Cloning of Six ERF Family Transcription Factor Genes from Peanut and Analysis of their Expression during Abiotic Stress

Several ethylene-responsive element binding factor (ERF) family proteins have been demonstrated to play important roles in transcriptional regulation of a variety of biological processes, including responses to environmental conditions such as drought, salt, and cold. To date, there have been no reports on this family in peanut. In this study, 40 ESTs in a peanut cDNA library, whose amino acid sequences contained AP2/ ERF domain, have been identified. Of these, full-length sequences of six genes were cloned. Sequence analysis indicated that all six proteins contained only one AP2/ ERF domain and should belong to the ERF family. The six genes were designated Arachis hypogaea ERF 1–6 (AhERF1–6). The expression patterns of AhERF1–6 were analyzed under cold, salt and drought stress. The results indicated that the expression of AhERF4 and AhERF6 were rapidly and substantially enhanced under abiotic stress. The expression of AhERF1 and AhEERF5 were slightly enhanced under certain stress conditions. Some genes were down-regulated when under stress, such as AhEERF3 in leaves under salt stress and AhERF2 in leaves under drought stress. Interestingly, the expression of AhERF3 and AhERF5 exhibited contrary expression patterns in peanut leaves and roots upon PEG treatment. These results suggested that different ERF proteins may have different functions in peanut abiotic stress acclimation.