1
|
Spawton KA, du Toit LJ. Prevalence of FRAC Group 11 Fungicide Resistance in Stemphylium vesicarium Isolates, but Not S. beticola Isolates, Causing Stemphylium Leaf Spot of Spinach ( Spinacia oleracea). PLANT DISEASE 2024; 108:2122-2135. [PMID: 38457632 DOI: 10.1094/pdis-11-23-2328-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
Abstract
Stemphylium leaf spot of spinach, caused by Stemphylium beticola and S. vesicarium, is a disease of economic importance in fresh market, processing, and seed production. There have been increasing reports of difficulty managing the disease in the southern United States using fungicides in Fungicide Resistance Action Committee (FRAC) group 11. Isolates of S. beticola and S. vesicarium obtained from spinach leaves and seed from 2001 to 2020 were screened for resistance to azoxystrobin and pyraclostrobin in vitro, in vivo, and using PCR assays to detect mutations in cytochrome b associated with resistance in other fungi (F129L, G137R, and G143A). EC50 values for mycelial growth and conidial germination of S. vesicarium isolates in vitro were significantly less (mean of 0.35 μg/ml) than that of S. vesicarium (mean of 14.17 μg/ml) with both fungicides. All isolates were slightly more sensitive to pyraclostrobin than azoxystrobin in both assays. In vivo assays of plants inoculated with the isolates of S. vesicarium demonstrated poor efficacy of fungicides with each of the two active ingredients. Only the G143A mutation was detected in all spinach isolates of S. vesicarium, including an isolate of S. vesicarium collected in 2003 and 82.9% of isolates from spinach seed lots harvested from crops grown in or after 2017 in Europe, New Zealand, and the United States. The FRAC 11 mutations were not detected in any isolates of S. beticola. The in vitro, in vivo, and DNA mutation assays suggest FRAC group 11 fungicide resistance is widespread in spinach isolates of S. vesicarium but not S. beticola.
Collapse
Affiliation(s)
- Kayla A Spawton
- Washington State University Mount Vernon Northwestern Washington Research and Extension Center, Mount Vernon, WA 98273
| | - Lindsey J du Toit
- Washington State University Mount Vernon Northwestern Washington Research and Extension Center, Mount Vernon, WA 98273
| |
Collapse
|
2
|
Yu YH, Cho YT, Xu YC, Wong ZJ, Tsai YC, Ariyawansa HA. Identifying and Controlling Anthracnose Caused by Colletotrichum Taxa of Welsh Onion in Sanxing, Taiwan. PHYTOPATHOLOGY 2024; 114:1263-1275. [PMID: 38105219 DOI: 10.1094/phyto-08-23-0301-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Leaves of Welsh onion (Allium fistulosum) are subject to various fungal diseases such as anthracnose (Colletotrichum species) and Stemphylium leaf blight (Stemphylium vesicarium). These diseases are the main biotic limitations to Welsh onion production in northern Taiwan. From 2018 to 2020, anthracnose symptoms were observed throughout Welsh onion fields in northern Taiwan, mainly the Sanxing area. In total, 33 strains of Colletotrichum species were isolated from diseased leaves, and major causative agents were identified based on a multilocus phylogenetic analysis using four genomic regions (act, tub2, gapdh, and internal transcribed spacer). Based on this phylogeny, Colletotrichum species causing anthracnose of Welsh onion were identified as C. spaethianum (C. spaethianum species complex) and C. circinans (C. dematium species complex) in the Sanxing area, northern Taiwan. To determine and compare the pathogenicity of each species, representative fungal strains of each species were inoculated on the cultivar 'Siao-Lyu' by spraying spore suspension onto the leaf surface. Welsh onion plants were susceptible to both species, but disease incidence and severity were higher in C. spaethianum. In total, 31 fungicides were tested to determine their efficacy in reducing mycelial growth and conidial germination of representative strains of C. spaethianum and C. circinans under laboratory conditions. Five fungicides-fluazinam, metiram, mancozeb, thiram, and dithianon-effectively reduced mycelial growth and spore germination in both C. spaethianum and C. circinans. In contrast, difenoconazole and trifloxystrobin + tebuconazole, which are commonly used in Welsh onion production in northern Taiwan, mainly the Sanxing area, were ineffective. These results serve as valuable insights for growers, enabling them to identify and address the emergence of anthracnose caused by C. spaethianum and C. circinans of Welsh onion, employing fungicides with diverse modes of action. The findings of this study support sustainable management of anthracnose in Sanxing, northern Taiwan, although further field tests of the fungicides are warranted.
Collapse
Affiliation(s)
- Yu-Hsiang Yu
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
- Institute of Genetics, Faculty of Biology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Yi-Tun Cho
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| | - Yuan-Cheng Xu
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| | - Zhang-Jian Wong
- Department of Horticulture and Landscape Architecture, National Taiwan University, Taipei, Taiwan
| | - Yi-Chen Tsai
- Hualien District Agricultural Research and Extension Station, Hualien, Taiwan
| | - Hiran A Ariyawansa
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, Taiwan
| |
Collapse
|
3
|
Zhang Y, Zhang N, Gao C, Cheng Y, Guan Y, Wei C, Guan J. The Fungal Diversity and Potential Pathogens Associated with Postharvest Fruit Rot of 'Huangguan' Pear ( Pyrus bretschneideri) in Hebei Province, China. PLANT DISEASE 2024; 108:1382-1390. [PMID: 38115565 DOI: 10.1094/pdis-08-23-1528-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Postharvest fruit rot caused by pathogens is a serious problem in the pear industry. This study investigated the fungal diversity and main pathogens and identified a new pathogen in the stored 'Huangguan' pear (Pyrus bretschneideri Rehd.), the dominant pear variety in northern China. We sampled 20 refrigeration houses from five main producing regions in Hebei Province and used Illumina sequencing technology to detect the fungal composition. Alternaria (56.3%) was the most abundant fungus, followed by Penicillium (9.2%) and Monilinia (6.2%). We also isolated and identified nine strains of Alternaria and four strains of Penicillium. Moreover, we observed a new postharvest fruit disease in 'Huangguan' pear caused by Stemphylium eturmiunum, which was confirmed by phylogenetic analysis by combining the sequences of three conserved genes, including internal transcribed spacer, gapdh, and calmodulin. This study marks the first documentation of S. eturmiunum causing fruit rot in 'Huangguan' pears, offering valuable insights for identifying and controlling this newly identified postharvest disease.
Collapse
Affiliation(s)
- Yang Zhang
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
- Key Laboratory of Plant Genetic Engineering Center of Hebei Province, Shijiazhuang, Hebei 050051, China
| | - Nan Zhang
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
| | - Congcong Gao
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
| | - Yudou Cheng
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
| | - Yeqing Guan
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
| | - Chuangqi Wei
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
| | - Junfeng Guan
- Institute of Biotechnology and Food Science, Hebei Academy of Agricultural and Forestry Sciences, Shijiazhuang, Hebei 050051, China
- Key Laboratory of Plant Genetic Engineering Center of Hebei Province, Shijiazhuang, Hebei 050051, China
| |
Collapse
|
4
|
Heck DW, Hay F, Pethybridge SJ. Enabling Population Biology Studies of Stemphylium vesicarium from Onion with Microsatellites. PLANT DISEASE 2023; 107:3886-3895. [PMID: 37330630 DOI: 10.1094/pdis-04-23-0706-re] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Stemphylium leaf blight (SLB), caused by the fungus Stemphylium vesicarium, is dominant within the foliar disease complex affecting onion production in New York (NY). The disease causes premature defoliation and significant reductions in bulb weight and quality. Foliar diseases of onion are usually managed by an intensive fungicide program, but SLB management is complicated by resistance to multiple single-site modes of action. The design of integrated disease management strategies is limited by incomplete knowledge surrounding the dominant sources of S. vesicarium inoculum. To facilitate genomic-based studies of S. vesicarium populations, nine microsatellite markers were developed. The markers were multiplexed into two PCR assays containing four and five fluorescently labeled microsatellite markers. Initial testing of the S. vesicarium isolates found the markers were highly polymorphic and reproducible with an average of 8.2 alleles per locus. The markers were used to characterize 54 S. vesicarium isolates from major NY onion production regions in 2016 (n = 27) and 2018 (n = 27). Fifty-two multilocus genotypes (MLGs) were identified between these populations. Genotypic and allelic diversities were high in both the 2016 and 2018 populations. A greater degree of genetic variation was observed within populations than between years. No distinct pattern of MLGs according to population was identified and some MLGs were closely related between 2016 and 2018. The lack of evidence for linkage among loci also was strongly suggestive of clonal populations with only minor differences between the two populations. These microsatellite markers will be a foundational resource for the testing of hypotheses surrounding the population biology of S. vesicarium and therefore informing disease management.
Collapse
Affiliation(s)
- Daniel W Heck
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| | - Frank Hay
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| | - Sarah J Pethybridge
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| |
Collapse
|
5
|
Wang JY, Jayasinghe H, Cho YT, Tsai YC, Chen CY, Doan HK, Ariyawansa HA. Diversity and Biocontrol Potential of Endophytic Fungi and Bacteria Associated with Healthy Welsh Onion Leaves in Taiwan. Microorganisms 2023; 11:1801. [PMID: 37512973 PMCID: PMC10386586 DOI: 10.3390/microorganisms11071801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 07/07/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Foliar diseases caused by Stemphylium and Colletotrichum species are among the major biotic factors limiting Welsh onion production in Taiwan. Owing to concerns about the environment and the development of pathogen resistance to existing fungicides, biological control using endophytes is emerging as an eco-friendly alternative to chemical control. The aim of the present study was to isolate endophytes from healthy Welsh onion leaves and investigate their antagonistic potential against the major phytopathogenic fungi associated with Welsh onion plants in Taiwan. A total of 109 bacterial and 31 fungal strains were isolated from healthy Welsh onion leaves and assigned to 16 bacterial and nine fungal genera using morphological and molecular characterization based on DNA sequence data obtained from nuclear internal transcribed spacer (nrITS) (fungi) and 16S rRNA (bacteria). Evaluation of these endophytic isolates for biocontrol activity against leaf blight pathogens Colletotrichum spaethianum strain SX15-2 and Stemphylium vesicarium strain SX20-2 by dual culture assay and greenhouse experiments resulted in the identification of two bacterial isolates (GFB08 and LFB28) and two fungal isolates (GFF06 and GFF08) as promising antagonists to leaf blight pathogens. Among the four selected isolates, Bacillus strain GFB08 exhibited the highest disease control in the greenhouse study. Therefore, Bacillus strain GFB08 was further evaluated to understand the mechanism underlying its biocontrol efficacy. A phylogenetic analysis based on six genes identified Bacillus strain GFB08 as B. velezensis. The presence of antimicrobial peptide genes (baer, bamC, bmyB, dfnA, fenD, ituC, mlna, and srfAA) and the secretion of several cell wall degrading enzymes (CWDEs), including cellulase and protease, confirmed the antifungal nature of B. velezensis strain GFB08. Leaf blight disease suppression by preventive and curative assays indicated that B. velezensis strain GFB08 has preventive efficacy on C. spaethianum strain SX15-2 and both preventive and curative efficacy on S. vesicarium strain SX20-2. Overall, the current study revealed that healthy Welsh onion leaves harbour diverse bacterial and fungal endophytes, among which the endophytic bacterial strain, B. velezensis strain GFB08, could potentially be used as a biocontrol agent to manage the leaf blight diseases of Welsh onion in Taiwan.
Collapse
Affiliation(s)
- Jian-Yuan Wang
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, Taiwan
| | - Himanshi Jayasinghe
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, Taiwan
| | - Yi-Tun Cho
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, Taiwan
| | - Yi-Chen Tsai
- Hualien District Agricultural Research and Extension Station, Hualien 973044, Taiwan
| | - Chao-Ying Chen
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, Taiwan
| | - Hung Kim Doan
- Small Farms & Specialty Crops Advisor, University of California Cooperative Extension, 2980 Washington Street, Riverside, CA 92504, USA
| | - Hiran A Ariyawansa
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei 106319, Taiwan
| |
Collapse
|
6
|
Chandel R, Kamil D, Singh S, Kumar A, Patel R, Verma P, Zimik M, Khar A. Screening of short-day onions for resistance to Stemphylium leaf blight in the seed-to-bulb stage (stage I) and bulb-to-seed stage (stage II). FRONTIERS IN PLANT SCIENCE 2022; 13:1063685. [PMID: 36466277 PMCID: PMC9709266 DOI: 10.3389/fpls.2022.1063685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
Stemphylium leaf blight, caused by Stemphylium vesicarium, is a very important fungal disease in onions since its epidemics are able to affect both the bulb yield and the seed quality. The aim of this study was to screen onion genotypes at stage I (seed to bulb) and further screen the identified resistant and susceptible genotypes at stage II (bulb to seed). One hundred and fifty-seven genotypes were screened against SLB under artificially inoculated field conditions. Results revealed a significant variation among the morphological and biochemical traits studied. Correlation studies revealed a significant and negative correlation between percent disease incidence (PDI), pseudostem width, neck thickness, and dry matter. Fifteen genotypes were identified as moderately resistant, and the rest were categorized as susceptible. Bulbs of the genotypes, identified as moderately resistant, were again screened for resistance in stage II. All the genotypes were categorized as moderately susceptible. Biochemical analysis revealed that total foliar phenol content, pyruvic acid, catalase, and peroxidase increased up to 20 days after inoculation (DAI) and thereafter declined. Protein content was highest in the initial stage and declined at 10, 20, and 30 DAI. The higher biochemical activity was observed in moderately resistant category genotypes compared with the susceptible ones. Correlation analysis showed a highly significant and negative correlation of PDI with total foliar phenol content (TFPC), pyruvic acid, catalase, peroxidase, and protein content. To conclude, it was observed that screening against SLB should be done at both the stages (stage I and Stage II) to identify resistant onion genotypes. Direction selection for genotypes with high dry matter, higher phenols, and enzymes may be an alternative pathway to select genotypes for a robust resistance breeding program.
Collapse
Affiliation(s)
- Rahul Chandel
- Division of Vegetable Science, The Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute, Delhi, India
| | - Deeba Kamil
- Division of Plant Pathology, The Indian Council of Agricultural Research-Indian Agricultural Research Institute, Delhi, India
| | - Shrawan Singh
- Division of Vegetable Science, The Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute, Delhi, India
| | - Amrender Kumar
- Agricultural Knowledge Management Unit, The Indian Council of Agricultural Research-Indian Agricultural Research Institute, Delhi, India
| | - Rumit Patel
- Department of Agricultural Biotechnology, Anand Agricultural University, Anand, Gujarat, India
| | - Priyanka Verma
- Division of Vegetable Science, The Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute, Delhi, India
| | - Masochon Zimik
- Division of Vegetable Science, The Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute, Delhi, India
| | - Anil Khar
- Division of Vegetable Science, The Indian Council of Agricultural Research (ICAR)-Indian Agricultural Research Institute, Delhi, India
| |
Collapse
|
7
|
Yu J, Guo M, Jiang W, Dao Y, Pang X. Illumina-Based Analysis Yields New Insights Into the Fungal Contamination Associated With the Processed Products of Crataegi Fructus. Front Nutr 2022; 9:883698. [PMID: 35634418 PMCID: PMC9135361 DOI: 10.3389/fnut.2022.883698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/13/2022] [Indexed: 12/12/2022] Open
Abstract
Crataegi Fructus, a medicinal and edible herb in China, has been considered a popular dietary supplement globally. It is used for the treatment of dyspepsia and chronic heart failure according to the Chinese Pharmacopoeia (2020). However, fungal contamination in Crataegi Fructus affects its quality and safety, thus preventing its global promotion. In this study, we comprehensively studied the fungal community in processed products of Crataegi Fructus by high-throughput sequencing. A total of 21 Crataegi Fructus samples were collected from five provinces in China, and the samples were divided into five groups based on collection areas, as well as into three groups based on processing methods. We then targeted the internal transcribed spacer 2 sequence through the Illumina Miseq PE300 platform to investigate fungal composition and diversity. Results showed that all 21 samples were detected with fungal contamination, and Ascomycota was dominant at the phylum level. In the groups based on collection areas, Dothideomycetes, Pleosporaceae, and Alternaria were dominant at the class, family, and genus levels, respectively. In the groups based on processing methods, Dothideomycetes, Aspergillaceae, and Alternaria were the most abundant at the class, family, and genus levels, respectively. Differences in fungal communities between various groups were also observed. Furthermore, a total of 115 species were identified, among which seven were potential toxigenic, namely, Trichothecium roseum, Alternaria tenuissima, Aspergillus carbonarius, Penicillium brevicompactum, Aspergillus fumigatus, Rhizopus microspores, and Pichia fermentans. In conclusion, this study reveals great fungal richness and diversity of Crataegi Fructus, providing references for the prevention and control of fungal contamination of Crataegi Fructus in practical production.
Collapse
|
8
|
Hay F, Heck DW, Klein A, Sharma S, Hoepting C, Pethybridge SJ. Spatiotemporal Dynamics of Stemphylium Leaf Blight and Potential Inoculum Sources in New York Onion Fields. PLANT DISEASE 2022; 106:1381-1391. [PMID: 34798786 DOI: 10.1094/pdis-07-21-1587-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Stemphylium leaf blight (SLB) caused by Stemphylium vesicarium is the dominant foliar disease affecting large-scale onion production in New York. The disease is managed by fungicides, but control failures are prevalent and are attributed to fungicide resistance. Little is known of the relative role of inoculum sources in initiation and spread of SLB epidemics. Plate testing of 28 commercially available organic onion seedlots from 2016 and 2017 did not detect S. vesicarium. This finding suggests that although S. vesicarium has been reported as seed-transmitted, this is unlikely to be a significant inoculum source in commercially available organic seed lots and even less so in fungicide-treated seed used to establish conventional fields. The spatial and spatiotemporal dynamics of SLB epidemics in six onion fields were evaluated along linear transects in 2017 and 2018. Average SLB incidence increased from 0 to 100% throughout the cropping seasons with an average final lesion length of 28.3 cm. Disease progress was typical of a polycyclic epidemic and the logistic model provided the best fit to 83.3% of the datasets. Spatial patterns were better described by the beta-binomial than binomial distribution in half of the datasets (50%) and random patterns were more frequently observed by the index of dispersion (59%). Geostatistical analyses also found a low frequency of datasets with aggregation (60%). Spatiotemporal analysis of epidemics detected that the aggregation was influenced by disease incidence. However, diseased units were not frequently associated with the previous time period according to the spatiotemporal association function of spatial analyses by distance indices. Variable spatial patterns suggested mixed inoculum sources dependent upon location, and likely an external inoculum source at the sampling scale used in this study. A small-plot replicated trial was also conducted in each of 2 years to quantify the effect of S. vesicarium-infested onion residue on SLB epidemics in a field isolated from other onion fields. SLB incidence was significantly reduced in plots without residue compared with those in which residue remained on the soil surface. Burial of infested residue also significantly reduced epidemic progress in 1 year. The effect of infested onion residue on SLB epidemics in the subsequent onion crop suggests rotation or residue management may have a substantial effect on epidemics. However, the presence of an inoculum source external to fields in onion production regions, as indicated by a lack of spatial aggregation, may reduce the efficacy of in-field management techniques.
Collapse
Affiliation(s)
- Frank Hay
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| | - Daniel W Heck
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| | - Audrey Klein
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| | - Sandeep Sharma
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| | - Christy Hoepting
- Cornell Vegetable Program, Cornell Cooperative Extension, Albion, NY 14424
| | - Sarah J Pethybridge
- Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech, Cornell University, Geneva, NY 14456
| |
Collapse
|
9
|
Hay F, Stricker S, Gossen BD, McDonald MR, Heck D, Hoepting C, Sharma S, Pethybridge S. Stemphylium Leaf Blight: A Re-Emerging Threat to Onion Production in Eastern North America. PLANT DISEASE 2021; 105:3780-3794. [PMID: 34546780 DOI: 10.1094/pdis-05-21-0903-fe] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium, is a foliar disease of onion worldwide, and has recently become an important disease in the northeastern United States and Ontario, Canada. The symptoms begin as small, tan to brown lesions on the leaves that can progress to defoliate plants. Crop loss occurs through reduced photosynthetic area, resulting in smaller, lower-quality bulbs. Leaf necrosis caused by SLB also can compromise bulb storage, as green leaves are required for the uptake of sprout inhibitors applied prior to harvest. The pathogen can overwinter on infested onion residue and infected volunteer plants. Asymptomatic weedy hosts near onion fields may also be a source of inoculum. Production of ascospores of the teleomorph (Pleospora allii) peaks in early spring in northeastern North America, often before the crop is planted, and declines rapidly as daily mean air temperatures rise. Conidia are usually present throughout the growing season. Application of fungicides is a standard practice for management of the complex of fungi that can cause foliar diseases of onion in this region. Recent assessments have shown that populations of S. vesicarium in New York and Ontario are resistant to at least three single-site mode-of-action fungicides. Three disease prediction systems have been developed and evaluated that may enable growers to reduce the frequency and/or number of fungicide applications, but the loss of efficacious fungicides due to resistance development within S. vesicarium populations threatens sustainability. The lack of commercially acceptable onion cultivars with sufficient resistance to reduce the number of fungicides for SLB also limits the ability to manage SLB effectively. Integrated disease management strategies for SLB are essential to maintain profitable, sustainable onion production across eastern North America.
Collapse
Affiliation(s)
- Frank Hay
- Cornell AgriTech, Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Sara Stricker
- Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Bruce D Gossen
- Agriculture and Agri-Food Canada, Saskatoon, SK S7N 0X2, Canada
| | - Mary Ruth McDonald
- Department of Plant Agriculture, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Daniel Heck
- Cornell AgriTech, Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Christy Hoepting
- Cornell Cooperative Extension, Cornell Vegetable Program, Albion, NY 14411, U.S.A
| | - Sandeep Sharma
- Cornell AgriTech, Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| | - Sarah Pethybridge
- Cornell AgriTech, Plant Pathology & Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, U.S.A
| |
Collapse
|
10
|
Wang CH, Tsai YC, Tsai I, Chung CL, Lin YC, Hung TH, Suwannarach N, Cheewangkoon R, Elgorban AM, Ariyawansa HA. Stemphylium Leaf Blight of Welsh Onion ( Allium fistulosum): An Emerging Disease in Sanxing, Taiwan. PLANT DISEASE 2021; 105:4121-4131. [PMID: 34213966 DOI: 10.1094/pdis-11-20-2329-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Welsh onion (Allium fistulosum L.) is one of the main and oldest vegetable crops grown in Taiwan. A severe epidemic of leaf blight in Welsh onion caused by a Stemphylium-like pathogen was found in Sanxing, Taiwan, from 2018 to 2020. However, correct species identification, biology, and control of Stemphylium leaf blight (SLB) of Welsh onion are not well-established. Therefore, the main objective of this study was to investigate the causal agent of SLB in Sanxing and evaluate the in vitro sensitivity of Stemphylium-like pathogen to commonly used fungicides. A phylogenetic analysis based on combining the internal transcribed spacer (ITS) region and glyceraldedyhe-3-phosphate dehydrogenase (gapdh) and calmodulin (cmdA) gene sequences together with morphological features identified that S. vesicarium is associated with SLB in Sanxing. When inoculated onto Welsh onion leaves, the isolates caused symptoms identical to those observed in the field; therefore, S. vesicarium was reisolated and Koch's postulates were confirmed. We observed a higher incidence of SLB symptoms on the oldest leaves compared with younger leaves. The maximum and minimum temperatures for in vitro mycelial growth and conidial germination (%) of S. vesicarium were 20 to 30°C and 5°C, respectively. Sixteen fungicides were tested for their effectiveness to reduce the mycelial growth and conidial germination of S. vesicarium in vitro. Boscalid plus pyraclostrobin, fluopyram, fluxapyroxad, and fluxapyroxad plus pyraclostrobin were highly effective at reducing mycelial growth and conidial germination in S. vesicarium. However, strobilurin fungicides (azoxystrobin and kresoxim-methyl) commonly used in Welsh onion production in Sanxing were ineffective. This study discusses the emergence of SLB caused by S. vesicarium in the foliar disease complex affecting Welsh onion and the management of the disease using fungicides with different modes of action in Taiwan. The research will support the sustainable management of SLB in Sanxing, Taiwan; however, further field assessments of the fungicides are warranted.
Collapse
Affiliation(s)
- Chun-Hsiang Wang
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Yi-Chen Tsai
- Hualien District Agricultural Research and Extension Station, Hualien, Taiwan
| | - Ichen Tsai
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
- Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt am Main, Germany
- Department for Biological Sciences, Institute of Ecology, Evolution and Diversity, Goethe University, Frankfurt am Main, Germany
| | - Chia-Lin Chung
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Yu-Chen Lin
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Ting-Hsuan Hung
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
- Research Center for Plant Medicine, National Taiwan University, Taipei, Taiwan
| | - Nakarin Suwannarach
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Ratchadawan Cheewangkoon
- Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
- Department of Entomology and Plant Pathology, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand
| | - Abdallah M Elgorban
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Hiran A Ariyawansa
- Department of Plant Pathology and Microbiology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
| |
Collapse
|
11
|
Roylawar P, Khandagale K, Randive P, Shinde B, Murumkar C, Ade A, Singh M, Gawande S, Morelli M. Piriformospora indica Primes Onion Response against Stemphylium Leaf Blight Disease. Pathogens 2021; 10:1085. [PMID: 34578118 PMCID: PMC8472787 DOI: 10.3390/pathogens10091085] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/14/2021] [Accepted: 08/15/2021] [Indexed: 12/11/2022] Open
Abstract
The root-endophytic fungus Piriformospora indica (=Serendipita indica) has been revealed for its growth-promoting effects and its capacity to induce resistance in a broad spectrum of host plants. However, the bioefficacy of this fungus had not yet been tested against any pathogen affecting onion (Allium cepa). In this study, the biocontrol potency of P. indica against onion leaf blight, an impacting disease caused by the necrotrophic fungal pathogen Stemphylium vesicarium, was evaluated. First, it was proved that colonisation of onion roots by P. indica was beneficial for plant growth, as it increased leaf development and root biomass. Most relevantly, P. indica was also effective in reducing Stemphylium leaf blight (SLB) severity, as assessed under greenhouse conditions and confirmed in field trials in two consecutive years. These investigations could also provide some insight into the biochemical and molecular changes that treatment with P. indica induces in the main pathways associated with host defence response. It was possible to highlight the protective effect of P. indica colonisation against peroxidative damage, and its role in signalling oxidative stress, by assessing changes in malondialdehyde and H2O2 content. It was also showed that treatment with P. indica contributes to modulate the enzymatic activity of superoxide dismutase, catalase, phenylalanine ammonia-lyase and peroxidase, in the course of infection. qPCR-based expression analysis of defence-related genes AcLOX1, AcLOX2, AcPAL1, AcGST, AcCHI, AcWRKY1, and AcWRKY70 provided further indications on P. indica ability to induce onion systemic response. Based on the evidence gathered, this study aims to propose P. indica application as a sustainable tool for improving SLB control, which might not only enhance onion growth performance but also activate defence signalling mechanisms more effectively, involving different pathways.
Collapse
Affiliation(s)
- Praveen Roylawar
- ICAR-Directorate of Onion and Garlic Research (DOGR), Rajgurunagar, Pune 410505, India; (P.R.); (P.R.); (M.S.)
- Tuljaram Chaturchand College of Arts, Science and Commerce, Baramati, Pune 413102, India;
- Department of Botany, Sangamner Nagarpalika Arts, D. J. Malpani Commerce, B. N. Sarda Science College, Sangamner, Ahamadnagar 422605, India
| | - Kiran Khandagale
- Department of Botany, Savitribai Phule Pune University, Pune 411007, India; (K.K.); (A.A.)
| | - Pragati Randive
- ICAR-Directorate of Onion and Garlic Research (DOGR), Rajgurunagar, Pune 410505, India; (P.R.); (P.R.); (M.S.)
| | - Bharat Shinde
- Vidya Pratishthan’s Arts, Science & Commerce College, Baramati, Pune 413133, India;
| | | | - Avinash Ade
- Department of Botany, Savitribai Phule Pune University, Pune 411007, India; (K.K.); (A.A.)
| | - Major Singh
- ICAR-Directorate of Onion and Garlic Research (DOGR), Rajgurunagar, Pune 410505, India; (P.R.); (P.R.); (M.S.)
| | - Suresh Gawande
- ICAR-Directorate of Onion and Garlic Research (DOGR), Rajgurunagar, Pune 410505, India; (P.R.); (P.R.); (M.S.)
| | - Massimiliano Morelli
- CNR-IPSP Istituto per la Protezione Sostenibile delle Piante, Sede Secondaria di Bari, 70124 Bari, Italy;
| |
Collapse
|
12
|
Gossen BD, Tayviah CS, McDonald MR. The Role of Ascospores and Conidia, in Relation to Weather Variables, in the Epidemiology of Stemphylium Leaf Blight of Onion. PLANT DISEASE 2021; 105:1912-1918. [PMID: 33320040 DOI: 10.1094/pdis-06-20-1283-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium, is an important foliar disease of onion in northeastern North America. The pathogen produces conidia and ascospores, but the relative contributions of these spore types to epidemics in onion is not known. Determining the abundance of ascospores and conidia during the growing season could contribute to a disease forecasting model. Airborne ascospores and conidia of S. vesicarium were trapped during the growing season of 2015 and 2016 at an onion trial in southern Ontario, Canada, using a Burkard 7-day volumetric sampler. Meteorological data were recorded hourly. Ascospore numbers peaked before the crop was planted and declined rapidly with time and at daily mean air temperatures >15°C. Conidia were present throughout the growing season and appear to be closely related to the development of SLB on onion. Daily spore concentrations were variable, but 59 to 73% of ascospores and approximately 60% of conidia were captured between 0600 and 1200 h. Spore concentrations increased 24 to 72 h after rainfall and precipitation and leaf wetness duration were consistently and positively associated with increases in numbers of conidia and subsequent SLB incidence. The first symptoms of SLB coincided with high numbers of conidia, rainfall, leaf wetness duration ≥8 h, and days with average daily temperature ≥18°C. The number of airborne ascospores was very low by the time SLB symptoms were observed. Ascospores may initiate infection on alternative hosts in early spring, while conidia are the most important inoculum for the epidemic on onions.
Collapse
Affiliation(s)
- Bruce D Gossen
- Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan, Canada
| | - C Selasi Tayviah
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Mary Ruth McDonald
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| |
Collapse
|
13
|
Liu B, Stein L, Cochran K, du Toit LJ, Feng C, Dhillon B, Correll JC. Characterization of Leaf Spot Pathogens from Several Spinach Production Areas in the United States. PLANT DISEASE 2020; 104:1994-2004. [PMID: 32441578 DOI: 10.1094/pdis-11-19-2450-re] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Leaf spot diseases have become a major concern in spinach production in the United States. Determining the causal agents of leaf spots on spinach, their prevalence and pathogenicity, and fungicide efficacy against these pathogens is vital for effective disease management. Spinach leaves with leaf spots were collected from Texas, California, Arizona, and South Carolina from 2016 to 2018, incubated in a moist chamber, and plated on potato dextrose and tryptic soy agar media. Fungal and bacterial colonies recovered were identified based on morphology and sequence analysis of the internal transcribed spacer rDNA and 16S rRNA, respectively. Two predominant genera were isolated: (i) Colletotrichum spp., which were identified to species based on sequences of both introns of the glutamate synthetase (GS-I) and glyceraldehyde-3-phosphate dehydrogenase (gapdh-I) genes; and (ii) Stemphylium spp., identified to species based on sequences of the gapdh and calmodulin (cmdA) genes. Anthracnose (Colletotrichum spinaciae) and Stemphylium leaf spot (Stemphylium vesicarium and S. beticola) were the predominant diseases. Additional fungi recovered at very limited frequencies that were also pathogenic to spinach included Colletotrichum coccodes, C. truncatum, Cercospora beticola, and Myrothecium verrucaria. All of the bacterial isolates were not pathogenic on spinach. Pathogenicity tests showed that C. spinaciae, S. vesicarium, and S. beticola caused significant leaf damage. The fungicides Bravo WeatherStik (chlorothalonil), Dithane F-45 (mancozeb), Cabrio (pyraclostrobin), and Merivon (fluxapyroxad and pyraclostrobin) were highly effective at reducing leaf spot severity caused by an isolate of each of C. spinaciae and S. vesicarium, when inoculated individually and in combination.
Collapse
Affiliation(s)
- Bo Liu
- Department of Plant Pathology, University of Arkansas, Fayetteville, AR 72701
| | - Larry Stein
- Department of Horticulture, Texas A&M University, College Station, TX 77840
| | - Kimberly Cochran
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77840
| | - Lindsey J du Toit
- Department of Plant Pathology, Washington State University, Mount Vernon, WA 98273-4768
| | - Chunda Feng
- Department of Plant Pathology, University of Arkansas, Fayetteville, AR 72701
| | - Braham Dhillon
- Department of Plant Pathology, University of Arkansas, Fayetteville, AR 72701
| | - James C Correll
- Department of Plant Pathology, University of Arkansas, Fayetteville, AR 72701
| |
Collapse
|
14
|
Sharma S, Hay FS, Pethybridge SJ. Genome Resource for Two Stemphylium vesicarium Isolates Causing Stemphylium Leaf Blight of Onion in New York. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:562-564. [PMID: 31916923 DOI: 10.1094/mpmi-08-19-0244-a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Stemphylium leaf blight caused by Stemphylium vesicarium was recently identified as an emerging disease and dominant in the foliar disease complex affecting onion in New York. Here, we report the genomes of two isolates of S. vesicarium, On16-63 and On16-391. The availability of the genomes will accelerate genomic studies of S. vesicarium, including population biology, sexual reproduction, and fungicide resistance. Additionally, comparative genomics with the other published genome of S. vesicarium causing brown spot of pear will help understand pathogen biology and underpin the development of management strategies for this disease.
Collapse
Affiliation(s)
- Sandeep Sharma
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, U.S.A
| | - Frank S Hay
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, U.S.A
| | - Sarah J Pethybridge
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell AgriTech at the New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, U.S.A
| |
Collapse
|