Genome-wide analysis of HSF family transcription factors and their responses to heat stress in Rosa chinensis

Heat shock factors (HSFs) play a central regulatory role in acquired thermotolerance. To understand the role of the major molecular players in heat stress response in rose, the HSF family was comprehensively analyzed in Rosa chinensis. A total of 18 HSF family genes were identified according to bioinformatic and phylogenetic analyses based on the genome sequence of Rosa chinensis. All these HSFs were classified into A, B, and C classes. The chromosomal locations of these HSFs were also presented. Comparative transcriptome analysis revealed that 10 members of RcHSFs were upregulated under high temperature stress treatments, and only one RcHSF gene was downregulated. Among these upregulated RcHSF genes, five belonged to A class and five belonged to B class. The transcriptional levels of the A1 and A2 subclass genes were extraordinarily high. The only one downregulated RcHSF gene belonged to A4 subclass. The data obtained from this investigation contribute to a better understanding of the complexity of the HSF gene family in rose, and serve as a foundation for further studies to dissect HSF function in response to heat stress.