Transgene expression of rice cysteine proteinase inhibitors for the development of resistance against sweetpotato feathery mottle virus.

Abstract

The sweetpotato feathery mottle virus (SPFMV) is a member of the potyvirus genus of the Family Potyviridae. SPFMV is economically important as one of the causal components of sweetpotato virus disease (SPVD). Developing resistance to SPFMV is essential for the control of SPVD using resistant varieties. A novel approach to controlling sweetpotato potyvirus involves the use of foreign cysteine proteinase inhibitors, which inhibit the proteolysis of a polyprotein in potyviruses, thus interfering with their replication. A rice cysteine-inhibitor gene (oryzacystatin I) was used to transform Jonathan sweetpotato, a cultivar susceptible to SPFMV. Improved resistance to SPFMV was observed in 18 of the 25 transgenic lines after challenge-inoculation with the russet crack strain of SPFMV. The sweetpotato feathery mottle virus (SPFMV) is a member of the potyvirus genus of the Fam. Potyviridae (Clark and Moyer, 1988). It occurs almost everywhere