Genome-Wide Analysis of the Trihelix Gene Family and Their Response to Cold Stress in Dendrobium officinale

Trihelix transcription factors play important roles in plant growth, development and various stress responses. In this study, we identified 32 trihelix family genes (DoGT) in the important Chinese medicinal plant Dendrobium officinale. These trihelix genes could be classified into five different subgroups. The gene structure and conserved functional domain of these trihelix genes were similar in the same subfamily but diverged between different subfamilies. Various stresses responsive cis-elements presented in the promoters of DoGT genes, suggesting that the trihelix genes might respond to the environmental stresses. Expressional changes of DoGT genes in three tissues and under cold treatment suggested that trihelix genes were involved in diverse functions during D. officinale development and cold tolerance. This study provides novel insights into the phylogenetic relationships and functions of the D. officinale trihelix genes, which will aid future functional studies investigating the divergent roles of trihelix genes belonging to other species.