PEANUT YELLOW SPOT VIRUS IS A MEMBER OF A NEW SEROGROUP OF TOSPOVIRUSGENUS BASED ON SMALL (S) RNA SEQUENCE AND ORGANIZATION

Peanut yellow spot virus (PYSV) represents a distinct tospovirus speci es based on serology and nucleic acid hybridization. The sequence of t he S RNA was 2970 nucleotides with 22 nucleotide long inverted repeats (with three mismatches) at the termini. The coding was ambisense with a long open reading frame (ORF) in each strand. The 5'-large ORF (144 0 nucleotides in the viral sense (v) strand) encoded a protein with a predicted size of 53.2 kDa that was identified as the nonstructural (N Ss) protein based on 16-21% sequence identity and 42-48% sequence simi larity with other tospoviruses. A 3' ORF (741 nucleotides) in the viru s complementary (vc) sense encoded a 28.0 kDa protein that was identif ied as the nucleocapsid (N) gene based on immune-blot analysis of the in vitro expressed protein with PYSV polyclonal antiserum. The predict ed N protein had 24-28% amino acid sequence identity and 44-51% sequen ce similarity with the members of other serogroups. In contrast to oth er tospoviruses, a third ORF (204 nucleotides) occurred in the vc stra nd, which could encode a protein with a predicted size of 7.5 kDa with two strong hydrophobic regions. The low degree of homology of N and N Ss protein sequences with other serogroup members coupled with an addi tional ORF suggests that PYSV should be classified as a distinct speci es of the Tospovirus genus. This conclusion also is supported by the a bsence of serological cross reaction with other serogroups, and biolog ical characteristics including thrips transmission, symptoms and host range.