Genome-Wide Identification of the BBR-BPC Gene Family in Phoebe bournei

BBR-BPC is a family of transcription factors unique to plants that contain the BPC structure domain and play a crucial regulatory role in controlling plant growth and development,as well as responses to stress.Phoebe bournei is a second-class rare and endangered tree species in China,and its BBR-BPC family has not been the subject of systematic research.This study,based on the whole-genome data of Phoebe bournei,systematically identified this family and analyzed its evolutionary characteristics,promoter elements,and tissue expression patterns.A total of 8 BBR-BPC genes were identified,and phylogenetic analysis divided them into 3 subfamilies distributed across 6 chromosomes.All members contain highly conserved five-cysteine structures and core motifs Motif1,2,4,and no tandem repeat events were detected.Interspecific collinearity analysis showed that this family exhibits a significantly higher degree of collinearity with dicotyledonous plants compared to monocotyledonous plants,suggesting its evolutionary conservatism.Promoter analysis revealed that photoresponse elements account for the highest proportion(23.8%)and are widely present among all members.Tissue expression analysis showed that PbBBR-BPC7 exhibits high specificity in root bark and stem bark,with its promoter region enriched with ABA response elements.These findings indicate that the Phoebe bournei BBR-BPC family exhibits evolutionary conservatism and that members may have potential functional specializations.The study provides a reference for elucidating the biological functions of this family and for molecular breeding of valuable tree species.