Comparative transcriptome analysis of transcription factors in different maize varieties under salt stress conditions

Salt stress is a major environmental factor affecting plant growth and crop production worldwide, and the transcription factors (TFs) play crucial roles in plant response to salt stress. Identifying genes related to salt-tolerance contributes to salt-tolerant crop breeding. A comparative transcriptome analysis was carried out to investigate global gene expression of the entire TFs in two maize varieties with different salt-tolerant ability. Fifty-five TF families including 1283 TF genes were identified. Among them, 314 TF genes were differentially expressed in the two maize varieties under salt stress. 177 TF genes were detected with significantly higher expression levels in salt-tolerance variety compared with the salt-sensitive one. The differential expression of a set of TF families clearly demonstrated their important roles in salt tolerance. Further phylogenetic analysis and gene expression analysis of heat shock factors (HSFs) revealed that majority of these TFs were induced by salt stress, but different classes/subclasses had different response to salt stress. HSF class-B genes were detected with significantly higher expression levels in salt-tolerance variety compared with the salt-sensitive one under salt stress, which may result in different plants salt-tolerance ability. These results contribute to a better understanding of the complex mechanism of TFs in response to salt stress in maize and provide new sight for further research to perform systematic analysis of the TF families and to reveal their potential functions in the salt-tolerance for plants.