Expression Analysis for Drought Tolerance in Tomato

Abstract

Tomato (Solanum lycopersicum) is one of the most popular and nutritionally important vegetable crops around the world. and#932;omato cultivation suffers heavy losses due to drought worldwide including in India as well. Transcriptome sequencing is one of the important and widely used approaches to identify genes related to a trait of interest. In the present study, transcriptome sequencing was carried out on two genotypes viz. Kashi Vishesh (KV) and WIR-13706 (WIR) to investigate the molecular mechanisms and gene expression analysis under drought stress. A total of 436.8 million high quality transcriptome reads identified a total of 26,085 genes for all eight samples representing two conditions (control and drought) and two biological replicates each for KV and WIR genotypes. The expression analysis between drought and control samples identified a total of 5095 and 4667 differentially expression genes (DEGs) in WIR and KV, respectively. Top 50 differentially expressing genes for KV and WIR were used to create a subset of 10 genes for the validation of RNA-seq based expression patterns through quantitative Real Time (qRT) PCR. A total of nine genes were used for scoring of expression kinetics as one of the primer pairs was not functional. Out of these, four genes (Solyc03g096290, Solyc06g074200, Solyc03g007230, Solyc06g067980) showed differential expression profiles between control and drought samples of both the genotypes. The validation analysis identified a key gene coding for aquaporin-related protein (Solyc03g096290) having markedly differential expression pattern. Aquaporins are membrane channels that are involved in transport activity and regulation of molecules across the cellular membranes. Identification and validation of differentially expressed genes under normal and drought conditions will provide an insight into the molecular mechanism(s) associated with drought tolerance. The knowledge of drought tolerance molecular mechanism(s) could potentially lead to better breeding strategies in near future.