Plant disease最新文献

{"title":"Role of Soil Moisture in Disease Development of Charcoal Rot of Strawberries Caused by <i>Macrophomina phaseolina</i>.","authors":"Lindsey Pedroncelli, Andre Biscaro, Alexander I Putman","doi":"10.1094/PDIS-05-24-1131-RE","DOIUrl":"https://doi.org/10.1094/PDIS-05-24-1131-RE","url":null,"abstract":"<p><p>Charcoal rot, caused by the soilborne fungus <i>Macrophomina phaseolina</i>, is one of the most economically important diseases affecting strawberry (<i>Fragaria</i> ×<i>ananassa</i>) production in California. Previous studies on non-strawberry hosts have shown that proper soil moisture management can limit pathogen colonization of plants and decrease disease severity. We performed field and greenhouse studies for two seasons with the objective of investigating the role of soil moisture in disease development and management of charcoal rot of strawberries. Bare-root transplants of cultivars Monterey and Fronteras were inoculated or not inoculated and maintained at either a high, optimal, or low soil moisture level using tensiometers. Randomly selected plants from each treatment were sampled for pathogen colonization every 4 weeks after planting, and all plants were visually rated for disease severity every 2 weeks after symptom onset. In both seasons, low soil moisture significantly increased charcoal rot mortality among inoculated plants compared to optimal soil moisture by 16 and 24 percentage points, respectively. In the first season, mortality was significantly lower in the high compared to the optimal soil moisture treatment. Colonization of crowns was increased by low soil moisture among inoculated plants in the first season, but soil moisture did not influence root colonization in either year of the study. In the greenhouse, charcoal rot severity was highest in the low soil moisture treatment. These results indicate that soil moisture has a limited influence on colonization of strawberries by <i>M. phaseolina</i> and that maintaining optimal soil moisture can help prevent excess charcoal rot mortality.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818947","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":"Seed-transmission of turnip mosaic virus demonstrated unequivocally in a <i>Brassica</i> species.","authors":"Nuraizat Abidin, Martin John Barbetti, Ming Pei You, Roger Anthony Charles Jones","doi":"10.1094/PDIS-09-24-1981-SC","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1981-SC","url":null,"abstract":"<p><p>Turnip mosaic virus (TuMV) causes important diseases in Brassicaceae crops worldwide. In 2023, Brassica rapa ssp. perviridis cv. Tendergreen seedlings with virus-like symptoms were found growing within an insect-proof glasshouse. The affected seed lot (A), three others of Tendergreen, and five belonging to other B. rapa subspecies, B. juncea or Wasabia japonica were sown in trays within Controlled Environment Rooms (CER's) from which other plants were absent. TuMV was detected in 10% of seed lot A seedlings but none from other seed lots. Next, seed lot A (experiment 1) or seed from Tendergreen mother plants infected with B. napus TuMV resistance breaking strain isolate 12.1 (experiment 2) were sown in trays. In each experiment, these trays were subdivided into two batches, one being placed inside transparent plastic boxes, each batch then being placed in different CER's. TuMV was detected in 10% and 9% of seedlings inside or outside the boxes (experiment 1), or 1% of seedlings from both situations (experiment 2). Since virus contamination by aphid vectors or contact was excluded, TuMV seed transmission was demonstrated unequivocally. A complete TuMV genome obtained from an infected seedling (isolate BRSB1, accession PQ160044) was compared with 44 other genomic sequences from TuMV phylogroup World-B. It belonged to the same subclade as Australian resistance breaking strain isolates 12.1 and 12.5 (99.9% nucleotide identities) and 10 New Zealand sequences (99.2-99.5% nucleotide identities). Our findings have important implications concerning sowing crops with TuMV-infected seed and spreading readily seed-borne or resistance breaking TuMV strains nationally or internationally.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818948","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 wheat blast resistance in the USDA hard winter wheat (<i>Triticum aestivum</i> L.) Northern and Southern Regional Performance Nurseries.","authors":"Kerry F Pedley, Jeffrey Boehm, Guihua Bai, Paul St Amand, Gary L Peterson, Bryan Vinyard","doi":"10.1094/PDIS-09-24-1941-RE","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1941-RE","url":null,"abstract":"<p><p>Wheat blast, caused by the <i>Triticum</i> pathotype of <i>Pyricularia oryzae</i>, is an emerging disease that threatens the global supply of wheat. The pathogen was first reported in Brazil and subsequently spread to the neighboring countries of Argentina, Bolivia, and Paraguay. More recently, wheat blast was reported in Asia and Africa, having been observed in Bangladesh and Zambia. The transcontinental spread of the pathogen has heightened awareness of the disease and has underscored the need to prepare for potential introductions into major wheat production regions. To this end, we have conducted greenhouse evaluations of the 2017 - 2020 hard winter wheat (<i>Triticum aestivum</i> L.) entries of the USDA-coordinated Northern and Southern Regional Performance Nurseries (NRPN and SRPN, respectively) of the U.S. Great Plains using an aggressive isolate of the pathogen, B-71, collected in Bolivia in 2012. Based on molecular marker analysis, all potentially resistant entries in both the NRPN and SRPN were in possession of the distal chromosomal translocation of 2N^VS from <i>Aegilops ventricosa</i>, which has previously been associated with wheat blast resistance. No potentially new sources of resistance were evident in the 2017 - 2020 regional performance nurseries, which highlights the need for the continued use of 2N^VS donor lines in Great Plains wheat breeding programs.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818943","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>Clonostachys rhizophaga</i> Causing Root Rot on Lentil in France and Cross-Pathogenicity on Pea.","authors":"Elodie Gautheron, Nadim Tayeh, Nadine Gautheron, Angélique André, Simon Gibert, Christian Steinberg, Véronique Edel-Hermann","doi":"10.1094/PDIS-09-24-1878-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1878-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Root rot affects legumes such as lentil (Lens culinaris subsp. culinaris Medik.) and pea (Pisum sativum L.) (Chatterton et al. 2019). In France, legume root rot occurs in 65% of cultivated areas and cause up to 60% yield loss (Augagneur et al. 2021; Moussart el al. 2011). Soil was sampled from plots where root rot disease was previously observed. Samplings were conducted in April 2019 from two plots in central France (46.59 N, 2.05 E; 46.57 N, 2.3 E). Pre-germinated lentil (cv. Anicia) seeds were transplanted in both soils and symptomatic plants were collected after two months. They showed yellowing and wilting symptoms associated with necrotic spots on the root system. The light brown color on the roots turned to dark brown as the necrotic spots progress. Diseased root fragments were surface-disinfected by soaking for 30 s in 70% ethanol, rinsed with sterile water and placed on malt extract agar (MEA). Fungal colonies growing from the root fragments were purified by single-spore sub-culturing and preserved in the Microorganisms of Interest for Agriculture and Environment (MIAE) collection (INRAE Dijon, France). They were transferred to potato dextrose agar and carnation leaf agar for macroscopic and microscopic observations. The colonies developed a dense and cottony aerial mycelium, pearly in color with pink reflections (Fig. S1). From below, the colonies were orange-pink. Under the microscope, Verticillium-like conidiophores arising on the same whorl released asymmetrical ovoid single-celled conidia, from 4 to 7 µm long and 2.5 to 3 µm wide, similar to the description of Clonostachys rhizophaga by Schroers (2001). Isolates MIAE08192 and MIAE08209 were identified as Clonostachys sp. based on their internal transcribed spacer (ITS) sequences (GenBank accessions OR902030 and OR902031). They were further identified based on their sequence of the translation elongation factor 1-α gene (TEF-1α) (Moreira et al. 2016) (GenBank accessions OR947648 and OR947649). A BLAST search identified the two isolates as C. rhizophaga based on 100% identity of their sequences to the published sequence KX184992 (382 bp out of 382 bp and 377 bp out of 377 bp, respectively). A phylogenetic analysis combining ITS and TEF-1α sequences confirmed that the two isolates clustered within the C. rhizophaga species (Fig. S2). Two strains MIAE07881 and MIAE07884 of C. rhizophaga have been reported to cause root rot on pea (Gibert et al. 2022). Due to equivalent symptoms on lentil and pea, and the fact that the strains belonged to the same taxon led to test cross-pathogenicity on the two plant species with the two strains collected from lentil and the two strains collected from pea. Surface-disinfected lentil (cv. Anicia) and pea (cv. Firenza) seeds were placed on MEA, and after 72 h, the germinated seeds were transferred into sterile glass tubes containing 30 mL of Hoagland's No. 2 basal salt mixture at 1.6 g.L-1 added with agar 8 g.L-1. Three days later, they were inocula","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a toolbox to study <i>Phytophthora cryptogea</i> - lettuce interactions: Characterization and detection of <i>P. cryptogea</i> in hydroponic lettuce.","authors":"Liese Vlasselaer, Joram Moons, Tim De Clercq, Bart Lievens, Barbara De Coninck","doi":"10.1094/PDIS-09-24-2018-RE","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-2018-RE","url":null,"abstract":"<p><p>Climate change poses a major threat to crop production, resulting in the emergence of new pests and diseases. <i>Phytophthora cryptogea</i> has recently emerged as a major concern in hydroponic lettuce cultivation, causing substantial yield and economic losses. This oomycete pathogen thrives in elevated water temperatures induced by warmer weather conditions (e.g., heatwaves), facilitating rapid pathogen propagation. Although the disease is already present for several decades in chicory cultivation, where it originates from the field, its origin in lettuce cultivation remains unclear. To get a better understanding of its origin, we conducted a multilocus sequence analysis (MLSA) using five reference genes (ITS, β-tub, COI, EF1α and HSP90) and 33 <i>P. cryptogea</i> isolates from various hosts, including chicory and lettuce. Results revealed a clear separation between lettuce and chicory isolates. Furthermore, we developed and implemented a robust disease bioassay and qPCR assay to investigate the interaction between <i>P. cryptogea</i> strains and lettuce. Our findings revealed that while lettuce isolates exhibited the highest virulence, some chicory isolates also caused disease in lettuce, suggesting a potential evolutionary link between <i>P. cryptogea</i> in lettuce and chicory. Our experiments also revealed that even a low concentration of zoospores (100 zoospores/L) can elicit severe symptoms, underscoring the pathogen's high virulence. Therefore, effective disease management strategies are needed for controlling (the spread of) the disease. Together, this research provides several tools that can be used to enhance our understanding of the interaction between <i>P. cryptogea</i> and its host plants, including the development of proper disease management strategies.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818942","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":"Variation of <i>avirulence</i> genes in the blast fungus from Jiangxi Province, China.","authors":"Runjing Li, Jiehua Qiu, Huanbin Shi, Nan Jiang, Bo Lan, Yanjun Kou","doi":"10.1094/PDIS-04-24-0926-SR","DOIUrl":"https://doi.org/10.1094/PDIS-04-24-0926-SR","url":null,"abstract":"<p><p>The avirulence (AVR) genes of Magnaporthe oryzae are pivotal in eliciting resistance responses in rice, which are mediated by resistance (R) genes in rice. Monitoring the variation of AVR genes in the pathogen is essential for strategically deploying R genes in rice cultivation regions. In this study, a total of 214 isolates were collected from Jiangxi Province, China, in 2022, and the distribution and variation of AVR genes in these isolates were analyzed by PCR amplification and sequencing. The results indicated that AVR-Pi9, AVR-Pib, AVR-Pita, and AVR-Pizt loci were detected in over 95% of isolates. In addition, the AVR-Pik and AVR-Pii loci were found in 84.1% and 0.9% of isolates, respectively. Notably, none of the isolates contained the AVR-Pia gene. Sequencing results revealed various types of variants, including base replacement, deletion, and insertion, in AVR-Pib, AVR-Pik, and AVR-Pita loci. Moreover, a transposon insertion was identified in the promoter region of AVR-Pib. Furthermore, variant isolates were then utilized to inoculate rice monogenic lines IRBLta-K1, IRBLkm-Ts, IRBLKh-K3 and IRBLb-B. The results demonstrated that the rice monogenic line carrying Pib or Pita was unable to recognize the isolates with variant AVR-Pib or AVR-Pita. However, the rice monogenic line with Pikm or Pikh remained capable of recognizing the isolates with AVR-Pik alleles in Jiangxi Province. The information obtained from this study is valuable for breeding blast-resistant rice varieties that will be cultivated in Jiangxi Province, China.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807761","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>Phytopythium vexans</i> Causing Root Rot on <i>Quercus bicolor</i> in Tennessee and the United States.","authors":"Cansu Oksel, Pratima Subedi, Prabha Liyanapathiranage, Batu Arik, Farhat A Avin, Terri Simmons, Fulya Baysal-Gurel","doi":"10.1094/PDIS-11-24-2355-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-24-2355-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Swamp white oak (&lt;i&gt;Quercus bicolor&lt;/i&gt;) is a North American species of medium-sized trees in the beech family. One-year-old swamp white oak seedlings grown in field conditions in a commercial nursery in Warren County, Tennessee exhibited severe root rot in July 2024. Dark brown lesions were observed in the affected roots (Fig. 1a). Disease severity was approximately 40% of root area affected, and disease incidence was approximately 20% of 100 plants. Symptomatic fine root tissues were surface sterilized with 70% ethanol and rinsed twice with distilled water. Then, symptomatic root parts (1-cm pieces) were plated on V8-PARPH (V8 juice agar amended with pimaricin, ampicillin, rifampicin, pentachloronitrobenzene, and hymexazol) and incubated at 24°C under an 8-hour photoperiod. The rosette pattern accompanied by whitish mycelium resembling &lt;i&gt;Phytopythium&lt;/i&gt; species was consistently observed after three days of incubation. Sporangia were globose or subglobose (19.11±1.71 μm, &lt;i&gt;n&lt;/i&gt;=50) with or without papilla (Fig. 1b). Oogonia were smooth, filamentous to globose (21.04±1.74 μm, &lt;i&gt;n&lt;/i&gt;=50) (Fig. 1c). Representative isolates (FBG7779-1 and FBG7779-2) were identified as &lt;i&gt;Phytopythium vexans&lt;/i&gt; based on morphological characterization (de Cock et al. 2015; Ghimire and Baysal-Gurel 2023). To confirm pathogen identity, total DNA was extracted using the DNeasy PowerLyzer Microbial Kit from 7-day-old cultures of the isolates grown on V8-PARPH. The primer pairs ITS1/ITS4 (White et al. 1990), NL1/NL4 (Baten et al. 2014), OomCoxI-Levup/Fm85mod (Robideau et al. 2011), and Cox2-F/Cox2-R (Hudspeth et al. 2000) were used to amplify and sequence the ribosomal internal transcribed spacer (ITS), the large subunit (LSU), and the mitochondrial cytochrome c oxidase subunits I (CoxI) and II (CoxII) genetic markers, respectively. The ITS, LSU, CoxI and CoxII sequences of the isolates FBG7779-1 and FBG7779-2 (ITS: PQ567140 and PQ567141; LSU: PQ567376 and PQ567377; CoxI: PQ570510 and PQ570511; CoxII: PQ570512, and PQ570513) were 100% identical to those of &lt;i&gt;P. vexans&lt;/i&gt; isolates MK011115, OQ754108, GU133478, and AB468910, respectively. To complete Koch's postulates, pathogenicity test was performed on two-year-old swamp white oak seedlings (165 to 170 cm height) grown in 3-gal containers. The plants were drench inoculated with pathogen slurry (150 ml per plant - two 9-cm plates of 7-day-old culture/liter) of the isolates FBG7779-1 and FBG7779-2 (five plants per isolate) (Panth et al. 2021). Five plants were drenched with agar slurry without the pathogen and served as a non-inoculated control plant. The study was conducted in a greenhouse condition (21 to 23°C, 70% relative humidity) and irrigated twice a day for 2 min each time using an overhead irrigation system. Two weeks after inoculation, dark brown lesions developed in the roots of all inoculated plants (Fig. 1d), whereas controls remained healthy (Fig. 1e). The morphology of the pathogen isolated on t","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807688","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 brown spot caused by <i>Diaporthe phoenicicola</i> on <i>Lithocarpus polystachyus</i> in China.","authors":"Yunpeng Jiang, Huiting Chen, Yue Sun, Wenting Long, Shengxiang Xiao, Dingjie Li, Keke Li, Jianglan Chen, Hao Chen","doi":"10.1094/PDIS-04-24-0846-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-04-24-0846-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;The leaves of Lithocarpus polystachyus (Wall. ex A. DC.), an economically significant tree species in China, are commonly referred to as 'sweat tea' due to their high dihydrochalcone content, which holds biomedical importance, particularly in the treatment of diabetes (Hou et al. 2011). In January 2024, brown spots on L. polystachyus leaves were widely observed in Ningxiang (28°23'N, 112°59'E), Hunan Province, China. According to the investigation, the incidence rate of this disease was about 74% (222/300 plants surveyed). On each infected plant, nearly 60% leaves had symptoms. The disease initially presented as small yellow lesions that eventually developed into large brown patches with dark brown edges. More than 80% of the area was covered by leaf lesions, which eventually turned into leaf necrosis. To ascertain the pathogenic species responsible for this disease, pathogen isolation was conducted using a tissue separation method (Xu et al. 2023). The infected leaf tissues were surface-disinfected by immersing in 75% ethanol followed by 0.1% HgCl2. Small pieces (0.5 × 0.5 cm) were then excised and placed onto PDA medium, and incubated at 28°C for 6-9 days. Sterilized dissecting needles were used to pick mycelia from the edge of the colonies and placed onto PDA for strains purification. On the PDA, the colony color of upper side initially appeared white (Rayner 1A1), and then turned grey (Rayner 11C1), while the reverse side turnd faint yellow (Rayner 4A3). Black pycnidia were induced on PDA at 28°C under a 12 h/12 h light/dark cycle for 12 days. Alpha conidia were 5.37 _8.84 × 1.53 _3.19 μm (average: 6.77 × 2.37 μm, n = 50), hyaline, fusiform or ellipsoidal. Beta conidia were 13.61 _23.45 μm × 0.94 _1.47 μm (average: 18.78×1.18 μm, n = 50), hyaline, aseptate, filiform, straight or hamate. Morphologically, the fungi were identified as Diaporthe sp. (Guarnaccia and Crous 2017). To further affirm the identification of the pathogen, the genomic DNA was extracted from representative isolate, referred to as Dip, for molecular identification. The internal transcribed spacer region (ITS), translation elongation factor 1α (EF1-α), β-tubulin (TUB2) and histone H3 (HIS) genes were amplified from genomic DNA using primers ITS1/ITS4, EF1-728F/EF1-986R, Bt2a/Bt2b, and CYLH3F/H3-1b, respectively, to sequence for BLAST (Huang et al. 2015). The results showed that the ITS (GenBank: PP502145), EF1-α (GenBank: PP505773), TUB2 (GenBank: PP505774) and HIS (GenBank: PP505772) sequences of Dip isolate, respectively, showed 100% (469/469 bp), 98.47% (257/261 bp), 97.63% (617/632 bp), and 100% (379/379 bp) identity to their counterparts (GenBank: MW504747, ON049530, MW514138 and ON113058) in Diaporthe phoenicicola. The Maximum Likelihood tree was built based on the ITS, EF1-α, HIS and TUB2 sequences using MEGA11.0. Isolate Dip clustered with D. phoenicicola. The fungus was finally identified as D. phoenicicola by combining morphological and molecular characterist","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807752","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 Crown and Root Rot on Eastern Redbud (<i>Cercis canadensis</i>) Caused by <i>Calonectria cylindrospora</i> in Tennessee.","authors":"Pratima Subedi, Prabha Liyanapathiranage, Seyed Mohammad Rouhani, Cansu Oksel, Terri Simmons, Farhat A Avin, Fulya Baysal-Gurel","doi":"10.1094/PDIS-10-24-2224-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2224-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Eastern redbuds (&lt;i&gt;Cercis canadensis&lt;/i&gt;) are the important trees in Tennessee nurseries, known for their vibrant spring blooms, and heart-shaped foliage (Kidwell-Slak and Pooler 2018). In May 2023, container-grown eastern redbuds exhibited crown and root rot symptoms. Disease incidence was 50% of 100 plants and severity was 40% for the affected root area. Symptoms appeared as sunken lesions localized around the crown region, while the roots showed dark brown to black discoloration. To isolate the causal agent, tissues from the symptomatic crown and roots were excised and surface sterilized with 1% sodium hypochlorite for 1 minute, followed by 70% ethanol for 30 seconds, and washed twice with sterile water. About 0.3 mm&lt;sup&gt;2&lt;/sup&gt; sections of the diseased tissues were placed on potato dextrose agar (PDA) and malt extract agar (MEA) and incubated at 25°C under 12 hours light/dark conditions. Colonies appeared orange to red-brown after 4 to 6 days on both PDA and MEA. Microscopic observations were conducted using two weeks old cultures grown on MEA. The conidiogenous apparatus (avg. 90 μm × 60 μm, n=50) consisted of penicillate conidiophore-bearing branches. The septate stipe extension (avg. 145 μm × 6 μm, n=50) terminated in a sphaeropedunculate vesicle (avg. 10 μm, n=50). The uniseptate macroconidia (avg. 45 μm × 4.5 μm, n=50) were hyaline, cylindrical, rounded at both ends and straight. The observed morphological traits aligned with &lt;i&gt;Calonectria cylindrospora&lt;/i&gt; described by Liu et al. (2020). Pathogen identity was confirmed by sequencing specific genetic markers amplified from genomic DNA extracted using DNeasy PowerLyzer Microbial Kit from 7-day-old pure cultures. The primer pairs ITS1/ITS4 (White et al. 1990), T1F/T222 (O'Donnell et al. 2000), and EF1/EF2 (Carbone and Kohn 1999) were used to amplify and sequence the ribosomal internal transcribed spacer (&lt;i&gt;ITS&lt;/i&gt;), and nuclear beta-tubulin (&lt;i&gt;TUB&lt;/i&gt;) and translation elongation factors 1-α (&lt;i&gt;EF1-α&lt;/i&gt;) genetic markers, respectively. The sequences of the three isolates were 99.8, 100, and 100% identical to &lt;i&gt;C. cylindrospora&lt;/i&gt; (CBS 136425, CBS 30978, and CBS 119670) in the NCBI database, respectively. Phylogenetic analysis of concatenated sequences of &lt;i&gt;ITS&lt;/i&gt;, &lt;i&gt;TUB&lt;/i&gt;, and &lt;i&gt;EF1-α&lt;/i&gt; of &lt;i&gt;C. cylindrospora&lt;/i&gt; and other closely related taxa (Liu et al. 2020) retrieved from GenBank confirmed the identity of the pathogen as &lt;i&gt;C. cylindrospora&lt;/i&gt; (Fig. 1). The sequences of three isolates (FBG5441, FBG5751, and FBG5752) were deposited in GenBank with accession numbers PQ482527, PQ482528, and PQ482529 (&lt;i&gt;ITS&lt;/i&gt;), PQ493360, PQ493361, and PQ493362 (&lt;i&gt;TUB&lt;/i&gt;), and PQ493363, PQ493364, PQ493365 (&lt;i&gt;EF1-α&lt;/i&gt;), respectively. Three isolates were used to inoculate 1-year-old container-grown (1-gal) healthy eastern redbud plants. Conidial suspension (1.0 × 10&lt;sup&gt;5&lt;/sup&gt; conidia/mL) was prepared for each isolate by using 14-day-old fungal cultures grown on MEA and was applie","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807712","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 Maize Ear Rot Caused by <i>Fusarium boothii</i> in Serbia.","authors":"Ana Obradović, Jelena Stepanovic, Vesna Krnjaja, Goran Stanković, Nikola Grčić, Milica Nikolic, Slavica Stankovic","doi":"10.1094/PDIS-10-24-2198-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2198-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Fusarium graminearum species complex (FGSC) includes at least fifteen species which are some of the most significant fungi that infect maize in temperate areas (Sarver et al. 2011). Agroecological conditions in Serbia are suitable for the development of infection by members of FGSC and therefore during the period of 1993-2010, maize samples collected from northern Serbia (46°5'55\" N, 19°39'47\" E) showed typical symptoms of gibberella ear rot. Twenty isolates were selected for study for FGSC identification. Appearance of colonies and macroconidia on potato dextrose agar (PDA) of all isolates (average 37.75-45.35×4.35-5.35 µm, No 50) were consistent with descriptions of F. graminearum (O'Donnell et al. 2004). Monosporal isolates were grown on PDA and used for molecular analyses. DNA isolation was performed using DNeasy Plant Mini Kit. Identification of FGSC was performed on the basis of the TEF-1α gene amplified with primers ef1/ef2 (Geiser et al. 2004) and sequenced in both directions. In four selected isolates two additional genomic regions (histone H3 and β-tubulin) were further analyzed using primers H3-1a/H3-1b and T1/T22, respectively (O'Donnell et al. 2000, Glass and Donaldson 1995). Nucleotide sequences of TEF-1α, β-tubulin, histone H3 have been deposited in GenBank under accession numbers: isolate 914 (MF974400, MG063784, MF999140), 1495 (MF974405, MG063789, MF999145), 2812 (MF974408, MG063792, MF999148), 2822 (MF974409, MG063793, MF999149), respectively. Isolates were molecularly identified using BLAST tool from NCBI and with phylogenetic analyses (Maximum Parsimony method with 1000 bootstrap replications on concatenated sequences of all three genes-TEF-1α, β-tubulin and histone H3) using MEGA 11 software package (Tamura et al. 2011). In BLAST analyses isolate 2822 shared 100% nucleotide identity with reference isolate Fusarium boothii NRRL26916 (GQ915470) originating from Central America based on histone H3 gene. Isolates 914, 1495 and 2812 shared 99% to 100% nucleotide identity with F. graminearum isolates. Phylogenetic analyses showed that all equally parsimonious trees made of 32 selected sequences of species within FGSC available in GenBank database and our four isolates, rooted with external outgroup species F. pseudograminearum, grouped three isolates (914, 1495, 2812) with F. graminearum isolates (NRRL28336, 29169, 28439) and one isolate (2822) grouped with F. boothii isolates (NRRL 29020, 26916). Pathogenicity of isolates was confirmed using the method of Reid et al. (1996). Artificial inoculation of maize ears was performed on the third day after silking by injecting 2 ml of a conidial suspension with a concentration of 1x105 conidia/ml into the silk channel. The same procedure was applied to control plants, using sterile water instead of inoculum. After three weeks, symptoms of Gibberella ear rot appeared and the pathogen was again successfully isolated. The fungus was identical to original isolates, thus completing Koch'","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807758","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}