Abstract: The AT2G14260 gene encodes proline iminopeptidase in Arabidopsis thaliana. Genechip expression profile indicate AT2G14260 responses to abiotic stress, such as high salt or cold. To analyze the function and expression specificity, we compared the wild type with mutants pip-1 under cold, drought and salt stresses. Under normal conditions, mutant plants showed similar growth performance with wild type plants. However, after stress treatments, mutant plants exhibited much shorter roots compared with wild type plants. In addition, the leaves of mutant plants were notably more yellow than wild-type leaves under drought stress. The average relative proline contents in wild type plants were 1.11, 1.23, 1.10, and 1.34 times of those in mutants. All these results showed that AT2G14260 gene plays an important role in plant tolerance to abiotic stress. Meanwhile, we isolated the gene promoter and constructed plant vector in which the GUS gene was expressed by AT2G14260 promoter, and then transformated into Arabidopsis thaliana. The results of the GUS staining revealed that the GUS gene did not express under normal conditions. After treatments, GUS gene expressed in the roots, stems and leaves of the transgenic seedlings at the two-leaf stage and the blooming stage, especially in the petals and flowers under drought stress or in the stigma under cold stress. Results of GUS relative activity measurement suggested this gene had the response ability to stress. Taken together, the promoter of AT2G14260 is stress inducible and tissue specific. Thus, AT2G14260 gene and its promoter have application potentials in genetic engineering.

Key words: AT2G14260, Stress-inducible promoter, Tissue-specific expression