Abstract

Salinity is one of the most serious environmental factors influencing crop growth and development, especially during germination period. In peanut, screening for salinity tolerance has been reported by several investigators, but there are few reports regarding isolation and identification of salt responsive genes from salt tolerant genotypes. In this study, we compared gene expression profile of a large-seeded saline tolerant peanut line 10L19 imbibed in 1.0% sodium chloride solution and seeds of the same genotype treated with distilled water, using the annealing control primer (ACP)-based GeneFishing technology. Total RNAs were extracted from seeds sampled at 1, 6 and 24 h after imbibition initiation. With 40 ACPs, a total of 20 differentially expressed transcripts were isolated. Thirteen of them were found to have high homology to genes with known functions in GenBank nr database. BLAST search revealed that those genes were related to gene expression regulation, signalling transduction, development and stress tolerance, among which S-38 was of direct relevance to hyperosmotic salinity response. S-14, S-15, S-17, S-28, S-31, S-32 and S-38, encoding ethylene-responsive element binding factor 4, DNA-directed RNA polymerase subunit, oleosin 5, polygalacturonase-inhibiting protein, vacuolarprocessing enzyme precursor, ribosomal protein s7 and nac domain protein, respectively, were selected and their relative expression levels determined by qRT-PCR using β-actin as internal control. The results confirmed that all the seven genes were expressed differentially in stressed and control peanut seeds. The highest relative expression for S-17 and S-38 was both at 6 h, while that for the rest genes was at 24 h.