Virus-induced Gene Silencing of SPY Gene Related to Drought Stress in Cotton

Abstract

Cotton (Gossypium spp.) is the most important crop in the world producing natural fiber for the textile industry as well as a source of feed and fuel. Cotton yield, fiber quality, and stress tolerance have all improved because of genetic engineering and molecular breeding of valuable genes/traits into the crop. Rapid and effective transient techniques to evaluate cotton gene function have been developed to assist high throughput functional genomics studies in cotton. Virus-mediated gene silencing is an efficient approach to inhibit viral growth which relies on host post-transcriptional gene silencing (PTGS). Tobacco rattle virus (TRV) is one of multiple viral VIGS vectors, infects a broad range of hosts, and can propagate widely all through the plant while causing very mild disease within the host. SPINDLY (SPY) gene encodes an O-linked N-acetylglucosamine transferase and is a known negative regulator of drought tolerance in Arabidopsis thaliana. The objective of the study was to use VIGS for SPY gene silencing. Drought stress was applied to trigger the expression of stress-responsive genes. SPY homolog in cotton was designed and cloned and put into the binary vector pYL156 (TRV RNA2) for VIGS-mediated gene silencing. The agroinfiltration method was used to introduce VIGS vectors in plant leaves. The gene expression was quantified through qPCR in both stressed and normal plants. Low gene expression was observed from 7-14 days post infiltration (dpi). The study could help in the functional analysis of the SPY gene and will explore its role in drought responsiveness in upland cotton that can be further exploited to develop drought tolerant varieties