An autophagy gene, MgATG5, is required for cell differentiation and pathogenesis in Magnaporthe oryzae
An autophagy gene, MgATG5, is required for cell differentiation and pathogenesis in Magnaporthe oryzae
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稻瘟病菌的细胞分化和发病机制需要自噬基因 Mgatg5
DOI：
10.1007/s00294-009-0259-5
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发表时间：
2009-08-01
期刊：
影响因子：
2.5
通讯作者：
Lin, Fu-Cheng
中科院分区：
文献类型：
--
作者：
Lu, Jian-Ping;Liu, Xiao-Hong;Lin, Fu-Cheng
自噬是一种保守的降解途径，参与维持细胞的正常分化和发育。酿酒酵母ATG5基因是自噬过程的重要组成部分。在这项研究中，我们确定MgATG5作为一个自噬相关的基因在Magnaporthe muscle是同源的ATG5。使用靶向基因置换，产生Mgatg5a匕首突变体，并阻断真菌自噬。细胞学分析表明，突变体有不良的真菌形态发生发展，包括气生菌丝寿命缩短，减少分生孢子和周皮形成，延迟分生孢子萌发和附着胞形成，推迟分生孢子细胞质转移附着胞形成过程中，并减少形成的渗透钉。在Mgatg5a匕首突变体的内源性物质的周转也受到影响，表现为分生孢子脂滴的形成缺陷，并在附着胞形成过程中的分生孢子糖原沉积物的降解。脂滴和糖原是附着胞产生足够的膨压以侵入寄主表面所必需的。由于附着胞膨胀和分化的减少，在两种寄主植物的测试，Mgatg5a匕首致病力不足。通过将完整拷贝的MgATG5引入Mgatg5a dagger中，恢复了发育和致病表型，表明MgATG5缺失是导致细胞缺陷的原因。总之，这些研究结果表明，自噬通过真菌发育过程中内源物质的周转促进细胞分化，因此对稻瘟病菌的致病性至关重要。
Autophagy is a conserved degradation pathway that is involved in the maintenance of normal cell differentiation and development. The Saccharomyces cerevisiae ATG5 gene is an important component of the autophagy process. In this study, we identified MgATG5 as an autophagy-related gene in Magnaporthe oryzae that is homologous to ATG5. Using targeted gene replacement, an Mgatg5a dagger mutant was generated and fungal autophagy was blocked. Cytological analysis revealed that the mutant had poor fungal morphogenic development, including a shortened aerial hyphae lifespan, decreased conidiation and perithecia formation, delayed conidial germination and appressorial formation, postponement of conidial cytoplasm transfer during appressorium formation, and reduction in formation of the penetration peg. Turnover of endogenous matter in the Mgatg5a dagger mutant was also affected, as demonstrated by defects in the formation of conidial lipid droplets, and in the degradation of conidial glycogen deposits during appressorium formation. Lipid droplets and glycogen are necessary to generate adequate turgor in appressoria for invading the host surface. As a result of the decreased appressorium turgor and differentiation in the penetration peg, Mgatg5a dagger pathogenicity was deficient in two host plants tested. The developmental and pathogenic phenotypes were restored by the introduction of an intact copy of MgATG5 into Mgatg5a dagger, demonstrating that the MgATG5 deletion was responsible for the cellular defects. Taken together, these findings suggest that autophagy promotes cell differentiation through turnover of endogenous matter during fungal development, and is thus essential for the pathogenicity of the rice blast fungus.