Sequence variability in the coat protein gene of Cowpea severe mosaic virus isolates from northeastern Brazil

Abstract

The comovirus Cowpea severe mosaic virus (CPSMV) causes a disease in cowpea (Vigna unguiculata) but, despite its importance, there are no studies on the genetic diversity of viral populations. We have determined the nucleotide sequences of part of the coat protein (CP) gene of six Brazilian isolates of CPSMV. Genomic fragments (521 nucleotides) were RT-PCR amplified, cloned, and their sequences were compared with each other and with other comoviruses. Sequence comparisons indicated a high degree of conservation for the CP gene, with 92-100{%} nucleotide and 97-100{%} amino acid sequence identity among the isolates. There was no correlation between geographical origin and sequence identity or phylogeny among the isolates.