香蕉MaTPS3 基因序列及表达特性分析
Characteristics and expression analysis of MaTPS3 from Musa acuminal L. AAA group cv. Brazilian
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摘要: 通过随机克隆测序的方法从香蕉根系cDNA 文库中获得海藻糖合成酶基因,命名为MaTPS3。MaTPS3 扩增获得的cDNA 序列全长为2 874 bp,包含一个完整的开放阅读框1 971 bp,编码蛋白含656 个氨基酸。其氨基酸理化性质分析表明,MaTPS3 蛋白属于不稳定、疏水性蛋白蛋白,等电点pI6.26,具有两个结构域TPS 和TPP;序列预测分析表明,MaTPS3 蛋白定位于细胞质中,该蛋白含一个跨膜区域,不存在信号肽。通过与已知植物的TPS 氨基酸同源序列比对,相似性为67.31%;其中与印度水稻、蒺藜状苜蓿TPS 氨基酸的进化关系较近,同源性分别为55.13%、54.71%。器官特异性分析表明,MaTPS3 在香蕉植株的根、球茎、假茎、叶、花、果实各器官中均有表达,在叶片和花中表达量较多。qPCR 分析表明,盐胁迫下MaTPS3 表达量增加,于24 h 时达到最高;在冷胁迫处理下,MaTPS3 表达量较0 h 时则明显下调;ACC 胁迫处理下,MaTPS3 表达量逐渐增加,在24 h 表达量为0 h 时4 倍。巴拿马病菌4 号生理小种(Foc4)侵染后,MaTPS3 在根系中下调表达,在24 h 时表达量显著低于0 h 时。因此,MaTPS3 可能参与调控香蕉抗盐胁迫机制,从而提高香蕉耐盐性,并参与调控植物激素生物合成。Abstract: A full-length MaTPS3 of 2 874 bp from banana roots cDNA library was obtained. It contained a complete open reading frame of 1 971 bp length,encoding 656 amino acids. Biological information analysis indicated that MaTPS3 protein belonged to the unstable protein,with isoelectric point of 6.26 and two domains TPS and TPP. Sequence prediction analysis indicated MaTPS3 protein was a hydrophobic transmembrane protein without signal peptide and located in cytoplasm. MaTPS3 protein sequence had 67.31% homology with other known plant TPS. Phylogenetic analysis indicated that MaTPS3 protein was closer with Oryza sativa Indica Group and Medicago truncatula,their homology respectively was 55.13%,54.71%. Organ-specific analysis showed that MaTPS3 was expressed in banana roots,corms,pseudo stems,leaves,flowers and fruits, but higher in leaves and flowers. qPCR analysis showed that the expression of MaTPS3 increased under salt stress,reached the highest at 24 h. The expression of MaTPS3 was significantly lower than the amount at 0 h under cold stress. The expression of MaTPS3 was four times at 24 h than that of 0 h,when the plantlets were under ACC treatment. When the banana plantlets were treated with FocTR4,The expression of MaTPS3 in roots significantly decreased lower than that at 0 h. ThereforeMaTPS3 may be involved in regulating the mechanism of banana salt stress resistance to improve the salt tolerance of banana,and participated in regulating plant hormone biosynthesis.