Evidence for diversifying selection in Potato virus Y and in the coat protein of other potyviruses

Abstract

The modes of evolution of the proteins of Potato virus Y were investigated with a maximumlikelihood method based on estimation of the ratio between non-synonymous and synonymous substitution rates. Evidence for diversifying selection was obtained for the 6K2 protein (one amino acid position) and coat protein (24 amino acid positions). Amino acid sites in the coat proteins of other potyviruses (Bean yellow mosaic virus, Yam mosaic virus) were also found to be under diversifying selection. Most of the sites belonged to the N-terminal domain, which is exposed to the exterior of the virion particle. Several of these amino acid positions in the coat proteins were shared between some of these three potyviruses. Identification of diversifying selection events in these different proteins will help to unravel their biological functions and is essential to an understanding of the evolutionary constraints exerted on the potyvirus genome. The hypothesis of a link between evolutionary constraints due to host plants and occurrence of diversifying selection is discussed.

Evolution of cassava brown streak disease-associated viruses

“…While similar results have been obtained on SPMMV (Tugume et al, 2010b) and Sweet potato virus C (previously known as the strain C of Sweet potato feathery mottle virus, genus Potyvirus) (Tugume et al, 2010a), the findings contrast the data on most of the potyviruses studied in which amino acid residues under positive selection are usually found at the CP N terminus (García-Arenal et al, 2001;Moury et al, 2002). The central part of the potyviral CP is involved in viral cell-to-cell and long distance movement in plants (Dolja et al, 1994(Dolja et al, , 1995Varrelmann & Maiss, 2000) and positive selection in this region can be implemented in host adaptation to ensure efficient systemic infection and subsequent transmission by vectors (e.g., Lalić et al, 2010).…”

Antibodies to Potato Virus Y Bind the Amyloid β Peptide

“…1. The N-terminal domain of PVY is exposed to the exterior of the virion particle, enhancing the likelihood that it is immunogenic (27,28). PVY has 6 amino acids (at positions 60 -65) that share a high homology to the N-terminal region of A␤.…”

Sequence characteristics of potato virus Y recombinants

“…In PVY, different genes were reported to be under different selective constraints, e.g. P1 (Ogawa et al, 2008), CP and 6K2 (Moury et al, 2002) GC-rich (¢60 mol% GC content) and AU-rich (¢60 mol% AU) regions were termed 'homologousrecombination activators', which can influence homologous recombination (Nagy et al, 1999a). The upstream GCrich region and downstream AU-rich region were observed in RNA recombinants in CTV (Vives et al, 2005), noroviruses (Rohayem et al, 2005) and TuMV (Ohshima et al, 2007).…”