香蕉果实MaGBSSI基因家族的克隆及表达分析

Cloning and Expression Analysis of MaGBSSI Gene Family Members of Banana Fruit

以＂巴西＂蕉（Musa acuminata L.AAA group cv.Brazilian）为试材,利用同源克隆法获得4个颗粒结合淀粉合成酶I（Granule-Bound Starch Synthase I,GBSSI）基因家族成员的cDNA全长,运用MEGA 5.05软件进行聚类分析,并通过quantitative real-time PCR（qPCR）技术检测MaGBSSI基因家族成员在香蕉果实不同发育时期及成熟阶段和不同组织中的表达情况。结果表明：香蕉4个MaGBSSI基因家族成员MaGBSSI-1、MaGBSSI-2、MaGBSSI-3、MaGBSSI-4的cDNA全长分别为1 851、1 851、675、1 845bp,登录号分别为KF512020、KF512021、KF512022、KF512023。聚类分析发现,香蕉MaGBSSI基因家族与其它植物GBSSI基因同源性达65%。qPCR分析发现,MaGBSSI-1、MaGBSSI-2、MaGBSSI-4在香蕉根、球茎、叶片和苞片等营养器官中明显上调表达,而MaGBSSI-3在花、果皮、果肉等生殖器官中表达量比较高,在根、球茎及叶片中几乎不表达。香蕉果实发育过程中,MaGBSSI-1、MaGBSSI-2、MaGBSSI-4在0~30d明显上调表达,而MaGBSSI-3在香蕉果实发育30~60d表达量比较高,在0~30d几乎不表达,且随着果实的成熟,MaGBSSI-3表达量逐渐下降。研究结果为阐明香蕉果实的直链淀粉生物合成及降解机制并对其进行表达调控奠定了基础。

Taking Musa acuminata L. A.AA group cv. Brazilian as material,PCR amplification method of homologous gene was used to clone the cDNA full length of Granule-Bound Starch Synthase I （GBSSI） gene family in banana. Then,the cluster analysis of the gene family was performed by MEGA 5. 05 software and its expression patterns in different tissues and different developmentals and harvest periods were tested by quantitative real-time PCR （qPCR）. The results showed that the cDNA full length of four MaGBSSI gene family members, i. e. MaGBSSI-1, MaGBSSI-2, MaGBSSI-3 and MaGBSSI-4 were 1 851 bp,1 851 bp,675 bp and 1 845 bp,respectively. The accession number of MaGBSSbl,MaGBSSI-2, MaGBSSI-3 and MaGBSSI-4 were KF512020,KF512021 ,KF512022 and KF512023 ,respectively. Cluster analysis showed that the MaGBSSI gene family from banana shared 65 ~ amino acid sequence identifies with GBSSI gene from other plant. Tissue-specific expression of the MaGBSSI gene family members were detected using qPCR. MaGBSSI-1, MaGBSSI-2,and MaGBSSI-4 were up-regulated in vegetative tissue such as root, stem, leaf, and bract. In contrast, MaGBSSI-3 was highly expressed in reproductive tissues such as flower, peel, and pulp, but was weakly expressed in root, stem, and leaf. Expression levels of MaGBSSI- 1, MaGBSSI-2, MaGBSSI-4, MaGBSSII- 1, and MaGBSSII-2 at earlier stages of banana development （from 0 d to 30 d） were higher than the later stages （from 30 d to 60 d）. In contrast,MaGBSSI-3 was weakly expressed at the early stages but was highly up-regulated at 50 d of development ,while the expression level of MaGBSSI-3 was gradually decreased with the ripening of banana fruit. The results had laid the foundation to illustrate the amylose biosynthesis and degradation mechanism and regulate the expression of MaGBSSI gene family members of banana fruit.