Phytochrome A （phyA） is a key receptor that enables plants to perceive far-red light signals and regulates their growth， development， and stress responses. To investigate the function of the MsphyA gene and its molecular mechanism in response to abiotic stress in alfalfa （Medicago sativa L.）， this study conducted a bioinformatic analysis of the cloned MsphyA gene and detected its expression patterns under various abiotic stresses using qRT-PCR. Bioinformatic analysis revealed that the MsphyA gene has a CDS length of 3375 bp， encoding 1124 amino acids， and possesses typical PAS， GAF， and PHY motifs characteristic of the PHY family. Protein analysis indicated that MsphyA has a relative molecular mass of 124.3 kDa and a theoretical isoelectric point of 6.1. It is classified as an unstable， hydrophilic， non-secretory protein without a signal peptide and lacks transmembrane domains. Subcellular localization prediction suggested that MsphyA is localized to the nucleus. Phylogenetic analysis showed that MsphyA is most closely related to MtphyA from M. truncatula. qRT-PCR results demonstrated that salt， drought， acid， high-temperature， and low-temperature stresses all induced MsphyA expression. These findings indicate that MsphyA is widely involved in the abiotic stress responses in alfalfa. This study provides a foundation for further exploration of the MsphyA gene’s function.

Alfalfa  /  phyA  /  Bioinformatics analysis  /  Abiotic stress