香蕉茉莉酸合成关键酶基因MaOPR的克隆和表达分析

Molecular Cloning and Expression Analysis of MaOPR Gene from Banana

从‘巴西’香蕉(Musaacuminata L.AAAgroup‘Brazilian’)根的cDNA文库中获得了一段12-氧-植物二烯酸还原酶OPR(12-oxo-phytodienoic acid reductase)基因的片段,RACE扩增获得全长,命名为MaOPR。该基因全长1512bp,存在一个完整的开放阅读框1287bp,编码429个氨基酸。生物信息学分析表明,该蛋白属稳定蛋白,等电点为8.11,具有一个活性位点,一个基质结合位点,一个黄素单核苷酸结合位点。序列预测分析该蛋白亚细胞定位为细胞质,其不属于跨膜蛋白且不存在信号肽。通过和已知植物的12-氧-植物二烯酸还原酶基因相比,同源性达到66%以上。其中与苜蓿、谷子、粳稻、紫云英的OPR编码的氨基酸序列的同源性均为71%。器官特异性分析表明,MaOPR在香蕉的根、茎、叶片、花和果实中均有所表达,其中在茎和果实中表达量较高。通过对其在ABA抑制剂、乙烯、枯萎病胁迫下的表达结果分析显示,该基因响应以上3种胁迫。

Through RACE approaches and bioinformatics analysis, the full-length cDNA of the cysteine synthase gene, named as MaOPR （ 12-oxo-phytodienoic acid reductase）, was obtained from root of banana （Musa acuminata L. AAA group ＇Brazilian＇ ） cDNA library, and its sequence characters were also analyzed. The full length of this gene was 1 512 bp, it had an 1 287 bp open reading frame in length encoding 429 amino acid. The result of bioinformatics showed that this protein was a stable protein with the active sites, the matrix attachment sites and the flavin mononucleotide binding sites, which pI is 8.11The sequence prediction showed that it located in the cytoplasm, it was not a transmembrane protein and had no signal peptide. Compared with other known plants, the homology of MaOPR was more than 66%, Amino acids homology analysis indicated that MaOPR had 71% similarity compared with Medicago sativa, Setaria italic, Oryza sativa, Astragalus sinicus. RT-PCR analysis showed that MaOPR was constitutively expressed in roots, stems, leaves, flowers and fruits. The expression level was the highest in fruits. Analysis showed that MaOPR responsed to the stress including the ABA inhibitor, ethylene and wilt disease stress.