Identification and Expression Analysis of the Ethylene Response Factor Gene Family in Tea Plant (Camellia sinensis)

Abstract

The ERF gene family is widely present in plants and has crucial regulatory importance in plant seed development, organ morphogenesis, the synthesis of secondary metabolites, and coping with abiotic stresses such as cold and drought. In this study, 90 members of CsERF were screened by bioinformatics tools analysis and named CsERF1–CsERF90. Their molecular characteristics and systematic evolution were studied, and the tissue expression characteristics of CSERF genes and the composition of promoter cis-acting elements were predicted. The results showed that 81 proteins encoded by CsERF genes had conserved motifs 1, 2, and 3, while 64 members possessed other motifs. The theoretical isoelectric point was between 4.49 and 10.24, and 85 members constituted unstable proteins, while the rest were stable proteins. Subcellular localization predicted that 77 members were in the nucleus, 8 were in the chloroplasts, and 5 were in the mitochondria. The promoter sequence of CsERFs was found to include not only cis-acting elements related to hormone regulation, such as gibberellin (41), methyl jasmonate (110), and abscisic acid (185), but also cis-acting elements involved in low-temperature response (56) and light response (22), indicating that CsERFs have a key role in plant growth and abiotic stress. Phylogenetic analysis of tea plant and Arabidopsis thaliana ERF gene families showed that the tea plant ERF gene families could be divided into six groups, with B3 having 29 members at most and B1 having only 3 members at least. The phylogenetic tree constructed using only the CsERF genes is also divided into six groups, with slightly different but minimal differences in members. Of the 90 tea plant ERF members, 85 were located on 15 chromosomes, whereas 5 were not located on chromosomes. The collinearity analysis showed that there were 41 homologous gene pairs among the CsERFs, and these homologous gene pairs may have the same function. According to the expression of CsERFs in cold-stressed tea plant and in different tissues, 90 CsERF genes played their respective roles in different tissues and stages to regulate plant growth, and some of them participated in the process of cold stress tolerance. This study provides a theoretical foundation for the study of tea plant growth and development and low-temperature resistance.