MSA - Ecology/Pathology
Douhan, Greg W. , Olsen, Mary W. , Herrell, Amanda , Wong, Frank , Entwistle, Kate .
Genetic diversity of Labyrinthula terrestris, a newly emergent plant disease correlated with increased soil salinity, and newly discovered Labyrinthulid organisms.
Labyrinthula terrestris is a unique net slime mold that is the only described terrestrial Labyrinthula species and is the causal agent of Rapid Blight of turfgrass. The disease is primarily associated with elevated salinity in irrigation water and soil and often results from deliberate and sometimes mandated use of elevated salinity irrigation water, making it a unique example of an emergent plant disease induced by human activity. Previous research on a limited number of isolates found no variability in two rDNA loci. Therefore, our objective was to examine diversity in an expanded selection of isolates using AFLP, sequence analysis of two rDNA loci (SSU & LSU-ITS), and pathogenicity tests. In contrast to previous work, 18 unique genotypes were found out of a total of 29 analyzed based on AFLP. Two putatively new non-pathogenic Labyrinthulid species were also found based on SSU & LSU-ITS analysis. Sequence variability was only found in a single pathogenic isolate that was isolated from the UK. The divergence based on AFLP and sequence analysis suggests that this isolate is a distinct species but closely related to the other L. terrrestris isolates examined. Our results suggest that these organisms may be widely distributed, may have long been associated with terrestrial plants, and that more Labyrinthulid organisms may emerge as new plant pathogens for major food crops in the future as salinification of agricultural systems increases worldwide.
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1 - University of California, Plant Pathology and Microbiology, Riverside, CA, 92521, USA
2 - The University of Arizona, Department of Plant Sciences, Division of Plant Pathology and Microbiology, Tuscon, AZ, 85721, USA
3 - The University of Arizona, Department of Plant Sciences, Division of Plant Pathology and Microbiology, Tuscon, AZ, 8, USA
4 - The Turf Disease Centre, Hampshire, RG26 5 AG, England
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM