Increasing evidence suggests that mitogen-activated protein kinase(MAPK)cascades play a crucial role in plant defense against viruses.However,the mechanisms that underlie the activation of MAPK cascades in response to...Increasing evidence suggests that mitogen-activated protein kinase(MAPK)cascades play a crucial role in plant defense against viruses.However,the mechanisms that underlie the activation of MAPK cascades in response to viral infection remain unclear.In this study,we discovered that phosphatidic acid(PA)repre-sents a major class of lipids that respond to Potato virus Y(PVY)at an early stage of infection.We identified NbPLDa1(Nicotiana benthamiana phospholipase Da1)as the key enzyme responsible for increased PA levels during PVY infection and found that it plays an antiviral role.6K2 of PVY interacts with NbPLDa1,lead-ing to elevated PA levels.In addition,NbPLDa1 and PA are recruited by 6K2 to membrane-bound viral repli-cation complexes.On the other hand,6K2 also induces activation of the MAPK pathway,dependent on its interaction with NbPLDa1 and the derived PA.PA binds to WIPK/SIPK/NTF4,prompting their phosphoryla-tion of WRKY8.Notably,spraying with exogenous PA is sufficient to activate the MAPK pathway.Knock-down of the MEK2-WIPK/SIPK-WRKY8 cascade resulted in enhanced accumulation of PVY genomic RNA.6K2 of Turnip mosaic virus and p33 of Tomato bushy stunt virus also interacted with NbPLDa1 and induced the activation of MAPK-mediated immunity.Loss of function of NbPLDa1 inhibited virus-induced activation of MAPK cascades and promoted viral RNA accumulation.Thus,activation of MAPK-mediated immunity by NbPLDa1-derived PA is a common strategy employed by hosts to counteract positive-strand RNA virus infection.展开更多
基金supported by the National Natural Science Foundation of China (31901855)the Youth Talent Support Program of Henan Province (2020HYTP042)the Special Fund for Young Talents of Henan Agricultural University。
文摘Increasing evidence suggests that mitogen-activated protein kinase(MAPK)cascades play a crucial role in plant defense against viruses.However,the mechanisms that underlie the activation of MAPK cascades in response to viral infection remain unclear.In this study,we discovered that phosphatidic acid(PA)repre-sents a major class of lipids that respond to Potato virus Y(PVY)at an early stage of infection.We identified NbPLDa1(Nicotiana benthamiana phospholipase Da1)as the key enzyme responsible for increased PA levels during PVY infection and found that it plays an antiviral role.6K2 of PVY interacts with NbPLDa1,lead-ing to elevated PA levels.In addition,NbPLDa1 and PA are recruited by 6K2 to membrane-bound viral repli-cation complexes.On the other hand,6K2 also induces activation of the MAPK pathway,dependent on its interaction with NbPLDa1 and the derived PA.PA binds to WIPK/SIPK/NTF4,prompting their phosphoryla-tion of WRKY8.Notably,spraying with exogenous PA is sufficient to activate the MAPK pathway.Knock-down of the MEK2-WIPK/SIPK-WRKY8 cascade resulted in enhanced accumulation of PVY genomic RNA.6K2 of Turnip mosaic virus and p33 of Tomato bushy stunt virus also interacted with NbPLDa1 and induced the activation of MAPK-mediated immunity.Loss of function of NbPLDa1 inhibited virus-induced activation of MAPK cascades and promoted viral RNA accumulation.Thus,activation of MAPK-mediated immunity by NbPLDa1-derived PA is a common strategy employed by hosts to counteract positive-strand RNA virus infection.
