Rapid alkalinization factors(RALFs)in plants have been reported to dampen pathogenassociated molecular pattern(PAMP)-triggered immunity via suppressing PAMP-induced complex formation between the pattern recognition re...Rapid alkalinization factors(RALFs)in plants have been reported to dampen pathogenassociated molecular pattern(PAMP)-triggered immunity via suppressing PAMP-induced complex formation between the pattern recognition receptor(PRR)and its co-receptor BAK1.However,the direct and positive role of RALFs in plant immunity remains largely unknown.Herein,we report the direct and positive roles of a typical RALF,RALF22,in plant immunity.RALF22alone directly elicited a variety of typical immune responses and triggered resistance against the devastating necrotrophic fungal pathogen Sclerotinia sclerotiorum in a FERONIA(FER)-dependent manner.LORELEI(LRE)-like glycosylphosphatidylinositol(GPI)-anchored protein 1(LLG1)and NADPH oxidase RBOHD were required for RALF22-elicited reactive oxygen species(ROS)generation.The mutation of cysteines conserved in the C terminus of RALFs abolished,while the constitutive formation of two disulfide bridges between these cysteines promoted the RALF22-elicited ROS production and resistance against S.sclerotiorum,demonstrating the requirement of these cysteines in the functions of RALF22 in plant immunity.Furthermore,RALF22 amplified the Pep3-induced immune signal by dramatically increasing the abundance of PROPEP3 transcript and protein.Supply with RALF22 induced resistance against S.sclerotiorum in Brassica crop plants.Collectively,our results reveal that RALF22 triggers immune responses and augments the Pep3-induced immune signal in a FER-dependent manner,and exhibits the potential to be exploited as an immune elicitor in crop protection.展开更多
Plants perceive pathogen-associated molecular patterns(PAMPs)using plasma-membrane-localized pattern recognition receptors(PRRs)to activate broad-spectrum pattern-triggered immunity.However,the regulatory mechanisms t...Plants perceive pathogen-associated molecular patterns(PAMPs)using plasma-membrane-localized pattern recognition receptors(PRRs)to activate broad-spectrum pattern-triggered immunity.However,the regulatory mechanisms that ensure robust broad-spectrum plant immunity remain largely unknown.Here,we reveal that the transcription factor WRKY8 has a dual role in the transcriptional regulation of PRR genes:repressing expression of the nlp20/nlp24 receptor gene RLP23 while promoting that of the chitin receptor gene CERK1.SsNLP1 and SsNLP2,two nlp24-type PAMPs from the destructive fungal pathogen Sclerotinia sclerotiorum,activate two calcium-elicited kinases,CPK4 and CPK11,which phosphorylate WRKY8 and thus release its inhibition on RLP23 to promote accumulation of RLP23 transcripts.Meanwhile,SsNLPs activate the RLCK-type kinase PBL19,which phosphorylates WRKY8 and thus enhances accumulation of CERK1 transcripts.Intriguingly,RLP23 is repressed at later stage by PBL19-mediated phosphorylation of WRKY8,thus avoiding excessive immunity and enabling normal growth.Our findings unveil a plant strategy of“killing two birds with one stone”to elicit robust broad-spectrum immunity.This strategy is based on PAMP-triggered fine-tuning of a dual-role transcription factor to simultaneously amplify two PRRs that recognize PAMPs conserved across a wide range of pathogens.Moreover,our results reveal a novel plant strategy for balancing the trade-off between growth and immunity by fine-tuning the expression of multiple PRR genes.展开更多
基金financial y supported by grants from the National Natural Science Foundation of China (No.31871947)the Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding (No.2021C02064)the Zhejiang Provincial Natural Science Foundation of China (No.LZ18C140002)。
文摘Rapid alkalinization factors(RALFs)in plants have been reported to dampen pathogenassociated molecular pattern(PAMP)-triggered immunity via suppressing PAMP-induced complex formation between the pattern recognition receptor(PRR)and its co-receptor BAK1.However,the direct and positive role of RALFs in plant immunity remains largely unknown.Herein,we report the direct and positive roles of a typical RALF,RALF22,in plant immunity.RALF22alone directly elicited a variety of typical immune responses and triggered resistance against the devastating necrotrophic fungal pathogen Sclerotinia sclerotiorum in a FERONIA(FER)-dependent manner.LORELEI(LRE)-like glycosylphosphatidylinositol(GPI)-anchored protein 1(LLG1)and NADPH oxidase RBOHD were required for RALF22-elicited reactive oxygen species(ROS)generation.The mutation of cysteines conserved in the C terminus of RALFs abolished,while the constitutive formation of two disulfide bridges between these cysteines promoted the RALF22-elicited ROS production and resistance against S.sclerotiorum,demonstrating the requirement of these cysteines in the functions of RALF22 in plant immunity.Furthermore,RALF22 amplified the Pep3-induced immune signal by dramatically increasing the abundance of PROPEP3 transcript and protein.Supply with RALF22 induced resistance against S.sclerotiorum in Brassica crop plants.Collectively,our results reveal that RALF22 triggers immune responses and augments the Pep3-induced immune signal in a FER-dependent manner,and exhibits the potential to be exploited as an immune elicitor in crop protection.
基金National Natural Science Foundation of China(no.31871947)Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(no.2021C02064)+1 种基金Hainan Provincial Natural Science Foundation of China(no.324CXTD430)Zhejiang Provincial Natural Science Foundation of China(no.LZ18C140002).
文摘Plants perceive pathogen-associated molecular patterns(PAMPs)using plasma-membrane-localized pattern recognition receptors(PRRs)to activate broad-spectrum pattern-triggered immunity.However,the regulatory mechanisms that ensure robust broad-spectrum plant immunity remain largely unknown.Here,we reveal that the transcription factor WRKY8 has a dual role in the transcriptional regulation of PRR genes:repressing expression of the nlp20/nlp24 receptor gene RLP23 while promoting that of the chitin receptor gene CERK1.SsNLP1 and SsNLP2,two nlp24-type PAMPs from the destructive fungal pathogen Sclerotinia sclerotiorum,activate two calcium-elicited kinases,CPK4 and CPK11,which phosphorylate WRKY8 and thus release its inhibition on RLP23 to promote accumulation of RLP23 transcripts.Meanwhile,SsNLPs activate the RLCK-type kinase PBL19,which phosphorylates WRKY8 and thus enhances accumulation of CERK1 transcripts.Intriguingly,RLP23 is repressed at later stage by PBL19-mediated phosphorylation of WRKY8,thus avoiding excessive immunity and enabling normal growth.Our findings unveil a plant strategy of“killing two birds with one stone”to elicit robust broad-spectrum immunity.This strategy is based on PAMP-triggered fine-tuning of a dual-role transcription factor to simultaneously amplify two PRRs that recognize PAMPs conserved across a wide range of pathogens.Moreover,our results reveal a novel plant strategy for balancing the trade-off between growth and immunity by fine-tuning the expression of multiple PRR genes.
