Objective Group Ⅲ WRKY genes play an important regulatory role in plant response to abiotic stress. The research was performed to analyze the expression profiles of their family members in response to drought stress so as to provide references for the study of biological function of such genes.

Method Downloading the microarray data from NCBI database, the expression profiles of group Ⅲ WRKY genes in response to drought, heat and combined stress were analyzed. Seedlings of sorghum variety BTx623 were treated with 20% PEG6000 under simulated drought stress, the expression profiles of these genes were detected by qRT-PCR techniques.

Result Microarray analysis shows that SbWRKY14 and SbWRKY32 are down-regulated under drought, heat and combined stress. SbWRKY39 is down-regulated under drought and heat stress, but up-regulated under combined stress. SbWRKY41 is up-regulated under three stress treatments. qRT-PCR analysis shows that SbWRKY10 is down-regulated at 3 and 6 h, but up-regulated at 12 h. SbWRKY14 is down-regulated at 1, 6 and 12 h. SbWRKY16, SbWRKY38, SbWRKY41 and SbWRKY42 are down-regulated at 1, 3, 6 and 12 h. SbWRKY17is down-regulated at 1, 6 and 12 h. SbWRKY39 and SbWRKY89 are down-regulated at 1, 3 and 12 h. SbWRKY53 is downregulated at 1 and 12 h while up-regulated at 6 h. The expression of SbWRKY75 is down-regulated at 1 h and up-regulated at 3, 6 and 12 h. SbWRKY93 is up-regulated at 6 h.

Conclusion These results indicate that the group Ⅲ WRKY genes of sorghum may play an important role in response to drought stress, and different SbWRKY genes may play different regulatory roles under drought stress.