关键词: 香蕉, 海藻糖-6-磷酸合成酶基因5（TPS5）, 生物信息学, 表达分析

Abstract: Our aim is to explore the role of trehalose-6-phosphate synthase gene in the stress tolerance of banana plant by studying its biological function. A gene from banana rhizome’s transcriptome,designated as MaTPS5,was reaped using the method of random cloning and sequencing. Bioinformatics analysis showed the full length of MaTPS5 cDNA sequence was 3 081 bp,containing a complete open reading frame of 2 559 bp,encoding 852 amino acids. Protein MaTPS5 was an unstable and hydrophobic protein with iso-electric point of 6.52,in which there were two structure domains of GT1-TPS and TPP. It was located in cytoplasm and had two trans-membrane regions but no signal peptide. Comparing MaTPS5 protein sequence to the known plant TPS amino acid sequence,the homology level was 77.31%. Phylogenetic analysis showed MaTPS5 protein sequence was clustered on a common branch with the TPS protein sequence of wild banana,indicating that they were the close relatives and had a common ancestor. Tissue-specific analysis indicated MaTPS5 expression level was high in corm,leaves,and flowers,but the lowest in the roots. qRT-PCR analysis showed MaTPS5 expression increased when banana plantlets were treated with ACC and salt,and peaked at 24 h. After treating banana plantlets with Foc TR4 pathogen,the MaTPS5 expression level rose and was constant in three hours. The results showed MaTPS5 may depend upon the ethylene signaling transduction pathways to induce itself expression,and synthesize trehalose,and therefore participate in stress tolerance of banana plants.

Key words: banana, trehalose-6-phosphate synthase gene（TPS5）, bioinformatics, expression analysis