Evolutionary and molecular population genetic analysis of Impatiens necrotic spot virus (INSV)

Impatiens necrotic spot virus (INSV) is a highly destructive plant virus in the family Bunyaviridae that causes widespread and devastating losses in ornamental greenhouse crops. Our goal is to formulate an attribution system based on an understanding of the population genetics of INSV, similar to th...

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Bibliographic Details
Published in:Phytopathology 2008-06, Vol.98 (6), p.S122-S122
Main Authors: Parks, E J, Speck, J, Abad, J, Carbone, I, Moyer, J W
Format: Article
Language:English
Subjects:
Bunyaviridae
Impatiens necrotic spot virus
Tomato spotted wilt virus
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Summary:Impatiens necrotic spot virus (INSV) is a highly destructive plant virus in the family Bunyaviridae that causes widespread and devastating losses in ornamental greenhouse crops. Our goal is to formulate an attribution system based on an understanding of the population genetics of INSV, similar to that for Tomato spotted wilt virus (TSWV). INSV exhibits geographical subdivision despite the shipment of plant material worldwide; it does not, however, have the extensive geographic structure of TSWV. Parsimony analysis does not illustrate the relationships between the isolates in a clear way as it does for TSWV due to unresolved polytomies and discordant phytogenies from the different genes. We present here an expansion of previous methods that builds on parsimony analysis, merges the data from the three genes, and improves the resolution of the phylogeny. Thirty-two isolates from six countries and seven U.S. states were selected for analysis based on the availability of sequence data for the N, NSm, and RdRp genes. Multiple isolates from North Carolina, California, and New Zealand permitted significance testing of population genetic statistics. Compatibility analysis was used to locate informative regions of the INSV genome and eliminate areas with phylogenetic conflict. The selected regions were examined for signatures of migration, population growth, and selection. Migration analysis suggested a recent divergence of the populations and no gene flow between populations, with sharing of ancestral polymorphisms the highest between the NC and CA populations. Neutrality testing revealed that the NZ population was evolving neutrally at all loci, but the evolutionary signatures of the loci in the NC and CA populations varied; some loci were evolving neutrally, while others contained evidence of population growth or background selection. This analysis of the INSV genome approximates a species tree for INSV and elucidates genomic regions with more useful phylogenetic information.
ISSN:0031-949X