Location: Wheat, Sorghum and Forage Research
Project Number: 3042-21000-033-05-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 15, 2018
End Date: Sep 14, 2023
Wheat streak mosaic virus (WSMV), transmitted by the wheat curl mite (WCM), is an economically important virus impacting wheat production in the Great Plains region. WSMV is the type member of the genus Tritimovirus of the family Potyviridae. The CP and HC-Pro proteins are identified as vector transmission determinants of both WCM-transmitted WSMV and aphid-transmitted members of the genus Potyvirus in the family Potyviridae. However, these viruses differ in the mode of vector transmission: WSMV is thought to be transmitted by the WCM in a persistent manner, while the members of the genus Potyvirus are transmitted by aphids in a non-persistent manner. The actual mechanisms of WSMV transmission by WCMs and WCM proteins involved in WSMV transmission are poorly understood. Specific objectives: 1. Define the type of WCM transmission of WSMV as a semipersistent or persistent. 2. Identify WCM proteins involved in WSMV transmission through examination of interactions between WSMV and WCMs proteins. 3. Screen wheat lines/cultivars in the Hard Winter Wheat Regional Nursery program for resistance against WSMV.
WCMs will be collected on WSMV-infected or buffer-inoculated wheat at weakly intervals starting with at 4 weeks postinfestation (wpi). Total RNA and proteins will be extracted from WCMs propagated on WSMV-infected or buffer-inoculated wheat plants. Accumulation of WSMV-specific positive- and negative-strand genomic RNAs will be examined by real-time RT-PCR and RT-PCR from WCM total RNA isolated from WSMV-infected and buffer-inoculated plants at different time intervals. Additionally, accumulation of WSMV CP, P1, and HC-Pro proteins in WCMs collected from WSMV-infected or buffer-inoculated wheat will be examined with antibodies to respective WSMV-encoded proteins. These data will provide information on the mode of WSMV transmission by the WCM. Total proteins extracted from nonviruliferous WCMs will be used for interaction studies with CP and HC-Pro of WSMV. WCM proteins that interact with WSMV CP and/or HC-Pro will be identified using mass spectrometry at the University of Nebraska-Lincoln Center for Biotechnology facility. Protein-protein interactions between CP and/or HC-Pro of WSMV and selective WCM proteins will be examined using a combination of Co-immunoprecipitation, pull-down assays, yeast-two hybrid system and BiFC assay using standard protocols. These studies will facilitate identification of WCM proteins that interact with CP and/or HC-Pro for transmission by WCMs. Wheat lines/cultivars received from breeders/industry will be sown in the field at the Eastern Nebraska Research and Education Center in head rows. These wheat lines will be screened for resistance against WSMV infection by wheat curl mite maintained in nearby fields in voluntary wheats and grasses. Syptoms of WSMV in wheat lines/cultivars will be recorded and wheat yields will be collected from mature heads. Maintaining green-bridge plants and screening of wheat lines will be performed annually.