Plant disease最新文献

{"title":"First Report of <i>Fusarium compactum</i> Causing Fusarium Head Blight of Wheat in China.","authors":"Qi Fan, Hui Li, Jiachen Xiao, Mingliang Ding, Luodong Huang, Zhuliang Yang, Peihong Shen, Yuanbing Wang","doi":"10.1094/PDIS-07-24-1375-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1375-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Fusarium head blight (FHB), a devastating wheat disease caused by several species of Fusarium, threatens global wheat yield and quality (Erenstein et al. 2022). In August 2023, wheat spikes exhibiting clear FHB symptoms were observed in fields in Yunnan, China (24°16'46″ N, 102°29'46″ E), with an incidence rate of approximately 10%. Diseased wheat spikes exhibited a bleached, wilted appearance, with abundant orange sporodochia on the glumes, similar to previous reports (Osborne et al. 2007). Twenty-four symptomatic spikes were collected from a single field, and sporodochia were washed with sterile water to prepare a spore suspension of 1 × 10³ spores/ml, which was inoculated onto potato dextrose agar (PDA) to obtain monosporic cultures. Four reference strains (KUNCC 3418 to KUNCC 3420, and KUNCC 3431) were deposited at the Kunming Institute of Botany Culture Collection, Chinese Academy of Sciences (KUNCC). For species identification, four strains were cultured on PDA and carnation leaf agar (CLA) at 25°C, with incubation under a 12-hour near-UV light/dark cycle on CLA and in complete darkness for 24 hours on PDA. Colonies on PDA grew rapidly, appearing white and loosely flocculent. Abundant pale orange, translucent sporodochia formed on CLA. Sporodochial conidiogenous cells were monophialidic or polyphialidic, subulate to subcylindrical, 9.5-12 μm × 3-3.5 μm. Sporodochial macroconidia were naviculate to fusiform, with an elongate, tapering apical cell and a foot-shaped basal cell, 3-6-septate, 33-67.5 μm × 3.5-5.5 μm. The ITS, tef1-α, rpb1, rpb2, and cam regions were amplified and sequenced using primers ITS1/ITS4, EF-1/EF-2, rpb1-F7/G2R, rpb2-5F2/11aR, and CL1/CL2A, respectively (White et al. 1990; O'Donnell et al. 2000; O'Donnell et al. 2010; Reeb et al. 2004; O'Donnell et al. 1998). These sequences were deposited in GenBank for cam (PP951603 to PP951606), ITS (PP946846 to PP946849), tef-1α (PP719217, PP731572 to PP731574), rpb1 (PP719219, PP737839 to PP737841), and rpb2 (PP719218, PP951607 to PP951609). BLASTn analyses of these sequences showed an identity range of 99.7% to 100% with the epitype strain NRRL 36323 of F. compactum (GenBank: cam = GQ505560, ITS = MH855177, tef-1α = GQ505648, and rpb2 = GQ505826), with base pair matches of 663/665 bp for cam, 488/488 bp for ITS, 641/641 bp for tef-1α, and 892/892 bp for rpb2. Both morphological and BLASTn analyses confirmed these isolates as F. compactum (Leslie & Summerell 2006; Han et al. 2023). Pathogenicity tests were performed by spraying 1 ml of spore suspension (1 × 108 spores/ml) of F. compactum strains onto spikes of the wheat cultivar Yunmai 126 at the flowering stage (n = 9). Controls (n = 9) were treated only with sterile water. Following treatment, the wheat spikes were covered with plastic bags and incubated at 25°C for 10 days. After 14 days, the inoculated spikes turned bleached and dry, showing FHB symptoms, while the wheat spikes in the control treatment remained asymptomat","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142366217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First Report of <i>Fusarium concentricum</i> Causing Leaf Blight, Shoot Blight, Flower and Fruit Rot on <i>Kadsura coccinea</i> in China.","authors":"Panpan Hu, Yuqing Xi, Yuhe Li, Yang Yin, Changbao Xu, Xiaoling Deng, Meirong Xu","doi":"10.1094/PDIS-05-24-1008-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-05-24-1008-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Kadsura coccinea&lt;/i&gt; (Lem.) A. C. Smith is a traditional medicinal plant grown in south China. Lignans and terpenoids extracted from the root, fruit and stem were found to have anti-proliferative, anti-HIV, anti-hepatitis, anti-oxidant, neuroprotective, and other pharmacological attributes for treating rheumatoid arthritis and gastroenteric et al. disorders (Yang et al., 2020). However, little is known about the biotic disorders of this evergreen climbing shrub. In surveys carried out in a 15- hectare -orchard located 23°59'55''N, 113°55'13''E, all &lt;i&gt;K&lt;/i&gt;. &lt;i&gt;coccinea&lt;/i&gt; plants were observed exhibiting an array of symptoms including leaf blight, shoot blight, flower rot and fruit rot from May to July of 2023, with disease incidences of 17% , 18%, 16% and 28%, respectively. A greyish -brown blight appeared predominantly on the leaf margins or tips. Light to dark brown lesions on the shoots, flower calyxes and fruits were slightly sunken, irregularly shaped, and watery, usually with white aerial mycelium. For pathogen isolation, infected tissues were cut into fragments of about 5 mm in diameter, surface sterilized with 75% ethanol for 15 s and 1% NaClO for 2 min, and then rinsed three times with sterilized distilled water. Filter paper-dried tissues were placed onto potato dextrose agar (PDA) and incubated at 28°C for 5 days. Seventy-one morphologically similar colonies were produced from 100 tissue fragments, with other tissues lacking colonies or with different colonies. Genomic DNA of 10 randomly selected isolates were extracted from 5-day-old pure cultures. Molecular characterization of the 10 subcultured strains was analyzed by sequencing three regions i.e. translation elongation factor 1-alpha (TEF-1), beta-tublin (TUB), and RNA polymerase Ⅱ second largest subunit (RPB2), amplified using primers EF1/EF2 (O'Donnell et al., 1998), T1/T22 (O'Donnell and Cigelnik 1997), and RPB2-5f2/RPB2-7cr (Liu et al. 1999). Maximum likelihood and Bayesian Inference analysis based on the dataset of the combined three sequences by MEGA 11.0 showed that nine strains were consistently identified as &lt;i&gt;F&lt;/i&gt;. &lt;i&gt;concentricum&lt;/i&gt;. The three sequences (OR632200, OR632199, and OR754282) of a representative strain (SGXF1) shared 99.42%, 99.62%, and 99.80% identity with those of the type strain CBS450. 97. The colonies were white to pale buff with serrated edges and sparse aerial mycelium that initially formed a loose, white cottony texture of 5-10 mm in height. After 7 d's culture at 26°C in an incubator with a photic door, dense and abundant fluffy reddish-white aerial mycelium covered the entire PDA medium of 9 cm-diameter, with alternating pale orange and reddish-grey concentric rings at center with diffusible pigments. Catenate microconidia were obovoid to fusoid-shaped, mostly 0-septate, with a flattened base, (10.98 ± 0.83) x (3.41 ± 0.15) μm (n=20), and were produced on both mono-and polyphialides, whereas macroconidia were curved and long, with a sl","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142366218","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 Leaf Rot on <i>Catalpa bungei</i> caused by <i>Fusarium verticillioides</i> in China.","authors":"Enping Zhou, Caixia Wang, Bingxue Dong, Wenjing Hong, Qiuhong Niu, FengXia Tian","doi":"10.1094/PDIS-09-24-1799-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1799-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;&lt;i&gt;Catalpa bungei&lt;/i&gt; originates from China. Because of its well-developed root system and strong resistance to wind and soil, it is one of the top ten recommended species of ecological management (Jian et al., 2022). In September 2023, a severe leaf rot of &lt;i&gt;C. bungei&lt;/i&gt; was observed at Lanlake farm (500 acres) in Nanyang (33°3'23\" N, 112°28'50\" E), China. The incidence rate of leaf rot reached 45% (n = 100). The pale-yellow spots initially appeared on the adaxial surface of leaf margins, subsequently enlarging to form irregular black rot lesions, with the yellow halos around the necrotic area of the lesion, ultimately causing the entire leaves to wither. Diseased leaves (20) were collected, cut into pieces, sterilized, and then placed on potato dextrose agar (PDA). A total of 25 purified fungal strains were isolated, and three strains (QS2-1, QS2-2, QS2-3) from distinct areas were selected for further analysis. Each strain produced abundant aerial mycelium, initially white, which later developed purple pigments. The aerial conidiophores were sparsely branched, ending with verticillate phialides. The strains generally produced many more microconidia than macroconidia on PDA media. Microconidia were clavate and measured 3.9 to 6.6 × 1.1 to 2.4 μm (n = 50). To produce macroconidia, we used YPG liquid medium (0.3% yeast extract, 1% peptone, and 2% glucose) with shaking (200 r.p.m.) for 5 days. Macroconidia were slender, straight, and measured 19.5 to 27.1 × 1.9 to 3.5 μm, with 3 to 5 septa (n = 50). The morphological characteristics matched the species description of &lt;i&gt;Fusarium verticillioides&lt;/i&gt; (Sacc.) Nirenberg 1976 (Leslie and Summerell, 2006). The rDNA internal transcribed spacer (ITS), &lt;i&gt;β&lt;/i&gt;-tubulin gene (&lt;i&gt;tub2&lt;/i&gt;), translation elongation factor 1-alpha gene (&lt;i&gt;tef1&lt;/i&gt;), calmodulin (&lt;i&gt;cmdA&lt;/i&gt;), RNA polymerase II largest subunit (&lt;i&gt;rpb1&lt;/i&gt;), and RNA polymerase II second largest subunit (&lt;i&gt;rpb2&lt;/i&gt;) were amplified for molecular identification (O'Donnell et al., 2022). The sequences were submitted to GenBank with accession numbers OR741762, OR741763, OR741765 (ITS), OR762222, OR762223, OR939807 (&lt;i&gt;tub2&lt;/i&gt;), OR939799, OR939800, PQ035927 (&lt;i&gt;tef1&lt;/i&gt;), OR778611, OR939808, OR939809 (&lt;i&gt;cmdA&lt;/i&gt;), PQ035921, PQ035922, PQ035923 (&lt;i&gt;rpb1&lt;/i&gt;), and PQ035924, PQ035925, PQ035926 (&lt;i&gt;rpb2&lt;/i&gt;). BLASTn analysis of QS2-1 sequences exhibited 99% similarity with &lt;i&gt;F. verticillioides&lt;/i&gt; sequences (strains CBS 576.78) MT010888 of &lt;i&gt;cmdA&lt;/i&gt; (711/713, 99%), MT010956 of &lt;i&gt;rpb1&lt;/i&gt; (1790/1791, 99%), and MT010972 of &lt;i&gt;rpb2&lt;/i&gt; (868/870, 99%). A phylogenetic tree was constructed using concatenated sequences along with the sequences of the type strains employing the neighbor-joining method, showing the three strains formed a clade with the type strain CBS 576.78. Pathogenicity was tested on 10 healthy potted seedlings by spraying them with a conidial suspension (10&lt;sup&gt;6&lt;/sup&gt; conidia ml&lt;sup&gt;-1&lt;/sup&gt;), while 5 seedlings were sprayed with ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142366220","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":"Evaluation of Ergot Resistance in Hard Red Spring Wheat in North Dakota.","authors":"LeAnn Lux, Andrew Green, Jessica Scherer, Bryan Hansen, Gabriel Dusek, Harlee Kilber, Andrew Friskop","doi":"10.1094/PDIS-02-24-0371-RE","DOIUrl":"10.1094/PDIS-02-24-0371-RE","url":null,"abstract":"<p><p>Higher levels of ergot (<i>Claviceps purpurea</i> [Fr.] Tul.) were reported in North Dakota hard red spring wheat (HRSW) in 2018, leading to questions pertaining to management and cultivar resistance. To better understand pathogen and HRSW cultivar responses, greenhouse experiments were conducted from 2020 to 2021 to evaluate the aggressiveness of nine <i>C. purpurea</i> isolates and ergot resistance in 21 HRSW cultivars. Results from the aggressiveness assay indicated significant cultivar-by-isolate interactions for the total weight of sclerotia produced and ergot incidence. Mean data across all cultivars by isolate combinations suggested isolates CC-3 and IA-Tim were the most aggressive, and these were subsequently used in ergot resistance experiments. Results from ergot resistance screening indicated that none of the HRSW cultivars were immune to <i>C. purpurea</i> because all cultivars produced sclerotia. However, differences in ergot incidence, kernel incidence, aborted kernel incidence, total sclerotia weight, sclerotia length, and sclerotia width occurred among cultivars. Both 'ND-Frohberg' and 'TCG-Spitfire' had the lowest ergot incidence values and were among the lowest in total sclerotia weight. 'Waldron' and 'LCS-Trigger' had the highest ergot incidence and the highest total sclerotia weight. Given that most concerns with ergot occur postharvest, we suggest two categories to describe ergot resistance: host resistance (fate of inoculation for a stigma) and logistical resistance (size characteristics of a sclerotium that influence its ability to remain with a seed lot after harvest and cleaning). This research provides a strong foundation for our understanding of HRSW resistance to ergot that will influence variety decisions in ergot-prone areas in North Dakota.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141076329","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":"Three Novel <i>er1</i> Alleles and Their Functional Markers for Breeding Resistance to Powdery Mildew (<i>Erysiphe pisi</i>) in Pea.","authors":"Junliang Zhan, Danhua Wang, Wenqi Wu, Dong Deng, Canxing Duan, Suli Sun, Zhendong Zhu","doi":"10.1094/PDIS-04-24-0859-RE","DOIUrl":"10.1094/PDIS-04-24-0859-RE","url":null,"abstract":"<p><p>Powdery mildew caused by <i>Erysiphe pisi</i> DC is a global notorious disease on peas. Deploying resistance pea cultivars is the most efficient and environmentally friendly method for disease control. This study focuses on revealing the resistance genes in three pea germplasms and developing their functional markers for resistance breeding. The identification of resistance genes involved genetic mapping and the sequencing of the pea mildew resistance locus O homolog <i>PsMLO1</i> gene. To confirm the heredity of three resistant germplasms, they were crossed with susceptible cultivars to generate F₁, F₂, and F_2:3 populations. The F₁ generation exhibited susceptibility to <i>E. pisi</i>, whereas the segregation patterns in subsequent generations adhered to the 3:1 (susceptible: resistant) and 1:2:1 (susceptible homozygotes: heterozygotes: resistant homozygotes) ratios, indicating that powdery mildew resistance was governed by a single recessive gene in each germplasm. Analysis of <i>er1</i>-linked markers and genetic mapping suggested that the resistance genes could be <i>er1</i> alleles in these germplasms. The multiple clone sequencing results of the three homologous <i>PsMLO1</i> genes showed they were novel <i>er1</i> alleles, named <i>er1</i>-15, <i>er1</i>-16, and <i>er1</i>-17. The <i>er1</i>-15 and <i>er1</i>-16 were caused by 1-bp deletion at position 335 (A) and 429 (T) in exon 3, respectively, whereas <i>er1</i>-17 was caused by a 1-bp insertion at position 248 in exon 3, causing a frame-shift mutation and premature termination of <i>PsMLO1</i> protein translation. Their respective functional markers, kompetitive allele-specific PCR (KASP)-<i>er1</i>-15, KASP-<i>er1</i>-16, and KASP-<i>er1</i>-17, were successfully developed and validated in respective mapping populations and pea germplasms. These results provide valuable tools for pea breeding resistance to <i>E</i>. <i>pisi</i>.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141158730","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":"Combining Thermotherapy with Shoot Tip Culture or Cryotherapy for Improved Virus Eradication from In Vitro <i>Actinidia macrosperma</i>.","authors":"A-Ling Zhang, Mingxing Hao, Zhimin Shi, Zhixiong Gao, Yan Xu, Zhande Liu","doi":"10.1094/PDIS-03-24-0546-RE","DOIUrl":"10.1094/PDIS-03-24-0546-RE","url":null,"abstract":"<p><p>In recent years, kiwifruit viral diseases have become increasingly prevalent in kiwifruit-producing regions of China, significantly impacting both the yield and quality of kiwifruit. This has emerged as a significant constraint on the healthy and sustainable development of the kiwifruit industry. The use of virus-free propagation materials has been proven the most effective strategy for controlling plant viral diseases. In the present study, shoot tip culture, shoot tip cryotherapy, and their combinations with thermotherapy were established to eradicate Actinidia virus A (AcVA), Actinidia virus B (AcVB), and Actinidia chlorotic ringspot-associated virus (AcCRaV) from <i>Actinidia macrosperma</i>. Additionally, the impact of shoot tip size on virus eradication was evaluated. Among the three confirmed viruses, regardless of the procedure, AcVB was the easiest to eradicate, followed by AcVA and AcCRaV. Combining thermotherapy with shoot tip culture or cryotherapy resulted in a higher virus-free frequency (up to 27.3 and 50%, respectively) than shoot tip culture or cryotherapy alone (0 to 20%). Notably, the combination of thermotherapy and 0.5- to 1-mm shoot tip cryotherapy was shown to be the most effective protocol for virus eradication from <i>A</i>. <i>macrosperma</i>, which produced 50% of regenerated shoots free from all the tested viruses. To the best of our knowledge, this is the first report on virus elimination from kiwifruit infected with multiple viruses based on conventional shoot tip culture and shoot tip cryotherapy.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141296586","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":"Potential Mechanisms of Hexaconazole Resistance in <i>Fusarium graminearum</i>.","authors":"Feng Zhou, Xiaoli Zhou, Yan Jiao, Aohui Han, Haichuan Su, Longhe Wang, Huanhuan Zhou, Weiguo Li, Runqiang Liu","doi":"10.1094/PDIS-04-24-0880-RE","DOIUrl":"10.1094/PDIS-04-24-0880-RE","url":null,"abstract":"<p><p>Fusarium head blight (FHB) caused by <i>Fusarium graminearum</i> is a serious fungal disease that can dramatically impact wheat production. At present, disease control is mainly achieved by the use of chemical fungicides. Hexaconazole (IUPAC name: 2(2,4-dichlorophenyl)-1-(1,2,4-triazol-1-yl)hexan-2-ol) is a widely used triazole fungicide, but the sensitivity of <i>F. graminearum</i> to this compound has yet to be established. The current study found that the EC₅₀ values of 83 field isolates of <i>F. graminearum</i> ranged between 0.06 and 4.33 μg/ml, with an average EC₅₀ value of 0.78 μg/ml. Assessment of four hexaconazole-resistant laboratory mutants of <i>F. graminearum</i> revealed that their mycelial growth and pathogenicity were reduced compared with their parental isolates and that asexual reproduction was reduced by resistance to hexaconazole. Meanwhile, the mutants appeared to be more sensitive to abiotic stress associated with SDS and H₂O₂, while their tolerance to high concentrations of Congo red, and Na⁺ and K⁺ increased. Molecular analysis revealed numerous point mutations in the <i>FgCYP51</i> target genes that resulted in amino acid substitutions, including L92P and N123S in FgCYP51A, as well as M331V, F62L, Q252R, A412V, and V488A in FgCYP51B, and S28L, S256A, V307A, D287G, and R515I in FgCYP51C, three of which (S28L, S256A, and V307A) were conserved in all of the resistant mutants. Furthermore, the expression of the <i>FgCYP51</i> genes in resistant strains was found to be significantly (<i>P</i> < 0.05) reduced compared with their sensitive parental isolates. Positive cross-resistance was found between hexaconazole and metconazole and flutriafol, as well as with the diarylamine fungicide fluazinam, but not with propiconazole, and the phenylpyrrole fungicide fludioxonil, or with tebuconazole, which actually exhibited negative cross-resistance. These results provide valuable insight into resistant mechanisms to triazole fungicides in <i>F. graminearum</i>, as well as the appropriate selection of fungicide combinations for the control of FHB to ensure optimal wheat production.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141432543","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":"Multiplex qPCR for the detection of bacteria associated with huanglongbing '<i>Candidatus</i> Liberibacter asiaticus', '<i>Ca</i>. L. americanus' and 16Sr IX group phytoplasma.","authors":"Elaine Cristina Martins, Diva do Carmo Teixeira, Daniela Aparecida Bononi Coletti, Nelson Arno Wulff","doi":"10.1094/PDIS-05-24-0970-RE","DOIUrl":"https://doi.org/10.1094/PDIS-05-24-0970-RE","url":null,"abstract":"<p><p>The occurrence of 'Candidatus Liberibacter' spp. and '<i>Ca</i>. Phytoplasma' spp. associated with blotchy mottle symptoms poses challenges to huanglongbing (HLB) diagnosis using molecular techniques. The ability to detect multiple targets simultaneously and specifically is a key aspect met by qPCR. A set of primers and hydrolysis probes useful either in single or multiplex reactions for the detection and quantification of HLB-associated bacteria were developed. Sequences from conserved genes of the ribosomal proteins for Liberibacter and phytoplasma circumvent the lack of specificity and cross-reactivity problems related to 16S rDNA gene amplification, allowing precise and specific detection of HLB-associated bacteria in citrus and in the Liberibacter vector, <i>Diaphorina citri</i>. The triplex reaction exhibited high quality and precision as a robust tool for quantifying '<i>Ca</i>. L. asiaticus' (CLas), '<i>Ca</i>. L. americanus' (CLam) and 16SrIX phytoplasma. Triplex qPCR showed consistent results and comparable sensitivity to the RNR test, though Cq values were higher when compared to 16S rDNA qPCR. Detection tests using field samples indicate that the qPCR triplex can identify HLB-associated bacteria in samples with varying levels of symptoms, ranging from typical to asymptomatic. Assessment of field samples from growers indicated more than 78.6% had Cq lower than 35.0, below the cut-off established for qPCR reactions used in this work. qPCR triplex is a safe, specific, and sufficiently sensitive technique for detecting CLas, CLam and 16Sr IX phytoplasma simultaneously, in both citrus and <i>D. citri</i> samples. Its application is of importance in assisting growers in making decisions for HLB management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142351989","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":"https://doi.org/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 <i>Solanaceae</i>), 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 Capsicum 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 acutatum, gloeosporioides, and truncatum species complexes, revealing significant genetic diversity. Morphological characterization supported these identifications, providing a comprehensive profiling. 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 C. <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":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","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":"Differential Sources of Resistance from <i>Lactuca serriola</i> Against Three Races of <i>Xanthomonas hortorum</i> pathovar <i>vitians</i> (Brown, 1918) Morinière et al. 2020 Causing Bacterial Leaf Spot of Lettuce.","authors":"German Valentin Sandoya Miranda, Mark Trent, Ryan J Hayes, Ales Lebeda, Emma Rosenthal, Ivan Simko, Carolee Theresa Bull","doi":"10.1094/PDIS-06-24-1239-RE","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1239-RE","url":null,"abstract":"<p><p>Bacterial leaf spot (BLS) of lettuce (<i>Lactuca sativa</i> L.) is caused by the bacterium <i>Xanthomonas hortorum</i> pv. <i>vitians</i> which is hypothesized to have at least three races of the pathogen present in North America as defined by their differential resistance phenotypes in lettuce cultivars/accessions. Though resistance to <i>X. hortorum</i> pv. <i>vitians</i> race 1 has been identified in cultivated lettuce, numerous other <i>X. hortorum</i> pv. <i>vitians</i> strains cause disease on cultivars carrying this resistance locus. Thus far, resistance to these 'additional' <i>X. hortorum</i> pv. <i>vitians</i> strains has not been adequately described in L. sativa or in any other wild <i>Lactuca</i> species sexually compatible with cultivated lettuce. We have performed an extensive screening of approximately 500 <i>Lactuca</i> accessions from <i>L. sativa, L. serriola, L. saligna, L. virosa, L. aculeata, L. altaica</i>, and <i>L. perennis</i> species to identify accessions resistant to these additional <i>X. hortorum</i> pv. <i>vitians</i> races. Following the initial screenings, greenhouse tests confirmed that <i>X. hortorum</i> pv. <i>vitians</i> race 2 and race 3 could be defined using <i>Lactuca sativa</i> accessions. Race 2 strain BS3217 had an incompatible response (hypersensitive response) on ten <i>Lactuca serriola</i> accessions including PI491114 and PI491108, while race 1 (BS0347) and race 3 (BS2861) strains of <i>X. hortorum</i> pv. <i>vitians</i> showed a compatible response (disease) on these genotypes. <i>L. serriola</i> accession ARM09-161 (and selections derived from it) was the only genotype resistant to the race 3 strain BS2861. <i>L. serriola</i> accessions identified in this study to be resistant to race 2 and race 3 of <i>X. hortorum</i> pv. <i>vitians</i>, together with race 1 resistant cultivars, can be used for pyramiding resistance loci against the three races of the BLS-causing pathogen.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142351920","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}