Genome-wide identification and functional analysis of Dof transcription factor family in Camelina sativa

Abstract

Background: Dof transcription factors (TFs) containing C2-C2 zinc finger domains are plant-specific regulatory proteins, playing crucial roles in a variety of biological processes. However, little is known about Dof in Camelina sativa, an important oil crop worldwide, with high stress tolerance. In this study, a genome-wide characterization of Dof proteins is performed to examine their basic structural characteristics, phylogenetics, expression patterns, and functions to identify the regulatory mechanism underlying lipid/oil accumulation and the candidate Dofs mediating stress resistance regulation in C. sativa.Results: Total of 103 CsDof genes were identified from the C. sativa genome, and they were classified into four groups (A, B, C and D). These genes were spread unevenly across 20 chromosomes. All of the CsDof proteins contained the highly-conserved typic CX2C-X21-CX2C structure. Segmental replication was detected to be the main force for expansion of CsDof gene family, and purifying selection happened during CsDof’s evolution. More than half of CsDof genes were expressed in multiple tissues, and a number of them showed tissue-specific expression patterns, suggesting that CsDof genes functioned differentially in different tissues of C. sativa. Remarkably, a set of CsDof members may mediate regulation of oil/lipid biosynthesis in C. sativa. Six CsDof genes exhibited significant expression changes in seedlings under salt stress treatment.Conclusions: This article describes a detailed analysis of the CsDof gene family and its expression profiles in various tissues and under salt stress. Segmental duplication is the key force responsible for the expansion of this gene family, and a strong purifying pressure plays a crucial role in CsDofs’ evolution. Several CsDof TFs may mediate lipid metabolism and stress responses in C. sativa. Collectively, our results provide a foundation for deep understanding the roles of CsDofs and genetic improvements of oil yield and stress resistance in this species and the related crops.