The chloroplast is a critical battleground in the arms race between plants and pathogens.Among microbe-secreted mycotoxins,tenuazonic acid(TeA),produced by the genus Alternaria and other phytopathogenic fungi,inhibits...The chloroplast is a critical battleground in the arms race between plants and pathogens.Among microbe-secreted mycotoxins,tenuazonic acid(TeA),produced by the genus Alternaria and other phytopathogenic fungi,inhibits photosynthesis,leading to a burst of photosynthetic singlet oxygen(1O2)that is implicated in damage and chloroplast-to-nucleus retrograde signaling.Despite the signicant crop damage caused by Alternaria pathogens,our understanding of the molecular mechanism by which TeA promotes pathoge-nicity and cognate plant defense responses remains fragmentary.We now reveal that A.alternata induces necrotrophic foliar lesions by harnessing EXECUTER1(EX1)/EX2-mediated chloroplast-to-nucleus retro-grade signaling activated by TeA toxin–derived photosynthetic 1O2 in Arabidopsis thaliana.Mutation of the 1O2-sensitive EX1-W643 residue or complete deletion of the EX1 singlet oxygen sensor domain compro-mises expression of 1O2-responsive nuclear genes and foliar lesions.We also found that TeA toxin rapidly induces nuclear genes implicated in jasmonic acid(JA)synthesis and signaling,and EX1-mediated retro-grade signaling appears to be critical for establishing a signaling cascade from 1O2 to JA.The present study sheds new light on the foliar pathogenicity of A.alternata,during which EX1-dependent 1O2 signaling in-duces JA-dependent foliar cell death.展开更多
基金funded by the National Key R&D Program (2021YFD1700100,2017YFD0201304)the Jiangsu Agricultural Science and Technology Innovation Fund (CX (21)3093)to S.C.+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB27040102)the National Natural Science Foundation of China (NSFC) (31871397)to C.K.
文摘The chloroplast is a critical battleground in the arms race between plants and pathogens.Among microbe-secreted mycotoxins,tenuazonic acid(TeA),produced by the genus Alternaria and other phytopathogenic fungi,inhibits photosynthesis,leading to a burst of photosynthetic singlet oxygen(1O2)that is implicated in damage and chloroplast-to-nucleus retrograde signaling.Despite the signicant crop damage caused by Alternaria pathogens,our understanding of the molecular mechanism by which TeA promotes pathoge-nicity and cognate plant defense responses remains fragmentary.We now reveal that A.alternata induces necrotrophic foliar lesions by harnessing EXECUTER1(EX1)/EX2-mediated chloroplast-to-nucleus retro-grade signaling activated by TeA toxin–derived photosynthetic 1O2 in Arabidopsis thaliana.Mutation of the 1O2-sensitive EX1-W643 residue or complete deletion of the EX1 singlet oxygen sensor domain compro-mises expression of 1O2-responsive nuclear genes and foliar lesions.We also found that TeA toxin rapidly induces nuclear genes implicated in jasmonic acid(JA)synthesis and signaling,and EX1-mediated retro-grade signaling appears to be critical for establishing a signaling cascade from 1O2 to JA.The present study sheds new light on the foliar pathogenicity of A.alternata,during which EX1-dependent 1O2 signaling in-duces JA-dependent foliar cell death.
