关键词: atpA, 紫花苜蓿, 基因克隆, 生物信息学分析, 基因表达

Abstract: The chloroplast atpA gene is a key indispensable gene for photosynthesis,which encodes ATP synthase α subunit and is located on chloroplast ATP synthase CF₁. atpA gene was cloned from Medicago sativa L. ‘Xinjiang Daye’ by RT-PCR,and bioinformatics analysis was carried out in our research. Then,expression pattern of this gene was detected by quantitative Real-time PCR. The results showed that MsatpA gene encoded 510 amino acids with the relative molecular weight of 55.71 KD and the isoelectric point of 5.22. MsatpA protein contained multiple phosphorylation without transmembrane structure and signal peptide. In the secondary structure of the protein,the α helix accounted for the highest proportion. The subcellular localization prediction showed that the protein encoded by the gene was located in chloroplast,and its amino acid sequence had high homology with Medicago falcata and Medicago truncatula which all belonged to Leguminosae Medicago genus. The results of gene expression pattern showed that the relative expression level of MsatpA gene was the highest in leaves and the lowest in roots,and the gene expression level in pod setting stage was significantly higher than that in other development stages. MsatpA gene responded to low temperature,high temperature,salt and osmotic stress,and showed different expression characteristics. The results laid the foundation for the functional study of ATP synthase α subunits in Medicago sativa.

Key words: atpA, Alfalfa, Gene cloning, Bioinformatics analysis, Gene expression