Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 1/15/2005
Publication Date: 6/19/2005
Citation: Stenger, D.C., Hein, G.L., Gildow, F.E., Horken, K., French, R.C. 2005. Wheat streak mosaic virus hc-pro is a determinant of eriophyid mite transmission. American Society for Virology Meeting. Oral presentation, not published in journal. Interpretive Summary:
Technical Abstract: Wheat streak mosaic virus (WSMV, genus Tritimovirus, family Potyviridae), is transmitted by the wheat curl mite, Aceria tosichella Keifer. WSMV shares a similar genome organization with aphid transmitted species of the genus Potyvirus, despite vast phylogenetic distances between their respective arthropod vectors. Although both tritimoviruses and potyviruses encode helper component-proteinase (HC-Pro) homologues (required for non-persistent aphid transmission of potyviruses), sequence conservation is low (amino acid identity ~16%) and a role for HC-Pro in semi-persistent transmission of WSMV by eriophyid mites has not been investigated. We previously demonstrated that WSMV strain Sidney 81 (WSMV-S81) tolerated replacement of HC-Pro with the corresponding cistron from diverse species within the Potyviridae and that these chimeric viruses retained the ability to systemically infect wheat. Here, we show that mite transmissibility was abolished by replacement of WSMV HC-Pro with that of an aphid transmitted potyvirus (Turnip mosaic virus), a rymovirus (Agropyron mosaic virus) vectored by a different eriophyid mite, or a closely related tritimovirus (Oat necrotic mottle virus, ONMV) with no known vector. In contrast, both WSMV-S81 and WSMV-S81 bearing HC-Pro of a divergent WSMV strain (El Batán 3, 86% amino acid sequence identity) were efficiently transmitted by A. tosichella. Replacing portions of WSMV-S81 HC-Pro with the corresponding regions from ONMV showed that determinants of mite transmission map to the N-terminal half of HC-Pro. Collectively, these results indicate that despite limited sequence identity and specialization for transmission by very different vector taxa, HC-Pro remains a critical determinant of vector transmission among diverse members of the Potyviridae.