ARS | Publication request: Amino acid substitutions of cysteine residues near the amino terminus of Wheat streak mosaic virus HC-Pro abolishes virus transmission by the wheat curl mite

Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2007
Publication Date: July 15, 2007
Citation: French, R.C., Young, B.A., Hein, G.L., Stenger, D.C. 2007. Amino acid substitutions of cysteine residues near the amino terminus of Wheat streak mosaic virus HC-Pro abolishes virus transmission by the wheat curl mite. American Society for Virology, 26th Annual Meeting, Corvallis, OR, July 2007, (abstracts of meeting not published).

Technical Abstract: The amino-terminal half of HC-Pro of Wheat streak mosaic virus (WSMV) is required for semi-persistent transmission by the wheat curl mite (Aceria tosichella Keifer). The amino-proximal region of WSMV HC-Pro is cysteine-rich with a zinc finger-like motif. Amino acid substitutions were made in this region and evaluated for phenotypic effects on infectivity and mite transmission. Alanine substitution at WSMV HC-Pro cysteine residues 16, 20, 46 and 49 had no effect on systemic infectivity to wheat. However, alanine substitutions at Cys16, Cys46 and Cys49 abolished transmission by the wheat curl mite. Although alanine substitution at Cys20 did not affect wheat curl mite transmission efficiency, substitution with arginine at this position substantially reduced vector transmission efficiency. Additional substitutions at three other positions (Lys7 to Asn, Asn19 to Ile, and Arg45 to Lys) did not affect infectivity or vector transmission. These results indicate that the WSMV HC-Pro cysteine-rich region is required for vector transmission and suggests that a zinc finger- like motif (His13-X2-Cys16-X31- Cys46-X2-Cys49) may be the critical vector transmission determinant affected by the substitution mutations.