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Bach RAK, Murithi HM, Slocum CR, Coyne D, Clough SJ. Remarkably High Internal Transcribed Spacer Haplotype Diversity of the Fungal Select Agent Coniothyrium glycines Discovered Throughout Its Range in Sub-Saharan Africa. PHYTOPATHOLOGY 2024; 114:955-960. [PMID: 38349782 DOI: 10.1094/phyto-09-23-0315-kc] [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: 02/15/2024]
Abstract
Red leaf blotch of soybean, caused by the fungus Coniothyrium glycines, is a foliar disease characterized by blotching, necrosis, and defoliation that has only been reported from Africa. The species is listed as a Select Agent by the Federal Select Agent Program due to its potentially devastating impacts to soybean production should it spread to the United States. Despite its potential import, very few isolates are available for study. Herein, we obtained 96 new C. glycines isolates from six soybean-producing countries throughout sub-Saharan Africa. Along with 12 previously collected ones, we sequenced each at the internal transcribed spacer (ITS) region. Between all isolates, we identified a total of 28 single-nucleotide polymorphisms and 23 haplotypes. One hypothesis to explain the tremendous diversity uncovered at the ITS-which is generally conserved within a species-is that our current species concept of C. glycines is too broad and that there may be multiple species that cause red leaf blotch. Zambia contained the highest haplotype diversity, a significant fraction of which remains unsampled. Most haplotypes were specific to a single country, except for two, which were found in Zambia and either neighboring Mozambique or Zimbabwe. This geographic specificity indicates that the ITS region may be useful for identifying source populations or routes of transmission should this pathogen spread beyond Africa. The observed geographic partitioning of this pathogen is likely the result of millions of years of replication on little-studied native hosts, given that soybean has only been cultivated in Africa since the early 1900s.
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Affiliation(s)
- Rachel A Koch Bach
- U.S. Department of Agriculture, Agricultural Research Service, Foreign Disease-Weed Science Research Unit, Fort Detrick, MD, U.S.A
| | - Harun M Murithi
- Agricultural Research Service Research Participation Program through the Oak Ridge Institute for Science and Education, Oak Ridge, TN, U.S.A
- International Institute of Tropical Agriculture, Nairobi, Kenya
| | - Clint R Slocum
- U.S. Department of Agriculture, Agricultural Research Service, Foreign Disease-Weed Science Research Unit, Fort Detrick, MD, U.S.A
| | - Danny Coyne
- International Institute of Tropical Agriculture, Nairobi, Kenya
| | - Steven J Clough
- U.S. Department of Agriculture, Agricultural Research Service, Soybean/Maize Germplasm, Pathology, and Genetics Research Unit, Urbana, IL, U.S.A
- University of Illinois, Department of Crop Sciences, Urbana, IL, U.S.A
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Poudel RS, Belay K, Nelson B, Brueggeman R, Underwood W. Population and genome-wide association studies of Sclerotinia sclerotiorum isolates collected from diverse host plants throughout the United States. Front Microbiol 2023; 14:1251003. [PMID: 37829452 PMCID: PMC10566370 DOI: 10.3389/fmicb.2023.1251003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 08/29/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction Sclerotinia sclerotiorum is a necrotrophic fungal pathogen causing disease and economic loss on numerous crop plants. This fungus has a broad host range and can infect over 400 plant species, including important oilseed crops such as soybean, canola, and sunflower. S. sclerotiorum isolates vary in aggressiveness of lesion formation on plant tissues. However, the genetic basis for this variation remains to be determined. The aims of this study were to evaluate a diverse collection of S. sclerotiorum isolates collected from numerous hosts and U.S. states for aggressiveness of stem lesion formation on sunflower, to evaluate the population characteristics, and to identify loci associated with isolate aggressiveness using genome-wide association mapping. Methods A total of 219 S. sclerotiorum isolates were evaluated for stem lesion formation on two sunflower inbred lines and genotyped using genotyping-by-sequencing. DNA markers were used to assess population differentiation across hosts, regions, and climatic conditions and to perform a genome-wide association study of isolate aggressiveness. Results and discussion We observed a broad range of aggressiveness for lesion formation on sunflower stems, and only a moderate correlation between aggressiveness on the two lines. Population genetic evaluations revealed differentiation between populations from warmer climate regions compared to cooler regions. Finally, a genome-wide association study of isolate aggressiveness identified three loci significantly associated with aggressiveness on sunflower. Functional characterization of candidate genes at these loci will likely improve our understanding of the virulence strategies used by this pathogen to cause disease on a wide array of agriculturally important host plants.
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Affiliation(s)
- Roshan Sharma Poudel
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States
| | - Kassaye Belay
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States
| | - Berlin Nelson
- Department of Plant Pathology, North Dakota State University, Fargo, ND, United States
| | - Robert Brueggeman
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, United States
| | - William Underwood
- Edward T. Schafer Agricultural Research Center, Sunflower and Plant Biology Research Unit, USDA Agricultural Research Service, Fargo, ND, United States
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Molecular Breeding to Overcome Biotic Stresses in Soybean: Update. PLANTS 2022; 11:plants11151967. [PMID: 35956444 PMCID: PMC9370206 DOI: 10.3390/plants11151967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 07/16/2022] [Accepted: 07/25/2022] [Indexed: 11/17/2022]
Abstract
Soybean (Glycine max (L.) Merr.) is an important leguminous crop and biotic stresses are a global concern for soybean growers. In recent decades, significant development has been carried outtowards identification of the diseases caused by pathogens, sources of resistance and determination of loci conferring resistance to different diseases on linkage maps of soybean. Host-plant resistance is generally accepted as the bestsolution because of its role in the management of environmental and economic conditions of farmers owing to low input in terms of chemicals. The main objectives of soybean crop improvement are based on the identification of sources of resistance or tolerance against various biotic as well as abiotic stresses and utilization of these sources for further hybridization and transgenic processes for development of new cultivars for stress management. The focus of the present review is to summarize genetic aspects of various diseases caused by pathogens in soybean and molecular breeding research work conducted to date.
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Buchwaldt L, Garg H, Puri KD, Durkin J, Adam J, Harrington M, Liabeuf D, Davies A, Hegedus DD, Sharpe AG, Gali KK. Sources of genomic diversity in the self-fertile plant pathogen, Sclerotinia sclerotiorum, and consequences for resistance breeding. PLoS One 2022; 17:e0262891. [PMID: 35130285 PMCID: PMC8820597 DOI: 10.1371/journal.pone.0262891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 01/09/2022] [Indexed: 11/18/2022] Open
Abstract
The ascomycete, Sclerotinia sclerotiorum, has a broad host range and causes yield loss in dicotyledonous crops world wide. Genomic diversity was determined in a population of 127 isolates obtained from individual canola (Brassica napus) fields in western Canada. Genotyping with 39 simple sequence repeat (SSR) markers revealed each isolate was a unique haplotype. Analysis of molecular variance showed 97% was due to isolate and 3% due to geographical location. Testing of mycelium compatibility among 133 isolates identified clones of mutually compatible isolates with 86-95% similar SSR haplotype, whereas incompatible isolates were highly diverse. In the Province of Manitoba, 61% of isolates were compatible forming clones and stings of pairwise compatible isolates not described before. In contrast, only 35% of isolates were compatible in Alberta without forming clones and strings, while 39% were compatible in Saskatchewan with a single clone, but no strings. These difference can be explained by wetter growing seasons and more susceptible crop species in Manitoba favouring frequent mycelium interaction and more life cycles over time, which might also explain similar differences observed in other geographical areas and host crops. Analysis of linkage disequilibrium rejected random recombination, consistent with a self-fertile fungus, restricted outcrossing due to mycelium incompatibility, and only a single annual opportunity for genomic recombination during meiosis in the ascospore stage between non-sister chromatids in the rare event nuclei from different isolates come together. More probable sources of genomic diversity is slippage during DNA replication and point mutation affecting single nucleotides that accumulate and likely increase mycelium incompatibility in a population over time. A phylogenetic tree based on SSR haplotype grouped isolates into 17 sub-populations. Aggressiveness was tested by inoculating one isolate from each sub-population onto B. napus lines with quantitative resistance. Analysis of variance was significant for isolate, line, and isolate by line interaction. These isolates represent the genomic and pathogenic diversity in western Canada, and are suitable for resistance screening in canola breeding programs.
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Affiliation(s)
- Lone Buchwaldt
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Harsh Garg
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Krishna D. Puri
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Jonathan Durkin
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Jennifer Adam
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Myrtle Harrington
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Debora Liabeuf
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Alan Davies
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Dwayne D. Hegedus
- Agriculture and Agri-Food Canada, Saskatoon Research and Development Centre, Saskatoon, Canada
| | - Andrew G. Sharpe
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, Canada
| | - Krishna Kishore Gali
- Department of Plant Sciences, Crop Development Centre, University of Saskatchewan, Saskatoon, Canada
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Mueller B, Groves CL, Smith DL. Chemotype and Aggressiveness Evaluation of Fusarium graminearum and Fusarium culmorum Isolates from Wheat Fields in Wisconsin. PLANT DISEASE 2021; 105:3686-3693. [PMID: 33487016 DOI: 10.1094/pdis-06-20-1376-re] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fusarium graminearum commonly causes Fusarium head blight on wheat, barley, rice, and oats. F. graminearum produces nivalenol (NIV) and deoxynivalenol (DON) and forms derivatives of DON based on its acetylation sites. The fungus is profiled into chemotypes based on DON derivative chemotypes (3 acetyldeoxynivalenol [3ADON] chemotype; 15 acetyldeoxynivalenol [15ADON] chemotype), and/or the NIV chemotype. This study assessed the Fusarium population found on wheat and the chemotype profile of the isolates collected from 2016 and 2017 in Wisconsin. F. graminearum was isolated from all locations sampled in both 2016 and 2017. Fusarium culmorum was isolated only from Door County in 2016. Over both growing seasons, 91% of isolates were identified as the 15ADON chemotype, while 9% of isolates were identified as the 3ADON chemotype. Aggressiveness was quantified by area under the disease progress curve (AUDPC). The isolates with the highest AUDPC values were from the highest wheat-producing cropping districts in the state. Deoxynivalenol production in grain and sporulation and growth rate in vitro were compared with aggressiveness in the greenhouse. Our results showed that 3ADON isolates in Wisconsin were among the highest in sporulation capacity, growth rate, and DON production in grain. However, there were no significant differences in aggressiveness between the 3ADON and 15ADON isolates. The results of this research detail the baseline frequency and distribution of 3ADON and 15ADON chemotypes observed in Wisconsin. Chemotype distributions within populations of F. graminearum in Wisconsin should continue to be monitored in the future.
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Affiliation(s)
- Brian Mueller
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Carol L Groves
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Damon L Smith
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
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Webster RW, Roth MG, Reed H, Mueller B, Groves CL, McCaghey M, Chilvers MI, Mueller DS, Kabbage M, Smith DL. Identification of Soybean ( Glycine max) Check Lines for Evaluating Genetic Resistance to Sclerotinia Stem Rot. PLANT DISEASE 2021; 105:2189-2195. [PMID: 33231521 DOI: 10.1094/pdis-10-20-2193-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Soybean production in the upper midwestern United States is affected by Sclerotinia stem rot (SSR) caused by the fungal pathogen Sclerotinia sclerotiorum. Genetic resistance is an important management strategy for this disease; however, assessing genetic resistance to S. sclerotiorum is challenging because a standardized method of examining resistance across genotypes is lacking. Using a panel of nine diverse S. sclerotiorum isolates, four soybean lines were assessed for reproducible responses to S. sclerotiorum infection. Significant differences in SSR severity were found across isolates (P < 0.01) and soybean lines (P < 0.01), including one susceptible, two moderately resistant, and one highly resistant line. These four validated lines were used to screen 11 other soybean genotypes to evaluate their resistance levels, and significant differences were found across genotypes (P < 0.01). Among these 11 genotypes, five commercial and public cultivars displayed high resistance and were assessed during field studies across the upper midwestern United States growing region to determine their response to SSR and yield. These five cultivars resulted in low disease levels (P < 0.01) in the field that were consistent with greenhouse experiment results. The yields were significantly different in fields with disease present (P < 0.01) and disease absent (P < 0.01), and the order of cultivar performance was consistent between environments where disease was present or absent, suggesting that resistance prevented yield loss to disease. This study suggests that the use of a soybean check panel can accurately assess SSR resistance in soybean germplasm and aid in breeding and commercial soybean development.
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Affiliation(s)
- Richard W Webster
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Mitchell G Roth
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Hannah Reed
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Brian Mueller
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Carol L Groves
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Megan McCaghey
- Department of Plant Pathology, University of California-Davis, Davis, CA 95616
| | - Martin I Chilvers
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824
| | - Daren S Mueller
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA 50011
| | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
| | - Damon L Smith
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706
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7
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McCaghey M, Shao D, Kurcezewski J, Lindstrom A, Ranjan A, Whitham SA, Conley SP, Williams B, Smith DL, Kabbage M. Host-Induced Gene Silencing of a Sclerotinia sclerotiorum oxaloacetate acetylhydrolase Using Bean Pod Mottle Virus as a Vehicle Reduces Disease on Soybean. FRONTIERS IN PLANT SCIENCE 2021; 12:677631. [PMID: 34354721 PMCID: PMC8329588 DOI: 10.3389/fpls.2021.677631] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/26/2021] [Indexed: 05/05/2023]
Abstract
A lack of complete resistance in the current germplasm complicates the management of Sclerotinia stem rot (SSR) caused by Sclerotinia sclerotiorum in soybean. In this study, we used bean pod mottle virus (BPMV) as a vehicle to down-regulate expression of a key enzyme in the production of an important virulence factor in S. sclerotiorum, oxalic acid (OA). Specifically, we targeted a gene encoding oxaloacetate acetylhydrolase (Ssoah1), because Ssoah1 deletion mutants are OA deficient and non-pathogenic on soybean. We first established that S. sclerotiorum can uptake environmental RNAs by monitoring the translocation of Cy3-labeled double-stranded and small interfering RNA (ds/siRNAs) into fungal hyphae using fluorescent confocal microscopy. This translocation led to a significant decrease in Ssoah1 transcript levels in vitro. Inoculation of soybean plants with BPMV vectors targeting Ssoah1 (pBPMV-OA) also led to decreased expression of Ssoah1. Importantly, pBPMV-OA inoculated plants showed enhanced resistance to S. sclerotiorum compared to empty-vector control plants. Our combined results provide evidence supporting the use of HIGS and exogenous applications of ds/siRNAs targeting virulence factors such as OA as viable strategies for the control of SSR in soybean and as discovery tools that can be used to identify previously unknown virulence factors.
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Affiliation(s)
- Megan McCaghey
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Dandan Shao
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Jake Kurcezewski
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Ally Lindstrom
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Ashish Ranjan
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Steven A. Whitham
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States
| | - Shawn P. Conley
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI, United States
| | - Brett Williams
- Centre for Tropical Crops and Biocommodities, Queensland University of Technology, Brisbane, QLD, Australia
| | - Damon L. Smith
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
- Damon L. Smith
| | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
- *Correspondence: Mehdi Kabbage
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Townsend RV, Rioux RA, Kabbage M, Stephens C, Kerns JP, Koch P. Oxalic Acid Production in Clarireedia jacksonii Is Dictated by pH, Host Tissue, and Xylan. Front Microbiol 2020; 11:1732. [PMID: 32849370 PMCID: PMC7418575 DOI: 10.3389/fmicb.2020.01732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/02/2020] [Indexed: 11/23/2022] Open
Abstract
Dollar spot is caused by the fungus Clarireedia jacksonii and is the most common disease of golf course turfgrass in temperate climates. Oxalic acid (OA) is an important pathogenicity factor in other fungal plant pathogens, such as the dicot pathogen Sclerotinia sclerotiorum, but its role in C. jacksonii pathogenicity on monocot hosts remains unclear. Herein, we assess fungal growth, OA concentration, and pH change in potato dextrose broth (PDB) following incubation of C. jacksonii. In addition, OA production by C. jacksonii and S. sclerotiorum was compared in PDB amended with creeping bentgrass or common plant cell wall components (cellulose, lignin, pectin, or xylan). Our results show that OA production is highly dependent on the environmental pH, with twice as much OA produced at pH 7 than pH 4 and a corresponding decrease in PDB pH from 7 to 5 following 96 h of C. jacksonii incubation. In contrast, no OA was produced or changes in pH observed when C. jacksonii was incubated in PDB at a pH of 4. Interestingly, C. jacksonii increased OA production in response to PDB amended with creeping bentgrass tissue and the cell wall component xylan, a major component of grass cell walls. S. sclerotiorum produced large amounts of OA relative to C. jacksonii regardless of treatment, and no treatment increased OA production by this fungus, though pectin suppressed S. sclerotiorum’s OA production. These results suggest that OA production by C. jacksonii is reliant on host specific components within the infection court, as well as the ambient pH of the foliar environment during its pathogenic development.
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Affiliation(s)
- Ronald V Townsend
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Renee A Rioux
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
| | - Cameron Stephens
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - James P Kerns
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Paul Koch
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI, United States
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Yu Y, Cai J, Ma L, Huang Z, Wang Y, Fang A, Yang Y, Qing L, Bi C. Population Structure and Aggressiveness of Sclerotinia sclerotiorum From Rapeseed ( Brassica napus) in Chongqing City. PLANT DISEASE 2020; 104:1201-1206. [PMID: 32065567 DOI: 10.1094/pdis-07-19-1401-re] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sclerotinia sclerotiorum is one of the most devastating fungal plant pathogens of oilseed Brassica and is distributed worldwide. In particular, Sclerotinia stem rot has always been a serious threat to rapeseed production in Chongqing City, China. In this study, simple sequence repeat (SSR) markers and mycelial compatibility groups (MCGs) were used to characterize the population structure of 90 geographic isolates of S. sclerotiorum collected from rapeseed in nine counties of Chongqing. A total of 52 microsatellite haplotypes were identified, and a few haplotypes were found with high frequency. Gene diversity ranged from 0.1570 to 0.4700 in nine populations. A constructed unweighted pair group with arithmetic mean dendrogram based on Nei genetic distance and a STRUCTURE analysis revealed that the genetic composition of the isolates collected in the five counties located in western Chongqing are different from those collected in the two eastern counties, suggesting that breed lines should be cultivated in both the western and eastern regions to effectively evaluate resistance levels. A total of 47 MCGs were identified, and 72% of the MCGs was represented by single isolates. Seven of 13 MCGs that included at least two isolates contained isolates from only one county. SSR haplotypes were not correlated with MCGs. A subset of 34 isolates were inoculated on rapeseed stems, and the aggressiveness showed variation. This research revealed the population genetic structure and aggressiveness of this pathogen in Chongqing, and the results will help to develop disease management and resistance screening strategies.
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Affiliation(s)
- Yang Yu
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Junsong Cai
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Linhao Ma
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Zhiqiang Huang
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Yabo Wang
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Anfei Fang
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Yuheng Yang
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Ling Qing
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
| | - Chaowei Bi
- College of Plant Protection, Southwest University, Chongqing City, 400715, People's Republic of China
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Purnamasari MI, Erskine W, Croser JS, You MP, Barbetti MJ. Comparative Reaction of Camelina sativa to Sclerotinia sclerotiorum and Leptosphaeria maculans. PLANT DISEASE 2019; 103:2884-2892. [PMID: 31486740 DOI: 10.1094/pdis-03-19-0664-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Sclerotinia sclerotiorum and Leptosphaeria maculans are two of the most important pathogens of many cruciferous crops. The reaction of 30 genotypes of Camelina sativa (false flax) was determined against both pathogens. C. sativa genotypes were inoculated at seedling and adult stages with two pathotypes of S. sclerotiorum, highly virulent MBRS-1 and less virulent WW-1. There were significant differences (P < 0.001) among genotypes, between pathotypes, and a significant interaction between genotypes and pathotypes in relation to percent cotyledon disease index (% CDI) and stem lesion length. Genotypes 370 (% CDI 20.5, stem lesion length 1.8 cm) and 253 (% CDI 24.8, stem lesion length 1.4 cm) not only consistently exhibited cotyledon and stem resistance, in contrast to susceptible genotype 2305 (% CDI 37.7, stem lesion length 7.2 cm), but their resistance was independent to S. sclerotiorum pathotype. A F5-recombinant inbred line population was developed from genotypes 370 × 2305 and responses characterized. Low broad-sense heritability indicated a complex pattern of inheritance of resistance to S. sclerotiorum. Six isolates of L. maculans, covering combinations of five different avirulent loci (i.e., five different races), were tested on C. sativa cotyledons across two experiments. There was a high level of resistance, with % CDI < 17, and including development of a hypersensitive reaction. This is the first report of variable reaction of C. sativa to different races of L. maculans and the first demonstrating comparative reactions of C. sativa to S. sclerotiorum and L. maculans. This study not only provides new understanding of these comparative resistances in C. sativa, but highlights their potential as new sources of resistance, both for crucifer disease-resistance breeding in general and to enable broader adoption of C. sativa as a more sustainable oilseed crop in its own right.
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Affiliation(s)
- Maria I Purnamasari
- Centre for Plant Genetics and Breeding, UWA, School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
- School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
| | - William Erskine
- Centre for Plant Genetics and Breeding, UWA, School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
- School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
| | - Janine S Croser
- Centre for Plant Genetics and Breeding, UWA, School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
- School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
| | - Ming Pei You
- School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
| | - Martin J Barbetti
- School of Agriculture and Environment and the UWA Institute of Agriculture, The University of Western Australia, WA, 6009, Australia
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11
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Westrick NM, Ranjan A, Jain S, Grau CR, Smith DL, Kabbage M. Gene regulation of Sclerotinia sclerotiorum during infection of Glycine max: on the road to pathogenesis. BMC Genomics 2019; 20:157. [PMID: 30808300 PMCID: PMC6390599 DOI: 10.1186/s12864-019-5517-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/07/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Sclerotinia sclerotiorum is a broad-host range necrotrophic pathogen which is the causative agent of Sclerotinia stem rot (SSR), and a major disease of soybean (Glycine max). A time course transcriptomic analysis was performed in both compatible and incompatible soybean lines to identify pathogenicity and developmental factors utilized by S. sclerotiorum to achieve pathogenic success. RESULTS A comparison of genes expressed during early infection identified the potential importance of toxin efflux and nitrogen metabolism during the early stages of disease establishment. The later stages of infection were characterized by an apparent shift to survival structure formation. Analysis of genes highly upregulated in-planta revealed a temporal regulation of hydrolytic and detoxification enzymes, putative secreted effectors, and secondary metabolite synthesis genes. Redox regulation also appears to play a key role during the course of infection, as suggested by the high expression of genes involved in reactive oxygen species production and scavenging. Finally, distinct differences in early gene expression were noted based on the comparison of S. sclerotiorum infection of resistant and susceptible soybean lines. CONCLUSIONS Although many potential virulence factors have been noted in the S. sclerotiorum pathosystem, this study serves to highlight soybean specific processes most likely to be critical in successful infection. Functional studies of genes identified in this work are needed to confirm their importance to disease development, and may constitute valuable targets of RNAi approaches to improve resistance to SSR.
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Affiliation(s)
| | - Ashish Ranjan
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI USA
| | - Sachin Jain
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI USA
| | - Craig R. Grau
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI USA
| | - Damon L. Smith
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI USA
| | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI USA
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Huzar-Novakowiski J, Dorrance AE. Ascospore Inoculum Density and Characterization of Components of Partial Resistance to Sclerotinia sclerotiorum in Soybean. PLANT DISEASE 2018; 102:1326-1333. [PMID: 30673564 DOI: 10.1094/pdis-11-17-1786-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Germplasm screening programs have primarily relied on inoculation with mycelia to determine the resistance reaction of soybean genotypes to Sclerotinia sclerotiorum. However, under field conditions, ascospores are the primary source of inoculum. Therefore, the objective of this study was to determine which components most accurately differentiate the resistance reaction of soybean genotypes inoculated with ascospores of S. sclerotiorum. Ascospores were produced in the laboratory and all of the experiments were carried out under controlled conditions with inoculations at flowering stage. Initially, inoculum densities of 1 × 104, 1 × 105 and 1 × 106 ascospores ml-1 were compared on six soybean genotypes with known resistance reactions. Disease symptoms developed on all genotypes and at all inoculum densities. The highest ascospore concentration increased infection efficiency but it was not correlated with an increase in lesion length. Components of resistance were then measured on a set of 17 cultivars with known resistance reactions at 1 × 105 ascospores ml-1. Resistance reactions could be differentiated based on the level of infection efficiency and lesion length on the main stem. Although inoculation with ascospores presents some limitations such as the time required for inoculum production as well as the time and space required for plant growth, it has the potential to be used to complement other methods for the characterization of resistance of soybean genotypes.
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Affiliation(s)
- Jaqueline Huzar-Novakowiski
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691
| | - Anne E Dorrance
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691
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13
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Kandel R, Chen CY, Grau CR, Dorrance AE, Liu JQ, Wang Y, Wang D. Soybean Resistance to White Mold: Evaluation of Soybean Germplasm Under Different Conditions and Validation of QTL. FRONTIERS IN PLANT SCIENCE 2018; 9:505. [PMID: 29731761 PMCID: PMC5921182 DOI: 10.3389/fpls.2018.00505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 04/03/2018] [Indexed: 05/05/2023]
Abstract
Soybean (Glycine max L. Merr.) white mold (SWM), caused by Sclerotinia sclerotiorum (Lib) de Barry), is a devastating fungal disease in the Upper Midwest of the United States and southern Canada. Various methods exist to evaluate for SWM resistance and many quantitative trait loci (QTL) with minor effect governing SWM resistance have been identified in prior studies. This study aimed to predict field resistance to SWM using low-cost and efficient greenhouse inoculation methods and to confirm the QTL reported in previous studies. Three related but independent studies were conducted in the field, greenhouse, and laboratory to evaluate for SWM resistance. The first study evaluated 66 soybean plant introductions (PIs) with known field resistance to SWM using the greenhouse drop-mycelium inoculation method. These 66 PIs were significantly (P < 0.043) different for resistance to SWM. However, year was highly significant (P < 0.00001), while PI x year interaction was not significant (P < 0.623). The second study compared plant mortality (PM) of 35 soybean breeding lines or varieties in greenhouse inoculation methods with disease severity index (DSI) in field evaluations. Moderate correlation (r) between PM under drop-mycelium method and DSI in field trials (r = 0.65, p < 0.0001) was obtained. The PM under spray-mycelium was also correlated significantly with DSI from field trials (r = 0.51, p < 0.0018). Likewise, significant correlation (r = 0.62, p < 0.0001) was obtained between PM across greenhouse inoculation methods and DSI across field trials. These findings suggest that greenhouse inoculation methods could predict the field resistance to SWM. The third study attempted to validate 33 QTL reported in prior studies using seven populations that comprised a total of 392 F4 : 6 lines derived from crosses involving a partially resistant cultivar "Skylla," five partially resistant PIs, and a known susceptible cultivar "E00290." The estimates of broad-sense heritability (h2) ranged from 0.39 to 0.66 in the populations. Of the seven populations, four had h2 estimates that were significantly different from zero (p < 0.05). Single marker analysis across populations and inoculation methods identified 11 significant SSRs (p < 0.05) corresponding to 10 QTL identified by prior studies. Thus, these five new PIs could be used as new sources of resistant alleles to develop SWM resistant commercial cultivars.
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Affiliation(s)
- Ramkrishna Kandel
- Horticultural Sciences Department, University of Florida, Gainesville, FL, United States
| | - Charles Y. Chen
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL, United States
| | - Craig R. Grau
- Department of Plant Pathology, University of Wisconsin, Madison, WI, United States
| | - Ann E. Dorrance
- Department of Plant Pathology, Ohio Agricultural Research and Development Center (OARDC), The Ohio State University, Wooster, OH, United States
| | - Jean Q. Liu
- Pioneer Hi-Bred International, Inc., Johnston, IA, United States
| | - Yang Wang
- Soybean Research Center, Jilin Academy of Agricultural Sciences, Changchun, China
| | - Dechun Wang
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
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McCaghey M, Willbur J, Ranjan A, Grau CR, Chapman S, Diers B, Groves C, Kabbage M, Smith DL. Development and Evaluation of Glycine max Germplasm Lines with Quantitative Resistance to Sclerotinia sclerotiorum. FRONTIERS IN PLANT SCIENCE 2017; 8:1495. [PMID: 28912790 PMCID: PMC5584390 DOI: 10.3389/fpls.2017.01495] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 08/14/2017] [Indexed: 05/18/2023]
Abstract
Sclerotinia sclerotiorum, the causal agent of Sclerotinia stem rot, is a devastating fungal pathogen of soybean that can cause significant yield losses to growers when environmental conditions are favorable for the disease. The development of resistant varieties has proven difficult. However, poor resistance in commercial cultivars can be improved through additional breeding efforts and understanding the genetic basis of resistance. The objective of this project was to develop soybean germplasm lines that have a high level of Sclerotinia stem rot resistance to be used directly as cultivars or in breeding programs as a source of improved Sclerotinia stem rot resistance. Sclerotinia stem rot-resistant soybean germplasm was developed by crossing two sources of resistance, W04-1002 and AxN-1-55, with lines exhibiting resistance to Heterodera glycines and Cadophora gregata in addition to favorable agronomic traits. Following greenhouse evaluations of 1,076 inbred lines derived from these crosses, 31 lines were evaluated for resistance in field tests during the 2014 field season. Subsequently, 11 Sclerotinia stem rot resistant breeding lines were moved forward for field evaluation in 2015, and seven elite breeding lines were selected and evaluated in the 2016 field season. To better understand resistance mechanisms, a marker analysis was conducted to identify quantitative trait loci linked to resistance. Thirteen markers associated with Sclerotinia stem rot resistance were identified on chromosomes 15, 16, 17, 18, and 19. Our markers confirm previously reported chromosomal regions associated with Sclerotinia stem rot resistance as well as a novel region of chromosome 16. The seven elite germplasm lines were also re-evaluated within a greenhouse setting using a cut petiole technique with multiple S. sclerotiorum isolates to test the durability of physiological resistance of the lines in a controlled environment. This work presents a novel and comprehensive classical breeding method for selecting lines with physiological resistance to Sclerotinia stem rot and a range of agronomic traits. In these studies, we identify four germplasm lines; 91-38, 51-23, SSR51-70, and 52-82B exhibiting a high level of Sclerotinia stem rot resistance combined with desirable agronomic traits, including high protein and oil contents. The germplasm identified in this study will serve as a valuable source of physiological resistance to Sclerotinia stem rot that could be improved through further breeding to generate high-yielding commercial soybean cultivars.
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Affiliation(s)
- Megan McCaghey
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Jaime Willbur
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Ashish Ranjan
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Craig R. Grau
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Scott Chapman
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Brian Diers
- Department of Crop Sciences, University of Illinois Urbana–Champaign, ChampaignIL, United States
| | - Carol Groves
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Mehdi Kabbage
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
| | - Damon L. Smith
- Department of Plant Pathology, University of Wisconsin-Madison, MadisonWI, United States
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15
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Huzar-Novakowiski J, Paul PA, Dorrance AE. Host Resistance and Chemical Control for Management of Sclerotinia Stem Rot of Soybean in Ohio. PHYTOPATHOLOGY 2017; 107:937-949. [PMID: 28398874 DOI: 10.1094/phyto-01-17-0030-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recent outbreaks of Sclerotinia stem rot (SSR) of soybean in Ohio, along with new fungicides and cultivars with resistance to this disease, have led to a renewed interest in studies to update disease management guidelines. The effect of host resistance (in moderately resistant [MR] and moderately susceptible [MS] cultivars) and chemical control on SSR and yield was evaluated in 12 environments from 2014 to 2016. The chemical treatments evaluated were an untreated check, four fungicides (boscalid, picoxystrobin, pyraclostrobin, and thiophanate-methyl), and one herbicide (lactofen) applied at soybean growth stage R1 (early flowering) alone or at R1 followed by a second application at R2 (full flowering). SSR developed in 6 of 12 environments, with mean disease incidence in the untreated check of 2.5 to 41%. The three environments with high levels of SSR (disease incidence in the untreated check >20%) were used for further statistical analysis. There were significant effects (P < 0.05) of soybean cultivar and chemical treatment on SSR levels. Significantly lower levels of SSR were observed in MR cultivars. Both boscalid and lactofen reduced SSR but did not increase yield. Pyraclostrobin increased SSR compared with the untreated check in the three environments with high levels of disease. In the six fields where SSR did not develop, chemical treatment did not increase yield, nor was the yield from the MR cultivar significantly different from the MS cultivar. For Ohio, MR cultivars alone were effective for management of SSR in soybean fields where this disease has historically occurred.
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Affiliation(s)
- Jaqueline Huzar-Novakowiski
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691
| | - Pierce A Paul
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691
| | - Anne E Dorrance
- Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691
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