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Title: SAMPLING AND AFLP FINGERPRINTING OF WHITE MOLD ISOLATES FROM PEA AND LENTIL IN THE PACIFIC NORTHWEST

Author
item Grunwald, Niklaus - Nik
item Chen, Weidong
item KOHN, L - UNIV TORONTO

Submitted to: Proceedings of the International Sclerotinia Workshop
Publication Type: Proceedings
Publication Acceptance Date: 1/21/2003
Publication Date: 1/21/2003
Citation: GRUNWALD, N.J., CHEN, W., KOHN, L.M. SAMPLING AND AFLP FINGERPRINTING OF WHITE MOLD ISOLATES FROM PEA AND LENTIL IN THE PACIFIC NORTHWEST. Proceedings of the International Sclerotinia Workshop. 2003. p. 28.

Interpretive Summary: Understanding the population structure of the white mold pathogen is crucial to two aspects of disease management: breeding for resistance and monitoring durability of control practices, such as effectiveness of chemical treatments or new crop varieties. The population structure of Sclerotinia on cruciferous crops in the US and Canada and on soybean in central Canada is very well elucidated. Canadian field populations of this pathogen on canola and on soybean are part of one population of the pathogen with some local subdivision; this population is mainly clonal. The population structure of S. sclerotiorum existing in the U.S. on pea and lentil has not been described, but we would expect to find a similarly clonal population where a few clones dominate a single agricultural field and there exists a large number of clones in different regions of the U.S. The objective of our research is to describe the population structure of S. sclerotiorum in pea and lentil growing regions of the US to improve management of the disease. We will use molecular approaches to describe genetic variation and pathogenicity and fungicide resistance assays to describe phenotypes of the pathogen population. To date, a total of 124 isolates have been collected from pea and lentil from WA and ID. Sampling of isolates from other areas including OR, ND and MN is ongoing. Our preliminary work shows that pea and lentil isolates from WA characterized to date are clonal confirming expectations from previous work in Canada.

Technical Abstract: Understanding the population structure of the white mold pathogen is crucial to two aspects of disease management: breeding for resistance and monitoring durability of control practices, such as effectiveness of chemical treatments or new crop varieties. The population structure of Sclerotinia on cruciferous crops in the US and Canada and on soybean in central Canada is very well elucidated, based on both phylogenetic analysis of single nucleotide polymorphism (SNPs) that shows the historical relationships of genotypes, and identification of genotypes (genetic individuals) by three genetically unlinked types of markers, mycelial compatibility grouping, DNA fingerprinting (RFLPs), and microsatellites. Canadian field populations of S. sclerotiorum on canola and on soybean are part of one population of the pathogen with some local subdivision; this population is mainly clonal. The population structure of S. sclerotiorum existing in the U.S. on pea and lentil has not been described, but we would expect to find a similarly clonal population where a few clones dominate a single agricultural field and there exists a large number of clones in different regions of the U.S. The objective of our research is to describe the population structure of S. sclerotiorum in pea and lentil growing regions of the US to improve management of the disease. We will use AFLP markers, microsatellite markers and mycelial compatibility groups to describe genotypes and pathogenicity and fungicide resistance assays to describe phenotypes of the pathogen population. To date, a total of 124 isolates have been collected from pea and lentil from WA and ID. Sampling of isolates from other areas including OR, ND and MN is ongoing. Several AFLP primer combinations have been screened on a subset of isolates and AFLP primer combinations EcoRI-AC/MseI-CT and EcoRI-AC/MseI-CT were selected for further studies. These primer combinations show that pea and lentil isolates from WA characterized to date are clonal confirming expectations from previous work in Canada. Work using microsatellite markers and mycelial compatibility groups to describe genotypes and pathogenicity and fungicide resistance assays to describe phenotypes of the pathogen population is in progress. RFLP fingerprinting using probe pLK44.20 will be conducted on a subset of isolates to provide for cross-referencing of isolates to the global database in Dr. Kohn's laboratory.