Diversity among isolates of squash mosaic virus

• Published in: Journal of general virology Vol. 79; no. 10; pp. 2331 - 2341
• Main Authors: Haudenshield, JS, Palukaitis, P
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01-10-1998
• Subjects: Amino Acid Sequence; Base Sequence; Comovirus - classification; Comovirus - genetics; Cucurbitaceae - virology; Molecular Sequence Data; RNA, Viral - chemistry; Squash mosaic virus; Viral Proteins - metabolism
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-79-10-2331

JS Haudenshield and P Palukaitis
Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.
cDNA clones of RNA-2 of two isolates of squash mosaic virus (SqMV) were
constructed and sequenced, revealing 87% sequence similarity. In Northern
blot hybridization analyses, DNA probes made from these clones defined two
SqMV hybridization subgroups. This grouping was verified by reciprocal
hybridizations of purified RNA from five SqMV isolates, as probed with cDNA
made from a member of each subgroup. Comparison of the RNA-2 sequence among
the two SqMV isolates, and the reported sequence of other comoviruses,
showed that SqMV constitutes one of four major branches in a phylogenetic
tree of the genus. Analysis of the terminal noncoding sequences showed that
although potentially similar folding patterns may form, neither nucleotide
sequence nor secondary structural elements are highly conserved among
comoviruses. In vitro translation products from purified RNA-1 of each
subgroup (encoding the viral proteases) were found to process the
polyprotein generated by in vitro translation of purified RNA-2 from either
subgroup.