Autophagy contributes to regulation of nuclear dynamics during vegetative growth and hyphal fusion in Fusarium oxysporum
Autophagy contributes to regulation of nuclear dynamics during vegetative growth and hyphal fusion in Fusarium oxysporum
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DOI：
10.4161/15548627.2014.994413
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发表时间：
2015-01-01
期刊：
影响因子：
13.3
通讯作者：
Ruiz-Roldan, Carmen
中科院分区：
文献类型：
--
作者：
Corral-Ramos, Cristina;Gabriela Roca, M.;Ruiz-Roldan, Carmen
在真菌病原体尖孢镰刀菌（Fusarium oxysporum）中，营养菌丝融合触发入侵菌丝中的核有丝分裂，随后核迁移到受体菌丝中并降解驻留核。在这里，我们研究了自噬在融合诱导的核降解中的作用。对F. oxysporum基因组数据库中的自噬途径组分鉴定了酵母中16个核心自噬相关（ATG）基因的推定直向同源物，包括形成自噬体膜所需的泛素样蛋白Atg 8。F.在含有H1-樱桃荧光蛋白（ChFP）标记的核的菌株中产生尖孢菌Foatg 8 δ突变体，以便于核动力学分析。与野生型和FoATG 8互补（cfoATG 8）菌株相比，Foatg 8 Delta突变体没有显示MDC阳性染色，表明FoAtg 8是F.尖孢菌属Foatg 8 Delta菌株显示菌丝生长、分生孢子形成和融合的速率降低，并且在番茄植物和非脊椎动物宿主大蜡螟中的毒力显著减弱。与几乎完全由单核菌丝隔室组成的野生型菌丝相反，Foatg 8 Delta突变体的菌丝含有具有2个或更多个核的菌丝隔室的显著部分。每个菌丝室的细胞核数量的增加是特别明显的菌丝融合事件后。延时显微镜分析显示，在Foatg 8三角洲突变体的营养生长过程中异常的有丝分裂模式。我们的研究结果表明，自噬介导菌丝融合后的核降解，并在控制核分布在F。尖孢菌属
In the fungal pathogen Fusarium oxysporum, vegetative hyphal fusion triggers nuclear mitotic division in the invading hypha followed by migration of a nucleus into the receptor hypha and degradation of the resident nucleus. Here we examined the role of autophagy in fusion-induced nuclear degradation. A search of the F. oxysporum genome database for autophagy pathway components identified putative orthologs of 16 core autophagy-related (ATG) genes in yeast, including the ubiquitin-like protein Atg8, which is required for the formation of autophagosomal membranes. F. oxysporum Foatg8 Delta mutants were generated in a strain harboring H1-cherry fluorescent protein (ChFP)-labeled nuclei to facilitate analysis of nuclear dynamics. The Foatg8 Delta mutants did not show MDC-positive staining in contrast to the wild type and the FoATG8-complemented (cFoATG8) strain, suggesting that FoAtg8 is required for autophagy in F. oxysporum. The Foatg8 Delta strains displayed reduced rates of hyphal growth, conidiation, and fusion, and were significantly attenuated in virulence on tomato plants and in the nonvertebrate animal host Galleria mellonella. In contrast to wild-type hyphae, which are almost exclusively composed of uninucleated hyphal compartments, the hyphae of the Foatg8 Delta mutants contained a significant fraction of hyphal compartments with 2 or more nuclei. The increase in the number of nuclei per hyphal compartment was particularly evident after hyphal fusion events. Timelapse microscopy analyses revealed abnormal mitotic patterns during vegetative growth in the Foatg8 Delta mutants. Our results suggest that autophagy mediates nuclear degradation after hyphal fusion and has a general function in the control of nuclear distribution in F. oxysporum.