Molecular variability of sugarcane streak mosaic virus in China based on an analysis of the P1 and CP protein coding regions.

Sequences of the protein 1 (P1) and coat protein (CP) coding regions of 22 sugarcane streak mosaic virus (SCSMV) isolates were determined. Phylogenetic analysis showed that SCSMV had at least three major lineages, and the lineages seemed to reflect geographical origin. The sudden expansions of the Chinese and Indian subpopulations were supported by calculations showing deviations from the neutral equilibrium model for the individual lineages with an overall lack of nucleotide diversity. Our study shows that Chinese and Indian SCSMV isolates are part of a distinct population, and the subpopulations probably reflect founder effects.