Virus-Induced Gene Silencing (VIGS) in Aegilops tauschii and Its Use in Functional Analysis of AetDREB2

Among the available reverse genetic approaches for studying gene function, virus-induced gene silencing (VIGS) has several advantages. It allows rapid characterization of gene function independent of stable transformation, which is basically difficult to achieve in monocots, and offers the potential to silence individual or multiple genes of a gene family. In order to establish a VIGS system in Aegilops tauschii, modified vectors derived from Barley stripe mosaic virus (BSMV) were used for silencing a phytoene desaturase gene that provides a convenient visual reporter for silencing. The results demonstrated a high efficiency of BSMV-VIGS in A. tauschii. Moreover, the BSMV-VIGS system was used to target a 354 bp specific region of the Dehydration-responsive element-binding (AetDreb2) gene, resulting in successful silencing of the gene in A. tauschii plants, as verified by real-time qRT-PCR. Indeed, in comparison with plants that were inoculated with an empty vector (BSMV:00), a faster rate of wilting and a lower relative water content were observed in plants inoculated with BSMV:AetDreb2 when they were exposed to drought stress. Therefore, BSMV-VIGS can be efficiently employed as a novel tool for reverse genetics in A. tauschii. It can also be used to study the effects of polyploidization on the gene function by a comparative analysis between bread wheat and its diploid progenitor.