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ARS Home » Plains Area » Lincoln, Nebraska » Wheat, Sorghum and Forage Research » Research » Publications at this Location » Publication #326902
Title: Temperature-dependent Wsm1 and Wsm2 gene-specific blockage of viral long-distance transport provides resistance to Wheat streak mosaic virus and Triticum mosaic virus in wheat

Author
item Tatineni, Satyanarayana - Ts
item WOSUL, EVERLYNE - University Of Nebraska
item Bartels, Melissa
item HEIN, GARY - University Of Nebraska
item Graybosch, Robert

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2016
Publication Date: 10/19/2016
Publication URL: https://handle.nal.usda.gov/10113/63318
Citation: Tatineni, S., Wosul, E.N., Bartels, M.S., Hein, G.L., Graybosch, R.A. 2016. Temperature-dependent Wsm1 and Wsm2 gene-specific blockage of viral long-distance transport provides resistance to Wheat streak mosaic virus and Triticum mosaic virus in wheat. Molecular Plant-Microbe Interactions. 29(9):724-738.

Interpretive Summary: Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are important wheat viruses negatively impacting wheat production in the Great Plains region. Both viruses are transmitted by a common vector, the wheat curl mite, and co-transmission of both viruses may contribute to double infections in wheat. Wheat cultivars Mace and Snowmass provide temperature-dependent resistance against WSMV and TriMV and WSMV, respectively, at 18ºC or below. Virus resistance in Mace and Snowmass is conditioned by the Wsm1 and Wsm2 genes, respectively. The Wsm1- and Wsm2-conferred viral resistance mechanism was examined using red fluorescent protein-tagged WSMV and green fluorescent protein-tagged TriMV. Replication and cell-to-cell movement of both viruses in resistant wheat cultivars were comparable to those in susceptible cultivar Tomahawk at 18ºC. However, both viruses failed to move long-distance as they failed to enter the leaf sheath and crowns of resistant wheat cultivars at 18ºC, indicating that resistance in Mace and Snowmass cultivars operates by blocking viruses from entering the vasculature, thus preventing the systemic spread of virus. The exclusion of WSMV and TriMV from the vascular system likely facilitates the Wsm1- and Wsm2-based resistance by restricting the virus locally in mite-infested leaves under field conditions. The combination of Wsm- harboring wheat cultivars together with low daytime temperatures during the late fall and early spring seasons can provide effective management of the WSMV/TriMV disease complex.

Technical Abstract: Wheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are economically important viral pathogens of wheat. Wheat cultivars Mace with the resistance gene Wsm1 and Snowmass with the resistance gene Wsm2 are resistant to WSMV and TriMV, and WSMV, respectively. Viral resistance in both cultivars is temperature-sensitive and is effective at 18ºC or below but not at higher temperatures. The underlying mechanisms of viral resistance of these genes are not known. In this study, we found that WSMV and TriMV efficiently replicated and moved cell-to-cell in inoculated leaves of resistant wheat cultivars at 18ºC but failed to establish systemic infection, suggesting that Wsm1- and Wsm2-mediated resistance debilitated viral long-distance transport. Furthermore, neither virus was able to enter the leaf sheaths of inoculated leaves or crowns of resistant wheat cultivars at 18ºC but were able to do so at 20 to 26ºC. Thus, wheat cultivars Mace and Snowmass provide resistance at the long-distance movement stage of virus life-cycle by specifically blocking virus entry into the vasculature. Taken together, these data suggest that both Wsm1 and Wsm2, non-allelic single dominant genes, similarly confer virus resistance by temperature-dependent impairment of viral long-distance movement.