Foxtail Mosaic Virus-Induced Gene Silencing in Monocot Plants

Virus-induced gene silencing (VIGS) is a powerful technique to study gene function in plants. However, very few VIGS vectors are available for monocot plants. Here we report that Foxtail mosaic virus (FoMV) can be engineered as an effective VIGS system to induce efficient silencing of endogenous genes in monocot plants including barley ( Hordeum vulgare L.), wheat ( Triticum aestivum ) and foxtail millet ( Setaria italica ). This is evidenced by FoMV-based silencing of phytoene desaturase ( PDS ) and magnesium chelatase in barley, of PDS and Cloroplastos alterados1 in foxtail millet and wheat, and of an additional gene IspH in foxtail millet. Silencing of these genes resulted in photobleached or chlorosis phenotypes in barley, wheat, and foxtail millet. Furthermore, our FoMV-based gene silencing is the first VIGS system reported for foxtail millet, an important C 4 model plant. It may provide an efficient toolbox for high-throughput functional genomics in economically important monocot crops.