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

Analysis of the intergenic region (IGR) of S and M RNAs of tospoviruses (Fa mily Bunyaviridae) indicated their heterogeneity both in length and sequenc e. 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 seque nces of distinct tospovirus species varied from 42 to 57%, whereas it was 7 9 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 sa me tospovirus species (84 to 98%) than among distinct tospovirus species (4 6 to 59%). Percent nucleotide identities and maximum likelihood trees of IG R sequences of S and M RNAs indicated that their sequence divergence is sim ilar to that of nucleocapsid gene at inter and intra-species levels. This i s the first detailed sequence analysis of IGRs of S and M RNAs of known tos poviruses.