Location: Wheat, Sorghum and Forage Research
Project Number: 3042-21000-035-003-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jun 1, 2020
End Date: May 31, 2025
Develop transgenic wheat with binary constructs comprising the RNAi elements with wheat streak mosaic virus (WSMV) sequence, sequence of host and wheat curl mite proteins interacting with WSMV, and superinfection elicitors of WSMV.
Wheat streak mosaic virus (WSMV) is an economically important virus infecting wheat in the Great Plains region of the USA. It has been demonstrated that a transgene with separate short hairpins (300-500 nucleotides) derived from different viruses or host genes have been used to provide resistance against viruses and silence the expression of host genes, respectively. In this study, we propose to develop hairpin constructs from the conserved regions of WSMV isolates between the maize ubiquitin promoter and NOS-terminator sequences in a binary vector. Similarly, sequences encoding wheat and wheat curl mite proteins interacting with WSMV for systemic infection and wheat curl mite transmission, respectively, will be used for the generation of RNAi construct in a binary vector. These binary constructs will be used for wheat transformation. Recently, the coat protein and NIa-Pro proteins were identified as superinfection exclusion or cross protection elicitors of WSMV. Sequences encoding CP and/or NIa-Pro will be cloned in a binary vector under the tobacco etch virus leader sequence as a translation enhancer for efficient expression of CP and/or NIa-Pro proteins in transgenic wheat. Currently, we are in the process of identifying wheat and wheat curl mite proteins required for systemic infection of wheat by WSMV and horizontal transfer of WSMV by wheat curl mites, respectively. The identified wheat and wheat curl mite proteins will be used for developing RNAi constructs for the down-regulation of these proteins’ functions. The RNAi constructs with wheat and wheat curl mite proteins will be used for wheat transformation. Transgenic wheat possessing the RNAi construct comprising the WSMV, wheat, or wheat curl mite sequence or CP and/or NIa-Pro sequences for the expression of respective proteins will be screened for resistance against WSMV. The homogeneous population of transgenic wheat will be obtained through single-seed descent by transferring five generations.