摘要： 为了探究杧果PAO基因在杧果果皮叶绿素降解中的作用，利用转录组测序得到PAO部分片段信息设计兼并引物，采取3'和5'cDNA末端快速克隆（RACE）的技术方法，选取了红色贵妃、黄色金煌、绿色桂七等3个不同着色杧果品种为试验材料，分别克隆得到了杧果果皮PAO基因的全长cDNA序列，生物信息学分析后将其命名为MiPAO。结果表明，3个着色品种cDNA序列只有几个碱基的差异，以红色贵妃品种为例，经过分析可得全长cDNA序列的大小为1 979 bp，开放阅读框大小为1 641 bp，总共编码546个氨基酸，其分子质量为61.82 ku，等电点为6.54。通过生物软件预测得到了MiPAO蛋白的二级结构和3种三级结构图，同时发现MiPAO蛋白为亲水性蛋白。对NCBI上登录的部分植物的PAO蛋白构建系统发育树发现MiPAO蛋白与橙子的亲缘关系近。成功构建出pTRV₂-MiPAO基因沉默载体，希望能为后续研究杧果果皮着色的分子机理和桂七杧果的滞绿原因提供一定的试验支持。

关键词: 杧果, MiPAO, 叶绿素降解, 病毒诱导的基因沉默

Abstract: In order to explore the role of mango PAO gene in the degradation of chlorophyll in mango peel,we used PAO partial fragments some from transcriptome sequencing to design primers,3' and 5' rapid-amplification of cDNA ends(RACE) was adopted,three different colored mango varieties,red Guifei,yellow Jinhuang and green Guiqi,were selected as experimental materials,and finally the full-length cDNA sequences of PAO genes in mango pericarp were cloned. It was named MiPAO by bioinformatics analysis. The results showed that only a few bases group differences in the MiPAO genes cDNA sequences of three different colored mango varieties. For example,the full-length cDNA of MiPAO was 1 979 bp length,its open reading frame (ORF) was 1 641 bp,encoding a protein of 546 amino acids,with a predicted molecular weight of 61.82 ku,the isoelectric point of the predicted protein was 6.54 in red Guifei mango. Secondary structure and three kinds of tertiary structure diagram of MiPAO protein were obtained by the prediction of biological software. It was found that the gene encoding for the protein had close relationship with orange by other plants through phylogenetic analysis. It successfully constructed pTRV₂-MiPAO gene silencing vector. In order to support for the color formation and color regulation of mango fruits during ripening. It also provided some experimental support for the reasons for the stay-green of the Guiqi mango.

Key words: Mango, MiPAO, Chlorophyll degradation, Virus-induced gene silencing

中图分类号: 

• Q78

• S667.03