The cysteine protease MoAtg4 interacts with MoAtg8 and is required for differentiation and pathogenesis in Magnaporthe oryzae
The cysteine protease MoAtg4 interacts with MoAtg8 and is required for differentiation and pathogenesis in Magnaporthe oryzae
复制标题
半胱氨酸蛋白酶 MoAtg4 与 MoAtg8 相互作用，是稻瘟病菌分化和发病机制所必需的
DOI：
10.4161/auto.6.1.10438
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发表时间：
2010-01-01
期刊：
影响因子：
13.3
通讯作者：
Lin, Fu-Cheng
中科院分区：
文献类型：
--
作者：
Liu, Tong-Bao;Liu, Xiao-Hong;Lin, Fu-Cheng
ATG4是一种独特的半胱氨酸蛋白酶，负责在酵母中形成自噬小体的过程中切割ATG8的羧基末端。在这里，我们报道了在稻瘟病菌中与自噬蛋白MoAtg8相互作用控制细胞分化和致病的MoAtg4。MoAtg8是自噬细胞死亡和致病所必需的自噬蛋白。酵母互补实验表明，MoATG4可以功能互补缺失突变株的缺陷。在酵母双杂交和双分子荧光互补(BIFC)实验中都检测到MoAtg4和MoAtg8之间的直接相互作用。我们还指定半胱氨酸残基Cys206作为MoAtg4中的活性残基，用于体外切割MoAtg8。表达谱分析表明，MoATG4基因在米曲霉的整个生长发育过程中都有表达，并可受饥饿诱导，MoATg4蛋白定位于米曲霉的细胞质中。MoATG4基因的缺失导致气生菌丝、分生孢子、壳层形成显著减少，分生孢子萌发和附着胞形成延迟。此外，由于附着胞的膨压降低，∆Moatg4突变体失去了穿透水稻和大麦的能力。通过将完整的MoATG4基因重新导入突变体，恢复了其发育表型和致病表型，表明MoATG4在米曲霉的发育过程中是不可或缺的，对该真菌的致病性也是必不可少的。
Atg4 is a unique cysteine protease responsible for the cleavage of the carboxyl terminus of Atg8 during the formation of autophagosomes in yeast. Here we report that MoAtg4, an Atg4 homologue in Magnaporthe oryzae, controls cell differentiation and pathogenicity by interacting with MoAtg8, an autophagic protein essential for autophagic cell death and pathogenicty. Yeast complementation assay revealed that MoATG4 can fuctionally complemented the defects of the yeast ATG4 deletion mutant. The direct interaction between MoAtg4 and MoAtg8 was detected in both yeast two hybrid and bimolecular fluorescence complementation (BiFC) assays. We also specify a cysteine residue, Cys206, as the active residue within MoAtg4 for the cleavage of MoAtg8 in vitro. Expression pattern analysis revealed that MoATG4 gene is expressed throughout growth and development by M. oryzae and can be induced by starvation and MoAtg4 protein localized in the cytoplasm of M. oryzae. Deletion of MoATG4 in M. oryzae caused significant reduction of aerial hyphae, conidiation, perithecia formation, and delay of conidial germination and appressorium formation. Furthermore, as a result of lower turgor pressure of the appressorium, the ∆Moatg4 mutant lost its ability to penetrate rice and barley. The developmental and pathogenic phenotypes were recovered by re-introduction of an intact copy of MoATG4 into the mutant, suggesting that MoATG4 is indispensable in the development of M. oryzae and essential to pathogenicity of this fungus.