The ent-kaurenoids(e.g.,oridonin and enmein)from the Isodon genus(Lamiaceae)are one class of diterpenoids with rich structural diversity and intriguing pharmaceutical activity.In contrast to the well-established gibbe...The ent-kaurenoids(e.g.,oridonin and enmein)from the Isodon genus(Lamiaceae)are one class of diterpenoids with rich structural diversity and intriguing pharmaceutical activity.In contrast to the well-established gibberellin pathway,oxidative modifications diversifying the ent-kaurene skeleton in Isodon have remained undetermined for half a century.Here we report a chromosome-level genome assembly of I.rubescens,a well-recognized oridonin producer long favored by Asian people as a traditional herb with antitumor effects.The shoot apex was confirmed to be the actual region actively producing ent-kaurene diterpenoids.Through comparative genomics and phylogenetic analyses,we discovered a cluster of tandem-duplicated CYP706V oxygenase-encoding genes located on an ancient genomic block widely distributed in eudicots,whereas almost exclusively emerged in Isodon plants.In the shoot apex,IrCYP706V2 and IrCYP706V7 oxidized the ent-kaurene core in the initial stage of oridonin biosynthesis.Loss of CYP706Vs in other Lamiaceae plants offered an explanation for the specific kaurenoid production in Isodon plants.Moreover,we found that the Isodon genomes encode multiple diterpenoid synthases that are potentially involved in generating diterpenoid diversity.These findings provided new insights into the evolution of the lineage-specific diterpenoid pathway and laid a foundation for improving production of bioactive ent-kaurene-type diterpenoids by molecular breeding and synthetic biology approaches.展开更多
Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essentia...Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essential for plant survival in natural environments.A growing appreciation of microbiota for plant health is fuelling rapid advances in genetic mechanisms of controlling microbiota by host plants.PSMs have long been proposed to mediate plant and single microbe interactions.However,the effects of PSMs,especially those evolutionarily new PSMs,on root microbiota at community level remain to be elucidated.Here,we discovered sesterterpenes in Arabidopsis thaliana,produced by recently duplicated prenyltransferase-terpene synthase(PT-TPS) gene clusters,with neo-functionalization.A single-residue substitution played a critical role in the acquisition of sesterterpene synthase(sesterTPS) activity in Brassicaceae plants.Moreover,we found that the absence of two root-specific sesterterpenoids,with similar chemical structure,significantly affected root microbiota assembly in similar patterns.Our results not only demonstrate the sensitivity of plant microbiota to PSMs but also establish a complete framework of host plants to control root microbiota composition through evolutionarily dynamic PSMs.展开更多
Class I terpene synthase(TPS)generates bioactive terpenoids with diverse backbones.Sesterterpene synthase(sester-TPS,C25),a branch of class I TPSs,was recently identified in Brassicaceae.However,the catalytic mechanis...Class I terpene synthase(TPS)generates bioactive terpenoids with diverse backbones.Sesterterpene synthase(sester-TPS,C25),a branch of class I TPSs,was recently identified in Brassicaceae.However,the catalytic mechanisms of sester-TPSs are not fully understood.Here,we first identified three nonclustered functional sester-TPSs(AtTPS06,AtTPS22,and AtTPS29)in Arabidopsis thaliana.AtTPS06 utilizes a type-B cyclization mechanism,whereas most other sester-TPSs produce various sesterterpene backbones via a type-A cyclization mechanism.We then determined the crystal structure of the AtTPS18–FSPP complex to explore the cyclization mechanism of plant sester-TPSs.We used structural comparisons and site-directed mutagenesis to further elucidate the mechanism:(1)mainly due to the outward shift of helix G,plant sester-TPSs have a larger catalytic pocket than do mono-,sesqui-,and di-TPSs to accommodate GFPP;(2)type-A sester-TPSs have more aromatic residues(five or six)in their catalytic pocket than classic TPSs(two or three),which also determines whether the type-A or type-B cyclization mechanism is active;and(3)the other residues responsible for product fidelity are determined by interconversion of AtTPS18 and its close homologs.Altogether,this study improves our understanding of the catalytic mechanism of plant sester-TPS,which ultimately enables the rational engineering of sesterterpenoids for future applications.展开更多
基金funded by the National Key R&D Program of China(2018YFA0900600)the National Natural Science Foundation of China(32070328,22077129,and 41876084),the Program of Shanghai Academic Research Leader(20XD1404400)+2 种基金the Strategic Priority Research Program“Molecular Mechanism of Plant Growth and Development”of CAS(XDB27020202)the Construction of the Registry and Database of Bioparts for Synthetic Biology of the Chinese Academy of Sciences(ZSYS-016),the International Partnership Program of the Chinese Academy of Sciences(153D31KYSB20170121),Derivative Bank of Chinese Biological Resources(KFJ-BRP-009-002)the National Key Laboratory of Plant Molecular Genetics,SIPPE,CAS.Y.S.is supported by the Foundation of Youth Innovation Promotion Association of the Chinese Academy of Sciences.
文摘The ent-kaurenoids(e.g.,oridonin and enmein)from the Isodon genus(Lamiaceae)are one class of diterpenoids with rich structural diversity and intriguing pharmaceutical activity.In contrast to the well-established gibberellin pathway,oxidative modifications diversifying the ent-kaurene skeleton in Isodon have remained undetermined for half a century.Here we report a chromosome-level genome assembly of I.rubescens,a well-recognized oridonin producer long favored by Asian people as a traditional herb with antitumor effects.The shoot apex was confirmed to be the actual region actively producing ent-kaurene diterpenoids.Through comparative genomics and phylogenetic analyses,we discovered a cluster of tandem-duplicated CYP706V oxygenase-encoding genes located on an ancient genomic block widely distributed in eudicots,whereas almost exclusively emerged in Isodon plants.In the shoot apex,IrCYP706V2 and IrCYP706V7 oxidized the ent-kaurene core in the initial stage of oridonin biosynthesis.Loss of CYP706Vs in other Lamiaceae plants offered an explanation for the specific kaurenoid production in Isodon plants.Moreover,we found that the Isodon genomes encode multiple diterpenoid synthases that are potentially involved in generating diterpenoid diversity.These findings provided new insights into the evolution of the lineage-specific diterpenoid pathway and laid a foundation for improving production of bioactive ent-kaurene-type diterpenoids by molecular breeding and synthetic biology approaches.
基金supported by the Priority Research Program of the Chinese Academy of Sciences(ZDRW-ZS-2019-2,QYZDBSSW-SMC021)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA08000000,XDB11020700)+1 种基金the National Program on Key Basic Research Projects(2013CB127000)the State Key Laboratory of Plant Genomics of China(2016A0219-11,SKLPG2013A0125-5)
文摘Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essential for plant survival in natural environments.A growing appreciation of microbiota for plant health is fuelling rapid advances in genetic mechanisms of controlling microbiota by host plants.PSMs have long been proposed to mediate plant and single microbe interactions.However,the effects of PSMs,especially those evolutionarily new PSMs,on root microbiota at community level remain to be elucidated.Here,we discovered sesterterpenes in Arabidopsis thaliana,produced by recently duplicated prenyltransferase-terpene synthase(PT-TPS) gene clusters,with neo-functionalization.A single-residue substitution played a critical role in the acquisition of sesterterpene synthase(sesterTPS) activity in Brassicaceae plants.Moreover,we found that the absence of two root-specific sesterterpenoids,with similar chemical structure,significantly affected root microbiota assembly in similar patterns.Our results not only demonstrate the sensitivity of plant microbiota to PSMs but also establish a complete framework of host plants to control root microbiota composition through evolutionarily dynamic PSMs.
基金supported by the National Key R&D Program of China(grant no.2018YFA0900600)the National Natural Science Foundation of China(grant nos.31970315 and 31700263)+3 种基金the“Priority Research Program”of the Chinese Academy of Sciences(grant nos.ZDRW-ZS-2019-2 and XDB27020103)the Grant-in-Aid Program for Scientific Research from the MEXT,Japan(JSPS KAKENHI grant no.JP16H06443)the State Key Laboratory of Plant Genomics of China(grant no.SKLPG2016A-13)supported by the Foundation of Youth Innovation Promotion Association of the Chinese Academy of Sciences.
文摘Class I terpene synthase(TPS)generates bioactive terpenoids with diverse backbones.Sesterterpene synthase(sester-TPS,C25),a branch of class I TPSs,was recently identified in Brassicaceae.However,the catalytic mechanisms of sester-TPSs are not fully understood.Here,we first identified three nonclustered functional sester-TPSs(AtTPS06,AtTPS22,and AtTPS29)in Arabidopsis thaliana.AtTPS06 utilizes a type-B cyclization mechanism,whereas most other sester-TPSs produce various sesterterpene backbones via a type-A cyclization mechanism.We then determined the crystal structure of the AtTPS18–FSPP complex to explore the cyclization mechanism of plant sester-TPSs.We used structural comparisons and site-directed mutagenesis to further elucidate the mechanism:(1)mainly due to the outward shift of helix G,plant sester-TPSs have a larger catalytic pocket than do mono-,sesqui-,and di-TPSs to accommodate GFPP;(2)type-A sester-TPSs have more aromatic residues(five or six)in their catalytic pocket than classic TPSs(two or three),which also determines whether the type-A or type-B cyclization mechanism is active;and(3)the other residues responsible for product fidelity are determined by interconversion of AtTPS18 and its close homologs.Altogether,this study improves our understanding of the catalytic mechanism of plant sester-TPS,which ultimately enables the rational engineering of sesterterpenoids for future applications.