SILENCING OF G-PROTEIN alpha-SUBUNIT IN BARLEY (Hordeum vulgare L.) BY VIGS AND ITS EFFECT ON THE PLANT GROWTH

G-proteins play important roles in a number of cellular and developmental processes in plants. In this study, we have cloned a 317-bp fragment encoding a part of barley G protein alpha-subunit into gamma-genome of barley stripe mosaic virus (BSMV). Barley seedlings were inoculated with this construct denoted as pSL038-1/G alpha at 3-leaf stage, and assayed for their growth, leaf area and membrane ion leakage. Silencing was achieved after 2 weeks of inoculation and confirmed by the decrease in G alpha subunit mRNAs in barley leaves. There was a significant decrease in plant growth in terms of plant height and leaf area following the viral infection. Leaf area in silenced plants were decreased by >10% compared to control plants (wild-type or inoculated by BSMV-PDS constructs). In conclusion, silencing resulted in etiolated phenotypes and growth retardation. Our optimized VIGS protocol in barley could be adopted to evaluate extensive physiological parameters and molecular changes in G alpha silenced plants.