毛荚苜蓿DIR基因家族成员的鉴定及表达模式分析OA

[Objective]The study aimed to identify the members of the DIR gene family in Medicago edgeworthii,examine the expression pro-files of MeDIR genes in response to diverse abiotic stresses,and lay the foundation for elucidating the biological functions of the MeDIR gene family members.[Method]The MeDIR gene family members were identified through bioinformatics analysis,and a phylogenetic tree was con-structed with their counterparts from Arabidopsis thaliana and M.truncatula.The online tool ExPASy was used to predict the physicochemical properties of the MeDIR family proteins,characterize the chromosomal distribution,gene architecture,and promoter cis-elements of the gene family members,and additionally predict the three-dimensional protein structures of the DIR-a subfamily members in M.edgeworthii.[Re-sult]32 DIR gene family members were identified in the M.edgeworthii genome,designated as MeDIR1 to MeDIR32.They were unevenly dis-tributed across six chromosomes,with some members containing introns and untranslated regions.Based on phylogenetic analysis,they were classified into five subfamilies(DIR-a,DIR-b,DIR-c,DIR-d and DIR-e).84％of the MeDIR proteins exhibited high stability,and 44％were hydrophobic.Subcellular localization predictions indicated that 11 MeDIR proteins were localized in the chloroplast,4 proteins in the en-doplasmic reticulum,and 8 proteins in the extracellular space and cytoplasm,while the remaining were localized in the vacuolar membrane,peroxisomes,cytoskeleton,and nucleus.The diversity of protein localization suggested that MeDIR proteins might perform a variety of biologi-cal functions.Cis-acting element analysis revealed that the promoter regions of MeDIR genes contained multiple elements related to growth and development,plant hormones,and stress responses.Quantitative real-time PCR revealed that the expression of MeDIR genes was differentially regulated under drought,low-temperature,and ABA stress conditions,indicating that the MeDIR gene family might be involved in the adaptive regulation of M.edgeworthii to abiotic stresses.[Conclusion]The MeDIR gene family exhibited a large number of members and wide distribu-tion,with significant differences in promoter cis-acting elements.Some MeDIR genes were induced by low temperature,drought,and ABA treatment,actively responding to abiotic stresses.