Genome-wide Identification of HSF Gene Family and Their Response to Hot Ambient Temperature During Flower Development in Passion Fruit(Passiflora edulis)
Heat shock transcription factor(HSF)is an important regulatory factor that plays a crucial role in plant re-sponse to hot ambient temperature(HAT).High temperature stress has a serious negative impact on the flowering of passion fruit,therefore,studying the regulation of heat tolerance by HSF in passion fruit is of great significance.In this study,we identified 26 HSF genes on the genome of passion fruit using bioinformatics technology,named PeHSF1-PeHSF26.The genes could encode proteins of 100-1589 amino acids,with molecular weight 11 544.9-177 157.8 g/mol,and a theoretical isoelectric point of 4.25-10.80.The 26 genes were distributed on chromosomes 1,4,5,6,7,8 and 9,and were divided into 10 subpopulations.The analysis of the whole genome replication event showed that ZX01G0033270,ZX01G0052790 and ZX01G0052980 were located within the genome duplications.The genes contained 1-12 introns and 2-13 exons,all contained HSF-DNA binding domains.RNA-seq analysis of Huangguo original species and Jinlingziguo HSF genes to HAT revealed that there were significant differences in the expression levels of genes,including ZX01G0002530,ZX01G0052790 and ZX01G0121040 in flower buds.The expression levels of candidate HSF genes were validated by RT-qPCR.Based on comprehensive analysis,it is supposed that the most ideal candidate HSF gene for passion flower response to high temperature stress was ZX01G0121040.The results would contribute to under-stand the function of HSF in response to high temperature stress during the flowering of passion fruit,and provide im-portant genetic resources and theoretical basis for genetic improvement of passion fruit.