Sun Aiqing

In silico Expression Profile of Genes in Response to Drought in Peanut

Drought, one of the most important abiotic stresses, usually causes adverse effects on the productivity and quality of crops. In this study, a drought-resistant variety Fenghua 5 was used to analyse leaf cDNA library of peanut treated with 15% PEG by Solexa high-throughput technology, and detect the differentially expressed genes under drought stress. The results of Solexa sequencing indicated the gene expression in peanut transcriptome presented strong nonhomogeneity and redundancy. The sequenced tags less than 10 copies accounted for 73.1% of the total tag types, however its expression level only accounted for 9.0% of the total. A total of 935 differentially expressed genes were screened out based on the reference tags, of which 64.5% were down-regulated. These differentially expressed genes were involved in metabolisms of carbohydrate, protein, nucleic acid, lipid and energy, and secondary metabolism. Gene expression analysis of peanut also showed that nine transcripts related to flavonoid metabolism significantly up-regulated under drought stress, including four encoding flavonoid biosynthesis enzymes, three encoding methyltransferase and two encoding MYB transcription factor. The gene expression analysis using semiquantitative RT-PCR assays indicated that AhPAL was induced significantly by 15% PEG treatment for 6 h. The result showed that flavonoid metabolism might play an important role in peanut responding to drought stress.