The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of pro...The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of proinflammatory cytokines and reactive oxygen species, phagocytosis, and induced programmed cell death are processes initiated by innate immune cells in order to combat invading pathogens. However, pathogens have evolved various virulence mechanisms to subvert these responses. One strategy utilized by Gram-negative bacterial pathogens is the deployment of a complex machine termed the type Ⅲ secretion system(T3SS). The T3SS is composed of a syringe-like needle structure and the effector proteins that are injected directly into a target host cell to disrupt a cellular response. The three human pathogenic Yersinia spp.(Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are Gramnegative bacteria that share in common a 70 kb virulence plasmid which encodes the T3 SS. Translocation of the Yersinia effector proteins(YopE, YopH, YopT, YopM, YpkA/YopO, and YopP/J) into the target host cell results in disruption of the actin cytoskeleton to inhibit phagocytosis, downregulation of proinflammatory cytokine/chemokine production, and induction of cellular apoptosis of the target cell. Over the past 25 years, studies on the Yersinia effector proteins have unveiled tremendous knowledge of how the effectors enhance Yersinia virulence. Recently, the long awaited crystal structure of YpkA has been solved providing further insights into the activation of the YpkA kinase domain. Multisite autophosphorylation by YpkA to activate its kinase domain was also shown and postulated to serve as a mechanism to bypass regulation by host phosphatases. In addition, novel Yersinia effector protein targets, such as caspase-1, and signaling pathways including activation of the inflammasome were identified. In this review, we summarize the recent discoveries made on Yersinia effector proteins and their contribution to Yersinia pathogenesis.展开更多
In this study,Hy322 gene was cloned from Vibrio alginolyticus.The total length of its gene was 969 bp,and it could encode 322 amino acids.The physicochemical properties,protein structure,genetic evolutionary relations...In this study,Hy322 gene was cloned from Vibrio alginolyticus.The total length of its gene was 969 bp,and it could encode 322 amino acids.The physicochemical properties,protein structure,genetic evolutionary relationship and antigenic characteristics of the effector protein Hy322 of V.alginolyticus HY9901 type Ⅲ secretion system were studied and analyzed by bioinformatics methods and tools.The results showed that Hy322 is an unstable hydrophilic and acidic protein without a transmembrane region and a signal peptide,and secondary structure to α-helix.The evolutionary analysis showed that V.alginolyticus HY9901 and V.harveyi were clustered together,which indicated that the genetic relationship between the two species was closest.HY322 contains a FliN super family conserved domain associated with Flagellar motor switch.Bioinformatics analysis showed that the B-cell preponderant epitopes of Hy322 might be localized in the regions of 32-33,100-102,138-140,215-216,235-238 and 246-249.The 3D structure model of Hy322 subunit was simulated by SWISS-MODEL software and itwas found that the yscQ of Yersinia were similar and the similarity was 42.25%.In this study,the feasibility of Hy322 as a common antigen of Vibrio was verified from the perspective of bioinformatics,which laid the foundation for the next step in vaccine development.展开更多
An ideal type-Ⅲnodal point is generated by crossing a completely flat band and a dispersive band along a certain momentum direction.To date,the type-Ⅲnodal points found in two-dimensional(2D)materials have been most...An ideal type-Ⅲnodal point is generated by crossing a completely flat band and a dispersive band along a certain momentum direction.To date,the type-Ⅲnodal points found in two-dimensional(2D)materials have been mostly accidental and random rather than ideal cases,and no one mentions what kind of lattice can produce ideal nodal points.Here,we propose that ideal type-Ⅲnodal points can be obtained in a diamond-like lattice.The flat bands in the lattice originate from destructive interference of wavefunctions,and thus are intrinsic and robust.Moreover,the specific lattice can be realized in some 2D carbon networks,such as T-graphene and its derivatives.All the carbon structures possess type-ⅢDirac points.In two of the structures,consisting of triangular carbon rings,the type-ⅢDirac points are located just on the Fermi level and the Fermi surface is very clean.Our research not only opens a door to finding the ideal type-ⅢDirac points,but also provides 2D materials for exploring their physical properties experimentally.展开更多
目的对病原菌Ⅲ型分泌系统(TTSS)效应蛋白在非致病菌中进行直系同源基因预测,以获得病原菌Ⅲ型分泌系统特有效应蛋白,并进一步对特有效应蛋白模体构成进行分析,旨在更深入地认识TTSS效应蛋白,为理论研究和生物学实验提供参考。方法利用...目的对病原菌Ⅲ型分泌系统(TTSS)效应蛋白在非致病菌中进行直系同源基因预测,以获得病原菌Ⅲ型分泌系统特有效应蛋白,并进一步对特有效应蛋白模体构成进行分析,旨在更深入地认识TTSS效应蛋白,为理论研究和生物学实验提供参考。方法利用彼此最佳blast方法对效应蛋白在构建的非致病性细菌蛋白质数据库中进行直系同源基因预测,并利用Inter Pro Scan对预测获得的特有效应蛋白序列进行模体搜索分析。结果在49个收集整理的致病菌Ⅲ型分泌系统效应蛋白序列中,有18个效应蛋白在非致病菌中存在直系同源基因,31个效应蛋白(即TTSS特有效应蛋白)在非致病菌中没有直系同源基因;对31个Ⅲ型分泌系统特有效应蛋白序列进行模体分析,获得了12个效应蛋白特有模体。结论 31个致病菌Ⅲ型分泌系统特有效应蛋白序列的获得,为更精确地在致病性细菌基因组内预测获得新的效应蛋白序列奠定了基础;12个效应蛋白特有模体的获得及其基因本体注释分析进一步理解了效应蛋白的作用机制。展开更多
Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type Ⅲ effectors(T3Es)to cause disease.In this study,we isolate a pathogenic R.solanacearum strain named P380 from tomato rhi...Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type Ⅲ effectors(T3Es)to cause disease.In this study,we isolate a pathogenic R.solanacearum strain named P380 from tomato rhizosphere.Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants.DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression,ROS burst,and callose deposition.RipAE,RipU,and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana.The derivatives RipC1^(△DDXDX(T/V))and RipW^(△DDKXXQ)but not RipAE^(K310R) fail to suppress ROS burst.Moreover,RipAE^(K310R) and RipW^(△DDKXXQ) retain the cell death elicitation ability.RipAE and RipW are associated with salicylic acid and jasmonic acid pathways,respectively.RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants.The five core T3Es localize in diverse subcellular organelles of nucleus,plasma membrane,endoplasmic reticulum,and Golgi network.The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N.benthamiana.These results indicate that the core T3Es in R.solanacearum play diverse roles in plantpathogen interactions.展开更多
Plant stomata close rapidly in response to a rise in the plant hormone abscisic acid(ABA)or salicylic acid(SA)and after recognition of pathogenassociated molecular patterns(PAMPs).Stomatal closure is the result of vac...Plant stomata close rapidly in response to a rise in the plant hormone abscisic acid(ABA)or salicylic acid(SA)and after recognition of pathogenassociated molecular patterns(PAMPs).Stomatal closure is the result of vacuolar convolution,ion efflux,and changes in turgor pressure in guard cells.Phytopathogenic bacteria secrete typeⅢeffectors(T3Es)that interfere with plant defense mechanisms,causing severe plant disease symptoms.Here,we show that the virulence and infection of Xanthomonas oryzae pv.oryzicola(Xoc),which is the causal agent of rice bacterial leaf streak disease,drastically increased in transgenic rice(Oryza sativa L.)plants overexpressing the Xoc T3E gene Xop AP,which encodes a protein annotated as a lipase.We discovered that Xop AP binds to phosphatidylinositol 3,5-bisphosphate(Ptd Ins(3,5)P_(2)),a memb rane phospholipid that functions in p H control in lysosomes,membrane dynamics,and protein trafficking.Xop AP inhibited the acidification of vacuoles by competing with vacuolar H^(+)-pyrophosphatase(V-PPase)for binding to Ptd Ins(3,5)P_(2),leading to stomatal opening.Transgenic rice overexpressing Xop AP also showed inhibition of stomatal closure when challenged by Xoc infection and treatment with the PAMP flg22.Moreover,Xop AP suppressed flg22-induced gene expression,reactive oxygen species burst and callose deposition in host plants,demonstrating that Xop AP subverts PAMP-triggered immunity during Xoc infection.Taken together,these findings demonstrate that Xop AP overcomes stomatal immunity in plants by binding to lipids.展开更多
Soybean is one of the most important food crops worldwide.Like other legumes,soybean can form symbiotic relationships with Rhizobium species.Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for...Soybean is one of the most important food crops worldwide.Like other legumes,soybean can form symbiotic relationships with Rhizobium species.Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for sustainable agriculture.Type Ⅲ effectors(T3Es)are essential regulators of the establishment of the symbiosis,and nodule number is a feature of nitrogen-affected nodulation.However,genes encoding T3Es at quantitative trait loci(QTLs)related to nodulation have rarely been identified.Chromosome segment substitution lines(CSSLs)have a common genetic background but only a few loci with heterogeneous genetic information;thus,they are suitable materials for identifying candidate genes at a target locus.In this study,a CSSL population was used to identify the QTLs related to nodule number in soybean.Single nucleotide polymorphism(SNP)markers and candidate genes within the QTLs interval were detected,and it was determined which genes showed differential expression between isolines.Four candidate genes(GmCDPK28,GmNAC1,GmbHLH,and GmERF5)linked to the SNPs were identified as being related to nodule traits and pivotal processes and pathways involved in symbiosis establishment.A candidate gene(GmERF5)encoding a transcription factor that may interact directly with the T3E NopAA was identified.The confirmed CSSLs with important segments and candidate genes identified in this study are valuable resources for further studies on the genetic network and T3Es involved in the signaling pathway that is essential for symbiosis establishment.展开更多
基金Supported by the ASM Robert D Watkins Graduate FellowshipUC Davis Hellman Fellowship
文摘The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of proinflammatory cytokines and reactive oxygen species, phagocytosis, and induced programmed cell death are processes initiated by innate immune cells in order to combat invading pathogens. However, pathogens have evolved various virulence mechanisms to subvert these responses. One strategy utilized by Gram-negative bacterial pathogens is the deployment of a complex machine termed the type Ⅲ secretion system(T3SS). The T3SS is composed of a syringe-like needle structure and the effector proteins that are injected directly into a target host cell to disrupt a cellular response. The three human pathogenic Yersinia spp.(Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are Gramnegative bacteria that share in common a 70 kb virulence plasmid which encodes the T3 SS. Translocation of the Yersinia effector proteins(YopE, YopH, YopT, YopM, YpkA/YopO, and YopP/J) into the target host cell results in disruption of the actin cytoskeleton to inhibit phagocytosis, downregulation of proinflammatory cytokine/chemokine production, and induction of cellular apoptosis of the target cell. Over the past 25 years, studies on the Yersinia effector proteins have unveiled tremendous knowledge of how the effectors enhance Yersinia virulence. Recently, the long awaited crystal structure of YpkA has been solved providing further insights into the activation of the YpkA kinase domain. Multisite autophosphorylation by YpkA to activate its kinase domain was also shown and postulated to serve as a mechanism to bypass regulation by host phosphatases. In addition, novel Yersinia effector protein targets, such as caspase-1, and signaling pathways including activation of the inflammasome were identified. In this review, we summarize the recent discoveries made on Yersinia effector proteins and their contribution to Yersinia pathogenesis.
基金Supported by Shenzhen Science and Technology Project(JCYJ20170818111629778,JCYJ20170306161613251)National Natural Science Foundation of Guangdong Province(2017A030313174)+1 种基金Natural Science Foundation of Guangdong Ocean University(C17379)Undergraduate Innovative and Entrepreneurial Team Project(CCTD201802)
文摘In this study,Hy322 gene was cloned from Vibrio alginolyticus.The total length of its gene was 969 bp,and it could encode 322 amino acids.The physicochemical properties,protein structure,genetic evolutionary relationship and antigenic characteristics of the effector protein Hy322 of V.alginolyticus HY9901 type Ⅲ secretion system were studied and analyzed by bioinformatics methods and tools.The results showed that Hy322 is an unstable hydrophilic and acidic protein without a transmembrane region and a signal peptide,and secondary structure to α-helix.The evolutionary analysis showed that V.alginolyticus HY9901 and V.harveyi were clustered together,which indicated that the genetic relationship between the two species was closest.HY322 contains a FliN super family conserved domain associated with Flagellar motor switch.Bioinformatics analysis showed that the B-cell preponderant epitopes of Hy322 might be localized in the regions of 32-33,100-102,138-140,215-216,235-238 and 246-249.The 3D structure model of Hy322 subunit was simulated by SWISS-MODEL software and itwas found that the yscQ of Yersinia were similar and the similarity was 42.25%.In this study,the feasibility of Hy322 as a common antigen of Vibrio was verified from the perspective of bioinformatics,which laid the foundation for the next step in vaccine development.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174157,12074150,and 11874314)。
文摘An ideal type-Ⅲnodal point is generated by crossing a completely flat band and a dispersive band along a certain momentum direction.To date,the type-Ⅲnodal points found in two-dimensional(2D)materials have been mostly accidental and random rather than ideal cases,and no one mentions what kind of lattice can produce ideal nodal points.Here,we propose that ideal type-Ⅲnodal points can be obtained in a diamond-like lattice.The flat bands in the lattice originate from destructive interference of wavefunctions,and thus are intrinsic and robust.Moreover,the specific lattice can be realized in some 2D carbon networks,such as T-graphene and its derivatives.All the carbon structures possess type-ⅢDirac points.In two of the structures,consisting of triangular carbon rings,the type-ⅢDirac points are located just on the Fermi level and the Fermi surface is very clean.Our research not only opens a door to finding the ideal type-ⅢDirac points,but also provides 2D materials for exploring their physical properties experimentally.
文摘目的对病原菌Ⅲ型分泌系统(TTSS)效应蛋白在非致病菌中进行直系同源基因预测,以获得病原菌Ⅲ型分泌系统特有效应蛋白,并进一步对特有效应蛋白模体构成进行分析,旨在更深入地认识TTSS效应蛋白,为理论研究和生物学实验提供参考。方法利用彼此最佳blast方法对效应蛋白在构建的非致病性细菌蛋白质数据库中进行直系同源基因预测,并利用Inter Pro Scan对预测获得的特有效应蛋白序列进行模体搜索分析。结果在49个收集整理的致病菌Ⅲ型分泌系统效应蛋白序列中,有18个效应蛋白在非致病菌中存在直系同源基因,31个效应蛋白(即TTSS特有效应蛋白)在非致病菌中没有直系同源基因;对31个Ⅲ型分泌系统特有效应蛋白序列进行模体分析,获得了12个效应蛋白特有模体。结论 31个致病菌Ⅲ型分泌系统特有效应蛋白序列的获得,为更精确地在致病性细菌基因组内预测获得新的效应蛋白序列奠定了基础;12个效应蛋白特有模体的获得及其基因本体注释分析进一步理解了效应蛋白的作用机制。
基金supported by the National Key R&D Program of China(2019YFD1002000)the Science and Technology Programs of the Shandong Tobacco(KN273)Zunyi Tobacco(2021XM03).
文摘Ralstonia solanacearum is a widespread plant bacterial pathogen that can launch a range of type Ⅲ effectors(T3Es)to cause disease.In this study,we isolate a pathogenic R.solanacearum strain named P380 from tomato rhizosphere.Five out of 12 core T3Es of strain P380 are introduced into Pseudomonas syringae DC3000D36E separately to determine their functions in interacting with plants.DC3000D36E that harbors each effector suppresses FliC-triggered Pti5 and ACRE31 expression,ROS burst,and callose deposition.RipAE,RipU,and RipW elicit cell death as well as upregulate the MAPK cascades in Nicotiana benthamiana.The derivatives RipC1^(△DDXDX(T/V))and RipW^(△DDKXXQ)but not RipAE^(K310R) fail to suppress ROS burst.Moreover,RipAE^(K310R) and RipW^(△DDKXXQ) retain the cell death elicitation ability.RipAE and RipW are associated with salicylic acid and jasmonic acid pathways,respectively.RipAE and RipAQ significantly promote the propagation of DC3000D36E in plants.The five core T3Es localize in diverse subcellular organelles of nucleus,plasma membrane,endoplasmic reticulum,and Golgi network.The suppressor of G2 allele of Skp1 is required for RipAE but not RipU-triggered cell death in N.benthamiana.These results indicate that the core T3Es in R.solanacearum play diverse roles in plantpathogen interactions.
基金supported by the Shanghai Agriculture Applied Technology Development Program,China(2020-02-08-00-08-F01462)the National Natural Science Foundation of China(31830072,32102147)。
文摘Plant stomata close rapidly in response to a rise in the plant hormone abscisic acid(ABA)or salicylic acid(SA)and after recognition of pathogenassociated molecular patterns(PAMPs).Stomatal closure is the result of vacuolar convolution,ion efflux,and changes in turgor pressure in guard cells.Phytopathogenic bacteria secrete typeⅢeffectors(T3Es)that interfere with plant defense mechanisms,causing severe plant disease symptoms.Here,we show that the virulence and infection of Xanthomonas oryzae pv.oryzicola(Xoc),which is the causal agent of rice bacterial leaf streak disease,drastically increased in transgenic rice(Oryza sativa L.)plants overexpressing the Xoc T3E gene Xop AP,which encodes a protein annotated as a lipase.We discovered that Xop AP binds to phosphatidylinositol 3,5-bisphosphate(Ptd Ins(3,5)P_(2)),a memb rane phospholipid that functions in p H control in lysosomes,membrane dynamics,and protein trafficking.Xop AP inhibited the acidification of vacuoles by competing with vacuolar H^(+)-pyrophosphatase(V-PPase)for binding to Ptd Ins(3,5)P_(2),leading to stomatal opening.Transgenic rice overexpressing Xop AP also showed inhibition of stomatal closure when challenged by Xoc infection and treatment with the PAMP flg22.Moreover,Xop AP suppressed flg22-induced gene expression,reactive oxygen species burst and callose deposition in host plants,demonstrating that Xop AP subverts PAMP-triggered immunity during Xoc infection.Taken together,these findings demonstrate that Xop AP overcomes stomatal immunity in plants by binding to lipids.
基金received from the National Natural Science Foundation of China(32070274,32072014 and 31971899)the China Postdoctoral Science Foundation(2020M681072)+4 种基金the Natural Science Foundation for the Excellent Youth Scholars of Heilongjiang Province,China(YQ2019C008)the Europe Horizon 2020(EUCLEG and 727312)the Youth Science and Technology Innovation Leader,China(2018RA2172)the National Key Research&Development Program of China(2016YFD0100500,2016YFD0100300 and 2016YFD0100201)the Heilongjiang Postdoctoral Science Foundation,China(LBH-Q16014)。
文摘Soybean is one of the most important food crops worldwide.Like other legumes,soybean can form symbiotic relationships with Rhizobium species.Nitrogen fixation of soybean via its symbiosis with Rhizobium is pivotal for sustainable agriculture.Type Ⅲ effectors(T3Es)are essential regulators of the establishment of the symbiosis,and nodule number is a feature of nitrogen-affected nodulation.However,genes encoding T3Es at quantitative trait loci(QTLs)related to nodulation have rarely been identified.Chromosome segment substitution lines(CSSLs)have a common genetic background but only a few loci with heterogeneous genetic information;thus,they are suitable materials for identifying candidate genes at a target locus.In this study,a CSSL population was used to identify the QTLs related to nodule number in soybean.Single nucleotide polymorphism(SNP)markers and candidate genes within the QTLs interval were detected,and it was determined which genes showed differential expression between isolines.Four candidate genes(GmCDPK28,GmNAC1,GmbHLH,and GmERF5)linked to the SNPs were identified as being related to nodule traits and pivotal processes and pathways involved in symbiosis establishment.A candidate gene(GmERF5)encoding a transcription factor that may interact directly with the T3E NopAA was identified.The confirmed CSSLs with important segments and candidate genes identified in this study are valuable resources for further studies on the genetic network and T3Es involved in the signaling pathway that is essential for symbiosis establishment.