Genome-wide identification and expression pattern analysis of the CPP transcription factor family in Medicago sativa...

The Cysteine-rich Polycomb-like Protein (CPP) gene family is a small transcription factor family commonly found in animals and plants. It plays a crucial regulatory role in their reproductive development. To date, this gene family has been characterized in various species, such as Arabidopsis thaliana, Medicago truncatula, Oryza sativa, and Glycine max. However, no research has been done on the CPP gene family in Medicago sativa L.

This study used bioinformatics to identify 31 CPP gene family members in Medicago sativa L., spread across 20 of its 32 chromosomes and named MsCPP1-MsCPP31 in chromosomal order. Phylogenetic analysis classified the 31 MsCPP proteins into five subgroups (Group I-V), each with similar conserved motifs and gene structures. Promoter cis-acting element analysis found that over two-thirds of these genes have MBS (drought-inducibility) responsive elements, indicating the MsCPP gene family may mainly respond to drought stress. Transcriptomic data analysis showed two genes have tissue-specific expression and six are expressed in all tested tissues. Moreover, transcriptomic profiling revealed that 18, 18, and 21 family members respond to drought, cold, and salt stresses, respectively, highlighting the significant role of MsCPP genes in abiotic stress responses. RT-qPCR validation confirmed the transcriptional responses of selected MsCPP genes to drought and salt stress. Our characterization of the MsCPP gene family enhances our understanding of Medicago sativa L.'s molecular mechanisms for environmental adaptation and growth regulation.

This study performed a comprehensive analysis of the CPP gene family in Medicago sativa L., covering gene structures, physicochemical characteristics, cis-acting elements, and expression patterns. The findings demonstrate that the MsCPP gene family is essential for the growth, development, hormone signaling, and stress response of Medicago sativa L.