Sequence characteristics of Medicago truncatula cyclophilin family members and function analysis of MsCYP20-3B involved in axillary shoot development. 
Cyclophilins (CYPs) belonging to the immunophilin family are present in all organisms and widely distributed in various cells associated with the activity of peptidyl-prolyl cis/trans isomerase.  Plant CYPs are members of a multi-gene family and are involved in a series of biological processes.  However, little is known about their structure, evolution, developmental expression and functional analysis in Medicago truncatula.  In this study, a total of 33 CYP genes were identified and found to be unevenly distributed on eight chromosomes.  Among them, 21 are single-domain and 12 are multi-domain proteins, and most were predicted to be localized in the cytosol, nucleus or chloroplast.  Phylogenetic and gene structure analysis revealed seven segmental gene pairs, indicating that segmental duplication probably made a large contribution to the expansion of MtCYP gene family.  Furthermore, gene expression analysis revealed that about 10 MtCYP genes (were) highly expressed involved in vegetative and reproduction tissues in M. truncatula, and MsCYP20-3B was mainly upregulated in stems, leaves and flower buds in alfalfa (Medicago sativa).  Overexpression of MsCYP20-3B was shown to regulate axillary shoot development associated with higher jasmonic acid and abscisic acid contents in M. truncatula.  Our study suggests the importance of the CYP genes family in development, reproduction and stress responses, and provides a reference for future studies and application of CYP genes for alfalfa genetic improvement.