Cloning of Two Salt-responsive Genes and Their Expression Analysis in Tomato

Based on the ESTs derived from previous microarray results under salt stress,the full-length cDNAs of two salt-inducible genes(SlSRG1,SlSRG2) were isolated from a salt tolerant tomato cultivar,Edkawi,using Rapid Amplification of cDNA Ends(RACE).The accession numbers of SlSRG1 and SlSRG2 in GenBank are EU670751and EU670752,respectively.The corresponding cDNAs are 1300 bp and 1810 bp in length and the deduced proteins contain 287 and 499 amino acids,respectively.Tissue expression profile analysis using semi-quantitative RT-PCR showed that SlSRG1 was expressed mainly in the stem,leaf and flower,while SlSRG2 was expressed at a very high level in the leaf and flower.Upon salt stress,SlSRG1 was induced slowly,while SlSRG2 was induced rapidly in Edkawi;however,the general trend of their expression in the untreated control was declining.These two genes are potential novel candidates for abiotic tolerance research in tomato.