Ophiostomatalean fungi may facilitate bark beetle colonization and reproduction.In the present study of the fungal community associated with bark beetle species belonging to Tomicus in Yunnan,China,six ophiostomatalea...Ophiostomatalean fungi may facilitate bark beetle colonization and reproduction.In the present study of the fungal community associated with bark beetle species belonging to Tomicus in Yunnan,China,six ophiostomatalean fungi(Ophiostoma canum,O.ips,O.tingens,Leptographium yunnanense,Leptographium sp.1 and Leptographium sp.2)were isolated from the beetles or their galleries;O.canum was the most common fungal species.The distribution of O.canum was associated with stands heavily damaged by Tomicus species and a higher percentage of valid galleries of Tomicus yunnanensis and T.minor in Yunnan pine(Pinus yunnanensis).After inoculation of Yunnan pine with the fungus,a phloem reaction zone formed and monoterpenes accumulated in the phloem.These results suggested that O.canum was pathogenic to Yunnan pine and that the wide distribution of the fungus might be benefi cial to reproduction of pine shoot beetles in Yunnan pine.However,because the reaction zone and monoterpene accumulation were mild,fungal damage of Yunnan pine might be limited.A more integrated study considering all the fungal species should be done to better understand the interactions among bark beetles,blue-stain fungi,and the tree hosts in the region.展开更多
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...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.展开更多
文摘Ophiostomatalean fungi may facilitate bark beetle colonization and reproduction.In the present study of the fungal community associated with bark beetle species belonging to Tomicus in Yunnan,China,six ophiostomatalean fungi(Ophiostoma canum,O.ips,O.tingens,Leptographium yunnanense,Leptographium sp.1 and Leptographium sp.2)were isolated from the beetles or their galleries;O.canum was the most common fungal species.The distribution of O.canum was associated with stands heavily damaged by Tomicus species and a higher percentage of valid galleries of Tomicus yunnanensis and T.minor in Yunnan pine(Pinus yunnanensis).After inoculation of Yunnan pine with the fungus,a phloem reaction zone formed and monoterpenes accumulated in the phloem.These results suggested that O.canum was pathogenic to Yunnan pine and that the wide distribution of the fungus might be benefi cial to reproduction of pine shoot beetles in Yunnan pine.However,because the reaction zone and monoterpene accumulation were mild,fungal damage of Yunnan pine might be limited.A more integrated study considering all the fungal species should be done to better understand the interactions among bark beetles,blue-stain fungi,and the tree hosts in the region.
基金This work was supported by the National Basic Research Program of China(2013CB127500)the National Natural Science Foundation of China(31160021,31270131 and U1502262)+1 种基金sponsored by the Nanjing University of Posts and Telecommunications Scientific Foundation(NUPTSF)(NY218140)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.
文摘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.
