【摘要】 【目的】克隆甜玉米蔗糖合成酶(Sus)基因ZmSus6和ZmSus7,并进行生物信息学分析及组织表达特异性检测,为深入研究其在甜玉米生长发育和品质形成过程中的调控机制提供理论参考。【方法】以甜玉米品种佛甜10号为材料,采用RT-PCR克隆ZmSus6和ZmSus7基因,通过ProtParam、SOPMA、SignalP 4.0 Server等进行生物信息学分析,利用MEGA 6.0构建系统发育进化树,并采用实时荧光定量PCR检测其组织表达特异性。【结果】ZmSus6和ZmSus7基因的开放阅读框(ORF)长度分别为2550和2574 bp,编码849和857个氨基酸残基,对应的蛋白分子量为96.27和97.79kD,理论等电点为7.63和8.19,均无信号肽和跨膜区域,二级结构以α-螺旋为主。ZmSus6蛋白为不稳定的亲水性蛋白,定位于叶绿体或线粒体;ZmSus7蛋白为稳定的亲水性蛋白,定位于细胞质中。ZmSus6和ZmSus7蛋白归属于PLN00142家族(Sus超级家族),具有Sus和糖基转移酶的两个功能域,分别与高粱SbSus6和SbSus7蛋白的氨基酸序列同源性最高,其同源性对应为88.44%和96.62%,归属为单子叶植物III型Sus基因家族。ZmSus6和ZmSus7基因在甜玉米的根、茎、叶、玉米芯和籽粒中均有表达,但存在显著差异(P<0.05),分别以叶和根中的相对表达量最高。【结论】ZmSus6和ZmSus7基因具有一定的组织表达特异性,可能在甜玉米生长发育和品质形成过程中发挥重要作用。更多还原

【Abstract】 【Objective】To lay the foundation for further revealing role of genes ZmSus6 and ZmSus7 in sweet corn growth and quality formation,the sucrose synthase(Sus)genes ZmSus6 and ZmSus7 of sweet corn were cloned,and their bioinformatics and tissue expression specificity were analyzed.【Method】RT-PCR was applied to clone ZmSus6 and ZmSus7 genes from sweet corn variety Fotian No. 10,then their biological information was analyzed by ProtParam,SOPMA,SignalP 4.0 Server,the phylogenetic tree was established using MEGA 6.0,and the tissue expression specificity was detected by real-time fluorescent quantitative PCR.【Results】The open reading frames(ORF)of ZmSus6 and ZmSus7 genes were 2550 and 2574 bp,encoding 849 and 857 amino acids residues,with molecular weights of 96.27 and 97.79 kD,and theoretical isoelectric points(pI)of 7.63 and 8.19,respectively. In addiction,both of protein peptide chains had no signal peptide or obvious transmembrane region,and the secondary structure were mainly α-helix. Stability prediction indicated that SbSus6 was an unstable hydrophilicprotein but ZmSus7 was stable hydrophilic protein. Subcellular localization prediction showed ZmSus6 might locate in the chloroplast or mitochondria,while ZmSus7 in the cytoplasm. Domain analysis suggested both ZmSus6 and ZmSus7 belonged to PLN00142 family(Sus superfamily)including Sus and glycosyltransferase fuctional domains. Moreover,amino acid sequence alignment showed that ZmSus6 had highest homology with SbSus6(88.44%)protein of Sorghum bicolor,while ZmSus7 had the highest homology(96.62%)with SbSus7 of S. bicolor,respectively,and assigned to the monocotyledonous type III Sus gene family. Finally,the ZmSus6 and ZmSus7 genes widely expressed in root,stem,leaf,cob and kernel of sweet corn with significant differences(P<0.05),but the highest expressions of ZmSus6 and ZmSus7 genes were in leaves and root tissues respectively.【Conclusion】The ZmSus6 and ZmSus7 genes have certain tissue specificity expression,and their encoded proteins may play an important role in the growth and quality formation of sweet corn.更多还原