香蕉中2条MaMLO基因的克隆及表达分析

MLO基因是一类植物特有的抗病基因,为了研究香蕉MLO基因在香蕉抗枯萎病中的作用,利用RACE技术从香蕉中克隆获得了香蕉2条MLO基因,分别命名为MaMLO1和MaMLO2。序列分析表明,MaMLO1的开放阅读框为1 473 bp,编码490个氨基酸;MaMLO2的开放阅读框为1 689 bp,编码562个氨基酸。系统进化树分析表明,MaMLO1与已登录的香蕉MLO1(XP_009413424)亲缘关系较近,MaMLO2与已登录的香蕉MLO6(XP_009411538)亲缘关系较近。组织特异性研究表明,这2个基因在香蕉各器官中均有表达,但MaMLO2在根中的表达量最大。不同激素处理下的研究表明,MaMLO1受ABA、乙烯和水杨酸诱导上调表达,受茉莉酸诱导下调表达;MaMLO2受ABA、乙烯、水杨酸和茉莉酸4种激素诱导上调表达。在感病品种中2个基因均是下调表达,在抗病品种中均是上调表达。结果表明,克隆到的2条MLO在感病品种中没有参与到香蕉抗枯萎病的过程,而在抗病品种中参与了香蕉抗枯萎病的过程。

Molecular Cloning and Expression of Two MLO Genes from Banana (Musa acuminata L.AAA Group,cv.Cavendish

MLO is a kind of disease resistance genes in plant. In order to study the role of MaMLO in banana blight resistance, two MaMLOs named MaMLO1 and MaMLO2 were cloned from banana using the RACE technology. Sequence analysis showed that MaMLO1 had an open reading frame of 1 473 bp, encoding 490 amino acids; MaMLO2 had an open reading frame of 1 689 bp, encoding 562 amino acids. Phylogenetic tree analysis showed that MaMLO1 was close affinity to MLO1(XP_009413424), MaMLO2 was close affinity to MLO6(XP_009411538). Tissue specificity study showed that the two genes expressed in all organs of banana, but the biggest expression quantity of MaMLO2 was in the root. The study showed that the expression of MaMLO1 was induced to raise by ABA, ethylene and salicylic acid, while was induced to reduce by jasmonic acid; The expression of MaMLO2 was induced to raise by ABA, ethylene, salicylic acid and jasmonic acid. The expression of MaMLO1 and MaMLO2 was induced to reduce in cultivars, but raised in disease-resistant varieties. The results showed that the two MaMLOs were not involved in the process of the banana cultivars blight resistance, but they involved in resistant varieties.