Comprehensive Genomic Analysis and Expression Profile of Hsp70 Gene Family Related to Abiotic and Biotic Stress in Cucumber

Abstract

Heat shock protein 70 (Hsp70) is a class of HSPs involved in plant growth and development, stress response and regulation. The Hsp70 proteins exist widely in the plant world, but the detail information about Hsp70s is still unclear in cucumber. Based on the available cucumber genome, a total of 12 Hsp70 genes (CsHsp70-1 to CsHsp70-12) were identified in this study, and they were distributed among five out of seven chromosomes. The CsHsp70s were divided into four groups based on a phylogenetic analysis by using protein sequences from cucumber and other plants, and their conserved motifs were relatively conserved. Gene duplication analysis showed that segmental duplication is the main driving force of expansion in cucumber CsHsp70 genes. Promoter analysis of CsHsp70 genes showed that they contained many cis-acting elements involved in hormone and stress responses. Expression analysis by RNA-seq and qRT-PCR indicated that the expression of most CsHsp70 genes was associated with multiple biotic and abiotic stresses in cucumber. This study introduces the characteristics of cucumber CsHsp70 genes and the regulation of their expression levels in various abiotic and biotic stresses, which provided a basis for functional exploration and utilization of CsHsp70 genes in the future.