Mitochondrial β-oxidation regulates organellar integrity and is necessary for conidial germination and invasive growth in Magnaporthe oryzae
Mitochondrial β-oxidation regulates organellar integrity and is necessary for conidial germination and invasive growth in Magnaporthe oryzae
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DOI：
10.1111/mmi.12060
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发表时间：
2012-12-01
影响因子：
3.6
通讯作者：
Naqvi, Naweed I.
中科院分区：
文献类型：
--
作者：
Patkar, Rajesh N.;Ramos-Pamplona, Marilou;Naqvi, Naweed I.
作为细胞能量的重要来源，以甘油三酯形式储存的脂肪酸通过β-氧化途径被分解代谢，该途径预计发生在丝状真菌的过氧化物酶体和线粒体中。在这里，我们的特点的功能，烯酰辅酶A水合酶Ech 1，线粒体β-氧化酶，在模式植物病原体Magnaporthe Magnaporthe。Ech 1被认为是必不可少的孢子萌发和活力的老菌丝。与野生型Magnaporthe不同，ech 1？不能利用C14脂肪酸，并且在C16和C18脂肪酸上生长受到部分阻碍。令人惊讶的是，β-氧化损失导致显着改变线粒体形态和完整性与ech 1？与野生型Magnaporthe中的融合管状网络相反，显示主要为囊泡/点状线粒体。ech1？附着胞是异常的，并且显示出减少的黑化。重要的是，我们表明，显着降低的ech 1？穿透宿主并在其中建立是突变体对氧化应激的敏感性增强的直接结果，因为通过外源抗氧化剂可以显著地逆转缺陷。总的来说，我们的比较分析表明，过氧化物酶体脂质催化剂是必不可少的附着胞功能的主机渗透，而线粒体β-氧化主要有助于分生孢子的活力和维持氧化还原稳态在主机殖民Magnaporthe。
Fatty acids stored as triglycerides, an important source of cellular energy, are catabolized through beta-oxidation pathways predicted to occur both in peroxisomes and mitochondria in filamentous fungi. Here, we characterize the function of Enoyl-CoA hydratase Ech1, a mitochondrial beta-oxidation enzyme, in the model phytopathogen Magnaporthe oryzae. Ech1 was found to be essential for conidial germination and viability of older hyphae. Unlike wild-type Magnaporthe, the ech1? failed to utilize C14 fatty acid and was partially impeded in growth on C16 and C18 fatty acids. Surprisingly, loss of beta-oxidation led to significantly altered mitochondrial morphology and integrity with ech1? showing predominantly vesicular/punctate mitochondria in contrast to the fused tubular network in wild-type Magnaporthe. The ech1? appressoria were aberrant and displayed reduced melanization. Importantly, we show that the significantly reduced ability of ech1? to penetrate the host and establish therein is a direct consequence of enhanced sensitivity of the mutant to oxidative stress, as the defects could be remarkably reversed through exogenous antioxidants. Overall, our comparative analyses reveal that peroxisomal lipid catabolism is essential for appressorial function of host penetration, whereas mitochondrial beta-oxidation primarily contributes to conidial viability and maintenance of redox homeostasis during host colonization by Magnaporthe.