Constitutive expression of the pea ABA-responsive 17 (ABR17) cDNA confers multiple stress tolerance in Arabidopsis thaliana.

The constitutive expression of the pea ABR17 (abscisic acid-responsive 17) cDNA, which is a member of the group 10 family of pathogenesis-related proteins (PR 10), in Arabidopsis thaliana is reported. The presence of ABR17 transcripts and the protein in the three transgenic lines is demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) and two-dimensional electrophoresis followed by tandem mass spectrometry, respectively. Three independently derived transgenic lines containing ABR17 germinated better in the presence of salt, cold temperature or both. Furthermore, the transgenic plants also exhibited enhanced tolerance to freezing temperature, suggesting the potential utility of the ABR17 gene to engineer multiple stress tolerance. In order to obtain insights into the mechanism underlying ABR17-mediated stress tolerance, we have compared the proteome of a transgenic line with that of its wild-type counterpart. Several proteins were observed to be significantly altered in the transgenic line, including some with a role(s) in photosynthesis, stress tolerance and the regulation of gene expression. Our findings are discussed within the context of available genes to engineer multiple stress tolerance as well as the biological activities of the ABR17 protein.