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    Author(s): Jennifer Britt; Everett Hansen
    Date: 2011
    Source: New Zealand Journal of Forestry Science. 41S: S133-S141. [published on-line: 11/11/2011]
    Publication Series: Scientific Journal (JRNL)
    PDF: View PDF  (1.29 MB)


    Since the discovery of Phytophthora ramorum Werres, De Cock & Man In't Veld in south-western Oregon forests in 2001, newly infected areas are detected each year. Yet, there are still gaps in our knowledge about how the pathogen spreads or where new infections come from. Our study aims to track the spread of P. ramorum in Oregon forests and within individual trees using DNA fingerprinting. We examined the genetic diversity of 1589 samples collected from 2001 to 2008 on several temporal and spatial scales. We identified 60 novel multilocus genotypes (MGs# with 9 to 44 MGs found in each year. While the majority of MGs were present in very low numbers #< 1%) one MG was dominant in all years representing 39 to 73% of isolates. The dominance of one MG was not attributable to higher fitness by any measure examined. Frequency of the dominant MG declined with time. This supports the hypothesis that it represents the founder genotype, and is being progressively diluted by new genotypes that arise through mutation. Our data also demonstrate that P. ramorum populations in Oregon forest are genetically distinct from those in nurseries and in California forests.

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    Britt, Jennifer; Hansen, Everett. 2011. Tracking populations of Phytophthora ramorum within trees and across the South-western Oregon tanoak (Notholithocarpus densiflorus) forest with DNA fingerprinting and the relative fitness of dominant and rare individuals. New Zealand Journal of Forestry Science. 41S: S133-S141. [published on-line: 11/11/2011]


    epidemiology, microsatellites, multilocus genotypes.

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