Plant disease最新文献

{"title":"First report of <i>Stenocarpella macrospora</i> causing Diplodia leaf streak disease of maize in Yunnan Province, China.","authors":"Yinglong Liu, Wanqian Cheng, Zhenglong Zhao, Bo Kang, Peng-Bo He, Pengfei He, Yixin Wu, Shahzad Munir, Yueqiu He","doi":"10.1094/PDIS-10-24-2127-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2127-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Maize (Zea mays. L) is cultivated globally as a staple food crop, animal feed, and biofuel. However, persistent diseases in maize have led significant yield losses and a decline in grain quality (Yang et al., 2017). In August 2024, long and narrow lesions were observed on the leaves of maize growing in a field in Luoping County, Qujing City, Yunnan Province, China (24° 94' 87\" N, 101° 32' 24\" E). The incidence of the disease was investigated to be about 15-30% in different varieties of maize planting areas in seven townships. Initial symptoms appeared as yellow to tan stripes, with the lesions measuring 3 to 48 mm in width and 45 to 560 mm in length. In severe cases, the lesions expanded, leading to complete leaf necrosis, which caused significant damage to maize production. Dark brown sub-epidermal pycnidia and conidia were observed on the necrotic leaf tissue. The pycnidia were globose or sac-like structures, with short and narrow conidiophores. The newly formed conidia are narrow, non-septate, and have transparent cytoplasm. The conidia are subcylindrical to narrowly ellipsoid, straight, curved, or occasionally irregular, measuring 38 to 86 × 7.2 to 12.3 µm. They are 0-3-septate, smooth-walled, pale brown, apex obtuse, base truncate. Therefore, 80 individual conidia were picked under a dissecting microscope, transferred to PDA plates containing antibiotics (10 mg/L rifampicin and ampicillin) followed by incubation at 28°C for 7 days (Fei et al., 2019). After seven days, the colonies of all isolates were turned grey and downy. Based on the maize leaf symptoms and the morphological characteristics of the pycnidia and conidia, the fungus was tentatively identified as Stenocarpella spp. (Luna et al., 2016). To confirm the identity of all isolates, DNA was extracted from 10 randomly selected isolates using the cetyl trimethyl ammonium bromide (CTAB) method. The internal transcribed spacer (ITS) region and the translation elongation factor 1α (TEF-1α) gene were amplified using the primer pairs ITS-1/ITS-4 and EF-1/EF-2, respectively, and then sequenced (Lamprecht et al., 2011). After comparison, the two target sequences of 10 isolates were consistent. BLASTn analysis revealed 99.27% and 100.00% homology with the two target sequences of Stenocarpella macrospora (syn. = Diplodia macrospora) (GQ259128.1, MG934504.1). Based on phylogenetic analysis of two targets, the isolate MS01 was clustered on the same evolutionary branch with S. macrospora. The two target sequences of isolate MS01 was submitted to GenBank under the accession numbers PQ241617.1 and PQ243292.1. To confirm the pathogenicity, a suspension (1 × 106 spores /mL) of isolate MS01 conidial was sprayed onto nine healthy leaves of maize plants in vitro and three pots cultivated with the plants (five plants per pot) in vivo. Plant treated with sterilized water served as control group. The treated plants were incubated at 28°C, 90% relative humidity with alternating light-dark cycles (i.e.","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of Two Novel Recombinant Types of Potato Virus Y from <i>Solanum tuberosum</i> Plants in Southern Region of Russia.","authors":"Viktoriya Samarskaya, Maria Kuznetsova, Nikita Gryzunov, Nadezhda Spechenkova, Polina Bagdasarova, Eugene Ryabov, Michael Taliansky, Natalia O Kalinina","doi":"10.1094/PDIS-10-24-2151-SC","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2151-SC","url":null,"abstract":"<p><p>Potato virus Y (PVY, genus Potyvirus, family Potyviridae) is one of the most devastating and economically important potato pathogens. Members of the Potyviridae family demonstrate high recombination rates. In nature, 5 major parental variants of PVY were identified with at least 35 recombinants. In this study we report two novel PVY recombinants discovered in the sprouts of potato tubers produced in field conditions in Astrakhan region of Russia in 2021 using high-throughput sequencing and de novo genome assembly. These recombinants, which were named Ast-A-I and Ast-A-II, have previously unknown arrangements of genome sections derived from PVYO and PVYN with a novel recombination junction at the position 7850 nt of the PVY genome, in the middle part of the RNA-dependent RNA polymerase (NIb) gene, with PVYO-type sequence at the 5'-end of this junction and PVYN-type at the 3'-end. Other recombinant junctions in the novel PVY variants were previously found in PVYNTNa and PVYNTNb. This includes those at the positions 2390 and 9200 (PVYN at the 5'-end and PVYO at the 3'-end) which were present in both novel recombinants, and at the position 500 (PVYO at the 5'-end and PVYN at the 3'-end) which present in Ast-A-II. The presence of PVY variants with novel recombinant point is verified by Sanger sequencing. Phylogenetic analysis of genomic RNA showed that the sequences of these recombinants form a separate branch which do not cluster with previously described PVY strains.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786450","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 Spot Caused by <i>Alternaria alternata</i> on <i>Artemisia stolonifera</i> (Maxim) Komar. in China.","authors":"Yang Xu, Nana Chang, Chu Wang, Ye Wang, Hui Li","doi":"10.1094/PDIS-10-24-2180-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2180-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Artemisia stolonifera (Maxim.) Komar., also known as the 'elite of Artemisia', is currently widely planted in Jiangxi, Hubei, and other provinces in China. Since April 2023, a leaf spot on Ar. stolonifera was observed in the total cultivation area of 33.33 ha in Zhangshu City, Jiangxi Province. The incidence was 50% to 60%. Small irregular blackish-brown spots first appeared on the leaves, some with chlorotic margins, which later joined into clumps. In severe cases, the leaves were completely necrotic, seriously affected the growth and quality of Ar. stolonifera. Small pieces (3 to 4 mm) were excised from the necrotic borders of 20 typical symptomatic infected leaves, disinfected with 2.5% sodium hypochlorite solution for 3 min, rinsed five times with sterile water, and placed on potato dextrose agar (PDA) medium, incubated at 25℃ for 5 days. 15 purified isolates with similar morphological characteristics were obtained by transferring hyphal tips (isolation frequency of 75%). The colonies on PDA initially were white, and then became olive green with a white rim. After 10 days of culture on potato carrot agar medium (PCA), the conidia were septate, light brown in color, with dimensions ranging from 10.82 to 30.59 × 7.12 to 11.97 μm (n=50). The culture and morphological characteristics corresponded to Alternaria spp. (Simmons 2007), and the representative isolates JNC01 and JNC02 were used for further identification. To further identify the isolates, the RNA polymerase II second largest subunit (RPB2), internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Alternaria major allergen (Alt a1), translation elongation factor 1-alpha (TEF-α) and histone 3 (HIS3) were amplified using primers RPB2-5F2/RPB2-7CR, ITS1/ITS4, gpd1/gpd2, Alt a1-F/Alt a1-R , EF1-728F/EF1-986R and H3-1a/1b, respectively (Glass and Donaldson 1995; Lawrence et al. 2013; Berbee et al. 1999; Hong et al. 2005). The subsequent sequences were deposited in GenBank (accession nos. PP101993 and PQ458469; PP350760 and PQ45545; PP409573 and PQ474679; PP746506 and PQ474680; PP375820 and PQ458468; PQ001738 and PQ458467 for JNCO1 and JNC02 respectively. NCBI BLASTn sequence analysis revealed that all sequences, except for HIS3 had 100% homology with those of the Al. alternata strain CBS 612.72 (RPB2: KP124777.1, ITS: KP124308.1, GAPDH: KP124165.1, Alt a1: KP123861.1, TEF-α: KP125084.1), meanwhile, HIS3 had 100% identity with the Al. alternata strain MRY1 (MK210171.1). Phylogenetic trees, constructed using concatenated sequences based on ITS, GAPDH, Alt a1, TEF and RPB2 genes, as well as one built solely with HIS3, both placed JNC01 and JNC02 in the Al. alternata clade with high confidence. To test pathogenicity, about 5 mL of conidia suspension (1×106 conidia/mL) of JNC01 was sprayed on five 1-year-old healthy seedlings, while five seedlings were sprayed with sterile distilled water as a control. All plants were covered with plastic bags and placed in a gree","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786407","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 New Era in Federal Quarantine and State Certification Diagnostics at Clean Plant Centers in the USA.","authors":"Maher Al Rwahnih, Vicki Klaassen, Teresa Erickson, Olufemi Joseph Alabi, Kristian Stevens, Min Sook Hwang, Lauren Port","doi":"10.1094/PDIS-10-24-2104-FE","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2104-FE","url":null,"abstract":"<p><p>Quarantine and certification programs exist to prevent the entry or spread of harmful pests and pathogens into agricultural systems. Their common objective is to identify pathogen-free source material through the application of validated testing methods for subsequent release for propagation. Tests must be accurate, efficient and cost-effective. In recent decades, the best tests have been biological assays in conjunction with PCR testing. High throughput sequencing (HTS) has now become a reliable and cost-effective diagnostic method having greater accuracy and efficiency than biological assays. In this article, we review the role of clean plant centers in quarantine and certification programs, as well as the process by which HTS was evaluated as a testing method to replace biological assays for screening source material. The data from this evaluation included a side-by-side comparison of HTS and biological assays for cultivars of grapevine, Prunus and rose, and intra- and inter-laboratory validations of an HTS protocol. Based on the results of these evaluations, in 2021 USDA-APHIS and several state regulatory agencies accepted the use of HTS and quantitative polymerase chain reaction (qPCR) to test new introductions of source material, replacing biological indexing. This new protocol requires testing at two timepoints within at least a six-month interval and a dormancy separating the two tests. Under ideal conditions, testing can be completed in 18-24 months with subsequent release from quarantine of plant material that has tested negative for regulated pathogens. This new testing protocol has a profound impact on quarantine and certification programs, facilitating quicker access of stakeholders to clean materials for propagation and increasing the number of pathogens that are detected, and even discovered, with reduced cost, effort, and time.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786104","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":"Fungal trunk pathogens of fruit and nut tree crops: identification, characterization, detection and perspectives for a critical global issue.","authors":"Ilaria Martino, Davide Spadaro, Vladimiro Guarnaccia","doi":"10.1094/PDIS-10-24-2069-FE","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2069-FE","url":null,"abstract":"<p><p>Fungal trunk pathogens are a growing global issue, significantly affecting fruit and nut tree crop cultivation. These pathogens, mainly ascomycetes, belong to several families including Botryosphaeriaceae, Calosphaeriaceae, Cytosporaceae, Diaporthaceae, Diatrypaceae, Nectriaceae and Togniniaceae. The large number of species involved represent a challenge in clarifying the etiology of trunk diseases, further complicated by frequent co-infections of different fungi. Typically, these pathogens enter plants through wounds and natural openings, and some can persist in a latent phase, switching to pathogenicity under favorable conditions. This aspect represents a significant concern for both nurseries and orchards. Moreover, the current climatic conditions and the intensification of cropping systems are likely exacerbating the spread and development of these pathogens, making their management more difficult. This review provides an overview of the main ascomycetes causing trunk diseases, discussing their identification, characterization, and detection methods. Accurate identification and characterization are crucial to increase the knowledge on these pathogens and to develop effective management strategies. An insight on the current preventive and curative strategies is provided as well to explore sustainable crop protection strategies, including agronomic practices, biological control, the use of new active ingredients and tolerant and/or resistant cultivars, to address this escalating problem.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786449","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":"Data mining redefines the timeline and geographic spread of cotton leafroll dwarf virus.","authors":"Alejandro Olmedo-Velarde, Hayk Shakhzadyan, Michael Rethwisch, Michael J West-Ortiz, Philip Waisen, Michelle L Heck","doi":"10.1094/PDIS-06-24-1265-SC","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1265-SC","url":null,"abstract":"<p><p>Cotton leafroll dwarf virus (CLRDV), a threat to the cotton industry, was first reported in the United States (US) as an emergent pathogen in 2017. Phylogenetic analysis supports the hypothesis that US CLRDV strains are genetically distinct from strains in South America and elsewhere, which is not consistent with the hypothesis that the virus is newly introduced into the country. Using database mining, we evaluated the timeline and geographic distribution of CLRDV in the country. We uncovered evidence that shows CLRDV had been in the US for over a decade before its official first report. CLRDV sequences were detected in datasets derived from Mississippi in 2006, Louisiana in 2015, and California in 2018. Additionally, through field surveys of upland cotton in 2023, we confirmed that CLRDV is present in California, which had no prior reports of the virus. Viral sequences from these old and new datasets exhibited high nucleotide identities (>98%) with recently characterized US isolates, and phylogenetic analyses with their homologs placed these sequences within a US-specific clade, further supporting the earlier presence of CLRDV in the country. Moreover, potential new hosts, including another fiber crop, flax, were determined through data mining. Retrospective analysis suggests CLRDV has been present in the US since at least 2006 (Mississippi). Our findings challenge the current understanding of the arrival and spread of CLRDV in the US, highlight the power of data mining for virus discovery, and underscore the need for further investigation into CLRDV's impact on US cotton.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786203","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, detection, and prevalence of a novel strawberry crinivirus.","authors":"Mohammad Hajizadeh, Nasrin Ghaderi Zandan, Igor Koloniuk, Andrea Sierra-Mejia, Ioannis Emmanouil Tzanetakis","doi":"10.1094/PDIS-08-24-1682-SC","DOIUrl":"https://doi.org/10.1094/PDIS-08-24-1682-SC","url":null,"abstract":"<p><p>A new crinivirus, hereafter referred to as strawberry Kurdistan virus (SKV), has been identified using high-throughput sequencing. The 16,553-nucleotide genome is divided into two RNA segments and exhibits 44-56% nucleotide identity with other criniviruses. Phylogenetic analysis indicates that SKV is a member of the Crinivirus group 2. A diagnostic assay was developed and used to screen for the virus in strawberry-producing areas in both Iran and the United States, yet it was only detected in the former. The virus is whitefly-transmissible and can infect several herbaceous plants besides strawberries. SKV was prominent in several areas with symptomatic plants, underscoring the importance of further research and monitoring to understand its potential impact on strawberry yield and to develop effective management strategies.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786073","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":"Effect of Temperature on the Development of Fruiting Bodies of <i>Phaeoacremonium minimum</i> and <i>Phaeomoniella chlamydospora</i> on Grapevine Cuttings In Vitro and Survival of Both Pathogens in Vineyards.","authors":"Mónica Berbegal, Elisa González-Domínguez, Josep Armengol","doi":"10.1094/PDIS-11-23-2493-RE","DOIUrl":"10.1094/PDIS-11-23-2493-RE","url":null,"abstract":"<p><p>In this study, isolates of <i>Phaeoacremonium minimum</i> and <i>Phaeomoniella chlamydospora</i>, fungal pathogens associated with Petri and esca diseases of grapevine, were used to determine the effect of temperature on the development of their fruiting bodies in vitro. Perithecia of <i>Pm. minimum</i> and pycnidia of <i>Pa. chlamydospora</i> were induced at 5, 10, 15, 20, 25, and 30°C on pieces of 1-year-old grapevine cuttings of 110 Richter rootstock, which were incubated for 45 days under continuous white light. Both species were able to produce abundant fruiting bodies at temperatures ranging from 15 to 25°C, but <i>Pm. minimum</i> produced more perithecia at 25°C and <i>Pm. chlamydospora</i> produced more pycnidia at 20°C. At 30°C, only very few reproductive structures were observed. Calculated optimal temperatures ranged from 23.3 to 25.6°C, and equations providing a proper description of temperature effect on <i>Pm. minimum</i> and <i>Pa. chlamydospora</i> fruiting body development were obtained. Moreover, the development of fruiting bodies and the survival of both pathogens on artificially inoculated grapevine cuttings were investigated in two vineyards. No fruiting bodies were observed during the vineyard experiments, but both fungal species were systematically recovered by fungal isolation from the cuttings. Differences in pathogen survival based on incidence data were observed relative to the species, location, and time of exposure, and generalized linear mixed-models analysis showed a progressive reduction of inoculum viability with time. The present research increases our knowledge about the biology and epidemiology of <i>Pm. minimum</i> and <i>Pa. chlamydospora</i>, being particularly useful to improve epidemiological models that could be developed for the prediction of Petri and esca diseases.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS11232493RE"},"PeriodicalIF":4.4,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142018241","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 Triticale leaf rust caused by <i>Puccinia triticina</i> in Canada.","authors":"Mehrdad Abbasi, Sarah Hambleton, Julie Carey, Mazen Aljarrah, Gurcharn Singh Brar","doi":"10.1094/PDIS-10-24-2063-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-10-24-2063-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Triticale (× Triticosecale), was initially produced by crossing wheat (Triticum) with rye (Secale). Although still a minor crop in Canada, triticale grain is used both as human food (in bread, pastry products, and the brewing industry) and as livestock feed (Larter 2015). In September 2023 typical leaf rust samples were observed and collected in winter Triticale at Lacombe, Alberta. Typical exposed rust colored uredinia were mainly on adaxial leaf surface. Urediniospores obovoid, ellipsoid or globoid, measured 24-33 × 19-26 µm; with yellow-brown echinulate wall 1-1.5 µm thick. These spores mostly had 8 to 9 scattered germ pores, approximately bizonate with moderate to strong internal ring. Telia not present. Due to the absence of the telial stage, the morphological features of uredinia and urediniospores align our species with Puccinia triticina and P. recondita. These species have overlapping uredinial characteristics and can potentially both cause disease on Triticale (Yekelo et al. 2019). For testing pathogenicity on Triticale, two-week-old winter Triticale seedlings were infected with single pustule isolate from the Albertan leaf rust sourced from Triticale (AB-1). For seedling inoculation, we used 20 mg of pure urediniospores suspended in 5-6 ml of NOVEC 7100™ Engineered fluid, applied with an airbrush compressor system equipped with a 0.3 mm nozzle. All inoculated plants were kept in a dew chamber at 13°C for 24 hours in the dark, and then transferred to a Reach-In growth chamber with a 16-hour photoperiod (21°C day/15°C night). After 10 days, all inoculated seedlings showed uredinia. Control plants that were only sprayed with NOVEC 7100 and kept under the same conditions remained healthy, showing no rust symptoms. To clarify the identity of leaf rust, we sequenced the nuclear ribosomal rRNA internal transcribed spacer region (ITS) and elongation factor 1 alpha gene (EF1-a) for both the field collection (DAOM 985259) and the single pustule inoculated collection (DAOM 985258) and the data were deposited in NCBI GenBank (accession # PQ317950 and PQ317949 for ITS and PQ338170 and PQ338169 for EF1-a, respectively). Obtained sequences of both field and the inoculated collections were identical and shared %100 identity with available sequences of P. triticina in GenBank (MT955180 for ITS and JX533504 for EF1-a) (Liu et al. 2013). To further investigate the pathogenicity of the Albertan leaf rust isolate (AB-1) on Triticale, we conducted additional rounds of inoculation tests. In those experiments, two-week-old seedlings of winter rye and Avocet wheat were inoculated under the above-mentioned conditions and methods. After 9 to 10 days, both rye and wheat plants showed uredinia on the infected leaves. This indicates that the Triticale isolate of leaf rust was capable of infecting rye and wheat in addition to Triticale. Since Triticale is primarily planted as a forage or cover crop, its susceptibility to wheat leaf rust could contribute to the","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786413","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 Twig Dieback Caused by <i>Neopestalotiopsis rosae</i> on Highbush Blueberry in the Continental United States.","authors":"Brooke Dietsch, Xiaochen Yuan, Jenna Goslin, Chelsea J Harbach, Suzanne M Slack","doi":"10.1094/PDIS-06-24-1256-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1256-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Highbush blueberry (Vaccinium corymbosum) is an important fruit crop for pick-your-own agritourism farms in the Midwest. Declining or diseased plants are a major concern for pick-your-own farms, as consumers prioritize healthy plants and organic practices (Norby and Retallick 2012). In August 2023, leaf spot and dieback symptoms were observed sporadically on the current year's growth throughout an organic berry agritourism farm in Eastern Iowa. Small red spots on the twigs and leaves progressed into larger lesions with gray centers, and brown borders with no observable acervuli or pycnidia. Symptomatic samples from 20 individual 'Duke' blueberry plants were collected for disease identification. Tissue was cut from lesion edges, surface sterilized with 10% bleach for 1 min, rinsed thrice in sterilized water, cultured on potato dextrose agar amended with 800 mg/L yeast extract (PDAY) and 100 µg/ml streptomycin, then kept at 20°C. Twenty isolates were identified morphologically, and three were submitted for molecular analysis. Isolated colonies had white aerial mycelia, irregular margins, and were light yellow underneath. Black, globular acervuli produced five-celled fusoid conidia that ranged from straight to slightly curved. The center three cells were light to dark brown. The basal cell was generally conical, with a small basal appendage. The apical cell ranged from conical to cylindrical, with 2-3 appendages. The spores averaged 23.7 µm long (range 19.7-30.1 µm) and 5.9 µm wide (range 5.0-6.5 µm), n=50. BLAST analysis demonstrated that sequences of ITS (ITS1-F/ITS4; PP764834, PQ344945-46), TUB2 (Bt2a/Bt2b; PP786462, PQ356370-71), and TEF1-α (EF1-526-F/; PP789161, PQ356368-69) were ~98 to 100% similar to KM199360, KM199430, and KM199524 published for Neopestalotiopsis rosae. Using MEGA 11 program (Kumar et al. 2018), maximum likelihood analysis based on the concatenated ITS, TUB2, and TEF1-α sequences placed all three isolates in a high-confidence cluster with N. rosae (Baggio et al. 2021; Jayawardena et al. 2016; Lee et al. 2019), confirming their identification. Pathogenicity of one isolate, NPB-1, was confirmed by inoculating three twigs on three 1-year-old V. corymbosum 'Blue Gold' plants (n=9). Twigs were pierced using a sterile 20-gauge needle with a mycelium plug to mimic pruning wounds, or a PDAY plug as a control (Borrero et al. 2018). Inoculated and control plants were kept at 28°C, 50% relative humidity, with an 18-hour photoperiod. Ten days post inoculation (dpi), inoculated plants showed symptoms of reddish-brown spots along wounded stems which were not present on control plants. At 35 dpi, inoculated plants displayed blight symptoms like the field-observed ones. Inoculated twigs had internal discoloration beyond the inoculation point, unlike the control twigs. N. rosae was successfully reisolated 2 cm away from the inoculation site and confirmed by sequencing in all inoculated twigs (n=9), but not in control plants (n=9). Neop","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142786414","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}