WRKY-type transcription factors are involved in multiple aspects of plant growth, development and stress responses. SlWRKY, a cDNA clone encoding a polypeptide of 552 amino acids and exhibiting the structural features of group I of WRKY protein family, was isolated from tomato (Solanum lycopersicum L. cv Zhongshu No. 4) using the homologous cloning method. Semi-quantitative RT-PCR analysis indicated that SlWRKY was up-regulated by salt and drought treatment in tomato seedlings. To investigate the biological roles of SlWRKY, we generated transgenic tobaccos overexpressing the SlWRKY and analyzed their responses to salt and drought stresses. Transgenic tobacco plants exhibited more vigorous growth than wild-type plants and display high tolerance to salt and drought stresses. In order to minimize oxidative damage, the activities of antioxidant enzymes were increased but EC and the MDA content were decreased in the transgenic tobacco leaves. Furthermore, it was observed that the SlWRKY proteins regulate the downstream genes and increased the expression of defense-related PR1 and PR2 genes. These results demonstrate that, SlWRKY plays an important role in responding to abiotic stress.
Amino Acid Sequence Droughts