Genome-Wide Analysis of FK506-Binding Protein Genes in Populus trichocarpa

FK506-binding proteins (FKBPs) are characterized by peptidyl–prolyl cis/trans isomerization activity that may confer analogous functions to molecular chaperones in various organisms. In this study, genome-wide analysis of FKBP genes in Populus trichocarpa was performed. A total of 31 genes were identified to encode FK506-binding proteins in P. trichocarpa. These genes were distributed on 11 chromosomes. The subcelluar locations and evolutionary relationships of FKBPs in P. trichocarpa and other plants were analyzed, and the functions of the FKBPs isoforms were determined bioinformatically. A phylogenetic tree was generated from alignments of PtFKBP protein sequences, while phylogenetic relationships were also examined between PtFKBPs and FKBP in Arabidopsis thaliana and Oryza sativa. Duplication played a significant role in poplar FKBP gene family evolution and expansion. The expression patterns of chloroplastic FKBP genes in response to different periods of illumination were measured, indicating that many FKBP genes are regulated by light. Meanwhile, several PtFKBPs were differentially regulated at the transcriptional level under cold and heat stress. This study provides new information that should permit further studies to characterize the functions of FKBPs in P. trichocarpa and other plants.