2个14-3-3蛋白基因在香蕉果实成熟过程中的表达分析

Expression Analysis of Two 14-3-3 Genes During Ripening of Banana Fruit

通过简并引物和降落PCR方法结合RACE(rapid amplification of c DNA end)技术在香蕉果实c DNA文库中获得2个14-3-3基因,分别命名为Ma14-3-3d和Ma14-3-3h,把Ma14-3-3d和Ma14-3-3h与Ma14-3-3a、Ma14-3-3c、Ma14-3-3e、Ma14-3-3i进行多重序列比对和同源性比较。结果表明:Ma14-3-3d和Ma14-3-3h与Ma14-3-3a、Ma14-3-3c、Ma14-3-3e、Ma14-3-3i具有较高的同源性,同时具有一定的差异性。遗传进化分析结果表明,Ma14-3-3d与Ma14-3-3a、Ma14-3-3c、Ma14-3-3e、Ma14-3-3i同属于non-ε类14-3-3基因,Ma14-3-3h属于ε类14-3-3基因。RT-PCR分析结果表明,Ma14-3-3d和Ma14-3-3h在香蕉不同器官中差异表达,Ma14-3-3d在香蕉的根、茎、叶、花和果中均有表达,且在茎、叶和花中的表达量高于根和果;Ma14-3-3h在根、花和果中的表达量较高,而在茎和叶中的表达量较低。q RT-PCR分析结果表明,Ma14-3-3d基因的表达明显受乙烯的诱导,而Ma14-3-3h在正常成熟、乙烯处理与1-MCP处理的果实中表达量均很低,与果实成熟的相关性不明显。推测Ma14-3-3d可能与香蕉果实成熟密切相关,可能参与乙烯调控果实成熟过程中的生物合成与信号转导。

Two cDNAs homologous with 14-3-3 protein genes were obtained by screening cDNA library of banana fruit by degenerate primer, landing PCR and RACE （rapid amplification of cDNA ends） approaches, and they were designated as Ma14-3-3d and Ma14-3-3h, respectively. Multiple alignment and homology comparison of deduced amino acid sequences of Ma14-3-3d and Ma14-3-3h together with Ma14-3-3a, Ma14-3-3c, Ma14-3-3e, and Ma14-3-3i revealed that they shared high similarity and specificity. Phylogenetic analysis showed that Ma14-3-3d with Ma14-3-3a, Mal4- 3-3c, Ma14-3-3e, and Ma14-3-3i belonged to the non- e group 14-3-3 genes, while Ma14-3-3h was classed into the e group. Expression analysis showed that Ma14-3-3d and Ma14-3-3h were differentially expressed in different organs of banana as detemlined by RT-PCR （reverse transcriptase-polymerase chain reaction）, Ma14-3-3d was expressed in roots, stems, leaves, flowers and fruits of banana, and its expression in stems, leaves and flowers was higher than that in roots and fruits; the expression of Ma14-3-3h in roots, flowers and fruits was higher, and its expression in stems and leaves was low. Expression of Ma14-3-3d was obviously indueed by ethylene as determined by qRT-PCR analysis, while the expression of Ma14-3-3h in ethylene treated and 1-MCP treated fruits was very low, its correlation with fruit ripening was not obvious. It is speculated that Ma14-3-3d may be closely related to the physiological process of ripening of banana fruit, and may be involved in ethylene biosynthesis, regulation of fruit ripening and signal transduction.