Genome-wide identification of the DNA-binding one zinc finger (Dof) transcription factor gene family and their potential functioning in nitrogen remobilization in tea plant (Camellia sinensis L.)

The DNA-binding one zinc finger (Dof) proteins are a type of transcription factor (TF) specific to plants that are involved in various aspects of their biological processes. Although the Dof TF has been identified in a variety of species, its systemic analysis in tea (Camellia sinensis L.) is lacking and its potential role in this plant's nitrogen remobilization remains unclear. Here, we carried out a genome-wide identification of Dofs in tea and identified 41 CsDofs at the chromosome level. Their genetic structure, conserved motif, and synteny relations were analyzed and visualized, using information extracted from a newly available genome database. Phylogenetic analysis of Dofs from seven different plant species revealed that Dof members could be clustered into six groups. Heatmap analysis showed that CsDofs have similar expression patterns among different species of genus Camellia, and tissue-specific transcription patterns among tea tissues. Expression patterns of CsDofs in mature leaves during the development of new shoots revealed that most of CsDofs peaked on March 24 when the new shoots developed into one bud and two leaves. Furthermore, the expression pattern of CsDof13/16/29/33/34/35/36/39 was significantly correlated with that of genes involved in N metabolism, such as GDH or GS, indicating these CsDofs might play roles in regulating the expression of genes participating in N metabolism of tea. Taken together, this study provides information on the genome-wide identification of the CsDofs' family in tea, and identifies putative candidates possible involved in N remobilization in mature leaves during the development of new shoots in spring.