The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe res...The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe resource for the manufacture of antimicrobial feed additive for livestock. The active constituents from M. cordata are known to include benzylisoquinoline alkaloids （BIAs） such as sanguinarine （SAN） and chelerythrine （CHE）, but their metabolic pathways have yet to be studied in this non-model plant. The active biosynthesis of SAN and CHE in M. cordata was first examined and confirmed by feeding ^13C-labeled tyrosine. To gain further insights, we de novo sequenced the whole genome of M. cordata, the first to be sequenced from the Papaveraceae family. The M. cordata genome covering 378 Mb encodes 22,328 predicted protein-coding genes with 43.5% being transposable elements. As a member of basal eudicot, M. cordata genome lacks the paleohexaploidy event that occurred in almost all eudicots. From the genomics data, a complete set of 16 metabolic genes for SAN and CHE biosynthesis was retrieved, and 14 of their biochemical activities were validated. These genomics and metabolic data show the conserved BIA metabolic pathways in M. cordata and provide the knowledge foundation for future productions of SAN and CHE by crop improvement or microbial pathway reconstruction.展开更多
Functional manipulation of biosynthetic enzymes such as cytochrome P450 s(or P450 s) has attracted great interest in metabolic engineering of plant natural products.Cucurbitacins and mogrosides are plant triterpenoids...Functional manipulation of biosynthetic enzymes such as cytochrome P450 s(or P450 s) has attracted great interest in metabolic engineering of plant natural products.Cucurbitacins and mogrosides are plant triterpenoids that share the same backbone but display contrasting bioactivities.This structural and functional diversity of the two metabolites can be manipulated by engineering P450 s.However,the functional redesign of P450 s through directed evolution(DE) or structure-guided protein engineering is time consuming and challenging,often because of a lack of high-throughput screening methods and crystal structures of P450 s.In this study,we used an integrated approach combining computational protein design,evolutionary information,and experimental data-driven optimization to alter the substrate specificity of a multifunctional P450(CYP87 D20)from cucumber.After three rounds of iterative design and evaluation of 96 protein variants,CYP87 D20,which is involved in the cucurbitacin C biosynthetic pathway,was successfully transformed into a P450 mono-oxygenase that performs a single specific hydroxylation at C11 of cucurbitadienol.This integrated P450-engineering approach can be further applied to create a de novo pathway to produce mogrol,the precursor of the natural sweetener mogroside,or to alter the structural diversity of plant triterpenoids by functionally manipulating other P450 s.展开更多
Sterols and triterpenes are structurally diverse bioactive molecules generated through cyclization of linear 2,3-oxidosqualene. Based on carbocationic intermediates generated during initial substrate preorganization s...Sterols and triterpenes are structurally diverse bioactive molecules generated through cyclization of linear 2,3-oxidosqualene. Based on carbocationic intermediates generated during initial substrate preorganization step, oxidosqualene cyclases （OSCs） are roughly segregated into protosteryl cation group that mainly catalyzes tetracyclic products and dammarenyl cation group which mostly generates pentacyclic products. However, in contrast to well-studied cascade of ring-forming reactions, little is known about the mechanism underlying the initial sub- strate folding process. Previously, we have identified a cucurbitadienol synthase （Bi） and its null allele bi （C393Y） from cucumber. By integration of homology modeling, residue coevolution and site-directed mutagenesis, we discover that four covarying amino acids including C393 constitute a dynamic domain that may be involved in substrate folding process for Bi. We also reveal a group of co-conserved residues that closely associated with the segregation of plant OSCs. These residues may act col- laboratively in choice of specific substrate folding inter- mediate for OSCs. Thus, engineer plant OSCs from into five-ringed producer. our findings open a door to four-ringed skeleton catalysts展开更多
Dear Editor,Plants have evolved great plasticity to adapt to external environments. A huge number of structurally diverse metabolites gener- ated through the glycosylation process is one potential mechanism that contr...Dear Editor,Plants have evolved great plasticity to adapt to external environments. A huge number of structurally diverse metabolites gener- ated through the glycosylation process is one potential mechanism that contributes to this plasticity （Bowles et al., 2005）.展开更多
Soyasaponins are a class of triterpenoid saponins that accumulate in soybean(Glycine max)seeds and give a bitter flavor to some soybean products(Berhow et al.,2006).Acetylated sugars at C22 in type-A soyasaponins are ...Soyasaponins are a class of triterpenoid saponins that accumulate in soybean(Glycine max)seeds and give a bitter flavor to some soybean products(Berhow et al.,2006).Acetylated sugars at C22 in type-A soyasaponins are largely responsible for the undesirable bitterness in soybean-derived foods.展开更多
Plants are talented biochemists that produce a broad diversity of small molecules.These so-called specialized metabolites(SMs)play critical roles in the adaptive evolution of plants to defend against biotic and abioti...Plants are talented biochemists that produce a broad diversity of small molecules.These so-called specialized metabolites(SMs)play critical roles in the adaptive evolution of plants to defend against biotic and abiotic stresses,attract pollinators,and modulate soil microbiota for their own benefits.Many plant SMs have been used as nutrition and flavor compounds in our daily food,as well as drugs for treatment of human diseases.Current multi-omics tools have significantly accelerated the process of biosynthetic pathway elucidation in plants through correlation analyses,genetic mapping,and de novo biosynthetic gene cluster predictions.Understanding the biosynthesis of plant SMs has enabled reconstitution of naturally occurring specialized metabolic pathways in microbial hosts,providing a sustainable supply of these high-value molecules.In this review,we illustrate the general functions of several typical plant SMs in natural ecosystems and for human societies.We then provide an overview of current methods elucidating the biosynthetic pathways of plant SMs,and synthetic biology strategies that optimize the efficiency of heterologous biosynthetic pathways in microbial hosts.Moving forward,dissection of the functions and application of plant SMs by using current multidiscipline approaches would be greatly benefit to the scientific community and human societies.展开更多
基金This work was supported by National Natural Science Foundation of China （31200615, 31600238）, Postgraduate Research and Innovation Project of Hunan Province （CX2014B302）, National Key Laboratory Cultivation Base Construction Project （15KFXM09）, the National Science-Technology Support Plan Projects of China （2012BAI29B04）, The talent introduction Science Foundation of Hunan Agricultural University （13YJ09）, and the Natural Science Foundation of Hunan Province （2016JJ4040）.
文摘The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe resource for the manufacture of antimicrobial feed additive for livestock. The active constituents from M. cordata are known to include benzylisoquinoline alkaloids （BIAs） such as sanguinarine （SAN） and chelerythrine （CHE）, but their metabolic pathways have yet to be studied in this non-model plant. The active biosynthesis of SAN and CHE in M. cordata was first examined and confirmed by feeding ^13C-labeled tyrosine. To gain further insights, we de novo sequenced the whole genome of M. cordata, the first to be sequenced from the Papaveraceae family. The M. cordata genome covering 378 Mb encodes 22,328 predicted protein-coding genes with 43.5% being transposable elements. As a member of basal eudicot, M. cordata genome lacks the paleohexaploidy event that occurred in almost all eudicots. From the genomics data, a complete set of 16 metabolic genes for SAN and CHE biosynthesis was retrieved, and 14 of their biochemical activities were validated. These genomics and metabolic data show the conserved BIA metabolic pathways in M. cordata and provide the knowledge foundation for future productions of SAN and CHE by crop improvement or microbial pathway reconstruction.
基金supported by the National Natural Science Foundation of China(31672171,81773597)Shenzhen municipal(JCYJ20160530191729620 to Y.S.)Dapeng district governments
文摘Functional manipulation of biosynthetic enzymes such as cytochrome P450 s(or P450 s) has attracted great interest in metabolic engineering of plant natural products.Cucurbitacins and mogrosides are plant triterpenoids that share the same backbone but display contrasting bioactivities.This structural and functional diversity of the two metabolites can be manipulated by engineering P450 s.However,the functional redesign of P450 s through directed evolution(DE) or structure-guided protein engineering is time consuming and challenging,often because of a lack of high-throughput screening methods and crystal structures of P450 s.In this study,we used an integrated approach combining computational protein design,evolutionary information,and experimental data-driven optimization to alter the substrate specificity of a multifunctional P450(CYP87 D20)from cucumber.After three rounds of iterative design and evaluation of 96 protein variants,CYP87 D20,which is involved in the cucurbitacin C biosynthetic pathway,was successfully transformed into a P450 mono-oxygenase that performs a single specific hydroxylation at C11 of cucurbitadienol.This integrated P450-engineering approach can be further applied to create a de novo pathway to produce mogrol,the precursor of the natural sweetener mogroside,or to alter the structural diversity of plant triterpenoids by functionally manipulating other P450 s.
基金supported by funding from the National Natural Science Foundation of China (31401886)the Agricultural Science and Technology Innovation Program
文摘Sterols and triterpenes are structurally diverse bioactive molecules generated through cyclization of linear 2,3-oxidosqualene. Based on carbocationic intermediates generated during initial substrate preorganization step, oxidosqualene cyclases （OSCs） are roughly segregated into protosteryl cation group that mainly catalyzes tetracyclic products and dammarenyl cation group which mostly generates pentacyclic products. However, in contrast to well-studied cascade of ring-forming reactions, little is known about the mechanism underlying the initial sub- strate folding process. Previously, we have identified a cucurbitadienol synthase （Bi） and its null allele bi （C393Y） from cucumber. By integration of homology modeling, residue coevolution and site-directed mutagenesis, we discover that four covarying amino acids including C393 constitute a dynamic domain that may be involved in substrate folding process for Bi. We also reveal a group of co-conserved residues that closely associated with the segregation of plant OSCs. These residues may act col- laboratively in choice of specific substrate folding inter- mediate for OSCs. Thus, engineer plant OSCs from into five-ringed producer. our findings open a door to four-ringed skeleton catalysts
基金This work was funded by the National Natural Science Foundation of China （31672171 to Y.S., 31401886 to Y.Z., 31322047 to Z.H.Z）, the Leading Talents of Guangdong Province Program （00201515 to S.W.H）, the National Key R ＆ D Program for Crop Breeding （2016YFD0100506）, the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences （CAAS-ASTIP-IVFCAAS）, the Chinese Ministry of Finance （1251610601001）. This work was also supported by the Shenzhen Municipal and Dapeng District Governments.
文摘Dear Editor,Plants have evolved great plasticity to adapt to external environments. A huge number of structurally diverse metabolites gener- ated through the glycosylation process is one potential mechanism that contributes to this plasticity （Bowles et al., 2005）.
文摘Soyasaponins are a class of triterpenoid saponins that accumulate in soybean(Glycine max)seeds and give a bitter flavor to some soybean products(Berhow et al.,2006).Acetylated sugars at C22 in type-A soyasaponins are largely responsible for the undesirable bitterness in soybean-derived foods.
基金supported by the National Natural Science Foundation of China(31788103 to J.L.)the National Key R&D Program of China(2019YFA0906200 to S.H.)the National Natural Science Foundation of China(31920103003 to X.Q.).
文摘Plants are talented biochemists that produce a broad diversity of small molecules.These so-called specialized metabolites(SMs)play critical roles in the adaptive evolution of plants to defend against biotic and abiotic stresses,attract pollinators,and modulate soil microbiota for their own benefits.Many plant SMs have been used as nutrition and flavor compounds in our daily food,as well as drugs for treatment of human diseases.Current multi-omics tools have significantly accelerated the process of biosynthetic pathway elucidation in plants through correlation analyses,genetic mapping,and de novo biosynthetic gene cluster predictions.Understanding the biosynthesis of plant SMs has enabled reconstitution of naturally occurring specialized metabolic pathways in microbial hosts,providing a sustainable supply of these high-value molecules.In this review,we illustrate the general functions of several typical plant SMs in natural ecosystems and for human societies.We then provide an overview of current methods elucidating the biosynthetic pathways of plant SMs,and synthetic biology strategies that optimize the efficiency of heterologous biosynthetic pathways in microbial hosts.Moving forward,dissection of the functions and application of plant SMs by using current multidiscipline approaches would be greatly benefit to the scientific community and human societies.
