FOC4的2个过氧化氢酶基因的克隆与表达分析

为探讨香蕉枯萎病菌与寄主互作过程中过氧化氢酶的作用，分别利用硫酸钛法和羟胺氧化法测定了尖孢镰刀菌古巴专化型4号生理小种(FOC4)侵染香蕉苗根部后H2O2及超氧阴离子(O2?–)的含量变化；同时，借助Genbank中香蕉枯萎病病原菌Fo5176菌株基因组信息，采用RT-PCR方法克隆获得了FOC4的2个过氧化氢酶基因cDNA序列并对其进行了生物信息学分析以及在外源H2O2和普通巴西蕉苗诱导下的不同阶段表达模式分析。结果表明，FOC4的侵染能引起香蕉苗根部H2O2及超氧阴离子的含量增加，香蕉苗根部存在活性氧迸发；2个过氧化氢酶中，一个为孢子特异的过氧化氢酶，另一个为细胞质特异的过氧化氢酶；在香蕉苗及外源H2O2诱导下，2个过氧化氢酶表达均有上调，其中Foc4 CatalaseA可能是消除强氧化胁迫环境起主要作用的过氧化氢酶之一。

Cloning and Expression Analysis of Two Catalase Gene of FOC4 and the Study on the Oxidative Burst in Banana by FOC4

The aim was to explore the role of catalases of Fusarium oxysporum f.sp.Cubense(race 4,FOC4) in pathogenesis.Titanium sulfate and hydroxylamine oxidation methods were used to detect the content changes of H2O2 and O2-.in the roots infected by FOC4.At the same time,two catalases in FOC4 were cloned and characterized by using genome information of Fusarium oxysporum(strain Fo5176) from GenBank.And then,gene expression patterns induced by exogenous H2O2 and Musa paradisiaca were detected by RT-PCR.The results showed thats the infected by FOC4 could cause oxidative burst in the roots of banana seedlings.Phylogenetic analysis showed that,two catalases belonged to CatalaseA and CatalaseC.The expression of 2 catalases increased after induced by exogenous H2O2 and Musa paradisiaca.Foc4 CatalaseA might be one of the catalases which played a major role in eliminating the strong oxidative stress environment.