Genome-wide analysis of HSF family transcription factors and their responses to abiotic stresses in two Chinese cabbage varieties

HSF family transcription factors were analyzed in genome of Chinese cabbage. Chromosomal locations showed that duplication might result in expansion. Response to abiotic stresses was elucidated in Chinese cabbage varieties. The major heat shock factors regulating the heat stress response are heat shock transcription factors (HSFs), which interact with heat shock elements. In this study, Chinese cabbage (Brassica rapa L. ssp. pekinensis) HSFs were comprehensively analyzed. A total of 52 HSF family genes were identified for phylogenetic relationships and motif analysis based on the genome sequence of Chinese cabbage. All HSFs were divided into classes A, B, and C. The chromosomal locations and gene duplications of these HSFs were also presented. Nine potential duplication events were found in Chinese cabbage chromosomes. Expression of three HSF genes in two varieties of Chinese cabbage using quantitative real-time PCR revealed that BraHSF039 and BraHSF043 were up-regulated under temperature and salt stresses treatments, and only BraHSF043 gene was also down-regulated under salt stress in 'Lubaisanhao'. BraHSF001 gene was down-regulated in the 'Lubaisanhao' variety under heat and cold stresses, under drought stress in 'Qingdao 87-114'. These results can serve as a foundation for further studies on HSFs in Brassica.