Characterization and analysis of some chilling-response WRKY transcription factors in tomato

Abstract WRKY transcription factors play various important roles in biotic and abiotic stress. In present study, a total of 81 WRKYs in tomato (Solanum lycopersicum) was identified and their gene structure, phylogeny and sub-location were analyzed. Here, we further analyzed their expression and potential roles under chilling stress. Nevertheless, the predicted chloroplast-located WRKYs are failed to be detected in the chloroplast. Then, 27 SlWRKYs with high chilling-induced mRNA levels (more than 3 fold to the control) are selected from these WRKYs. Promoter analysis showed that some cold stress-related cis-acting elements (CBFs binding site) existed in many promoter regions of these chilling response WRKYs (WRKY2, WRKY50, WRKY59 etc.), implying that these WRKY transcription factors may participate in CBFs mediated pathway under chilling stress. The interaction proteins of WRKYs are essential to affect the DNA binding and transcription regulatory activities of WRKYs, thus controlling its downstream genes expression. Therefore, we predicted and analyzed the protein-protein interactions of those chilling related WRKY transcription factors and then speculated the complex regulatory and functional network of WRKY transcription factors under chilling stress. A better understanding of SlWRKYs would be helpful for providing a theoretical basis for further illustrating the regulatory mechanism of SlWRKYs under chilling stress.