Plant disease最新文献

{"title":"Genome Wide Association Mapping for Stripe Rust Resistance in Domesticated Emmer Wheat (<i>Triticum turgidum</i> ssp. <i>dicoccum</i>).","authors":"Yan Liu, Yukiko Naruoka, Sajal Ratna Sthapit, Travis Ruff, Karol Marlowe, Deven R See","doi":"10.1094/PDIS-01-25-0215-RE","DOIUrl":"https://doi.org/10.1094/PDIS-01-25-0215-RE","url":null,"abstract":"<p><p>Wheat (Triticum aestivum L.) is one of the major crops and a staple food for about 35% of the world population. Wheat production is constantly threatened by the stripe rust, one of the devastating wheat diseases and caused by Puccinia striiformis f. sp. tritici (Pst). Improving the disease resistance of wheat cultivars is the most efficient and sustainable way to control stripe rust. In this study, we aimed to explore the novel resistance resources in a collection of 180 cultivated emmer wheat accessions (T. turgidum ssp. dicoccum) collected from 32 countries on five continents. The cultivated emmer wheat accessions were genotyped by wheat Illumina® iSelect 9 K SNP array and phenotypes were evaluated in greenhouse using four races and in five field environments. Conducting genome wide association study (GWAS), we identified 14 QTLs associated with stripe rust resistance. Two QTLs, QYr.emmer-4A.2 and QYr.emmer-6A confer all stage resistance (ASR) and 12 QTLs, located on chromosome 1A, 2A, 2B, 3A, 3B, 4A, 5A, 5B, 7A and 7B, confer adult plant resistance (APR) to stripe rust. Compared with the known stripe rust resistance QTLs, most of the QTLs identified in this study are very likely novel QTLs. The APR QTL, QYr.emmer-7A, was consistently detected among multiple data sets from different environments and was validated using a bi-parental mapping population. The SNPs, SSR markers and the genomic loci identified in this study will provide very useful information for QTLs mapping and resistance breeding programs.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143812141","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":"A Streptomyces Agent for Biocontrol of Phytophthora Blight and Its Modulation of Rhizosphere Microbiomes in Passion Fruit.","authors":"Yu-Hsuan Chen, Kuan-Yao Sung, Shu-Jen Tuan, Jenn-Wen Huang, Yi-Hsien Lin, Tzu-Pi Huang","doi":"10.1094/PDIS-01-25-0089-RE","DOIUrl":"https://doi.org/10.1094/PDIS-01-25-0089-RE","url":null,"abstract":"<p><p>Passion fruit and its seedlings hold significant economic value for both domestic and export markets in Taiwan. Among the diseases affecting passion fruit, Phytophthora blight, caused by <i>Phytophthora nicotianae</i>, severely impacts seedling survival and fruit production. This study aimed to develop a microbial agent to control Phytophthora blight by evaluating the potential of <i>Streptomyces cavourensis</i> strain PES4, isolated from rhizosphere soils in Taiwan. Additionally, the impact of strain PES4 application on microbial communities in the field was investigated. Our results demonstrated that S. cavourensis PES4 exhibited strong antagonistic activity against several bacterial, fungal, and oomycete pathogens, including <i>P. nicotianae</i>. Applying a 100-fold diluted culture broth of the strain PES4 significantly reduced the severity of Phytophthora blight on passion fruit leaves and fruits. Weekly applications of the strain PES4 throughout the growing season enhanced plant growth, yield, and fruit quality compared to the water control. Next-generation sequencing was used to analyze the influence of the strain PES4 application on the rhizosphere microbiome. The application of strain PES4 did not affect microbial richness or diversity but did alter the composition of bacterial and fungal communities. Specifically, the strain PES4 application reduced the relative abundances of Proteobacteria and Actinobacteria while increasing Acidobacteria, Verrucomicrobia, and Gemmatimonadetes at the phylum level. At the genus level, <i>Rhodanobacter</i> and <i>Streptomyces</i> populations increased. Regarding fungal communities, the strain PES4 application promoted the populations of <i>Trichoderma</i> and <i>Mortierella</i>, while <i>Penicillium</i> and <i>Colletotrichum</i> populations declined. In conclusion, <i>S. cavourensis</i> PES4 is a promising plant probiotic with both growth-promoting and biocontrol activities against Phytophthora blight in passion fruit. Its application can modulate the rhizosphere microbiome by enhancing beneficial bacterial and fungal populations and suppressing plant pathogenic ones, suggesting its potential as a sustainable biocontrol agent.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143812044","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>Convolvulus arvensis</i> Is a Novel Host of '<i>Candidatus</i> Phytoplasma omanense'-Related Strains Causing Little Leaf Disease in Jordan.","authors":"Asem Hebes Abu Alloush, Junichi Inaba, Kristi Bottner-Parker, Jonathan Shao, Nizar Obeidat, Wei Wei","doi":"10.1094/PDIS-12-24-2635-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2635-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;The highly invasive field bindweed (Convolvulus arvensis), native to Europe and Asia, competes with crops, reduces yields, and acts as a reservoir for plant pathogens, increasing the potential for disease spread in agricultural systems (Sosnoskie et al. 2020; Wenninger et al. 2019). In July 2023, bindweed plants exhibiting little leaf, leaf discoloration, thickening, and overall stunted growth were observed in a 0.3 ha green cherry orchard in Kharja, Bani Kenanah, Irbid Governorate, Jordan (32°37'37.883\"N, 35°52'49.185\"E) (Fig. 1). Twenty out of 35 plants displayed symptoms, resulting in a 57% incidence rate. Since the symptoms resembled those associated with phytoplasma infections and bindweed's known role as a phytoplasma host (Jovic et al. 2021), DNA was extracted from six symptomatic plants and two healthy controls using the Qiagen DNeasy Plant Mini Kit, and PCR assay was conducted with the primer pair P1A/16S-SR to amplify near full-length phytoplasma 16S rDNA (about 1.5 kb) as described by Lee et al. (2004). All healthy controls tested negative, while all symptomatic plants tested positive. Amplicons were cloned into the pCRII-TOPO vector, sequenced, and a representative sequence was deposited in GenBank (Accession number PQ497569). Using iPhyClassifier (Zhao et al. 2009), the strain was identified as a 'Candidatus Phytoplasma omanense' (GenBank accession: EF666051, 16SrXXIX-A)-related strain, with 98.95% sequence identity, belonging to the 16SrXXIX group. The similarity coefficients were 0.93 and 0.97 compared to reference strains 16SrXXIX-A (EF666051) and 16SrXXIX-B (OL873126, Abu Alloush et al. 2023a), respectively. The phylogenetic analysis indicated that the newly detected field bindweed little leaf phytoplasma strain (designated FBLL1) is genetically distinct from these known subgroups and represents a novel subgroup, 16SrXXIX-C (Fig. 2). Further characterization of the FBLL1 strains was performed by PCR amplification of the rp (1.9 kb) and secY (1.3 kb) gene segments using specially designed primers: FBRP-F2/FBRP-R4 (5'-TTGGCCGCCTTCAAATCCTA-3'/5'-TCGGAGGAGAAGTTTTGGCT-3') for rp, and FBSecYF1/FBSecR1 (5'-CTTCTTTTGGTGATATCCCA-3'/5'-TGGCGGAAGTATTGAGATAAGAA-3') for secY. The resulting rp and secY gene sequences were deposited in GenBank (Accession numbers PQ505136 and PQ505137). BLASTN analysis revealed that the rp gene's top hit was 'Ca. P. pruni' (CP119306) with 75.60% identity, while the secY gene's top hit was 'Ca. P. phoenicium' (MN076652), with 73.47% identity. Compared to the 16S rRNA gene, the lower percent identity is due to the limited availability of 16SrXXIX rp and secY gene sequences for comparison. Field bindweed hosts several phytoplasmas, such as 'Ca. P. solani' (16SrXII-A), which is linked to Bois noir (BN) in grapevines, and 'Ca. P. convolvuli' (16SrXII-H), associated with bindweed yellows (Jovic et al. 2021; Abu Alloush et al. 2023b). 'Ca. P. omanense' has also been documented in bindweed in Lebanon (Fossaic et a","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143812041","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":"Disentangling Co-Occurring Pathogens: Lack of Significant Interaction Between <i>Agrobacterium tumefaciens</i> and <i>Ganoderma adspersum</i> in Almond Orchards.","authors":"Daisy Ahumada, Ali McClean, Daniel Kluepfel, David Rizzo","doi":"10.1094/PDIS-12-24-2664-RE","DOIUrl":"https://doi.org/10.1094/PDIS-12-24-2664-RE","url":null,"abstract":"<p><p>While plant diseases often involve co-infections of multiple pathogens, there are few studies that focus on understanding plant host-multi-pathogen interactions. To understand the complexities of cross-taxa co-infections, we investigated the interactions between an almond tree, wood-decay pathogen, Ganoderma adspersum, and a bacterial pathogen, Agrobacterium tumefaciens. The high co-incidence of the fungal and bacterial pathogens in almond orchards suggests mutualistic effects in pathogenesis. However, co-inoculation assays revealed that the pathogens do not significantly interact directly with each other nor promote increased initial disease development. The rise of multi-pathogen diseases in almonds likely results from the adoption of management practices that have created a system capable of sustaining multiple pathogens.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143812063","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 Brassica Yellows Virus (BrYV) Naturally Infecting Wheat in China.","authors":"Peipei Zhang, Linzhu Liang, Wenya Liu, Zixuan Zhou, Xinyuan Zhang, Zhongtian Xu","doi":"10.1094/PDIS-02-25-0403-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-02-25-0403-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Brassica yellows virus (BrYV) was first reported in rutabaga as a new species in the genus Polerovirus in China in 2011, which was closely related to turnip yellows virus (TuYV) (Zhang et al. 2014). Later, BrYV was widespread in cruciferous and tobacco plants, causing leaf malformations and yellowing (Wang et al. 2015; Zhang et al. 2022). Here, we report its presence in wheat (Triticum aestivum), identified by high-throughput sequencing. In 2023, we collected wheat plants with virus-like symptoms, such as yellow, dwarf, stripe and mosaic, from the fields in Hebei Province, China. Total RNA were extracted from symptomatic leaves using TransZol reagent (TransGen, Beijing, China). RNAs from the same field and having similar symptoms were mixed into a pooled RNA (9 pooled samples from 4 cities, 105 individual samples) to construct a rRNA-depleted RNA-seq library with the TruSeq total RNA Sample Prep Kit and a sRNA-seq library with the Small RNA Sample Prep Kit (Illumina, San Diego, CA). The Illumina Novaseq 6000 was used for the RNA- and sRNA-seq with PE150 and SE50, respectively. A total of tens of millions of clean reads were obtained from each pooled RNA. After de novo assembly using Trinity and Velvet program, and blast analysis using BLASTx and BLASTn program, contigs of four species of wheat-infecting viruses, including barley yellow dwarf virus-PAV, barley yellow striate mosaic virus, wheat yellow dwarf virus and triticum yellow stripe virus, were identified. Beet western yellows virus was also found in our samples, a polerovirus that infects dicotyledonous plants and was first report in wheat in 2023 (Jin et al. 2023). Additionally, three contigs from RNA-seq with high identity to TuYV-5594 (OQ377541) were also identified. The contig DN88565 (5,611 nt) was from the pooled BD-A, contig DN323 (5,662 nt) and DN16914 (699 nt) were from the pooled BD-C, respectively. For sRNA-seq, many short contigs from BD-A and BD-C with high identities to BrYV-R3b (LC428363) were also found. And the 22- and 21-nt BrYV-derived siRNA had the highest percentages, that consistent with BrYV-derived siRNAs in Nicotiana benthamiana (Zhou et al. 2017), which demonstrated the virus infected the wheat samples rather than contaminating them. A Blastn search online showed that the contigs were more identical to BrYV, thus we proposed the virus named as BrYV-Ta. When using contig DN323 as the reference, a total of 20,037 reads of BD-A and 16,156 reads of BD-C from RNA-seq were mapped with a coverage of 100%. For testing the incidence of BrYV-Ta, the contig-specific primers were designed to amplify a 1,444-bp fragment. The assay revealed that 3 of the 32 samples of BD-A and BD-C, from Baoding City, tested positive and no mixed infection happened. The symptoms of the positive samples were yellowing and striping. The full-length genome of BrYV-Ta was amplified by 4 overlapping pairs of primers and sequenced by Sanger sequencing. Identity analysis showed that the virus ha","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143780834","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>Neopestalotiopsis chrysea</i> Associated with Gray Blight of tea (<i>Camellia sinensis</i>) in China.","authors":"Zhihui Zhang, Xin Li, Jiao Miao, Wanping Fang, Changjun Chen","doi":"10.1094/PDIS-02-25-0313-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-02-25-0313-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Tea plants (Camellia sinensis (L.) O. Kuntze) are commercial perennial woody crops, which has been widely cultivated in more than 60 countries all over the world (Hajiboland 2017). Tea gray blight is a foliar disease that reduces quality and yield by 20-30% (Horikawa 1986). During March of 2022, a disease survey was conducted on a 300 ha tea plantation (Liyang Tianmu Lake tea research Institute) in the Liyang area of Jiangsu province (31°19'37.64''N, 119°23'46.37''E). The disease damaged 30% of the tea plants, and 'Baiye No. 1' was the most impacted with an average disease incidence rate of 50-60%. In early stages of infection, leaves exhibited small yellow-green lesions at the tips and margins. These lesions gradually expanded into round or irregular brown spots characterized by distinct concentric rings and black conidial disks arranged in whorls. These symptoms are consistent with tea gray blight disease associated with Neopestalotiopsis piceana reported by the previous study (Wang et al. 2022). A total of 15 lesions were collected from different plants and sent to the Plant Protection Laboratory of Nanjing Agricultural University for analysis. To identify the pathogens, leaves with necrotic lesions were cut into 5 × 5 mm pieces at the junction between diseased and healthy tissues, surface sterilized with 75% ethanol for 1 min, disinfected with 2% sodium hypochlorite for 3 min, and then rinsed three times with sterile water. The tissues were placed on potato dextrose agar (PDA) plates containing 100 μg/ml of streptomycin sulfate (Wang et al. 2022) and incubated at 25°C in the dark. A total of 15 isolates were obtained from 15 different lesions with typical symptoms as described earlier and identified as Pestalotiopsis-like fungus by spore morphological identification (Maharachchikumbura et al. 2014), the conidia length and width of which were shorter than that of Pseudopestalotiopsis theae. Pure cultures were obtained by monosporic isolation, and the representative isolates J15 and F22 randomly selected were used for morphological studies and phylogenetic analyses. The cultures of the two isolates grown on PDA were white, cottony, and flocculent and contained undulate edges with dense aerial mycelium on the surface, black, wet conidial masses emerged after 7 days. Conidia were five celled, clavate to fusiform, smooth, and 17.9 to 25.3 × 5.3 to 9.1 μm (n = 50). The three median cells were dark brown to olivaceous, the central cell was darker than the other two cells, and the basal and apical cells were hyaline. Conidia developed filiform appendages: one basal appendage (3.5 to 9.3 μm long; n = 50) and two to three apical appendages (15 to 35 μm long; n = 50). Morphological features were similar to Neopestalotiopsis chrysea (Maharachchikumbura et al. 2012). To further identify, the partial internal transcribed spacer (ITS) regions and ß-tubulin 2 (TUB2) regions and translation elongation factor 1-alpha (TEF1-a) genes of the two isolates we","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143780832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery of <i>Pratylenchus zeae</i> Causing Root Rot of Winter Wheat in Anhui Province of China.","authors":"Lingling Gao, Yunlong Lv, Can Zhang, Wen-Long Niu, Hong-Lian Li, Yu Li, Ke Wang","doi":"10.1094/PDIS-02-25-0327-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-02-25-0327-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Root-lesion nematode (RLN), Pratylenchus zeae Graham, 1951, is a serious nematode pest in a number of agronomic and industrial crops (Liu et al. 2017). Wheat (Triticum aestivum) is one of the most important food crops in Anhui province of China. In May 2023, a survey was conducted for RLNs in winter wheat fields in Woyang county of Bozhou City, Anhui province, China. The samples were collected about 20 days before wheat (cv. Gushenmai 19) harvest. The plants were growing poorly, with distinct brown lesions on the wheat roots. The RLNs were extracted with the modified Baermann funnel apparatus (Hooper et al. 2005). The RLNs were found in eight collected samples, an average of 51 nematodes per gram of root and 128 nematodes per 100 cm3 of soil. The extracted RLNs were disinfected with 0.3% streptomycin sulfate and one individual female nematode were cultured on carrot disks at 25°C for propagation as described before (Wang et al. 2021). The RLNs species identification was based on morphological and molecular criteria. The main morphological measurements of adult females (n = 15) included body length = 490.5 μm (mean) ± 13.1 (standard deviation) (range = 471.3 to 523.1 μm), stylet length = 16.1 μm ± 0.7 (14.0 to 16.9 μm), tail length = 27.3 μm ± 5.3 (18.9 to 34.1 μm), a = 24.8 ± 1.8 (21.9 to 27.8), b = 5.2 ± 0.3 (4.5 to 5.9), c = 17.8 ± 1.9 (14.9 to 20.3), two annules on the lip region. No males were found in the specimens. The morphological characters of this population are consistent with P. zeae as described previously (Castillo and Vovlas, 2007). Furthermore, the individual female was used for the molecular identification, and the DNA was extracted as described previously (Wang et al. 2011). The primers of D2A/D3B (Subbotin et al. 2006) and TW81/AB28 (Vovlas et al. 2011) were used to amplify the rDNA 28S D2-D3 region and rDNA-ITS region, respectively. The PCR products were sequenced, the newly obtained sequences of the rDNA 28S D2-D3 region (782 bp) and rDNA-ITS region (669 bp) in this study were submitted to NCBI. The obtained 28S D2-D3 region sequence (GenBank Accession No. PQ859281 and PV083139) had 100% identity with P. zeae sequences available from GenBank (KY424256 and KY424263). The obtained ITS sequences in this study (PQ857687 and PV089700) had more than 98% identity with P. zeae sequences available from GenBank (OP456372 and OP466367). Both morphological and molecular data confirmed the presence of P. zeae. To validate the reproductive capacity of the RLNs on winter wheat, a greenhouse experiment was conducted at 25°C, following the modified Koch's postulates protocol. Wheat plants were grown in 8 pots, each with three plants (cv. Gushenmai 19) were inoculated with 1000 P. zeae and grown in 1.5-liter pots. Two months after inoculation, the wheat roots were washed and brown lesions were observed. RLNs in the soil and roots were extracted as previously described and the population was found to have increased substantially. The aver","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143780830","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 Watermelon Crinkle Leaf-Associated Virus 1 (WCLaV-1) and WCLaV-2 in Watermelon in Slovenia.","authors":"Ana Vučurović, Irena Bajde, Jakob Brodarič, Anja Pecman, Zala Kogej-Zwitter, Veronika Bukvič, Nejc Jakoš, Denis Kutnjak, Mojca Rot, Natasa Mehle","doi":"10.1094/PDIS-02-25-0251-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-02-25-0251-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;In July 2024, a pooled leaf sample (D760/24) was collected from several plants of three watermelon cultivars (&lt;i&gt;Citrullus lanatus&lt;/i&gt; cvs. Crimson Sweet, Asahi Miyako Hybrid F1 and Top Gun) grown in an open field (approx. 0.5ha) in Dombrava, Slovenia. The plants which were included in the pooled sample showed virus-like symptoms, such as leaf mosaic, wilting and necrosis (eXtra Supplementary material Fig. S1). The disease incidence was estimated at 10%. DNA and RNA were extracted following Mehle et al. (2013) and RNeasy Plant Mini Kit (Qiagen, Germany) protocols, respectively. The sample was tested positive by reverse-transcription (RT)-PCR for watermelon crinkle leaf-associated virus 1 (WCLaV-1) and WCLaV-2 ( Hernandez et al. 2021) and negative for other viruses (details on viruses tested and primers used are available in eXtra Table S1). The obtained amplicons of expected sizes of WCLaV-1 and WCLaV-2 movement protein (MP) and RNA-dependent RNA polymerase (RdRp) genes (eXtra Fig S2) were then subjected to Sanger sequencing (Eurofins Genomics, Germany) and BLAST analysis. The MP (PQ570004, PQ570006) and the RdRp (PQ570005, PQ570007) sequences exhibited 100% identity with multiple accessions of WCLaV-1, such as PP792977 and PP792976, and WCLaV-2, such as LC636073 and LC636074. Illumina high-throughput sequencing (HTS, Novogene, Germany, NovaSeq X Plus, PE150) identified WCLaV-1 (PV012703-04) and WCLaV-2 (PV012705-06) reads, along with cucumis melo amalgavirus 1 (CmAV1, PV012707) and solanum nigrum ilarvirus 1 reads (insufficient reads to reconstruct genome segments, it may originate from pollen contamination of nearby infected plants in the field (Rivarez et al. 2023)). HTS data were analyzed in CLC Genomics Workbench v. 24 (Qiagen, USA) using the pipeline by (Pecman et al. 2022). Consensus genome sequences were reconstructed by iterative read mapping to the most similar reference sequence of the virus obtained from NCBI GenBank. To check for WCLaVs in watermelon seeds sold in Slovenia, we tested five seed samples from Sugar Baby, Crimstar F1, and Crimson Sweet (three lots) by RT-PCR. We also tested four leaf samples from plants grown from these seeds at 3-5 true leaves stage. Both viruses were found in all seed and leaf extracts. However, mechanical inoculations with the sap of two samples (plants grown from infected seed sample and sample D760/24) on several commonly used indicator plants including &lt;i&gt;Chenopodium quinoa&lt;/i&gt;, &lt;i&gt;Capsicum annuum&lt;/i&gt;, &lt;i&gt;Nicotiana clevelandii&lt;/i&gt;, &lt;i&gt;Nicotiana glutinosa&lt;/i&gt;, &lt;i&gt;Nicotiana benthamiana&lt;/i&gt;, &lt;i&gt;Nicotiana tabacum&lt;/i&gt; cv. White Burley, &lt;i&gt;Nicotiana rustica&lt;/i&gt;, &lt;i&gt;Datura stramonium&lt;/i&gt;, &lt;i&gt;Cucurbita pepo&lt;/i&gt; cv. Bianca di Trieste, and &lt;i&gt;Cucurbita maxima&lt;/i&gt; did not result in their infection. Retrospective analyses of our HTS data of two watermelon and 84 other cucurbits samples from previous years showed WCLaV-1 and WCLaV-2 reads in two pooled samples (containing equal amount of RNA of each sampl","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of Didymellaceae leaf spot associated with <i>Elymus</i> plants in the Tibetan Plateau of China.","authors":"Jiaqi Liu, Longhai Xue, Chunjie Li","doi":"10.1094/PDIS-10-24-2201-SR","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2201-SR","url":null,"abstract":"<p><p><i>Elymus</i> plant is a dominant herbage in the Tibetan Plateau of China. Leaf spot disease restricts the production and utilization of <i>Elymus</i> spp., yet comprehensive studies on the etiology, and epidemiology of this disease in <i>Elymus</i> plants remain notably limited. In this study, a two-year investigation (2021 to 2022) was conducted on <i>Elymus</i> plants across both natural and cultivated grasslands of Gansu, Qinghai, and Sichuan Province in the Tibetan Plateau of China. The results demonstrated that leaf spot disease is a prevalent disease, with particular severity occurring at the heading stage of growth. A total of 184 strains, representing 25% of all initially isolated strains, were attributed to the Didymellaceae family (comprising <i>Didymella</i>, <i>Leptosphaerulina</i>, and <i>Neoascochyta</i>) based on the identity of their ITS sequences in NCBI and the similarity of cultural characters, which suggested that Didymellaceae leaf spot (DLS) is likely to be one of the most predominant foliar diseases affecting <i>Elymus</i> plants. Fifteen representative cultures were selected for further study based on morphology, symptomatology, and the isolation rates. Multi-locus phylogenetic analysis (ITS, LSU, RPB2, and TUB2) coupled with morphological features showed that these isolates were finally identified as five new record species, including <i>D. boeremae</i>, <i>D. pomorum</i>, <i>L. miscanthi</i>, <i>N. cylindrispora</i>, and <i>N. europaea</i>. Pathogenicity analysis showed that the virulence of these five species varied on both <i>E. nutans</i> and <i>E. sibiricus</i> plants, of which <i>N. cylindrispora</i> and <i>N. europaea</i> was more aggressive. Coupling with natural and artificially inoculated symptoms, three typical symptoms of DLS on <i>Elymus</i> plants were specified in this study, i.e., small dark brown spots (<i>D. boeremae</i> and <i>D. pomorum</i>), white and linear spots with black margins (<i>L. miscanthi</i>), and dark brown spots with a yellow halo (<i>N. cylindrispora</i> and <i>N. europaea</i>). Overall, these findings will help us comprehend the diversity of the family Didymellaceae in <i>Elymus</i> spp. and provide a basis for diagnosis in the field and future management of leaf spot disease (especially for DLS) on <i>Elymus</i> plants.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772869","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>Ficus altissima</i>, a new host of <i>Colletotrichum fructicola</i> Causing anthracnose in China.","authors":"Airong Xie, Jia Min Guo, FuBao Huang, Xiao Min Zeng, Haiyuan Wang, Tao Li, Run Hua Yi","doi":"10.1094/PDIS-10-24-2131-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2131-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Ficus altissima Blume.，known as council tree or lofty fig, is a tall evergreen tree in the Moraceae family, widely planted as a roadside tree due to its exquisite tree posture in subtropical areas. During October 2023, an anthracnose disease was observed in approximately 90% of F. altissima plants in Mazhang, Zhanjiang, Guangdong Province ( 22°6'14.7''N,110°27'26.8''E ). Symptoms were small dark-brown or black spots with yellow halos on about 10% disease leaves, which downgraded its ornamental value (Figure 1). Twenty-four diseased tissues (5 × 5 mm) were cut and sterilized with 3% hydrogen peroxide for 2 min, rinsed three times with sterile water, and placed on potato dextrose agar (PDA) medium containing 50 mg/L of penicillin. The plates were incubated in the dark at 28°C. Nineteen isolates were obtained by the single-spore method (Choi et al. 1999). The colonies on PDA were cotton-like, gray-black with concentric ring on the mycelial mat, and orange conidiomata appeared after seven days (Figure 1). The conidia are unicellular, oblong in shape and 11.9-16.1 μm × 6.1-10.9 μm (av. 13.9 × 7.3 μm, n = 50) in size. Appressoria were irregularly, dark brown, some with lobes, elliptical, 10.9-12.4 × 6.4-9.5µm (av. 11.7 × 8.2 μm) (Figure 1). The morphological characteristics were consistent with those of Colletotrichum species (Weir et al. 2012). The internal transcribed spacer (ITS) region, actin (ACT), chitin synthase (CHS), glyceraldehydes-3-phosphate dehydrogenase (GAPDH), and B-tubulin (TUB) were amplified and sequenced for two isolates (R3-2 and R3-4) with primer pairs of ITS1/ITS4 (White et al. 1990), ACT-512F/ACT-783R, CHS-79F/345R, GAPDH-F/R, and TUB-2Fd/4Rd, respectively (Weir et al. 2012). The sequences were deposited in GenBank (ITS: PQ013063 and PQ432515, TUB: PQ066260 and PQ433584, ACT: PQ066256 and PQ433581, GAPDH: PQ066259 and PQ433583, CHS: PQ066258 and PQ433582). BLAST research showed the sequences of R3-2 and R3-4 had above 99% identity with these of C. fructicola ex-type ICMP: 18581 (ITS: 481/481 (100%) and 481/482 (99%); GAPDH: 277/280 (99%) and 278/281 (99%); TUB: 406/406 (100%) and 379/379 (100%); CHS: 267/267 (100%) and 299/299 (100%); ACT: 239/241 (99%) and 269/270 (99%)). The concatenated data of ITS, TUB, CHS, ACT and GAPDH sequences was used to phylogenetic analysis using Maximum Likelihood method in MEGA-X. The isolates R3-2 and R3-4 clustered in the same clade with C. fructicola ICMP 18581 (Figure 2). To confirm pathogenicity, three healthy leaves of 8 to 10-year-old F. altissima were surface sterilized with 75% ethanol and sterile water, wounded on each leaf with sterile needles. The wounded sites were inoculated with 10 µl of spore suspension (1×105 spore/ml) and inoculated with sterile water as control. The experiment was repeated three times. After three days, symptoms of anthracnose were observed on the leaves, similar to those described above; no symptoms occurred in the controls. Colletotrichum fructicola was r","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143772866","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}