Pathogen-associated molecular patterns(PAMPs)-triggered immunity(PTI)is an important component of plant innate immunity.In a previous study,we showed that the PAMP flg22 from Xanthomonas citri ssp.citri(Xflg22),the ca...Pathogen-associated molecular patterns(PAMPs)-triggered immunity(PTI)is an important component of plant innate immunity.In a previous study,we showed that the PAMP flg22 from Xanthomonas citri ssp.citri(Xflg22),the causal agent of citrus canker,induced PTI in citrus,which correlated with the observed levels of canker resistance.Here,we identified and sequenced two bacterial flagellin/flg22 receptors(FLS2-1 and FLS2-2)from‘Duncan’grapefruit(Citrus paradisi,CpFLS2-1 and CpFLS2-2)and‘Sun Chu Sha’mandarin(C.reticulata,CrFLS2-1 and CrFLS2-2).We were able to isolate only one FLS2 from‘Nagami’kumquat(Fortunella margarita,FmFLS2-1)and gene flanking sequences suggest a rearrangement event that resulted in the deletion of FLS2-2 from the genome.Phylogenetic analysis,gene structure and presence of critical amino acid domains all indicate we identified the true FLS2 genes in citrus.FLS2-2 was more transcriptionally responsive to Xflg22 than FLS2-1,with induced expression levels higher in canker-resistant citrus than in susceptible ones.Interestingly,‘Nagami’kumquat showed the highest FLS2-1 steady-state expression levels,although it was not induced by Xflg22.We selected FmFLS2-1,CrFLS2-2 and CpFLS2-2 to further evaluate their capacity to enhance bacterial resistance using Agrobacterium-mediated transient expression assays.Both FmFLS2-1 and CrFLS2-2,the two proteins from canker-resistant species,conferred stronger Xflg22 responses and reduced canker symptoms in leaves of the susceptible grapefruit genotype.These two citrus genes will be useful resources to enhance PTI and achieve resistance against canker and possibly other bacterial pathogens in susceptible citrus types.展开更多
Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recogni...Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recognize S. enterica and raise defense responses. Nonetheless, the molecular mechanisms controlling the interaction of S. enterica with plants are still largely unclear. Here, we show that flagellin from S. enterica represents a prominent pathogenassociated molecular pattern （PAMP） in Arabidopsis thaliana, which induces PAMP-triggered immunity （PTI） via the recognition of the fig22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system （T3SS） mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the fig22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI.展开更多
The receptor-like kinase FLAGELLIN-SENSITIVE 2(FLS2)functions as a bacterialflagellin receptor local-ized on the cell membrane of plants.In Arabidopsis,the co-receptor BRI1-ASSOCIATED RECEPTOR KI-NASE 1(BAK1)cooperate...The receptor-like kinase FLAGELLIN-SENSITIVE 2(FLS2)functions as a bacterialflagellin receptor local-ized on the cell membrane of plants.In Arabidopsis,the co-receptor BRI1-ASSOCIATED RECEPTOR KI-NASE 1(BAK1)cooperates with FLS2 to detect theflagellin epitopeflg22,resulting in formation of a signaling complex that triggers plant defense responses.However,the co-receptor responsible for recog-nizing and signaling theflg22 epitope in rice remains to be determined,and the precise structural mecha-nism underlying FLS2-mediated signal activation and transduction has not been claried.This study pre-sents the structural characterization of a kinase-dead mutant of the intracellular kinase domain of OsFLS2(OsFLS2-KDD1013A)in complex with ATP or ADP,resolved at resolutions of 1.98 A˚and 2.09 A˚,respectively.Structural analysis revealed that OsFLS2 can adopt an active conformation in the absence of phosphorylation,although it exhibits only weak basal catalytic activity for autophosphorylation.Subse-quent investigations demonstrated that OsSERK2 effectively phosphorylates OsFLS2,which reciprocally phosphorylates OsSERK2,leading to complete activation of OsSERK2 and rapid phosphorylation of the downstream substrate receptor-like cytoplasmic kinases OsRLCK176 and OsRLCK185.Through mass spectrometry experiments,we successfully identied critical autophosphorylation sites on OsSERK2,as well as sites transphosphorylated by OsFLS2.Furthermore,we demonstrated the interaction between OsSERK2 and OsFLS2,which is enhanced in the presence offlg22.Genetic evidence suggests that OsRLCK176 and OsRLCK185 may function downstream of the OsFLS2-mediated signaling pathway.Our study reveals the molecular mechanism by which OsFLS2 mediates signal transduction pathways in rice and provides a valuable example for understanding RLK-mediated signaling pathways in plants.展开更多
Background:Nuclear receptor-binding SET domain 2(NSD2)is a histone methyltrans-ferase,that catalyzes dimethylation of lysine 36 of histone 3(H3K36me2)and is asso-ciated with active transcription of a series of genes.N...Background:Nuclear receptor-binding SET domain 2(NSD2)is a histone methyltrans-ferase,that catalyzes dimethylation of lysine 36 of histone 3(H3K36me2)and is asso-ciated with active transcription of a series of genes.NSD2 is overexpressed in multiple types of solid human tumors and has been proven to be related to unfavorable prog-nosis in several types of tumors.Methods:We established a mouse model in which the NSD2 gene was conditionally knocked out in intestinal epithelial cells.We used azoxymethane and dextran sodium sulfate to chemically induce murine colorectal cancer.The development of colorectal tumors were investigated using post-necropsy quantification,immunohistochemistry,and enzyme-linked immunosorbent assay(ELISA).Results:Compared with wild-type(WT)control mice,NSD2^(fl/fl)-Vil1-Cre mice exhib-ited significantly decreased tumor numbers,histopathological changes,and cytokine expression in colorectal tumors.Conclusions:Conditional knockout of NSD2 in intestinal epithelial cells significantly inhibits colorectal cancer progression.展开更多
Numerical simulation has been widely applied to the assessment of debris flow hazards. In East Asia and especially Taiwan, the most widely used numerical programs are FLO-2D and Debris-aD. Although these two programs ...Numerical simulation has been widely applied to the assessment of debris flow hazards. In East Asia and especially Taiwan, the most widely used numerical programs are FLO-2D and Debris-aD. Although these two programs are applied to the same engineering tasks, they are different in many aspects. These two programs were compared according to their fundamental theories, input and output data, computational algorithms and results. Using both programs, the simulations of a real debris flow with abundant granular material induced by landslides at Xinfa village in southern Taiwan are performed for comparison. The simulation results show that Debris- 2D gives better assessment in hazard area delineating and flow depth predicting. Therefore, Debris-2D is better for simulation of granular debris flows.展开更多
The ocean could profoundly modulate the ever-increasing atmospheric CO_(2) by air-sea CO_(2) exchange process,which is also able to cause signifi cant changes of physical and biogeochemical properties in return.In thi...The ocean could profoundly modulate the ever-increasing atmospheric CO_(2) by air-sea CO_(2) exchange process,which is also able to cause signifi cant changes of physical and biogeochemical properties in return.In this study,we assessed the long-term average and spatial-temporal variability of global air-sea CO_(2) exchange fl ux(F CO_(2))since 1980s basing on the results of 18 Coupled Model Intercomparison Project Phase 6(CMIP6)Earth System Models(ESMs).Our fi ndings indicate that the CMIP6 ESMs simulated global CO_(2) sink in recent three decades ranges from 1.80 to 2.24 Pg C/a,which is coincidence with the results of cotemporaneous observations.What’s more,the CMIP6 ESMs consistently show that the global oceanic CO_(2) sink has gradually intensifi ed since 1980s as well as the observations.This study confi rms the simulated F CO_(2) could reach agreements with the observations in the aspect of primary climatological characteristics,however,the simulation skills of CIMP6 ESMs in diverse open-sea biomes are unevenness.None of the 18 CMIP6 ESMs could reproduce the observed F CO_(2) increasement in the central-eastern tropical Pacifi c and the midlatitude Southern Ocean.Defi ciencies of some CMIP6 ESMs in reproducing the atmospheric pressure systems of the Southern Hemisphere and the El Niño-Southern Oscillation(ENSO)mode of the tropical Pacifi c are probably the major causes.展开更多
基金This research was financially supported by the Citrus Research and Development Foundation(CRDF).
文摘Pathogen-associated molecular patterns(PAMPs)-triggered immunity(PTI)is an important component of plant innate immunity.In a previous study,we showed that the PAMP flg22 from Xanthomonas citri ssp.citri(Xflg22),the causal agent of citrus canker,induced PTI in citrus,which correlated with the observed levels of canker resistance.Here,we identified and sequenced two bacterial flagellin/flg22 receptors(FLS2-1 and FLS2-2)from‘Duncan’grapefruit(Citrus paradisi,CpFLS2-1 and CpFLS2-2)and‘Sun Chu Sha’mandarin(C.reticulata,CrFLS2-1 and CrFLS2-2).We were able to isolate only one FLS2 from‘Nagami’kumquat(Fortunella margarita,FmFLS2-1)and gene flanking sequences suggest a rearrangement event that resulted in the deletion of FLS2-2 from the genome.Phylogenetic analysis,gene structure and presence of critical amino acid domains all indicate we identified the true FLS2 genes in citrus.FLS2-2 was more transcriptionally responsive to Xflg22 than FLS2-1,with induced expression levels higher in canker-resistant citrus than in susceptible ones.Interestingly,‘Nagami’kumquat showed the highest FLS2-1 steady-state expression levels,although it was not induced by Xflg22.We selected FmFLS2-1,CrFLS2-2 and CpFLS2-2 to further evaluate their capacity to enhance bacterial resistance using Agrobacterium-mediated transient expression assays.Both FmFLS2-1 and CrFLS2-2,the two proteins from canker-resistant species,conferred stronger Xflg22 responses and reduced canker symptoms in leaves of the susceptible grapefruit genotype.These two citrus genes will be useful resources to enhance PTI and achieve resistance against canker and possibly other bacterial pathogens in susceptible citrus types.
文摘Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recognize S. enterica and raise defense responses. Nonetheless, the molecular mechanisms controlling the interaction of S. enterica with plants are still largely unclear. Here, we show that flagellin from S. enterica represents a prominent pathogenassociated molecular pattern （PAMP） in Arabidopsis thaliana, which induces PAMP-triggered immunity （PTI） via the recognition of the fig22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system （T3SS） mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the fig22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI.
基金supported by grants from the National Natural Science Foundation of China (32160064 and 32360085)the Guangxi Natural Science Foundation (2020GXNSFFA297007)+2 种基金the Ba-Gui Scholar Program of Guangxi (to Z.G.H.)the State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources (sklcusa-a02)the Innovation Project of Guangxi Graduate Education (YCBZ2023037).
文摘The receptor-like kinase FLAGELLIN-SENSITIVE 2(FLS2)functions as a bacterialflagellin receptor local-ized on the cell membrane of plants.In Arabidopsis,the co-receptor BRI1-ASSOCIATED RECEPTOR KI-NASE 1(BAK1)cooperates with FLS2 to detect theflagellin epitopeflg22,resulting in formation of a signaling complex that triggers plant defense responses.However,the co-receptor responsible for recog-nizing and signaling theflg22 epitope in rice remains to be determined,and the precise structural mecha-nism underlying FLS2-mediated signal activation and transduction has not been claried.This study pre-sents the structural characterization of a kinase-dead mutant of the intracellular kinase domain of OsFLS2(OsFLS2-KDD1013A)in complex with ATP or ADP,resolved at resolutions of 1.98 A˚and 2.09 A˚,respectively.Structural analysis revealed that OsFLS2 can adopt an active conformation in the absence of phosphorylation,although it exhibits only weak basal catalytic activity for autophosphorylation.Subse-quent investigations demonstrated that OsSERK2 effectively phosphorylates OsFLS2,which reciprocally phosphorylates OsSERK2,leading to complete activation of OsSERK2 and rapid phosphorylation of the downstream substrate receptor-like cytoplasmic kinases OsRLCK176 and OsRLCK185.Through mass spectrometry experiments,we successfully identied critical autophosphorylation sites on OsSERK2,as well as sites transphosphorylated by OsFLS2.Furthermore,we demonstrated the interaction between OsSERK2 and OsFLS2,which is enhanced in the presence offlg22.Genetic evidence suggests that OsRLCK176 and OsRLCK185 may function downstream of the OsFLS2-mediated signaling pathway.Our study reveals the molecular mechanism by which OsFLS2 mediates signal transduction pathways in rice and provides a valuable example for understanding RLK-mediated signaling pathways in plants.
基金supported by the National Key Research and Development Program of China (2022YFF0710705)the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2021-I2M-1-0 13)+2 种基金funding support from the Special Research Fund for Central UniversitiesPeking Union Medical College (3332022182)the 111 Project (B20095)
文摘Background:Nuclear receptor-binding SET domain 2(NSD2)is a histone methyltrans-ferase,that catalyzes dimethylation of lysine 36 of histone 3(H3K36me2)and is asso-ciated with active transcription of a series of genes.NSD2 is overexpressed in multiple types of solid human tumors and has been proven to be related to unfavorable prog-nosis in several types of tumors.Methods:We established a mouse model in which the NSD2 gene was conditionally knocked out in intestinal epithelial cells.We used azoxymethane and dextran sodium sulfate to chemically induce murine colorectal cancer.The development of colorectal tumors were investigated using post-necropsy quantification,immunohistochemistry,and enzyme-linked immunosorbent assay(ELISA).Results:Compared with wild-type(WT)control mice,NSD2^(fl/fl)-Vil1-Cre mice exhib-ited significantly decreased tumor numbers,histopathological changes,and cytokine expression in colorectal tumors.Conclusions:Conditional knockout of NSD2 in intestinal epithelial cells significantly inhibits colorectal cancer progression.
基金support from National Science Council of Chinese Taipei(Grant No.NSC 96-2625-Z-002-006-MY3)
文摘Numerical simulation has been widely applied to the assessment of debris flow hazards. In East Asia and especially Taiwan, the most widely used numerical programs are FLO-2D and Debris-aD. Although these two programs are applied to the same engineering tasks, they are different in many aspects. These two programs were compared according to their fundamental theories, input and output data, computational algorithms and results. Using both programs, the simulations of a real debris flow with abundant granular material induced by landslides at Xinfa village in southern Taiwan are performed for comparison. The simulation results show that Debris- 2D gives better assessment in hazard area delineating and flow depth predicting. Therefore, Debris-2D is better for simulation of granular debris flows.
基金Supported by the National Natural Science Foundation of China(No.41806133)the Marine S&T Fund of Shandong Province for the Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2022QNLM040003-1)+1 种基金the National Key Research and Development Program of China(No.2017YFA0603204)the Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry,MNR(No.GCMAC1905)。
文摘The ocean could profoundly modulate the ever-increasing atmospheric CO_(2) by air-sea CO_(2) exchange process,which is also able to cause signifi cant changes of physical and biogeochemical properties in return.In this study,we assessed the long-term average and spatial-temporal variability of global air-sea CO_(2) exchange fl ux(F CO_(2))since 1980s basing on the results of 18 Coupled Model Intercomparison Project Phase 6(CMIP6)Earth System Models(ESMs).Our fi ndings indicate that the CMIP6 ESMs simulated global CO_(2) sink in recent three decades ranges from 1.80 to 2.24 Pg C/a,which is coincidence with the results of cotemporaneous observations.What’s more,the CMIP6 ESMs consistently show that the global oceanic CO_(2) sink has gradually intensifi ed since 1980s as well as the observations.This study confi rms the simulated F CO_(2) could reach agreements with the observations in the aspect of primary climatological characteristics,however,the simulation skills of CIMP6 ESMs in diverse open-sea biomes are unevenness.None of the 18 CMIP6 ESMs could reproduce the observed F CO_(2) increasement in the central-eastern tropical Pacifi c and the midlatitude Southern Ocean.Defi ciencies of some CMIP6 ESMs in reproducing the atmospheric pressure systems of the Southern Hemisphere and the El Niño-Southern Oscillation(ENSO)mode of the tropical Pacifi c are probably the major causes.
