Autophagy-assisted glycogen catabolism regulates asexual differentiation in Magnaporthe oryzae
Autophagy-assisted glycogen catabolism regulates asexual differentiation in Magnaporthe oryzae
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DOI：
10.4161/auto.5.1.7175
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发表时间：
2009-01-01
期刊：
影响因子：
13.3
通讯作者：
Naqvi, Naweed I.
中科院分区：
文献类型：
--
作者：
Deng, Yi Zhen;Ramos-Pamplona, Marilou;Naqvi, Naweed I.
自噬是真核生物中大量细胞降解和回收的保守途径，调节细胞器、细胞膜和某些蛋白质的正常周转。这种受调节的降解对于细胞生长和发育非常重要，特别是在环境应激条件下，它是自噬的关键诱导剂。我们发现，在 Magnaporthe oryzae 的无性发育过程中，自噬和 MoATG8 被显着诱导。 RFP 标记的 MoAtg8 在气生菌丝、分生孢子梗和分生孢子中显示出特异性定位和富集。我们证实，MoATG8 的缺失会导致形成分生孢子的能力显着降低，分生孢子是传播稻瘟病的无性孢子。外源供应葡萄糖或蔗糖显着抑制 MoATG8 缺失突变体中的分生孢子形成缺陷。 Gph1（一种催化糖原分解的糖原磷酸化酶）基于比较蛋白质组学的鉴定和表征表明，自噬辅助的糖原稳态可能对于 Magnaporthe 的正常空中生长和分生孢子形成很重要。 Gph1 的缺失或 G6P 的添加显着恢复了 Moatg8 Delta 突变体中的分生孢子形成。 Gph1 的过量产生导致野生型 Magnaporthe 菌株中分生孢子的减少。我们认为，在 Magnaporthe 的无性发育过程中，糖原自噬会积极响应并调节细胞生长和分化所需的碳利用。
Autophagy, a conserved pathway for bulk cellular degradation and recycling in eukaryotes, regulates proper turnover of organelles, membranes and certain proteins. Such regulated degradation is important for cell growth and development, particularly during environmental stress conditions, which act as key inducers of autophagy. We found that autophagy and MoATG8 were significantly induced during asexual development in Magnaporthe oryzae. An RFP-tagged MoAtg8 showed specific localization and enrichment in aerial hyphae, conidiophores and conidia. We confirmed that loss of MoATG8 results in dramatically reduced ability to form conidia, the asexual spores that propagate rice-blast disease. Exogenous supply of glucose or sucrose significantly suppressed the conidiation defects in a MoATG8-deletion mutant. Comparative proteomics-based identification and characterization of Gph1, a glycogen phosphorylase that catalyzes glycogen breakdown, indicated that autophagy-assisted glycogen homeostasis is likely important for proper aerial growth and conidiation in Magnaporthe. Loss of Gph1, or addition of G6P, significantly restored conidiation in the Moatg8 Delta mutant. Overproduction of Gph1 led to reduced conidiation in wild-type Magnaporthe strain. We propose that glycogen autophagy actively responds to and regulates carbon utilization required for cell growth and differentiation during asexual development in Magnaporthe.