香蕉延长因子1A(MaEF1A)基因的分离及特征分析

Isolation and functional analysis of a elongation factor 1A(MaEF1A) gene from banana

采用筛选香蕉果实采后cDNA文库的方法,首次获得了一条长为1 341 bp的cDNA序列,命名为MaEF1A。生物信息学分析结果表明,它与麝香百合延长因子1A 3的mRNA有84%的同源性,与烟草延长因子1A的mRNA有83%的同源性,推测它可能为编码香蕉延长因子1A(elongation factor-1 alpha,EF1A)的基因。该基因包含了一个完整的ORF,肽链序列中含有GTP-EFTU、GTP-EFTU-02和GTP-EFTU-03 3个保守结构域。采用RT-PCR的方法对该基因在香蕉不同组织以及果实采后不同时期的表达特征进行了初步的研究。结果表明,该基因在香蕉不同组织以及果实采后各个时期都是差异表达的。该基因在香蕉根和花中的表达量最高,茎叶最低。在香蕉果实采后的表达量开始是呈逐渐升高的趋势,到香蕉果实采后第20天,该基因的表达量达到高峰,随后该基因的表达量就逐渐下降。这一变化过程与香蕉果实采后乙烯释放量的变化进程是一致的。

A cDNA sequence with length of 1 341 bp named MaEF1A had been obtained by screening postharvest banana fruit cDNA library.The results of bioinformatics analysis showed that MaEF1A shared 84% and 83% homologous with Lilium longiflorum Thumb and tobacco,respectively,which was suggested to be a banana elongation factor 1 alhpa（EF 1A）.MaEF1A contained an integrated ORF and three conserved regions of GTP-EFTU,GTP-EFTU-02 and GTP-EFTU-03.The expressions of MaEF1A in different banana tissues and fruit in different postperiod was investigated by RT-PCR.The result indicated that MaEF1A was differently expressed in different banana tissues and different ripening stages of postharvest fruits.The expression levels in root and flower were higher than in stems and leaves.The expression trend of the gene was slowly increased from 0 d to 18 d and reached the peak at 20 d and then decreased,which was similar to ethylene release during postharvest ripening of banana fruits.