|Morris, T - UNIVERSITY OF NE, LINCOLN|
Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 21, 2000
Publication Date: July 12, 2000
Citation: Hall, J.S., French, R.C., Morris, T.J., Stenger, D.C. 2000. Temporal dynamics of wheat streak mosaic virus genetic variation. American Society For Virology Meeting. Not published. Technical Abstract: The temporal pattern of genetic variation was followed for a wheat streak mosaic virus (WSMV) isolate. A limiting dilution sub-isolate of WSMV Sidney 81 was subjected to nine serial passages in three host species under a constant environment. SSCP and sequence analyses permitted identification of changes in the predominant genotype. Fixed substitutions accumulated at an essentially linear rate (approximately 0.33 nt/passage/line) in wheat, barley, and corn. Most of the observed changes were single nucleotide changes and occurred within the NIa and CP genes, although some multiple substitutions and changes in other regions of the genome also were observed. No evidence for host-directed selection was observed. Accumulation of fixed mutations in the WSMV genome over time is more consistent with a stochastic model of genetic mutation and drift than with a deterministic model. Given sufficient time and genetic isolation (provided by cross-protection), genetic drift may account for much of the genotypic variation occurring between WSMV isolates recovered from complex field populations.