</i> subsp. <i>celebesensis</i>, and <i>R. syzygii</i> subsp. <i>syzygii</i>. This study fulfilled Koch's postulates for the Australian strains, <i>R</i>. <i>solanacearum</i> wilted potato plants, and <i>R. pseudosolanacearum</i> wilted blueberry plants, the hosts from which they were initially isolated. The data supports the hypothesis that Australia has native and introduced strains of <i>Ralstonia</i>.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS03240691SR"},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141982984","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>Cirsium arvense</i> var. <i>integrifolium</i> as a new host of <i>Podosphaera xanthii</i> in Sichuan, China.","authors":"Huafeng Liu, Tingfu Zhang, Yingqing Luo, Guoqin Wen, Na Li","doi":"10.1094/PDIS-07-24-1520-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1520-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Cirsium arvense (L.) Scop. var. integrifolium Wimm. & Grab. (syn. Cirsium setosum (Willd.) MB.), a perennial herbaceous plant in the Asteraceae family, is widely distributed across Europe, Australia, Asia, North Africa, North and South America (Nischwitz and Newcombe 2004; Yang et al. 2024). In China, its tender stems and leaves are utilized as a vegetable and also a traditional medicine because of its heat-clearing efficacy (Jiang et al. 2013). In July 2023, symptoms of powdery mildew were observed in C. arvense var. integrifolium populations in Deyang city (N30°35', E104°37'), Sichuan Province, China. Approximately 40.38% (63/156) of the surveyed plants showed symptoms. The disease manifested as irregular small white, powdery patches, typically on the upper surface of leaves, which progressed to extensive hyphal growth covered over 90% of the leaf surface. With the disease advanced, the infected leaves wilted and senesced. Voucher specimens of symptomatic leaves (CaPM-ZL) as representative samples have been deposited at China West Normal University. The conidiophores were unbranched, straight, and measured 78.47 to 246.69 µm (avg. 154.60±49.59 μm) × 4.98 to 29.50 µm (avg. 13.58±8.06 μm) (n= 30). The conidia, produced singly, were hyaline, ellipsoid-ovoid to nearly cylindrical with fibrosin bodies, measuring 53.12 to 72.47 μm (avg. 59.82±6.41 μm) in length and 25.86 to 41.72 μm (avg. 33.85±4.87 μm) in width (n=30). Scanning electron microscopy revealed the conidia were turgid and smooth, with gentle contractions or bulges at both poles. The pathogen was provisionally identified as Podosphaera xanthii based on morphological characteristics (Braun and Cook 2012). To confirm the identification, the internal transcribed spacer region (ITS) and nuclear ribosomal large subunit (LSU) for CaPM-ZL was amplified using primers ITS4/PM5 and LSU1/LSU2, and analyzed using the BLASTn search of GenBank, respectively. The ITS (PP951890) and LSU (PQ644087) sequences were deposited into GenBank and showed 100% similarity with P. xanthii sequences (ITS: MT260063, KY388504; LSU: OP765401, PP897382). Based on the concatenated sequences of ITS and LSU, the phylogenetic analysis was performed in MEGAX with maximum likelihood method (Kumar et al. 2016) clustered CaPM-ZL into the Podosphaera xanthii clade with a 99% bootstrap support value. Combining morphological and phylogenetic analyses, CaPM-ZL was conclusively identified as Podosphaera xanthii. To evaluate pathogenicity, leaves of 3 healthy potted C. arvense var. integrifolium plants (3 leaves per plant) were inoculated by gently pressing them with diseased leaves, while 3 no-contact plants served as controls. The inoculated plants were isolated from the controls in a greenhouse maintained at 27±1°C, with a 14-hour light period and 80% relative humidity. After 7 days, the inoculated plants exhibited powdery mildew symptoms, while the control remained asymptomatic. Morphological characteristics and sequencing o","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142801910","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 and Precise Mapping of <i>PmHSM</i>, a Novel Recessive Powdery Mildew Resistance Allele from Wheat Landrace Heshangmai.","authors":"Bisheng Fu, Qiaofeng Zhang, Jin Cai, Wei Guo, Caiyun Liu, Ying Liu, Wenling Zhai, Shuangjun Gong, Jizhong Wu","doi":"10.1094/PDIS-12-23-2754-RE","DOIUrl":"10.1094/PDIS-12-23-2754-RE","url":null,"abstract":"<p><p>Common wheat (<i>Triticum aestivum</i> L.) is the world's primary food crop, and ensuring its safe production is of utmost importance for global peace and human development. However, the continuous threat of fungal diseases, including Fusarium head scab, rusts, sharp eyespot, and powdery mildew (PM), poses a significant challenge to production. PM caused by <i>Blumeria graminis</i> f. sp. <i>tritici</i> causes substantial yield losses. Heshangmai (HSM), a wheat landrace originating from Sichuan Province, possesses high levels of resistance to PM. A comprehensive study using a large segregating population of a cross between HSM and Ningmaizi119 (NMZ119) revealed a single recessive allele conferring resistance. The gene, provisionally designated <i>PmHSM</i>, was located on the long arm of chromosome 4A (4AL). Molecular marker analysis, a PM response array, and an allelism test indicated that <i>PmHSM</i> is a novel recessive resistance gene that shares an allelic relationship with <i>PmHHXM</i>. Thirteen simple sequence repeat markers were developed using the sequence information of the 4AL region in the Chinese spring reference sequence version 2.1. <i>PmHSM</i> was flanked by the markers <i>Xmp1567</i> and <i>Xmp1444</i> at genetic distances of 0.11 and 0.18 cM, respectively, and cosegregated with the markers <i>Xmp1439</i>/<i>Xmp1440</i>/<i>Xmp1442</i>.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS12232754RE"},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142018245","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":"Investigating the Role of Soybean Genetic Resistance on the Production of <i>Sclerotinia sclerotiorum</i> Sclerotia.","authors":"Richard Wade Webster, Carol Groves, Brian Mueller, Hope Renfroe-Becton, Damon L Smith","doi":"10.1094/PDIS-10-24-2240-RE","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2240-RE","url":null,"abstract":"<p><p>Sclerotia serve as survival structures for many plant pathogens, including Sclerotinia sclerotiorum, which causes Sclerotinia stem rot (SSR) in soybeans and leads to significant yield losses. While partially resistant soybean varieties are effective in reducing SSR incidence, the relationship between resistance and sclerotial production remains unclear. This study investigated the sclerotial production of two soybean recombinant inbred lines (RILs) with differential levels of SSR resistance under both greenhouse and field conditions. In the greenhouse, three S. sclerotiorum isolates of varying aggressiveness were used to screen the two RILs, revealing differences in disease development and sclerotial characteristics. Under greenhouse conditions, the susceptible RIL resulted in greater SSR development, higher total sclerotia production, and greater sclerotial mass per plant than the resistant RIL. Field trials in 2022 and 2023 with the same two soybean RILs, demonstrated that the susceptible RIL consistently produced more sclerotia than the resistant. Further linear regressions between the SSR incidence (DI, %) and sclerotial mass were examined for the susceptible and resistant RILs, where on the susceptible each 10% increase in DI resulted in 28.5 kg ha-1 of sclerotia produced, and on the resistant RIL each 10% increase in DI resulted in 16.2 kg ha-1. These findings provide new insights into the impact of SSR resistance in soybeans on sclerotial production and highlight the importance of selecting resistant soybean varieties to reduce potential build-up of long-lasting inoculum loads.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142802039","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>Diaporthe caulivora</i> causing Phomopsis stem canker on sunflower (<i>Helianthus annuus</i> L.) in Minnesota.","authors":"Samuel Henning, William Underwood","doi":"10.1094/PDIS-10-24-2068-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2068-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Cultivated sunflower (Helianthus annuus L.) is a globally important oilseed crop that is grown primarily in the Northern Great Plains region of the United States. In September 2018, sunflower stems exhibiting brown stem lesions centered on the leaf axils and accompanied by pith degradation, consistent with symptoms of Phomopsis stem canker (PSC) disease, were sampled from a commercial field of approximately 520 hectares in Polk County, MN (47°50'24\" N, 96.34'13\" W). Incidence of PSC in this field was approximately 44%. Ten diseased stem samples were collected from plants spaced at least ten meters apart. Pieces of diseased stems 15 mm in length and 10 mm in width were excised, surface sterilized in 10% sodium hypochlorite and plated onto potato dextrose agar (PDA) containing 50 µg/ml streptomycin. Plates were incubated at 22°C for 3-5 days and hyphal tips of emerging mycelia were transferred twice to new PDA plates. Genomic DNA was extracted from each isolate and polymerase chain reaction (PCR) was carried out using primers specific to either Diaporthe helianthi or D. gulyae, the most common species causing PSC on sunflower (Elverson et al., 2020). Eight isolates were identified as D. helianthi by PCR, while the remaining two isolates, designated H48 and H49, exhibited morphologies on PDA plates distinct from those of D. helianthi or D. gulyae. The ITS region, along with portions of the EF-1α and β-tubulin (TUB) genes were amplified and sequenced, and the sequences were deposited in Genbank (H48: ITS-OP429627.1, EF-1α-OP429589.1, TUB-OP429587.1; H49: ITS-OP429628.1, EF-1α-OP429590.1, TUB-OP429588.1). BLAST analyses using the H48 and H49 ITS sequences revealed 100% identity with D. caulivora isolates including the type specimen CBS 127268 (Genbank accessions AF000567.2 and type specimen MH864501.1). Additionally, 100% identity of EF-1α and TUB sequences from H48 and H49 with those of type specimen CBS 127268 (Genbank accessions KC343771.1 and KC344013.1) were also observed. A multi-locus phylogenetic tree was constructed aligning the ITS, EF-1α, and TUB sequences of H48 and H49 with those of twenty Diaporthe species. Isolates H48 and H49 formed a clade with three other D. caulivora isolates, including the type specimen. Pathogenicity of isolate H49 on sunflower was confirmed by inoculating susceptible sunflower inbred line HA 410 using a stem wound method (Mathew et al., 2018; Thompson et al., 2011; Underwood & Misar, 2024). Plants were inoculated by creating a wound approximately 5 mm deep and 8 mm long using a scalpel and affixing a PDA plug carrying mycelium of isolate H49, D. helianthi isolate H45 known to be pathogenic, or mock inoculum of PDA with no mycelium over the wound using laboratory film. Three independent experimental runs were conducted in which two 6-week-old plants grown in 1-gallon pots under greenhouse conditions at 22 ± 3°C were inoculated with each treatment, resulting in inoculation of six total HA 410 plants per treat","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142801912","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":"Influence of Hybrid Class and Ensiling Duration on Deoxynivalenol Accumulation and Its Derivative Deoxynivalenol-3-Glucoside While Ensiling Corn for Silage.","authors":"Maxwell O Chibuogwu, Hannah Reed, Carol L Groves, Brian Mueller, Gregory Barrett-Wilt, Richard Wade Webster, John Goeser, Damon L Smith","doi":"10.1094/PDIS-06-24-1166-RE","DOIUrl":"10.1094/PDIS-06-24-1166-RE","url":null,"abstract":"<p><p>In silage corn (<i>Zea mays</i> L.), <i>Fusarium graminearum</i> causes diseases and produces the mycotoxin deoxynivalenol (DON). The work presented here investigated DON accumulation and its fate during the ensiling of ground, whole-plant material obtained from dual-purpose (DP) and brown midrib (BMR) corn hybrids. Multiyear field trials arranged in a randomized complete block design were conducted in Wisconsin to evaluate BMR and DP corn hybrids in response to fungicide treatment. At harvest, the samples were chopped and vacuum sealed for a mini-silo time series assessment with silos opened following anaerobic fermentation for 0, 30, 60, 90, and 120 days. Repeated measures analysis of ensiled corn showed that hybrid (<i>P</i> < 0.01) and ensiling duration (<i>P</i> < 0.01) significantly impacted DON concentration through ensiling, whereas fungicide treatment had no significant effect (<i>P</i> > 0.05). Across hybrids and treatments, DON concentrations detected at harvest were the lowest with DON-3-glucoside at harvest significantly (<i>P</i> < 0.01) and highly correlated (<i>r</i> = 0.74) with DON concentration 30-days after ensiling. These findings suggest that mycotoxin testing in corn should include not only DON but also conjugates of DON that can be metabolized back to DON and increase the final DON concentration during ensiling.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS06241166RE"},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142018246","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":"Occurrence of <i>Diplodia seriata</i> causing leaf blight on <i>Aucuba japonica</i> in China.","authors":"Caixia Wang, Enping Zhou, Liting Li, FaHu Pang","doi":"10.1094/PDIS-10-24-2117-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2117-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Aucuba japonica is widely planted in China for landscaping purposes, often used for decoration in gardens and parks. In October 2023, a leaf blight on A. japonica was observed in Meicheng Park of Nanyang City (32°59'21″ N, 112°32'54″ E), Henan province. Subsequently, surveys were conducted in different sections of the park, a plant diseases incidence rate of 52% (n = 100). Initial symptoms included black spots and enlarged to leaf blight lesions on leaves. These lesions subsequently spread throughout the plant, causing defoliation, and aesthetic damage. Twenty diseased leaves from 15 plants were collected, and sections between the symptomatic and healthy tissues were cut into 3 × 3 mm2 pieces to isolate the pathogen. The disinfestation process involved surface sterilization with 75% ethanol solution for 30 s, followed by 1% NaClO solution for 1 min., then rinsing with sterile water, and placing on potato dextrose agar (PDA) plates, incubating at 28°C for 5 days under a photoperiodic condition of 12-hour light and 12-hour dark. After isolation, purified fungal isolates (n = 28) were obtained from 33 samples plated. These fungal isolates showed similar morphological phenotypes. The three isolates (DS2, DS8, and DS28) from different park areas were selected for subsequent identification. The colonies were gray to dark brown with abundant aerial mycelium on the surface. For sporulation, isolates were cultivated on 2% water agar bearing autoclaved poplar twigs at 25°C for 21 days (Phillips et al. 2007). Immature conidia were oblong to ovoid with rounded ends, aseptate, and became dark brown at maturity, measuring 25.1 to 21.3 × 11.9 to 7.7 µm (n = 100 per isolate). These morphological characteristics were consistent with the genus Diplodia (Bhat et al. 2023), which may lead to canker, dieback, fruit rot, and leaf spots on economically important forest and horticultural species. For further molecular identification, the genomic DNA of three strains was extracted. The rDNA internal transcribed spacer (ITS) region and β-tubulin (tub) and translation elongation factor 1-alpha (tef1) genes were amplified using primers ITS1/ITS4, Bt2a/Bt2b, and EF1-728F/EF1-986R, respectively (Díaz et al. 2019). The ITS (PP957738 to PP957740), tub (PP960547 to PP960549), and tef1 (PP960550 to PP960552) sequences were submitted to GenBank. A phylogenetic tree of concatenated markers sequences (ITS, tub, and tef1) and ex-type strains sequences was constructed using MEGA software (version 11) with the neighbor-joining method. The three strains formed a clade with the strains CBS114791 and CBS113508 of D. seriata in the phylogenetic trees. Molecular analyses supported the identification of the strains as Diplodia seriata. To verify pathogenicity, conidial suspensions (106 conidia ml-1of isolate DS2) were sprayed onto the wound-free leaves of five A. japonica of three-month-old seedlings. In contrast, another five plants were sprayed with sterile water as a mock-inoculated","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142802040","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}