Plants usually keep resistance(R)proteins in a static state under normal conditions to avoid autoimmunity and save energy for growth,but R proteins can be rapidly activated upon perceiving pathogen invasion.Pib,the fi...Plants usually keep resistance(R)proteins in a static state under normal conditions to avoid autoimmunity and save energy for growth,but R proteins can be rapidly activated upon perceiving pathogen invasion.Pib,the first cloned blast disease R gene in rice,encoding a nucleotide-binding leucine-rich repeat(NLR)protein,mediates resistance to the blast fungal(Magnaporthe oryzae)isolates carrying the avirulence gene AvrPib.However,the molecular mechanisms about how Pib recognizes AvrPib and how it is inactivated and activated remain largely unclear.In this study,through map-based cloning and CRISPR-Cas9 gene editing,we proved that Pib contributes to the blast disease resistance of rice cultivar Yunyin(YY).Furthermore,an SH3 domain-containing protein,SH3P2,was found to associate with Pib mainly at clathrin-coated vesicles in rice cells,via direct binding with the coiled-coil(CC)domain of Pib.Interestingly,overexpression of SH3P2 in YY compromised Pib-mediated resistance to M.oryzae isolates carrying AvrPib and Pib-AvrPib recognition-induced cell death.SH3P2 competitively inhibits the self-association of the Pib CC domain in vitro,suggesting that binding of SH3P2 with Pib undermines its homodimerization.Moreover,SH3P2 can also interact with AvrPib and displays higher affinity to AvrPib than to Pib,which leads to dissociation of SH3P2 from Pib in the presence of AvrPib.Taken together,our results suggest that SH3P2 functions as a“protector”to keep Pib in a static state by direct interaction during normal growth but could be triggered off by the invasion of AvrPib-carrying M.oryzae isolates.Our study reveals a new mechanism about how an NLR protein is inactivated under normal conditions but is activated upon pathogen infection.展开更多
Intracellular polyamines(putrescine,spermidine,and spermine)have emerged as important molecules for viral infection;however,how viruses activate polyamines biosynthesis to promote viral infection remains unclear.Ornit...Intracellular polyamines(putrescine,spermidine,and spermine)have emerged as important molecules for viral infection;however,how viruses activate polyamines biosynthesis to promote viral infection remains unclear.Ornithine decarboxylase 1(ODC1)and its antienzyme 1(OAZ1)are major regulators of polyamine biosynthesis in animal cells.Here,we report that rice yellow stunt virus(RYSV),a plant rhabdovirus,could activate putrescine biosynthesis in leafhoppers to promote viral propagation by inhibiting OAZ1 expression.We observed that the reduction of putrescine biosynthesis by treatment with difluormethylornithine(DFMO),a specific nontoxic inhibitor of ODC1,or with in vitro synthesized dsRNAs targeting ODC1 mRNA could inhibit viral infection.In contrast,the supplement of putrescine or the increase of putrescine biosynthesis by treatment with ds RNAs targeting OAZ1 mRNA could facilitate viral infection.We further determined that both RYSV matrix protein M and ODC1 directly bind to the ODC-binding domain at the C-terminus of OAZ1.Thus,viral propagation in leafhoppers would decrease the ability of OAZ1 to target and mediate the degradation of ODC1,which finally activates putrescine production to benefit viral propagation.This work reveals that polyamine-metabolizing enzymes are directly exploited by a vector-borne virus to increase polyamine production,thereby facilitating viral infection in insect vectors.展开更多
基金This work was supported by the National Key R&D Program Foundation of China(grant no.2016YFD0300508)the National Rice Industry Technology System of Modern Agriculture for China(grant no.CARS-01-20)+2 种基金the“5511”Collaborative Innovation Project for High-Quality Development and Surpasses of Agriculture between Government of Fujian and Chinese Academy of Agricultural Sciences(grant no.XTCXGC2021001)Key Program of Science and Technology in Fujian province,China(no.2020NZ08016)the Special Foundation of Non-Profit Research Institutes of Fujian Province(grant no.2018R1021-5).
文摘Plants usually keep resistance(R)proteins in a static state under normal conditions to avoid autoimmunity and save energy for growth,but R proteins can be rapidly activated upon perceiving pathogen invasion.Pib,the first cloned blast disease R gene in rice,encoding a nucleotide-binding leucine-rich repeat(NLR)protein,mediates resistance to the blast fungal(Magnaporthe oryzae)isolates carrying the avirulence gene AvrPib.However,the molecular mechanisms about how Pib recognizes AvrPib and how it is inactivated and activated remain largely unclear.In this study,through map-based cloning and CRISPR-Cas9 gene editing,we proved that Pib contributes to the blast disease resistance of rice cultivar Yunyin(YY).Furthermore,an SH3 domain-containing protein,SH3P2,was found to associate with Pib mainly at clathrin-coated vesicles in rice cells,via direct binding with the coiled-coil(CC)domain of Pib.Interestingly,overexpression of SH3P2 in YY compromised Pib-mediated resistance to M.oryzae isolates carrying AvrPib and Pib-AvrPib recognition-induced cell death.SH3P2 competitively inhibits the self-association of the Pib CC domain in vitro,suggesting that binding of SH3P2 with Pib undermines its homodimerization.Moreover,SH3P2 can also interact with AvrPib and displays higher affinity to AvrPib than to Pib,which leads to dissociation of SH3P2 from Pib in the presence of AvrPib.Taken together,our results suggest that SH3P2 functions as a“protector”to keep Pib in a static state by direct interaction during normal growth but could be triggered off by the invasion of AvrPib-carrying M.oryzae isolates.Our study reveals a new mechanism about how an NLR protein is inactivated under normal conditions but is activated upon pathogen infection.
基金supported by the National Natural Science Foundation of China(31871931)the Fujian Agriculture and Forestry University Outstanding Young Scientists Project(xjq201705)National Key Research and Development Project of China(2018YFD0200306)。
文摘Intracellular polyamines(putrescine,spermidine,and spermine)have emerged as important molecules for viral infection;however,how viruses activate polyamines biosynthesis to promote viral infection remains unclear.Ornithine decarboxylase 1(ODC1)and its antienzyme 1(OAZ1)are major regulators of polyamine biosynthesis in animal cells.Here,we report that rice yellow stunt virus(RYSV),a plant rhabdovirus,could activate putrescine biosynthesis in leafhoppers to promote viral propagation by inhibiting OAZ1 expression.We observed that the reduction of putrescine biosynthesis by treatment with difluormethylornithine(DFMO),a specific nontoxic inhibitor of ODC1,or with in vitro synthesized dsRNAs targeting ODC1 mRNA could inhibit viral infection.In contrast,the supplement of putrescine or the increase of putrescine biosynthesis by treatment with ds RNAs targeting OAZ1 mRNA could facilitate viral infection.We further determined that both RYSV matrix protein M and ODC1 directly bind to the ODC-binding domain at the C-terminus of OAZ1.Thus,viral propagation in leafhoppers would decrease the ability of OAZ1 to target and mediate the degradation of ODC1,which finally activates putrescine production to benefit viral propagation.This work reveals that polyamine-metabolizing enzymes are directly exploited by a vector-borne virus to increase polyamine production,thereby facilitating viral infection in insect vectors.