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Title: Polymorphic SSR Markers for Plasmopara obducens (Peronosporaceae), the Newly Emergent Downy Mildew Pathogen of Impatiens (Balsaminaceae)

Premise of the study: Simple sequence repeat (SSR) markers were developed for Plasmopara obducens, the causal agent of the newly emergent downy mildew disease of Impatiens walleriana. Methods and Results: A 202-Mb draft genome assembly was generated from P. obducens using Illumina technology and mined to identify 13,483 SSR motifs. Primers were synthesized for 62 marker candidates, of which 37 generated reliable PCR products. Testing of the 37 markers using 96 P. obducens samples showed 96% of the markers were polymorphic, with 2-6 alleles observed. Observed and expected heterozygosity ranged from 0.000-0.892 and 0.023-0.746, respectively. Just 17 markers were sufficient to identify all multilocus genotypes. Conclusions: These are the first SSR markers available for this pathogen, and one of the first molecular resources. These markers will be useful in assessing variation in pathogen populations and determining the factors contributing to the emergence of destructive impatiens downy mildew disease.
 [1] ;  [1] ;  [2] ;  [3]
  1. USDA-ARS, Beltsville, MD (United States); Rutgers Univ., New Brunswick, NJ (United States)
  2. USDA-ARS, Beltsville, MD (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
  3. USDA-ARS, Beltsville, MD (United States)
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Applications in Plant Science
Additional Journal Information:
Journal Volume: 3; Journal Issue: 11; Journal ID: ISSN 2168-0450
Botanical Society of America
Research Org:
U.S. Department of Agriculture, Washington, DC (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States