Identification and Expression Analysis under Low Temperature Stress of COBRA Gene Family in Brassica rapa L.

PurposesTo identify the members of COBRA gene family in Chinese cabbage (Brassica rapa L.), and the gene expression under low temperature will be analyzed to predict the gene function.

MethodsThe COBRA gene family of B. rapa was identified by bioinformatics method, and the gene structure, phylogenetic evolution, promoter elements and expression pattern were analyzed.

ResultsThe COBRA gene family contained 23 members in B. rapa, named BrCOBL1-BrCOBL23, which were divided into two subfamilies according to the characteristics of gene sequence, and distributed on eight chromosomes. A total of 147 COBRA genes were identified from B. rapa, Arabidopsis thaliana, B. napus, B. oleracea, and B. juncea, which all belonged to Brassicaceae. Phylogenetic tree analysis showed that the members of COBRA gene family were divided into eight subgroups. The expression analysis of genes showed that: the expression levels of BrCOBL1, BrCOBL2, BrCOBL15 and BrCOBL16 were significantly increased under low temperature stress.

ConclusionCOBRA protein sequences contain common conserved motifs, and some motifs exist specifically in different subfamilies, indicating that these motifs may be related to the functional differentiation of each subfamily. According to the promoter analysis results, it is speculated that BrCOBL is involved in the regulation of abiotic stress response and hormone response in B. rapa.