Genome-wide Identification and Classification of HSF Family in Grape, and Their Transcriptional Analysis under Heat Acclimation and Heat Stress

Heat stress is one of the most serious threats in viticulture. Heat shock transcription factors (HSFs) have been proven to be the most important transcriptional factor family in the plant response to heat. In this study, a total of 19 putative HSF genes (VHSFs) were identified from the 12 x Vitis vinifera Pinot Noir PN4002 genome, and their chromosomal location, phylogenetic tree, exon-intron structure and conserved motifs were also analyzed. In addition, these HSFs transcriptional profiles in Vitis vinifera 'Jingxiu' (weak heat tolerance) and Vitis davidii 'Tangwei' (strong heat tolerance) under heat stress (47 degrees C) and heat acclimation (38 degrees C) were presented. Only VHSF01, VHSF05, VHSF15 and VHSF18 among 19 VHSFs showed different transcriptional models in these two genotypes under the same treatment, suggesting that these four VHSFs may be important factors which result in a thermotolerance difference between lingxiu' and `Tangwei'. This study provides novel insights into the response of 19 VHSFs to heat stress in the grape and suggests that potential key VHSFs in grape thermotolerance have great implications for molecular breeding in grapes.