A significant number of mycoviruses have been identified that are related to plant viruses,but their evolutionary relationships are largely unexplored.A fusarivirus,Rhizoctonia solani fusarivirus 4(RsFV4),was identified in phytopathogenic fungus Rhizoctonia solani(R.solani)strain XY74 co-infected by an alphaendornavirus.RsFV4 had a genome of 10,833 nt(excluding the poly-A tail),and consisted of four non-overlapping open reading frames(ORFs).ORF1 encodes an 825 aa protein containing a conserved helicase domain(Hel1).ORF3 encodes 1550 aa protein with two conserved domains,namely an RNA-dependent RNA polymerase(RdRp)and another helicase(Hel2).The ORF2 and ORF4 likely encode two hypothetical proteins(520 and 542 aa)with unknown functions.The phylogenetic analysis based on He12 and RdRp suggest that RsFV4 was positioned within the fusarivirus group,but formed an independent branch with three previously reported fusariviruses of R.solani.Notably,the Hel1 and its relatives were phylogenetically closer to helicases of potyviruses and hypo viruses than fusariviruses,suggesting fusarivirus Hel1 formed an evolutionary link between these three virus groups.This finding provides evidence of the occurrence of a horizontal gene transfer or recombination event between mycoviruses and plant viruses or between mycoviruses.Our findings are likely to enhance the understanding of virus evolution and diversity.

Assane Hamidou Abdoulaye;Jichun Jia;Aqleem Abbas;Du Hai;Jiasen Cheng;Yanping Fu;Yang Lin;Daohong Jiang;Jiatao Xie

State Key Laboratory of Agricultural Microbiology,Huazhong Agricultural University,Wuhan,430070,China;Hubei Key Laboratory of Plant Pathology,College of Plant Science and Technology,Huazhong Agricultural University,Wuhan,430070,China;Hubei Hongshan Laboratory,Wuhan,430070,China

中国病毒学

[1]Assane Hamidou Abdoulaye;Jichun Jia;Aqleem Abbas;Du Hai;Jiasen Cheng;Yanping Fu;Yang Lin;Daohong Jiang;Jiatao Xie-.Fusarivirus accessory helicases present an evolutionary link for viruses infecting plants and fungi)[J].中国病毒学,2022(03):427-436

Fusarivirus,mycoviruses,fusarivirus,RsFV4,XY74,alphaendornavirus,Hel1,Hel2,He12,fusariviruses,potyviruses

accessory,helicases,present,evolutionary,link,infecting,plants,fungi,significant,number,have,been,identified,that,are,related,but,their,relationships,largely,unexplored,Rhizoctonia,solani,was,phytopathogenic,fungus,strain,infected,by,had,genome,excluding,tail,consisted,four,overlapping,open,reading,frames,ORFs,ORF1,encodes,aa,containing,conserved,ORF3,two,domains,namely,polymerase,RdRp,another,ORF2,ORF4,likely,hypothetical,proteins,unknown,functions,analysis,positioned,within,formed,independent,branch,three,previously,reported,Notably,its,relatives,were,phylogenetically,closer,than,suggesting,between,these,groups,This,provides,evidence,occurrence,horizontal,transfer,recombination,event,Our,findings,enhance,understanding,diversity

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