Plant disease最新文献

{"title":"First report of <i>Botryosphaeria dothidea</i> causing root rot of sugar beet in Serbia.","authors":"Nina Vuckovic, Natasa Duduk, Emil Rekanovic, Bojan Duduk, Ivana Vico","doi":"10.1094/PDIS-06-24-1275-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1275-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Botryosphaeria dothidea (Moug.:Fr.) Ces. & De Not. is predominantly recognized as a pathogen of various woody plants, inducing symptoms of stem canker, dieback, and fruit rot worldwide. However, sporadic reports suggest its impact on field crops, including B. dothidea associated with stem canker in soybean and tobacco (Bian et al. 2015; Chen et al. 2021), as well as B. quercuum on sugar beet (Alfieri et al. 1984). In September 2023, during a survey of root rot pathogens of sugar beet (Beta vulgaris L.) in Rimski Šančevi, Serbia (N 45°19´57″; E 19°49'58″), 3% of collected samples exhibited root rot symptoms. Externally, the lesions exhibited a dark brown coloration. On cross-section, the tissue displayed a gradient of discoloration ranging from light to dark brown throughout the roots. The roots were completely rotted. From these samples, two fungal isolates (SR28/II and SR4/III) were obtained from rotted internal root fragments, after washing, surface disinfection (70% ethanol), and plating on potato dextrose agar (PDA). Colonies on PDA were fluffy with abundant aerial mycelium, surface light to dark grey-brown, reverse black in the centre and grey-brown towards the irregular margin, after 7 days at 25°C in the dark. To induce sporulation, isolates were cultivated on 2% water agar with pine needles and incubated under continuous near ultraviolet (NUV) light at room temperature for 30 days. Conidia were hyaline, aseptate, fusiform, subtruncate at the base, subobtuse at the apex, and measured (19.56-) 24.12 - 26.31 (-28.99) x (5.13-) 5.94 - 6.54 (-7.44) µm (mean 25.06 x 6.26 µm, n=100), consistent with description of B. dothidea (Phillips et al. 2013). For molecular identification, DNA was extracted from mycelium of 7-day-old cultures, and internal transcribed spacer region (ITS), partial translation elongation factor 1-alpha gene (TEF) and partial β-tubulin gene (TUB) were amplified using the primer pairs ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. Multiple sequence alignment and BLAST analyses showed that our isolates had 100% sequence similarity with reference isolates of B. dothidea, including ex-type isolate CBS 115476 (= CMW 8000) in ITS (AY236949), TEF (AY236898), and TUB (AY236927). Maximum likelihood phylogeny of concatenated sequences confirmed the identity of the isolates as B. dothidea. Sequences of ITS, TEF and TUB of isolate SR4/III were submitted to GenBank under accession numbers PP908658, PP911334, PP911333, respectively. The pathogenicity of obtained isolates was assessed on 3-month-old sugar beet plants grown in sterile substrate in the greenhouse. For inoculation, the upper parts of the roots were wounded (10x3 mm) 1 cm above the substrate, using a sterilized nail, and 2x2 mm mycelial plugs of 7-day-old culture grown on PDA were inserted and sealed with parafilm. Control plants were inoculated with sterile PDA plugs. Six plants were used ","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142472374","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":"Comparative Fitness of <i>Monilinia fructicola</i> Isolates with Multiple Fungicide-Resistant Phenotypes.","authors":"Pamela S S Dutra, Thiago A Carraro, Cristiano N Nesi, Lilian Amorim, Louise L May De Mio","doi":"10.1094/PDIS-12-23-2549-RE","DOIUrl":"10.1094/PDIS-12-23-2549-RE","url":null,"abstract":"<p><p>This study characterized 52 isolates of <i>Monilinia fructicola</i> from peach and nectarine orchards for their multiresistance patterns to thiophanate-methyl (TF), tebuconazole (TEB), and azoxystrobin (AZO) using in vitro sensitivity assays and molecular analysis. The radial growth of <i>M. fructicola</i> isolates was measured on media amended with a single discriminatory dose of 1 μg/ml for TF and AZO and 0.3 μg/ml for TEB. <i>Cyt b</i>, <i>CYP51</i>, and β-<i>tubulin</i> were tested for point mutations that confer resistance to quinone outside inhibitors (QoIs), demethylation inhibitors (DMIs), and methyl benzimidazole carbamates (MBCs), respectively. Eight phenotypes were identified, including isolates with single, double, and triple in vitro resistance to QoI, MBC, and DMI fungicides. All resistant phenotypes to TF and TEB presented the H6Y mutation in β<i>-tubulin</i> and the G641S mutation in <i>CYP51</i>. None of the point mutations typically linked to QoI resistance were present in the <i>Monilinia</i> isolates examined. Moreover, fitness of the <i>M. fructicola</i> phenotypes was examined in vitro and in detached fruit assays. Phenotypes with single resistance displayed equal fitness in vitro and in fruit assays compared with the wild type. In contrast, the dual- and triple-resistance phenotypes suffered fitness penalties based on osmotic sensitivity and aggressiveness on peach fruit. In this study, multiple resistance to MBC, DMI, and QoI fungicide groups was confirmed in <i>M. fructicola</i>. Results suggest that <i>Monilinia</i> populations with multiple resistance phenotypes are likely to be less competitive in the field than those with single resistance, thereby impeding their establishment over time and facilitating disease management.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS12232549RE"},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141545155","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 Pathogenicity of Soilborne Pathogens in <i>Gloriosa superba</i>: Effects of Single- and Multiple-Pathogen Coinfection on Disease Responses.","authors":"Shanmuga Priya Dhanabalan, Iruthayasamy Johnson, Parthiban V Kumaresan, Rajamani Kandasamy, Senthil Natesan, Sambasivam Periyannan, Karthikeyan Muthusamy","doi":"10.1094/PDIS-03-24-0496-RE","DOIUrl":"10.1094/PDIS-03-24-0496-RE","url":null,"abstract":"<p><p>Glory lily (<i>Gloriosa superba</i>), an ornamental climbing plant, contains the bioactive compound colchicine, attracting attention from the pharmaceutical industry. However, soilborne pathogens have emerged as a serious threat to the cultivation of glory lily, leading to substantial economic losses in the southern parts of India. Among these, the three major pathogens are <i>Macrophomina phaseolina</i>, <i>Fusarium oxysporum</i>, and <i>Agroathelia rolfsii</i>, causing dry root rot (also referred to as charcoal rot), wilt, and stem rot, respectively. Here, we characterized these pathogens using morphological characteristics and phylogenetic analysis of DNA sequences related to the internal transcribed spacer of ribosomal DNA, calmodulin (<i>CAL</i>), and translation elongation factor 1-alpha (<i>TEF-1α</i>). Furthermore, in the pathogenicity tests, the inoculation of <i>M. phaseolina</i> alone resulted in lesions measuring 7.54 ± 0.01 mm on tubers and 90% seedling mortality. This severity was comparable to the simultaneous inoculation of all three pathogens, indicating the prominence of dry root rot among soilborne diseases. This study marks the first detailed investigation of soilborne pathogens combined infection in <i>G. superba</i>, contributing to the understanding of fungal disease complexity in medicinal plants.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS03240496RE"},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141458691","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 leaf spot caused by <i>Alternaria alternata</i> on <i>Atractylodes lancea</i> in Jiangsu, China.","authors":"Longjiao Hu, Yang Li, Jiping Xuan, Yonghua Gu, Dongling Li, Zhenghai Mo, Panhua Liao","doi":"10.1094/PDIS-07-24-1349-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-07-24-1349-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Atractylodes lancea is an important Chinese herbal medicine, which is mainly produced in Jiangsu province, China. In June 2022, leaf spots symptom were observed on some A. lancea seedlings growing in a Chinese herbal medicine resource garden of Nanjing Botanical Garden, Jiangsu. Approximately 75% of 100 A. lancea seedlings suffered from the disease. Initially, gray to black spots appeared at the tip of the blade, then spread deep into the petiole, finally causing the blade to wither and fall. To isolate the pathogen, five diseased leaves were collected from five different seedlings. Leaf sections (3 to 4 mm) were excised from the margins between healthy and diseased tissues, surface sterilized in 75% alcohol for 30 s, then in 1.5% NaClO for 90 s, rinsed three times in sterilized distilled water, plated on potato dextrose agar (PDA) and incubated at 25℃in darkness. Pure cultures were obtained by monosporic isolation. Eighteen isolates were obtained, and 77.8% of isolates was identified as Alternaria spp. A representative isolate, CS4-1 was used for further investigation. The colony of CS4-1, growing on PDA was cotton-like and black to brown with gray-white aerial hyphae on their surfaces, and dark gray on the back. The conidia were solitary on conidiophores and were oval to pear-shaped, brown in color, with 1 to 4 transverse septa and 0 to 1 oblique septa, parietal cells extending into the beak, and measured 8.9 to 39.5×6.0 to 13.5 µm (n=35). These characteristics were consistent with the description of Alternaria spp. (Simmons 2007). Six DNA regions, i.e.,internal transcribed spacer (ITS), large subunit ribosomal RNA (LSU), small subunit ribosomal RNA (SSU), anonymous region OPA10-2, Alt a 1 major allergen (Alta1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1-alpha (TEF1) with the respective GenBank Accession No. OP836052, OP836054, OP836051, OP851487, OP851488, OP851489, and OP851490, were amplified and sequenced with the primer pairs described by White et al. (1990) and Woudenberg et al. (2015). A neighbor-joining phylogenetic tree was generated by combining all sequenced loci in MEGA7, and CS4-1 clustered in the A. alternata clade. To test pathogenicity, 12 leaves, on three one-month-old A. lancea seedlings (four leaves from each seedling) were wounded with a sterile needle and inoculated with 20 μL of conidial suspension (1×106 spores/mL) on the left sides of leaves. The right sides of the leaves were inoculated with 20 µL sterile water and used as the control. All inoculated detached leaves and seedlings were covered with clear polyethylene bags to keep moisture and were incubated in a greenhouse at 25℃, 80% relative humidity, and a 12-h light/dark cycle. The experiment was repeated three times. After 4 days, typical gray to black spots were visible on the left sides of all inoculated leaves and the inoculated seedlings, and the right sides remained asymptomatic. Subsequently, the same fungus was","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142472369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Fusarium</i> species associated with Bakanae Disease of Rice in Bangladesh.","authors":"Asmaul Husna, Md Assaduzzaman Miah, Latiffah Zakaria, Masratul Hawa Mohd, Nur Ain Izzati Mohd Zainudin, Nik Mohd Izham Mohamed Nor","doi":"10.1094/PDIS-03-24-0655-SR","DOIUrl":"https://doi.org/10.1094/PDIS-03-24-0655-SR","url":null,"abstract":"<p><p>Bakanae disease has become a serious threat for sustainable rice production in Asian countries including Bangladesh. <i>Fusarium</i> species are important seedborne pathogens that cause bakanae disease of rice. Typical bakanae symptomatic samples were collected through a series of sampling conducted in several districts of Bangladesh for 4 consecutive years from 2019 - 2022. The pathogens were confirmed using morphological characteristics, DNA sequences, and phylogenetic analyses of two genes, namely, translation elongation factor 1-alpha (<i>TEF1-α</i>), and RNA polymerase subunit II (<i>RPB2</i>). A total of 121 <i>Fusarium</i> isolates were recovered from diseased rice samples at different geographical locations. From the phylogenetics analyses of <i>TEF1-α</i> and <i>RPB2</i> gene sequences coupled with morphological characterization revealed that the collected isolates belonged to five species viz. <i>F. fujikuroi</i> (75.2% isolation frequency), <i>F. incarnatum</i> (17.35%), <i>F. commune</i> (4.95%), <i>F. verticillioides</i> (1.65%), and <i>F. proliferatum</i> (0.82%). Phylogenetic analysis also showed that 28 representative strains were attributed to five species. Finally, four <i>Fusarium</i> spp. <i>F. fujikuroi</i>, <i>F. commune</i>, <i>F. verticillioides</i> and <i>F. proliferatum</i> were found to be pathogenic under virulence assays of the isolates. The pathogenicity test results demonstrated that <i>F. fujikuroi</i> caused typical symptoms of bakanae, leaf elongation and chlorosis, whereas <i>F. proliferatum</i> and <i>F. verticillioides</i> only caused stunting of seedlings and <i>F. commune</i> caused wilt and root rot. <i>F. incarnatum</i> was found to be associated with bakanae disease of rice, however their pathogenicity could not be established. This study provides insight into the diversity and pathogenicity of <i>Fusarium</i> populations associated with bakanae disease in Bangladesh, which will help in formulating effective strategies and policies for better control of the bakanae disease.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142472368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Pseudomonas chlororaphis</i> Metabolites Reduce <i>MfCYP51</i> Expression and Yield Synergistic Efficacy in Mixture with Reduced Rates of Propiconazole Against DMI-Resistant <i>Monilinia fructicola</i> Isolates.","authors":"Johanna Wesche, Zhezheng Zeng, Chao-Xi Luo, Guido Schnabel","doi":"10.1094/PDIS-04-24-0869-RE","DOIUrl":"10.1094/PDIS-04-24-0869-RE","url":null,"abstract":"<p><p>Brown rot caused by <i>Monilinia fructicola</i> is one of the most important diseases affecting peach production in the southeastern United States. Management often involves the use of demethylation inhibitor (DMI) fungicides, but efficacy can be compromised because of overexpression of the <i>MfCYP51</i> gene encoding the 14α-demethylase of the ergosterol biosynthesis pathway. This study aimed to investigate the influence of the biorational fungicide Howler EVO containing <i>Pseudomonas chlororaphis</i> ASF009 metabolites on the expression of <i>MfCYP51</i> in <i>M. fructicola</i> and associated synergy with a DMI fungicide for control of DMI-resistant strains. Mycelia from two DMI-sensitive and three DMI-resistant <i>M. fructicola</i> isolates were exposed or not to propiconazole (0.3 μg/ml), Howler (88.1 μg/ml), or the combination propiconazole + Howler for 6 h prior to RNA extraction. Real-time PCR indicated that Howler reduced the constitutive expression of <i>MfCYP51</i> in DMI-sensitive and two of three DMI-resistant isolates. Propiconazole-induced expression of the DMI target gene was significantly reduced by Howler and by the mixture of Howler plus propiconazole in all isolates. Detached fruit studies on apple revealed that the combination of Howler plus a reduced label rate of Mentor (50 μg/ml propiconazole) was synergistic against brown rot caused by a DMI-resistant isolate in high and low inoculum spore concentration experiments (synergy values of 40.1 and 4.9, respectively). We hypothesize that the synergistic effects against <i>M. fructicola</i> resistant to DMI fungicides based on <i>MfCYP51</i> gene overexpression can be attributed to reduced 14α demethylase production due to transcription inhibition, which may necessitate fewer DMI fungicide molecules to arrest fungal growth. The use of Howler/DMI mixtures for brown rot control warrants further investigation because such mixtures could potentially allow for reduced DMI fungicide use rates in the field without compromising yield or increased resistance selection.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS04240869RE"},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141492996","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":"Biocontrol Efficacy of <i>Pseudomonas</i> Consortia Against Botrytis Blight in Petunias.","authors":"Sachin Naik, Laura J Chapin, Kaylee A South, Michelle Lyn Jones","doi":"10.1094/PDIS-06-24-1210-RE","DOIUrl":"https://doi.org/10.1094/PDIS-06-24-1210-RE","url":null,"abstract":"<p><p><i>Botrytis cinerea</i>, a fungal pathogen causing Botrytis blight, significantly impacts greenhouse crop management due to its broad host range and infection capabilities at various growth stages. Traditional control methods, primarily reliant on fungicides, are challenged by environmental concerns and the rise of fungicide-resistant strains. This study investigates the use of beneficial <i>Pseudomonas</i> bacteria as a sustainable alternative. We hypothesized that specific <i>Pseudomonas</i> consortia could provide more effective biocontrol of <i>B. cinerea</i> than individual strains. Our research investigated five <i>Pseudomonas</i> strains (14B11, AP54, 15H3, 94G2, and 89F1) known to reduce Botrytis blight in <i>Petunia × hybrida</i>. Compatibility for bacterial consortia was assessed through biofilm formation and direct bacterial inhibition assays. The biocontrol effects of the bacteria against <i>B. cinerea</i> were investigated in vitro using shared-air space dual culture assays and in planta by inoculating detached petunia flowers. We found strain 14B11 exhibited the highest biofilm formation, with consortia of 14B11 and 89F1 showing significant enhancement compared to individual cultures, while a slight, non-significant increase was observed in 14B11 and AP54 consortia. However, strain 14B11 efficacy was inhibited by strain 15H3. Genomic analyses identified antifungal compound-related gene clusters in 14B11 and AP54, contributing to their biocontrol potential. Trials with detached flowers of <i>Petunia × hybrida</i> 'Carpet Red Bright' confirmed significant disease severity reduction with 14B11, AP54, and their consortia. This research highlights strategic <i>Pseudomonas</i> consortia as promising, eco-friendly alternatives to chemical fungicides, promoting sustainable agriculture by enhancing our understanding of how microbial interactions can be used to manage Botrytis blight.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142472370","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 falciforme</i> Causing Fusarium Wilt on pepper in Hainan, China.","authors":"Xingliang Wang, Yue Huang, Na Yang, Xue Wang, Xiaoyu Shen, Lijuan Pei, Ying Wang, Hui Zhang","doi":"10.1094/PDIS-09-24-1854-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-09-24-1854-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Pepper (&lt;i&gt;Capsicum annuum&lt;/i&gt; L.) is a significant vegetable crop, valued for its nutritional and economic importance (Pang et al. 2023). Pepper cultivation in China accounts for about 8-10% of the total vegetable planting area, contributing an output value of approximately 250 billion yuan. This makes pepper the leading vegetable in terms of both planting area and economic value. In December 2023, a total of 70% disease incidence of Fusarium wilt was observed in a 1200 m² pepper seed breeding base in Sanya City, Hainan Province, China (18°38'60″ N, 109°16'51″ E). Symptoms initially appeared as wilting on upper leaves. Subsequently, the base of the stem started to necrosis, browning, and gradually spreading upward along the stem. As the lesions expanded, the whole plant gradually wilted and died. Ten diseased plants were randomly selected from the most severely affected area (667 m²). Diseased tissues (5 mm²) were subsequently removed from the lesion edges of these plants, surface sterilized in 75% ethanol for 30 s, and rinsed with sterile distilled water three times, finally cultured on potato dextrose agar (PDA) at 25 °C. Six fungal isolates were obtained using the single-spore isolation method (HN-01 to HN-06). Colonies produced white aerial mycelia with apricot pigments in the PDA medium. The spore morphology and size were observed and measured using synthetic nutrient-poor agar (SNA) medium. Macroconidia were hyaline, slightly curved in shape with 3 or 4 septa, measuring 28.6 to 41.4 × 3.2 to 6.2 μm (av. = 34.8 ± 3.32 × 4.6 ± 0.85 um, n = 20). Microconidia were elongated, oval with 0 or 1 septum, and measured 11.2 to 16.8 × 2.6 to 5.8 μm (av. = 13.5 ± 1.47 × 4.12 ± 1.03 um, n = 20). Chlamydospores were spherical, terminal or intercalary, solitary or chain-forming, with diameters ranging from 2.8 to 10.5 um (av. = 5.8 ± 2.31 um, n = 20). For molecular identification, genomic DNA from all six isolates was extracted using the cetyl trimethyl ammonium bromide (CTAB) method, and the internal transcribed spacer of rDNA (ITS), translation elongation factor 1-α (EF1-α), and RNA polymerase II beta subunit (RPB2) regions were amplified and sequenced using the primers ITS1/ITS4, EF-1/EF-2, and RPB2-5F/7cR (White et al. 1990; O'Donnell et al. 2010). The sequences were deposited in GenBank (ITS: PP779839, PP779840, PP779841, PP779842, PP779843, PP779844; EF1-α: PP797138, PP797139, PP797140, PP797141, PP797142, PP797143; RPB2: PP797144, PP797145, PP797146, PP797147, PP797148, PP797149). The sequences of all three genes showed 99 to 100% similarity with &lt;i&gt;Fusarium falciforme&lt;/i&gt; and other closely related &lt;i&gt;Fusarium&lt;/i&gt; species (ITS: PP735125, EF1-α: OP163897 and RPB2: MF467484). A maximum likelihood phylogenetic tree was constructed based on the ITS, EF1-α, and RPB2 sequences of all isolates, along with other closely related &lt;i&gt;Fusarium&lt;/i&gt; species. Based on morphological and phylogenetic characteristics, all isolates were identified as &lt;i&gt;F. falc","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142472375","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 Stripe Rust Resistance and Chip Detection Resistance Genes in 286 Xinjiang Wheat Cultivars and Breeding Lines.","authors":"Haohao Yan, Jianing Zhu, Yongjin Jin, Xingxuan Bai, Qingdong Zeng, Haifeng Gao, Jinbiao Ma, Lili Huang, Zhensheng Kang, Gangming Zhan","doi":"10.1094/PDIS-04-24-0780-RE","DOIUrl":"10.1094/PDIS-04-24-0780-RE","url":null,"abstract":"<p><p>Wheat stripe rust is a destructive disease worldwide, caused by <i>Puccinia striiformis</i> f. sp. <i>tritici</i> (<i>Pst</i>). Resistance breeding is the most effective method of controlling stripe rust. Xinjiang is a relatively independent epidemic region of wheat stripe rust in China. In recent years, wheat stripe rust in this area has shown an upward trend. Therefore, the purpose of this study was to evaluate the resistance level of wheat cultivars (lines) to the prevalent <i>Pst</i> races and determine the genetic background of stripe rust resistance genes in Xinjiang. Six predominant <i>Pst</i> races in China were used to study resistance of 286 wheat cultivars (lines) at both the seedling stage under controlled conditions and the adult-plant stage under field conditions. In the seedling tests, 175 (61.19%) entries were resistant to the race CYR23, 125 (43.71%) to CYR29, 153 (53.50%) to CYR31, 88 (30.77%) to CYR32, 174 (60.84%) to CYR33, and 98 (34.27%) to CYR34. Among the resistant entries, 23 (8.04%) were resistant to all six races. In the field test, 135 (47.20%) entries were resistant to the tested mixed races. Through comparing the responses in the seedling and adult-plant stages, 109 (38.11%) entries were found to have adult-plant resistance (APR), and 14 (4.90%) entries have all-stage resistance (ASR). The 286 wheat entries were also tested using a wheat breeder chip containing 12 <i>Yr</i> resistance loci. Among these entries, 44 (15.38%) were found to have a single gene, 221 (77.27%) have two or more genes, and 21 (7.34%) have none of the 12 genes, including 144 (50.35%) with <i>Yr30</i> and 5 (1.75%) with <i>YrSP</i>. Entries with two or more genes have stronger resistance to <i>Pst</i>. Overall, the majority of entries have all-stage and/or adult-plant resistance, but their genes for resistance in addition to the 12 tested <i>Yr</i> genes need to be determined. It is also necessary to introduce more effective resistance genes in the breeding programs to improve stripe rust resistance in wheat cultivars in Xinjiang.</p>","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":"PDIS04240780RE"},"PeriodicalIF":4.4,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141470071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Stevia rebaudiana</i> Is a New Host of <i>Stagonosporopsis pogostemonis</i> Associated with Leaf Spot Disease in China.","authors":"Shun Cao, Amei Xu, Yuankai Chi, Xiaofang Cui, Xueying Zhang, Rende Qi, Wei Zhao","doi":"10.1094/PDIS-11-23-2325-PDN","DOIUrl":"https://doi.org/10.1094/PDIS-11-23-2325-PDN","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Stevia rebaudiana is a promising medicinal and edible plant, widely cultivated in China. In 2022-2023, a new leaf spot disease occurred in S. rebaudiana in Hongxing country (32°34'55″N, 118°2'12″E), Dingyuan city, Anhui province. Symptoms were observed on 10 to 15% of plants in three S. rebaudiana nursery beds (0.1 ha in total). The typical symptoms included dark brown spots on the leaves and foliar wilting, the development of brown stems with dieback of top buds, and occasional plant death (Fig. 1a). To identify the pathogen, twenty diseased leaves were collected, cut into small pieces, surface sterilized with 75% ethanol for 30 s, in 0.5% sodium hypochlorite for 2 min, washed three times in sterile water, placed on PDA, and incubated at 25℃ for 5 days. Pure cultures were prepared by subculturing hyphal tips. Twenty-five Stagonosporopsis-like isolates with similar morphology were obtained. After 7 days growth on PDA, colonies had a regular margin, were cottony, and formed concentric circles on the surface that were gray-green. The reverse side of the culture was dark brown with a creme-orange and white, margin. The growth rate was 9.5 mm/day on PDA. Pycnidia were mostly solitary, globose or subglobose, pale to dark brown, thin-walled, glabrous, ostiolate, 95.735~250.851×90.93~266.32 μm (n=50). Conidia were oblong, cylindrical to ellipsoidal, smooth-walled, aseptate, with rounded ends and two polar guttules and measured 3.41 to 5.83 × 1.78 to 3.07 μm (n = 50) (Fig.1 b-d). For molecular identification, the internal transcribed spacer (ITS) rDNA, large ribosomal subunit (LSU) gene, β-tubulin (TUB2) gene and RNA polymerase II (RPB2) gene sequences of two representative isolates (TYJ-SP1 and TYJ-SP2) were amplified by PCR (Woudenberg et al. 2009; Dong et al. 2021). The sequences were deposited in GenBank (accession nos.: OR506193 and OR506194 for ITS, OR533526 and OR533527 for LSU, OR545221and OR545222 for TUB; OR545223 and OR545224 for RPB2) and showed 99.60% to 99.2% similarity to ITS (502/504 bp and 507/511 bp; MZ156571), 100% similarity to LSU (857/857 bp and 857/857 bp; MZ191532), 98.67% to 99.3% similarity to TUB2 (296/300 bp and 298/300 bp; MZ203132) and 99.78% (888/890 bp and 868/870 bp; MZ203135) of S. pogostemonis strain ZHKUCC 21-0001. A maximum likelihood phylogenetic analysis based on the concatenated sequences of ITS, LSU, TUB2 and RPB2 using MEGA 11.0 showed the strains TYJ-SP1 and TYJ-SP2 formed a clade with S. pogostemonis (Fig. 2). Thus, the strains were identified as S. pogostemonis (Dong et al. 2021). To test pathogenicity, the strain TYJ-SP1 was inoculated onto 30-day-old S. rebaudiana seedlings which were surface sterilized with 70% alcohol and washed 3 times with water and air dried prior to inoculation. Ten seedlings were sprayed with a conidial suspension (105 conidia/mL) and ten seedlings were sprayed with sterile water to serve as the negative control. All seedlings were maintained in a growth chamber (25°C, 90% relat","PeriodicalId":20063,"journal":{"name":"Plant disease","volume":" ","pages":""},"PeriodicalIF":4.4,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406700","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}