Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2011
Publication Date: June 1, 2011
Citation: Stenger, D.C., Sisterson, M.S., French, R.C. 2011. Population Genetics of Homalodisca Vitripennis phytoreovirus reveals a bottleneck in the CA population and validates timing and limited introduction of the glassy-winged sharpshooter. Phytopathology. 101:S171. Technical Abstract: Homalodisca vitripennis reovirus (HoVRV) is a phytoreovirus species infecting the glassy-winged sharpshooter (GWSS), an invasive insect introduced to California. Complete genome sequences of five Californian and four southeastern U. S. isolates of HoVRV were evaluated for polymorphism. Pairwise nucleotide sequence diversity was ~10-fold less for HoVRV in California (<0.1%) compared to the southeastern U.S. (~1%). Phylogenetic analysis of each dsRNA segment indicated that the Californian isolates grouped as a monophyletic lineage. In contrast, relative placement of southeastern U.S. isolates varied among dsRNA segments. To sample diversity at single locations, dsRNA segment 11 was sequenced for nine additional isolates each from Riverside, CA, and Johnston Co., NC. Whereas 9 of 10 Riverside isolates were identical (the 10th varied at one position), Johnston Co. isolates varied by up to 1.5%. Coalescent analyses estimated median time to most recent common ancestor of the Californian population at 11.6 to 26.3 years, depending upon the demographic model employed. Estimates of median molecular clock rate for the Californian population translated to 0.4 to 1.4 substitutions/genome/year. Collectively, the results indicate that HoVRV diversity in the native range (southeastern U.S.) was high relative to a newly established population (California), and that the Californian population of HoVRV was subjected to a bottleneck coinciding with introduction of GWSS.