Phylogenetic studies of tospoviruses (family: Bunyaviridae) based on intergenic region sequences of small and medium genomic RNAs.

Abstract

Analysis of the intergenic region (IGR) of S and M RNAs of tospoviruses (Family Bunyaviridae) indicated their heterogeneity both in length and sequence. In general, IGRs of M RNA were shorter in length compared to the IGRs of their respective S RNA species. Percent identity among the S RNA IGR sequences of distinct tospovirus species varied from 42 to 57%, whereas it was 79 to 99% among isolates of the same species. Similarly, when IGRs of M RNAs were compared, there was higher sequence identity among isolates of the same tospovirus species (84 to 98%) than among distinct tospovirus species (46 to 59%). Percent nucleotide identities and maximum likelihood trees of IGR sequences of S and M RNAs indicated that their sequence divergence is similar to that of nucleocapsid gene at inter and intra-species levels. This is the first detailed sequence analysis of IGRs of S and M RNAs of known tospoviruses.