To counter pathogen invasion,plants have evolved a large number of immune receptors,including membrane-resident pattern recognition receptors(PRRs)and intracellular nucleotide-binding and leucine-rich repeat receptors...To counter pathogen invasion,plants have evolved a large number of immune receptors,including membrane-resident pattern recognition receptors(PRRs)and intracellular nucleotide-binding and leucine-rich repeat receptors(NLRs).Our knowledge about PRR and NLR signaling mechanisms has expanded significantly over the past few years.Plant NLRs form multi-protein complexes called resistosomes in response to pathogen effectors,and the signaling mediated by NLR resistosomes converges on Ca2+-permeable channels.Ca2+-permeable channels important for PRR signaling have also been identified.These findings highlight a crucial role of Ca2+in triggering plant immune signaling.In this review,we first discuss the structural and biochemical mechanisms of non-canonical NLR Ca2+channels and then summarize our knowledge about immune-related Ca2+-permeable channels and their roles in PRR and NLR signaling.We also discuss the potential role of Ca2+in the intricate interaction between PRR and NLR signaling.展开更多
Plants have developed innate immune systems to fight against pathogenic fungi by monitoring pathogenic signals known as pathogen-associated molecular patterns(PAMP)and have established endo symbiosis with arbuscular m...Plants have developed innate immune systems to fight against pathogenic fungi by monitoring pathogenic signals known as pathogen-associated molecular patterns(PAMP)and have established endo symbiosis with arbuscular mycorrhizal(AM)fungi through recognition of mycorrhizal(Myc)factors.Chitin elicitor receptor kinase 1 of Oryza sativa subsp.Japonica(OsC ERK1)plays a bifunctional role in mediating both chitin-triggered immunity and symbiotic relationships with AM fungi.However,it remains unclear whether OsC ERK1 can directly recognize chitin molecules.In this study,we show that OsC ERK1 binds to the chitin hexamer((NAG)6)and tetramer((NAG)4)directly and determine the crystal structure of the OsC ERK1-(NAG)6complex at 2?.The structure shows that one OsC ERK1 is associated with one(NAG)6.Upon recognition,chitin hexamer binds OsC ERK1 by interacting with the shallow groove on the surface of LysM 2.These structural findings,complemented by mutational analyses,demonstrate that LysM 2 is crucial for recognition of both(NAG)6and(NAG)4.Altogether,these findings provide structural insights into the ability of OsC ERK1 in chitin perception,which will lead to a better understanding of the role of OsCERK1 in mediating both immunity and symbiosis in rice.展开更多
In Arabidopsis, the CLAVATA3/EMBRYO SURROUNDING REGION-RELATED （CLE） peptides play important roles in regulating proliferation and differentiation of plant-specific stem cells. Although receptors of CLEs are reporte...In Arabidopsis, the CLAVATA3/EMBRYO SURROUNDING REGION-RELATED （CLE） peptides play important roles in regulating proliferation and differentiation of plant-specific stem cells. Although receptors of CLEs are reported to be leucine-rich repeat receptor kinases, the mechanisms underlying CLE-induced receptor activation remain largely unknown. Here we show that SOMATIC EMBRYOGENESIS RECEPTOR KINASEs （SERKs） serve as co-receptors in CLE41/TDIF-PXY signaling to regulate plant vascular development. TDIF induces interaction of its receptor PXY with SERKs in vitro and in vivo. Furthermore, the serk1-1 serk2-1 bakl-5 mutant plants are less sensitive to TDIF, phenocopying the pxy mutant with a compromised promotion of procambial cell proliferation. Crystal structure of the PXY-TDIF-SERK2 complex reveals that the last amino acid of TDIF conserved among CLEs and other evolutionary-related peptides is important for the interaction between SERK2 and PXY. Taken together, our current study identifies SERKs as signaling components of the TDIF-PXY pathway and suggests a conserved activation mechanism of CLE receptors.展开更多
NLRs constitute intracellular immune receptors in both plants and animals. Direct or indirect ligand recognition results in formation of oligomeric NLR complexes to mediate immune signaling. Over the past 20 years, ra...NLRs constitute intracellular immune receptors in both plants and animals. Direct or indirect ligand recognition results in formation of oligomeric NLR complexes to mediate immune signaling. Over the past 20 years, rapid progress has been made in our understanding of NLR signaling. Structural and biochemical studies provide insight into molecular basis of autoinhibition,ligand recognition, and resistosome/inflammasome formation of several NLRs. In this review, we summarize these studies focusing on the structural aspect of NLRs. We also discuss the analogies and differences between plant and animal NLRs in their mechanisms of action and how the available knowledge may shed light on the signaling mechanisms of other NLRs.展开更多
基金Young Elite Scientists Sponsorship Program by CAST(grant YESS20210018 to J.W.)National Natural Science Foundation of China(grant 32271253 to J.W.)+3 种基金Alexander von Humboldt Foundation(professorship to J.C.)Max-Planck-Gesellschaft(a Max Planck fellowship to J.C.)Deutsche Forschungsgemeinschaft(grant SFB-1403-414786233 to J.C.)Germany's Excellence Strategy CEPLAS(EXC-2048/1,project 390686111 to J.C.).
文摘To counter pathogen invasion,plants have evolved a large number of immune receptors,including membrane-resident pattern recognition receptors(PRRs)and intracellular nucleotide-binding and leucine-rich repeat receptors(NLRs).Our knowledge about PRR and NLR signaling mechanisms has expanded significantly over the past few years.Plant NLRs form multi-protein complexes called resistosomes in response to pathogen effectors,and the signaling mediated by NLR resistosomes converges on Ca2+-permeable channels.Ca2+-permeable channels important for PRR signaling have also been identified.These findings highlight a crucial role of Ca2+in triggering plant immune signaling.In this review,we first discuss the structural and biochemical mechanisms of non-canonical NLR Ca2+channels and then summarize our knowledge about immune-related Ca2+-permeable channels and their roles in PRR and NLR signaling.We also discuss the potential role of Ca2+in the intricate interaction between PRR and NLR signaling.
基金financially supported by the National Natural Science Foundation of China (31421001 to Jijie Chai and 31971119 and 32171193 to Zhifu Han)the Alexander von Humboldt Foundation (Humboldt professorship to Jijie Chai)+1 种基金the MaxPlanck-Gesellschaft (Max Planck fellowship to Jijie Chai),Deutsche Forschungsgemeinschaft (SFB-1403-414786233 to Jijie Chai)Germany’s Excellence Strategy CEPLAS (EXC-2048/1,Project 390686111 to Jijie Chai)。
文摘Plants have developed innate immune systems to fight against pathogenic fungi by monitoring pathogenic signals known as pathogen-associated molecular patterns(PAMP)and have established endo symbiosis with arbuscular mycorrhizal(AM)fungi through recognition of mycorrhizal(Myc)factors.Chitin elicitor receptor kinase 1 of Oryza sativa subsp.Japonica(OsC ERK1)plays a bifunctional role in mediating both chitin-triggered immunity and symbiotic relationships with AM fungi.However,it remains unclear whether OsC ERK1 can directly recognize chitin molecules.In this study,we show that OsC ERK1 binds to the chitin hexamer((NAG)6)and tetramer((NAG)4)directly and determine the crystal structure of the OsC ERK1-(NAG)6complex at 2?.The structure shows that one OsC ERK1 is associated with one(NAG)6.Upon recognition,chitin hexamer binds OsC ERK1 by interacting with the shallow groove on the surface of LysM 2.These structural findings,complemented by mutational analyses,demonstrate that LysM 2 is crucial for recognition of both(NAG)6and(NAG)4.Altogether,these findings provide structural insights into the ability of OsC ERK1 in chitin perception,which will lead to a better understanding of the role of OsCERK1 in mediating both immunity and symbiosis in rice.
基金This research was funded by Projects of International Cooperation and Exchanges NSFC （31420103906）, the National Science Foundation of China （31130063 and 31421001） and the Chinese Ministry of Science and Technology （2015CB910200） to J.C and the National Science Foun- dation of China （31370173） to L.Q.ACKNOWLEDGEMENTS We thank Jianhua He at Shanghai Synchrotron Radiation Facility （SSRF） for assistance with X-ray data collection, Dr. Hiroo Fukuda （Tokyo University, Japan） for the pxy-5 single mutant seeds, Dr. Libo Shah （Texas A＆M University） for serk1-1 serk2-1^＋/- bakl-5 mutant seeds, and Dr. Jia Li for other serk mutant seeds, SERK1, SERK2 entry vectors, and pSERKI： SERK1-GFP vector. No conflict of interest declared.
文摘In Arabidopsis, the CLAVATA3/EMBRYO SURROUNDING REGION-RELATED （CLE） peptides play important roles in regulating proliferation and differentiation of plant-specific stem cells. Although receptors of CLEs are reported to be leucine-rich repeat receptor kinases, the mechanisms underlying CLE-induced receptor activation remain largely unknown. Here we show that SOMATIC EMBRYOGENESIS RECEPTOR KINASEs （SERKs） serve as co-receptors in CLE41/TDIF-PXY signaling to regulate plant vascular development. TDIF induces interaction of its receptor PXY with SERKs in vitro and in vivo. Furthermore, the serk1-1 serk2-1 bakl-5 mutant plants are less sensitive to TDIF, phenocopying the pxy mutant with a compromised promotion of procambial cell proliferation. Crystal structure of the PXY-TDIF-SERK2 complex reveals that the last amino acid of TDIF conserved among CLEs and other evolutionary-related peptides is important for the interaction between SERK2 and PXY. Taken together, our current study identifies SERKs as signaling components of the TDIF-PXY pathway and suggests a conserved activation mechanism of CLE receptors.
基金supported by the Alexander von Humboldt Foundation(Humboldt Professorship of Jijie Chai)。
文摘NLRs constitute intracellular immune receptors in both plants and animals. Direct or indirect ligand recognition results in formation of oligomeric NLR complexes to mediate immune signaling. Over the past 20 years, rapid progress has been made in our understanding of NLR signaling. Structural and biochemical studies provide insight into molecular basis of autoinhibition,ligand recognition, and resistosome/inflammasome formation of several NLRs. In this review, we summarize these studies focusing on the structural aspect of NLRs. We also discuss the analogies and differences between plant and animal NLRs in their mechanisms of action and how the available knowledge may shed light on the signaling mechanisms of other NLRs.
