Rice black-streaked dwarf virus(RBSDV)is a major viral pathogen threatening rice production worldwide.However,the molecular mechanisms underlying the arms race between RBSDV and its host remain largely elusive.Here,we...Rice black-streaked dwarf virus(RBSDV)is a major viral pathogen threatening rice production worldwide.However,the molecular mechanisms underlying the arms race between RBSDV and its host remain largely elusive.Here,we demonstrate that RBSDV infection,or the expression of viral RNA-silencing suppressor protein P6,promotes the ubiquitination and degradation of rice small ubiquitin-like modifiers(SUMO)conjugating enzyme 1b(OsSCE1b).OsSCE1b catalyzes the SUMOylation of Os Pelota,a protein involved in plant antiviral RNA decay.Furthermore,RBSDV P6enhances the interaction between rice ubiquitin E3 ligases SINAT3/4/5 and OsSCE1b in the cytoplasm,leading to increased ubiquitination and degradation of OsSCE1b.Rice plants overexpressing OsSCE1b exhibited reduced susceptibility to RBSDV infection.Conversely,OsSCE1b knockdown and knockout lines,as well as Os Pelota knockout lines,were more susceptible,indicating that both OsSCE1b and Os Pelota negatively regulate RBSDV infection.Additionally,our findings show that OsSCE1b-catalyzed SUMOylated Os Pelota interacts with the Hsp70subfamily B suppressor Os HBS1,forming a complex that degrades RBSDV genomic RNAs containing one or more GA6motifs.Taken together,our data demonstrate that OsSCE1b negatively regulates RBSDV infection by promoting Os Pelota SUMOylation and activating the antiviral RNA decay activity of the Os Pelota–Os HBS1 complex.Conversely,RBSDV P6 promotes viral infection by enhancing OsSCE1b ubiquitination and degradation,thereby suppressing Os Pelota SUMOylation and the rice antiviral RNA decay defense response.展开更多
基金funded by the National Natural Science Foundation of China(3177212532472496)the Earmarked Fund for Modern Agro-industry Technology Research System(nycytx-001)。
文摘Rice black-streaked dwarf virus(RBSDV)is a major viral pathogen threatening rice production worldwide.However,the molecular mechanisms underlying the arms race between RBSDV and its host remain largely elusive.Here,we demonstrate that RBSDV infection,or the expression of viral RNA-silencing suppressor protein P6,promotes the ubiquitination and degradation of rice small ubiquitin-like modifiers(SUMO)conjugating enzyme 1b(OsSCE1b).OsSCE1b catalyzes the SUMOylation of Os Pelota,a protein involved in plant antiviral RNA decay.Furthermore,RBSDV P6enhances the interaction between rice ubiquitin E3 ligases SINAT3/4/5 and OsSCE1b in the cytoplasm,leading to increased ubiquitination and degradation of OsSCE1b.Rice plants overexpressing OsSCE1b exhibited reduced susceptibility to RBSDV infection.Conversely,OsSCE1b knockdown and knockout lines,as well as Os Pelota knockout lines,were more susceptible,indicating that both OsSCE1b and Os Pelota negatively regulate RBSDV infection.Additionally,our findings show that OsSCE1b-catalyzed SUMOylated Os Pelota interacts with the Hsp70subfamily B suppressor Os HBS1,forming a complex that degrades RBSDV genomic RNAs containing one or more GA6motifs.Taken together,our data demonstrate that OsSCE1b negatively regulates RBSDV infection by promoting Os Pelota SUMOylation and activating the antiviral RNA decay activity of the Os Pelota–Os HBS1 complex.Conversely,RBSDV P6 promotes viral infection by enhancing OsSCE1b ubiquitination and degradation,thereby suppressing Os Pelota SUMOylation and the rice antiviral RNA decay defense response.
