Identification and expression analysis of genes responsive to drought stress in peanut

Although peanut (Arachis hypogaea L.) is a relatively drought-tolerant crop, its productivity and quality is adversely affected by drought stress. The identification of novel genes, the analysis of gene expression patterns in response to dehydration stress, and the evaluation of their potential functions in stress adaptation will provide the basis for effective engineering strategies to improve crop drought tolerance. However, little is known about stress tolerance of peanut. To investigate genes that are involved in the response to drought stress in peanut, a survey of genes responsive to drought stress was done by cDNA macroarray analysis, and about 277 unigenes were selected, including genes related among others to stress response and transcription factors. Totally, it was found that about 21 clones could respond to dehydration. The expression patterns of these 21 candidate drought-responsive genes and another 30 selected non-responsive genes were further analyzed by real-time PCR, and then we found another responsive gene P3617. Among these genes, 18 genes were up-regulated, and 4 genes were down-regulated by drought. The functional classification indicated that these genes belonged to gene families encoding stress-responsive proteins, transcription factors, auxin-responsive protein, Na+/H+ transporter SOS1, and chloroplast photosynthetic oxygen-evolving protein subunit of peanut. Collectively, the data presented in this study will facilitate the understanding of molecular mechanism of the peanut response to drought stress and also provide the potential strategies for effective genetic engineering to improve peanut stress tolerance.