Genome-wide identification and expression profiling of the YUCCA gene family in Brassica napus

Auxin is essential for plant growth and development, also closely related to plant architecture. YUCCA (YUC) proteins catalyse the rate-limiting step for endogenous auxin biosynthesis. In this study, we identified 57 BnYUC genes in Brassica napus (rapeseed) genome, located on 17 chromosomes. Among them, A09 chromosome contained the most BnYUCs as 6. Phylogenetic tree showed that all BnYUC members were divided into 2 evolutionary clusters, including 7 sub-groups. Among the sub-groups, CladeⅠ-C consisted 20 members, evolved independently from Arabidopsis thaliana, and motif 10 was unique. Genomic collinearity analysis showed that YUC collinear gene pairs widely existed in Brassica species, indicating that this family has a high retention rate in the evolution. Expression profile suggested that the BnYUC family genes tended to express in specific growth/development stages as well as suffering stress/hormone treatments. It suggested that dominant expression of specific members existed with each development stage or treatment, indicating that each BnYUC might have a clear division of work, and play a given biological function. This work was expected to build a basis for further study of the involvement of BnYUC in growth, development and stress response.