The lifestyle transition of Arthrobotrys oligospora is mediated by microRNA-like RNAs
The lifestyle transition of fungi, defined as switching from taking organic material as nutrients to pathogens, is a fundamental phenomenon in nature. However, the mechanisms of such transition remain largely unknown. Here we show microRNA-like RNAs (milRNAs) play a key role in fungal lifestyle transition for the first time. We identified milRNAs by small RNA sequencing in Arthrobotrys oligospora, a known nematode-trapping fungus. Among them, 7 highly expressed milRNAs were confirmed by northern-blot analysis. Knocking out two milRNAs significantly decreased A. oligospora’s ability to switch lifestyles. We further identified that two of these milRNAs were associated with argonaute protein QDE-2 by RNA-immunoprecipitation (RIP) analysis. Three of the predicted target genes of milRNAs were found in immunoprecipitation (IP) products of QDE-2. Disruption of argonaute gene qde-2 also led to serious defects in lifestyle transition. Interestingly, knocking out individual milRNAs or qde-2 lead to diverse responses under different conditions, and qde-2 itself may be targeted by the milRNAs. Collectively, it indicates the lifestyle transition of fungi is mediated by milRNAs through RNA interference (RNAi) machinery, revealing the wide existence of miRNAs in fungi kingdom and providing new insights into understanding the adaptation of fungi from scavengers to predators and the mechanisms underlying fungal infections.
Keywordslifestyle transition Arthrobotrys oligospora microRNA-like RNAs nematode-trapping fungi trap induction fungal adaptation
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This work was supported by the National Basic Research Program of China (2013CB127500), the National Natural Science Foundation of China (31160021, 31270131 and U1502262) and sponsored by the Nanjing University of Posts and Telecommunications Scientific Foundation (NUPTSF) (NY218140) and a grant (2018KF003) from YNCUB. We thank BGI-Shenzhen who contributed to the small RNA sequencing projects. We thank H. Yin for comments and discussion.
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