青香蕉苹果MdAFS基因序列与表达模式分析

The Sequence and Expression Analysis of MdAFS Gene in ‘White Winter Pearmain’ Apple

以青香蕉苹果叶片为材料,研究青香蕉苹果‘White Winter Pearmain’α-法尼烯合酶(α-farnesene synthase,Md AFS)全长基因结构特征及编码蛋白质性质,分析Md AFS基因的诱导表达模式。采用生物信息学软件对Md AFS及其编码蛋白质进行详细分析,应用MEGA 6.0对不同物种来源的AFS构建系统进化树,利用q RT-PCR技术研究Md AFS诱导表达模式。α-法尼烯合酶基因(Gen Bank No:AY563622)全长1 731 bp,由576氨基酸组成,是α螺旋为主要构成元件的混合型蛋白。不同物种的α-法尼烯合酶氨基酸序列相似度低,但α-法尼烯合酶N端RRx8W和C端的H-α1loop具有高度保守性。非生物胁迫和激素信号能诱导Md AFS基因上调表达,且MV、ABA和Me JA诱导该基因上调表达更加明显。α-法尼烯合酶氨基酸序列相似度低,但蛋白三维结构相似;α-法尼烯合酶在蛋白结构和功能上具有单萜合酶特征,初步揭示了非生物胁迫和激素信号能诱导青香蕉苹果α-法尼烯代谢途径的关键酶Md AFS基因上调表达。

This work is to study the full-length gene structural characteristics and encoded protein properties of α-farnesene synthase（Md AFS）from‘White Winter Pearmain＇ apple,and analyze the induced expression patterns of Md AFS gene. Bioinformatics software wasused for analyzing the Md AFS gene and its encoded protein,secondary structure,and tertiary structure,then MEGA6.0 for constructing thephylogenetic trees with AFS from different species,and q RT-PCR for studying the expression pattern of Md AFS gene. The full-length of Md AFSgene（Gen Bank accession number ：AY563622）was 1731 bp,contained the complete ORF,encoding 576 amino acids. The predictionanalysis of secondary structure and tertiary structure showed that the protein was α-helix as the main parts of the mixed type proteins. Thesequence similarity of α-farnesene synthase amino acid in different species was low,but the N-terminal RRx8 W and C-terminal the H-α1loopof α-farnesene synthase was highly conservative. Abiotic stress and hormones induced Md AFS expression up-regulated,and more remarkablyup-regulated expressions were observed in MV,ABA and Me JA treatments. In conclusion,α-farnesene synthase in ‘White Winter Pearmain＇apple has low similarity in amino acid sequence,but similar protein 3D structure. α-farnesene synthase presents monoterpene synthasescharacteristics in the protein structure and function. It is revealed that the abiotic stress and hormonal signal induce the up-regulation expressionof key enzyme Md AFS gene in the α-farnesene metabolic pathway in ‘White Winter Pearmain＇ apple.