The Basic Leucine Zipper Transcription Factor Moatf1 Mediates Oxidative Stress Responses and Is Necessary for Full Virulence of the Rice Blast Fungus Magnaporthe oryzae
The Basic Leucine Zipper Transcription Factor Moatf1 Mediates Oxidative Stress Responses and Is Necessary for Full Virulence of the Rice Blast Fungus Magnaporthe oryzae
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DOI：
10.1094/mpmi-23-8-1053
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发表时间：
2010-08-01
影响因子：
3.5
通讯作者：
Zheng, Xiaobo
中科院分区：
文献类型：
--
作者：
Guo, Min;Guo, Wang;Zheng, Xiaobo
稻瘟病是稻瘟病的病原，给水稻生产造成巨大损失。在这里，我们鉴定了M. oryzae中的碱性亮氨酸拉链（bZIP）转录因子Moatf1，这是一个调节氧化应激反应的Schizosaccharomyces pombe ATF/CREB的同源物。Moatf1缺失导致菌丝营养生长迟缓，且Moatf1突变体对过氧化氢（H2O2）的敏感性高于野生型菌株。该突变体细胞外酶活性、漆酶和过氧化物酶转录水平严重降低，对水稻CO-39的毒力显著降低。在水稻叶鞘上，突变体的大部分侵染菌丝在原代侵染细胞中肿胀，生长受限。被突变体感染的植株防御反应被强烈激活。双氨基联苯胺染色显示，在Moatf1突变体的附着胞和带有Moatf1菌丝的水稻细胞周围有H2O2的积累，而在野生型中没有。二苯乙烯对植物NADPH氧化酶的抑制抑制了宿主产生的H2O2积累，恢复了突变体在水稻细胞中的感染性菌丝生长。因此，我们得出结论，Moatf1通过调节漆酶和过氧化物酶的转录来破坏活性氧介导的植物防御，是M. oryzae完全毒力所必需的。
Magnaporthe oryzae is the causal agent of rice blast disease, leading to enormous losses of rice production. Here, we characterized a basic leucine zipper (bZIP) transcription factor, Moatf1, in M. oryzae, a homolog of Schizosaccharomyces pombe ATF/CREB that regulates the oxidative stress response. Moatf1 deletion caused retarded vegetative growth of mycelia, and the Moatf1 mutant exhibited higher sensitivity to hydrogen peroxide (H2O2) than did the wildtype strain. The mutant showed severely reduced activity of extracellular enzymes and transcription level of laccases and peroxidases and exhibited significantly reduced virulence on rice cultivar CO-39. On rice leaf sheath, most of the infectious hyphae of the mutant became swollen and displayed restricted growth in primary infected cells. Defense response was strongly activated in plants infected by the mutant. Diamino benzidine staining revealed an accumulation of H2O2 around Moatf1 mutant appressoria and rice cells with Moatf1 hyphae that was absent in the wild type. Inhibition of the plant NADPH oxidase by diphenyleneiodonium prevented host-derived H2O2 accumulation and restored infectious hyphal growth of the mutant in rice cells. Thus, we conclude that Moatf1 is necessary for full virulence of M. oryzae by regulating the transcription of laccases and peroxidases to impair reactive oxygen species mediated plant defense.