Transcription factor OsAP21 gene increases salt/drought tolerance in transgenic Arabidopsis thaliana.

Transcription factors play vital roles in stress signal transduction and gene expression modulation during plant growth and development. Sequence analysis showed that OsAP21 contained an AP2/ERF domain of 57 amino acids. By comparison of deduced amino acid sequences of AP2/ERF-related proteins, we deduced that OsAP21 is a transcription factor gene, which belonging to rice AP2/ERF family CBF/DREB subfamily. Further, we report that transgenic Arabidopsis thaliana plants expressing the OsAP21 gene exhibited stronger growth than wild type plants under salt/drought stress. Analysis of RT-PCR for RD29B gene implied that OsAP21 over-expressed plants had a higher expression level of RD29B gene than wild type plants, and drought and salt treatments could enlarge these differences. Collectively, our results indicate that OsAP21 may play an important role in the response of transgenic Arabidopsis plants to salt/drought stresses.