ARS | Publication request: Low genetic diversity of Squash vein yellowing virus in wild and cultivated cucurbits in the U.S. suggests a recent introduction

Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 19, 2011
Publication Date: December 1, 2011
Repository URL: http://doi:10.1016/j.virusres.2011.11.017
Citation: Webster, C.G., Adkins, S.T. 2011. Low genetic diversity of Squash vein yellowing virus in wild and cultivated cucurbits in the U.S. suggests a recent introduction. Virus Research. doi:10.1016/j.virusres.2011.11.017.

Interpretive Summary: The biological and genetic properties of a set of Squash vein yellowing virus (SqVYV) isolates from wild and cultivated cucurbits with temporal and spatial separation were examined. Nucleic acid sequences of the coat protein (CP) and two serine proteases (P1a and P1b) were determined which indicated the presence of two distinct groups, each of which had low diversity. Each region of the virus was found to be under negative selection pressure; however, this was insufficient to explain the observed low diversity. This indicates both groups of SqVYV have been recently introduced to the U.S. and subsequently spread into wild and cultivated cucurbits. This data along with that of other ipomoviruses suggests a common theme of worldwide movement and interactions with crop plants.

Technical Abstract: Biological properties and genetic diversity of a set of SqVYV isolates were determined for isolates from different hosts, locations and times. Biological properties were found to be similar across all isolates. The coat protein (CP) and two serine proteases (P1a and P1b) were sequenced from 41 isolates and compared using phylogenetic reconstructions. Selection pressures acting on each region of the genome were also examined and evidence of recombination between divergent isolates was also found. The results of this work imply a recent introduction of SqVYV to the U.S. and suggest a common theme of worldwide ipomovirus movement and recent interaction with crop plants.