Study On Hypovirus CHV1 Crosskingdom Infection Of Plants And Fungi

Diverse mycoviruses or fungal viruses infect and multiply in fungal hosts.As potential biological control agents,some fungal viruses are able to reduce the pathogenicity of fungal host,termed "hypovirulence".Mycoviruses naturally disseminate either vertically via spores or horizontally via hyphal fusion.However,transmission of virus through anastomosis between a virulent fungal strain and a hypovirulent fungal strain was often restricted if the two strains are vegetatively incompatible.In this study investigated whether fungal viruses are able to infect plant cell and shuttle between fungi and plant.1.We examined the infectivity of 4 mycovirus in Nicotiana tabacum plants,including a well-documented member of Hypoviridae,Cryphonectria hypovirus 1(CHV1),Alternaria alternata hypovirus 1(Aa HV1),and Botryosphaeria dothidea victorivirus 1(Bd V1),and a mitovirus which have double stranded RNA(ds RNA)genome,Rhizoctonia solani mitovirus328(Rs MV-328).By mechanical inoculation,CHV1 and Aa HV1 were able to replicate in inoculated leaves but could not spread systemically in the plants.2.Co-inoculation with an unrelated plant(+)ss RNA virus,tobacco mosaic virus(TMV,family Virgaviridae)or other plant RNA viruses,enables CHV1 to systemically infect the plant.3.CHV1 systemically infects the transgenic plants expressing the TMV movement protein,and co-infection with TMV further enhances CHV1 accumulation in these transgenic plants.4.CHV1 infection increased TMV accumulation when TMV was directly introduced to a plant pathogenic fungus,Fusarium graminearum.5.In the in-planta F.graminearum inoculation experiment,we demonstrated that TMV infection in either the plant or fungus enabled the horizontal transfer of CHV1 from the fungus to plant,while CHV1 infection in fungus enhanced the acquisition of TMV by the fungus.Our results demonstrate two-way facilitative interactions between the plant and fungal viruses that promote cross-kingdom virus infection and further imply the presence of a plant–fungus-mediated route for the dissemination of fungal or plant viruses in nature.Together,our findings provide evidence that occurrence of extracellular transmission of the fungal virus to plant if the plant is infected with the plant virus.Our finding impliesthe possibility to utilize the hypovirulent mycoviruses as biological control agents for phytopathogenic fungi through infection of fungal virus in plants.