Amplified Fragment Length Polymorphism Assessment of Population Diversity in California Bay (Umbellularia californica)

Sarah Gordon, Richard Whitkus, Ross Meentemeyer, Brian Anacker; Departments of Biology and Geography, Sonoma State University, Rohnert Park, CA 94928; (707) 664-2303, sarahgordon17@aol.com

Umbellularia californica is a major foliar host for Phytophthora ramorum. The population genetics of a host influences the spread of pathogens through the host population, however no information is available on the population genetics of U. californica. We are investigating the population genetics of U. californica using Amplified Fragment Length Polymorphism (AFLP) in a study of the factors underlying the spread of P. ramorum through the Sonoma Valley. Genomic DNA was extracted from leaves from 97 populations of U. californica, representing 1293 adults and 2119 juveniles. Forty-six AFLP primers pairs have been surveyed, resulting in six pairs providing strong signal. We surveyed two geographically proximate populations to find a combination of markers that provides representative genetic diversity. Comparing individual primers, noticeable variation was seen in the number of scorable loci (45-82), percent polymorphism (60-75%), total diversity (HT: 0.096-0.131), and between population diversity (GST: 0.071-0.105). One combination of three primers (186 loci) gave very similar diversity values when compared to all six primers (340 loci). This study produces a solid basis for conducting a population genetics study of an estimated 6000 U. californica trees in the study area’s plots and generating useful data for modeling the spread of P. ramorum.

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