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
We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the map...We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the mapbased cloning of the causal gene OsPELOTA（originally termed spl^（HM47））. We identified a single base substitution from T to A at position 556 in the coding sequence of OsPELOTA, effectively mutating phenylalanine to isoleucine at position 186 in the translated protein sequence. Both functional complementation and over-expression could rescue the spotted-leaf phenotype. OsPELOTA, a paralogue to eukaryotic release factor 1（eRF_1）, shows high sequence similarity to Drosophila Pelota and also localizes to the endoplasmic reticulum and plasma membrane.OsPELOTA is constitutively expressed in roots, leaves,sheaths, stems, and panicles. Elevated levels of salicylic acid and decreased level of jasmonate were detected in the pelota mutant. RNA-seq analysis confirmed that genes responding to salicylic acid were upregulated in the mutant. Our results indicate that the rice PELOTA protein is involved in bacterial leaf blight resistance by activating the salicylic acid metabolic pathway.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.
基金supported by the National Natural Science Foundation of China (31471572)the Ministry of Science and Technology of China (2016YFD0101104)
文摘We previously reported a spotted-leaf mutant pelota（originally termed HM_（47）） in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the mapbased cloning of the causal gene OsPELOTA（originally termed spl^（HM47））. We identified a single base substitution from T to A at position 556 in the coding sequence of OsPELOTA, effectively mutating phenylalanine to isoleucine at position 186 in the translated protein sequence. Both functional complementation and over-expression could rescue the spotted-leaf phenotype. OsPELOTA, a paralogue to eukaryotic release factor 1（eRF_1）, shows high sequence similarity to Drosophila Pelota and also localizes to the endoplasmic reticulum and plasma membrane.OsPELOTA is constitutively expressed in roots, leaves,sheaths, stems, and panicles. Elevated levels of salicylic acid and decreased level of jasmonate were detected in the pelota mutant. RNA-seq analysis confirmed that genes responding to salicylic acid were upregulated in the mutant. Our results indicate that the rice PELOTA protein is involved in bacterial leaf blight resistance by activating the salicylic acid metabolic pathway.
