Functional Differentiation of the Duplicated Gene in Turnip ( var. ).

Gene duplication is a key biological process in the evolutionary history of plants and an important driving force for the diversification of genomic and genetic systems. Interactions between the calcium sensor calcineurin B-like protein (CBL) and its target, CBL-interacting protein kinase (CIPK), play important roles in the plant's response to various environmental stresses. As a food crop with important economic and research value, turnip ( var. ) has been well adapted to the environment of the Tibetan Plateau and become a traditional crop in the region. The gene in turnip has not been characterized. In this study, two duplicated genes, and ., were screened from the turnip genome. Based on the phylogenetic analysis, and . were found located in different sub-branches on the phylogenetic tree. Real-time fluorescence quantitative PCR analyses revealed their differential expression levels between the leaves and roots and in response to various stress treatments. The differences in their interactions with BrrCBLs were also revealed by yeast two-hybrid analyses. The results indicate that and . have undergone Asparagine-alanine-phenylalanine (NAF) site divergence during turnip evolution, which has resulted in functional differences between them. Furthermore, responded to high-pH (pH 8.5) stress, while retained its ancestral function (low K), thus providing further evidence of their functional divergence. These functional divergence genes facilitate turnip's good adaptation to the extreme environment of the Tibetan Plateau. In summary, the results of this study reveal the characteristics of the duplicated genes and provide a basis for further functional studies of in turnip.