Location: Water Management and Systems ResearchTitle: Virus induced gene silencing of Arabidopsis gene homologues in wheat identify genes conferring improved drought tolerance Author
Submitted to: Journal of Experimental Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2012
Publication Date: 10/13/2013
Citation: Manmathan, H., Shaner, D.L., Snelling, J., Lapitan, N. 2013. Virus induced gene silencing of Arabidopsis gene homologues in wheat identify genes conferring improved drought tolerance. Journal of Experimental Botany. 64(5):1381-1392. Interpretive Summary: One of the major limitations for food production is water availability. Engineering crops to use less water is a goal of many researchers. This research examined the role of three genes involved in a plants response to abscisic acid, the primary hormone regulating a plant’s response to water stress. The results show that lowering the expression of two of the genes in wheat increased relative water status, improved water use efficiency and better vigor under limiting water conditions compared to control plants. The results indicate that these two genes may be promising targets of water stress management in wheat.
Technical Abstract: In a non-model staple crop like wheat, functional validation of potential drought stress responsive genes identified in Arabidopsis could provide gene targets for wheat breeding. Virus induced gene silencing (VIGS) of genes of interest can overcome the inherent problems of polyploidy and limited transformation potential that hamper functional studies in wheat. In this study, three potential candidate genes shown to be involved in abiotic stress response pathways in Arabidopsis were selected for VIGS experiments in wheat. These include Era1 (enhanced response to abscisic acid), Cyp707a (ABA 8'-hydroxylase), and Sal1 (inositol polyphosphate 1-phosphatase). Gene homologs for these three genes were identified in wheat and cloned in the viral vector Barley stripe mosaic virus (BSMV) in the antisense direction, followed by rub-inoculation of BSMV viral RNA transcripts onto wheat plants. Quantitative RT-PCR showed that VIGS-treated wheat plants had significant reductions in target gene transcripts. When VIGS treated plants generated for Era1 and Sal1 were subjected to limiting water conditions, they showed increased relative water content, improved water use efficiency, reduced gas exchange and better vigor compared to control un-inoculated plants. In comparison, the Cyp707a silenced plants showed no improvement over normal plants under limited water condition. These results indicate that Era1 and Sal1 are promising targets for water stress management in wheat. Other traits affected by Era1 silencing were also studied. Delayed seed germination in Era1-silenced plants suggests this gene may be a useful target for developing resistance to pre-harvest sprouting.