Genome-wide characterization of tea plant (Camellia sinensis) Hsf transcription factor family and role ofCsHsfA2in heat tolerance

Abstract

Background Heat stress factors (Hsfs) play vital roles in signal transduction pathways operating in responses to environmental stresses. However,Hsfgene family has not been thoroughly explored in tea plant (Camellia sinensisL.). Results In this study, we identified 25CsHsfgenes inC. sinensisthat were separated by phylogenetic analysis into three sub-families (i.e., A, B, and C). Gene structures, conserved domains and motifs analyses indicated that the CsHsf members in each class were relatively conserved. Variouscis-acting elements involved in plant growth regulation, hormone responses, stress responses, and light responses were located in the promoter regions ofCsHsfs. Furthermore, degradome sequencing analysis revealed that 7CsHsfscould be targeted by 9 miRNAs. The expression pattern of eachCsHsfgene was significantly different in eight tissues. ManyCsHsfswere differentially regulated by drought, salt, and heat stresses, as well as exogenous abscisic acid (ABA) and Ca2+. In addition, CsHsfA2 was located in the nucleus. Heterologous expression ofCsHsfA2improved thermotolerance in transgenic yeast, suggesting its potential role in the regulation of heat stress response. Conclusions A comprehensive genome-wide analysis of Hsf inC. sinensispresent the global identification and functional prediction ofCsHsfs. Most of them were implicated in a complex gene regulatory network controlling various abiotic stress responses and signal transduction pathways in tea plants. Additionally, heterologous expression ofCsHsfA2increased thermotolerance of transgenic yeast. These findings provide new insights into the functional divergence ofCsHsfsand a basis for further research on CsHsfs functions.