Carotenoids are indispensable to plants and play a critical role in human nutrition and health. Significant progress has been made in our understanding of carotenoid metabolism in plants. The biosynthetic pathway has ...Carotenoids are indispensable to plants and play a critical role in human nutrition and health. Significant progress has been made in our understanding of carotenoid metabolism in plants. The biosynthetic pathway has been extensively studied. Nearly all the genes encoding the biosynthetic enzymes have been isolated and characterized from various organisms. In recent years, there is an increasing body of work on the signaling pathways and plastid development, which might provide global control of carotenoid biosynthesis and accumulation. Herein, we will highlight recent progress on the biosynthesis, regulation, and metabolic engineering of carotenoids in plants, as well as the future research towards elucidating the regulatory mechanisms and metabolic network that control carotenoid metabolism.展开更多
Isoprenoids are functionally and structurally the most diverse group of plant metabolites reported to date. They can function as primary metabolites, participating in essential plant cellular processes, and as seconda...Isoprenoids are functionally and structurally the most diverse group of plant metabolites reported to date. They can function as primary metabolites, participating in essential plant cellular processes, and as secondary metabolites, of which many have substantial commercial, pharmacological, and agricultural value. Isoprenoid end products participate in plants in a wide range of physiological processes acting in them both synergistically, such as chlorophyll and carotenoids during photosynthesis, or antagonistically, such as gibberellic acid and abscisic acid during seed germination. It is therefore expected that fluxes via isoprenoid metabolic network are tightly controlled both temporally and spatially, and that this control occurs at different levels of regulation and in an orchestrated manner over the entire isoprenoid metabolic network. In this review, we summarize our current knowledge of the topology of the plant isoprenoid pathway network and its regulation at the gene expression level following diverse stimuli. We conclude by discussing agronomical and biotechnological applications emerging from the plant isoprenoid metabolism and provide an outlook on future directions in the systems analysis of the plant isoprenoid pathway network.展开更多
Astaxanthin is a red-colored carotenoid,used as food and feed additive.Astaxanthin is mainly produced by chemical synthesis,however,the process is expensive and synthetic astaxanthin is not approved for human consumpt...Astaxanthin is a red-colored carotenoid,used as food and feed additive.Astaxanthin is mainly produced by chemical synthesis,however,the process is expensive and synthetic astaxanthin is not approved for human consumption.In this study,we engineered the oleaginous yeast Yarrowia lipolytica for de novo production of astaxanthin by fermentation.First,we screened 12 different Y.lipolytica isolates for β-carotene production by introducing two genes for β-carotene biosynthesis:bi-functional phytoene synthase/lycopene cyclase(crtYB)and phytoene desaturase(crtI)from the red yeast Xanthophyllomyces dendrorhous.The best strain produced 31.1±0.5 mg/L β-carotene.Next,we optimized the activities of 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMG1)and geranylgeranyl diphosphate synthase(GGS1/crtE)in the best producing strain and obtained 453.9±20.2 mg/L β-carotene.Additional downregulation of the competing squalene synthase SQS1 increased the β-carotene titer to 797.1±57.2 mg/L.Then we introduced β-carotene ketolase(crtW)from Paracoccus sp.N81106 and hydroxylase(crtZ)from Pantoea ananatis to convert β-carotene into astaxanthin.The constructed strain accumulated 10.4±0.5 mg/L of astaxanthin but also accumulated astaxanthin biosynthesis intermediates,5.7±0.5 mg/L canthaxanthin,and 35.3±1.8 mg/L echinenone.Finally,we optimized the copy numbers of crtZ and crtW to obtain 3.5 mg/g DCW(54.6 mg/L)of astaxanthin in a microtiter plate cultivation.Our study for the first time reports engineering of Y.lipolytica for the production of astaxanthin.The high astaxanthin content and titer obtained even in a small-scale cultivation demonstrates a strong potential for Y.lipolytica-based fermentation process for astaxanthin production.展开更多
Although the cytosolic isoprenoid biosynthetic pathway, mavolonate pathway, in plants has been known for many years, a new plastidial 1–deoxyxylulose-5-phosphate (DXP) pathway was identified in the past few years and...Although the cytosolic isoprenoid biosynthetic pathway, mavolonate pathway, in plants has been known for many years, a new plastidial 1–deoxyxylulose-5-phosphate (DXP) pathway was identified in the past few years and its related intermediates, enzymes, and genes have been characterized quite recently. With a deep insight into the biosynthetic pathway of isoprenoids, investigations into the metabolic engineering of isoprenoid biosynthesis have started to prosper. In the present article, recent advances in the discoveries and regulatory roles of new genes and enzymes in the plastidial isoprenoid biosynthesis pathway are reviewed and examples of the metabolic engineering of cytosolic and plastidial isoprenoids biosynthesis are discussed.展开更多
Carotenoids are pigments required for photosynthesis, photoprotection and the production of carotenoid- derived hormones such as ABA and strigolactones. The carotenoid biosynthetic pathway bifurcates after lycopene to...Carotenoids are pigments required for photosynthesis, photoprotection and the production of carotenoid- derived hormones such as ABA and strigolactones. The carotenoid biosynthetic pathway bifurcates after lycopene to produce epsilon- and beta-carotenoids and this branch is critical for determining carotenoid composition. Here, we show how the branch point can be regulated by the chromatin-modifying histone methyltransferase, Set Domain Group 8 （SDG8） targeting the carotenoid isomerase （CRTISO）. SDG8 is required to maintain permissive expression of CRTISO during seedling development, in leaves, shoot apex, and some floral organs. The CRTISO and SDG8 promoters show overlapping tissue-specific patterns of reporter gene activity. Interestingly, CRTISO showed atypical reporter gene expression in terms of greater variability between different lines compared to the Cauliflower Mosaic Virus 35S promoter （CaMV35s） and ~LCY promoters, potentially due to chromosomal position effects. Regulation of the CRTISO promoter was dependent in part upon the presence or absence of SDG8. Knockouts of SDG8 （carotenoid and chloroplast regulation （ccrl）） and CRTISO （ccr2） result in altered carotenoid composition and this could be restored in ccr2 using the CaMV35s or CRTISO promoters. In contrast, varying degrees of GUS expression and carotenoid complementation by CRTISO overexpression using CaMV35S or CRTISO promoters in the ccrl background demonstrated that both the CRTISO promoter and open reading frame are necessary for SDG8-mediated expression of CRTISO.展开更多
The biosynthesis of isoprenoids in plant cells occurs from precursors produced in the cytosol by the mevalonate （MVA） pathway and in the plastid by the methylerythritol 4-phosphate （MEP） pathway, but little is kno...The biosynthesis of isoprenoids in plant cells occurs from precursors produced in the cytosol by the mevalonate （MVA） pathway and in the plastid by the methylerythritol 4-phosphate （MEP） pathway, but little is known about the mechanisms coordinating both pathways. Evidence of the importance of sugar signaling for such coordination in Arabi- dopsis thaliana is provided here by the characterization of a mutant showing an increased accumulation of MEP-derived isoprenoid products （chlorophylls and carotenoids） without changes in the levels of relevant MEP pathway transcripts, proteins, or enzyme activities. This mutant was found to be a new loss-of-function allele of PRL1 （Pleiotropic Regulatory Locus 1）, a gene encoding a conserved WD-protein that functions as a global regulator of sugar, stress, and hormone responses, in part by inhibition of SNFl-related protein kinases （SnRK1）. Consistent with the reported role of SnRK1 kinases in the phosphorylation and inactivation of the main regulatory enzyme of the MVA pathway （hydroxymethylglutaryl coenzyme-A reductase）, its activity but not transcript or protein levels was reduced in prll seedlings. However, the accumulation of MVA-derived end products （sterols） was unaltered in mutant seedlings. Sucrose supplementation to wild- type seedlings phenocopied the prll mutation in terms of isoprenoid metabolism, suggesting that the observed isoprenoid phenotypes result from the increased sugar accumulation in the prll mutant. In summary, PRL1 appears to coordinate isoprenoid metabolism with sugar, hormone, and stress responses.展开更多
Current yeast metabolic engineering in isoprenoids production mainly focuses on rewiring of cytosolic metabolic pathway.However,the precursors,cofactors and the enzymes are distributed in various sub-cellular compartm...Current yeast metabolic engineering in isoprenoids production mainly focuses on rewiring of cytosolic metabolic pathway.However,the precursors,cofactors and the enzymes are distributed in various sub-cellular compartments,which may hamper isoprenoid biosynthesis.On the other side,pathway compartmentalization provides several advantages for improving metabolic flux toward target products.We here summarize the recent advances on harnessing sub-organelle for isoprenoids biosynthesis in yeast,and analyze the knowledge about the localization of enzymes,cofactors and metabolites for guiding the rewiring of the sub-organelle metabolism.This review may provide some insights for constructing efficient yeast cell factories for production of isoprenoids and even other natural products.展开更多
Metabolic engineering has been widely used for production of natural medicinal molecules.However, engineering high-yield platforms is hindered in large part by limited knowledge of complex regulatory machinery of meta...Metabolic engineering has been widely used for production of natural medicinal molecules.However, engineering high-yield platforms is hindered in large part by limited knowledge of complex regulatory machinery of metabolic network. N~6-Methyladenosine(m^(6)A) modification of RNA plays critical roles in regulation of gene expression. Herein, we identify 1470 putatively m^(6)A peaks within 1151 genes from the haploid Saccharomyces cerevisiae strain. Among them, the transcript levels of 94 genes falling into the pathways which are frequently optimized for chemical production, are remarkably altered upon overexpression of IME4(the yeast m^(6)A methyltransferase). In particular, IME4 overexpression elevates the mRNA levels of the methylated genes in the glycolysis, acetyl-CoA synthesis and shikimate/aromatic amino acid synthesis modules. Furthermore, ACS1 and ADH2, two key genes responsible for acetyl-CoA synthesis, are induced by IME4 overexpression in a transcription factor-mediated manner.Finally, we show IME4 overexpression can significantly increase the titers of isoprenoids and aromatic compounds. Manipulation of m^(6)A therefore adds a new layer of metabolic regulatory machinery and may be broadly used in bioproduction of various medicinal molecules of terpenoid and phenol classes.展开更多
基金the National Natural Science Foundation of China (30771167)the State Key Basic Research and Development Plan of China(2007CB108802)the USDA National Research Initiative Competitive Grants (2007-35318-17794 and 2001-35318-11136)
文摘Carotenoids are indispensable to plants and play a critical role in human nutrition and health. Significant progress has been made in our understanding of carotenoid metabolism in plants. The biosynthetic pathway has been extensively studied. Nearly all the genes encoding the biosynthetic enzymes have been isolated and characterized from various organisms. In recent years, there is an increasing body of work on the signaling pathways and plastid development, which might provide global control of carotenoid biosynthesis and accumulation. Herein, we will highlight recent progress on the biosynthesis, regulation, and metabolic engineering of carotenoids in plants, as well as the future research towards elucidating the regulatory mechanisms and metabolic network that control carotenoid metabolism.
文摘Isoprenoids are functionally and structurally the most diverse group of plant metabolites reported to date. They can function as primary metabolites, participating in essential plant cellular processes, and as secondary metabolites, of which many have substantial commercial, pharmacological, and agricultural value. Isoprenoid end products participate in plants in a wide range of physiological processes acting in them both synergistically, such as chlorophyll and carotenoids during photosynthesis, or antagonistically, such as gibberellic acid and abscisic acid during seed germination. It is therefore expected that fluxes via isoprenoid metabolic network are tightly controlled both temporally and spatially, and that this control occurs at different levels of regulation and in an orchestrated manner over the entire isoprenoid metabolic network. In this review, we summarize our current knowledge of the topology of the plant isoprenoid pathway network and its regulation at the gene expression level following diverse stimuli. We conclude by discussing agronomical and biotechnological applications emerging from the plant isoprenoid metabolism and provide an outlook on future directions in the systems analysis of the plant isoprenoid pathway network.
基金This research was financially supported by the Novo Nordisk Foundation(grant number NNF15OC0016592)BAD was supported by the ERASMUS Traineeship program.We acknowledge Mette Kristensen for technical assistance on HPLC analysis.
文摘Astaxanthin is a red-colored carotenoid,used as food and feed additive.Astaxanthin is mainly produced by chemical synthesis,however,the process is expensive and synthetic astaxanthin is not approved for human consumption.In this study,we engineered the oleaginous yeast Yarrowia lipolytica for de novo production of astaxanthin by fermentation.First,we screened 12 different Y.lipolytica isolates for β-carotene production by introducing two genes for β-carotene biosynthesis:bi-functional phytoene synthase/lycopene cyclase(crtYB)and phytoene desaturase(crtI)from the red yeast Xanthophyllomyces dendrorhous.The best strain produced 31.1±0.5 mg/L β-carotene.Next,we optimized the activities of 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMG1)and geranylgeranyl diphosphate synthase(GGS1/crtE)in the best producing strain and obtained 453.9±20.2 mg/L β-carotene.Additional downregulation of the competing squalene synthase SQS1 increased the β-carotene titer to 797.1±57.2 mg/L.Then we introduced β-carotene ketolase(crtW)from Paracoccus sp.N81106 and hydroxylase(crtZ)from Pantoea ananatis to convert β-carotene into astaxanthin.The constructed strain accumulated 10.4±0.5 mg/L of astaxanthin but also accumulated astaxanthin biosynthesis intermediates,5.7±0.5 mg/L canthaxanthin,and 35.3±1.8 mg/L echinenone.Finally,we optimized the copy numbers of crtZ and crtW to obtain 3.5 mg/g DCW(54.6 mg/L)of astaxanthin in a microtiter plate cultivation.Our study for the first time reports engineering of Y.lipolytica for the production of astaxanthin.The high astaxanthin content and titer obtained even in a small-scale cultivation demonstrates a strong potential for Y.lipolytica-based fermentation process for astaxanthin production.
文摘Although the cytosolic isoprenoid biosynthetic pathway, mavolonate pathway, in plants has been known for many years, a new plastidial 1–deoxyxylulose-5-phosphate (DXP) pathway was identified in the past few years and its related intermediates, enzymes, and genes have been characterized quite recently. With a deep insight into the biosynthetic pathway of isoprenoids, investigations into the metabolic engineering of isoprenoid biosynthesis have started to prosper. In the present article, recent advances in the discoveries and regulatory roles of new genes and enzymes in the plastidial isoprenoid biosynthesis pathway are reviewed and examples of the metabolic engineering of cytosolic and plastidial isoprenoids biosynthesis are discussed.
文摘Carotenoids are pigments required for photosynthesis, photoprotection and the production of carotenoid- derived hormones such as ABA and strigolactones. The carotenoid biosynthetic pathway bifurcates after lycopene to produce epsilon- and beta-carotenoids and this branch is critical for determining carotenoid composition. Here, we show how the branch point can be regulated by the chromatin-modifying histone methyltransferase, Set Domain Group 8 （SDG8） targeting the carotenoid isomerase （CRTISO）. SDG8 is required to maintain permissive expression of CRTISO during seedling development, in leaves, shoot apex, and some floral organs. The CRTISO and SDG8 promoters show overlapping tissue-specific patterns of reporter gene activity. Interestingly, CRTISO showed atypical reporter gene expression in terms of greater variability between different lines compared to the Cauliflower Mosaic Virus 35S promoter （CaMV35s） and ~LCY promoters, potentially due to chromosomal position effects. Regulation of the CRTISO promoter was dependent in part upon the presence or absence of SDG8. Knockouts of SDG8 （carotenoid and chloroplast regulation （ccrl）） and CRTISO （ccr2） result in altered carotenoid composition and this could be restored in ccr2 using the CaMV35s or CRTISO promoters. In contrast, varying degrees of GUS expression and carotenoid complementation by CRTISO overexpression using CaMV35S or CRTISO promoters in the ccrl background demonstrated that both the CRTISO promoter and open reading frame are necessary for SDG8-mediated expression of CRTISO.
文摘The biosynthesis of isoprenoids in plant cells occurs from precursors produced in the cytosol by the mevalonate （MVA） pathway and in the plastid by the methylerythritol 4-phosphate （MEP） pathway, but little is known about the mechanisms coordinating both pathways. Evidence of the importance of sugar signaling for such coordination in Arabi- dopsis thaliana is provided here by the characterization of a mutant showing an increased accumulation of MEP-derived isoprenoid products （chlorophylls and carotenoids） without changes in the levels of relevant MEP pathway transcripts, proteins, or enzyme activities. This mutant was found to be a new loss-of-function allele of PRL1 （Pleiotropic Regulatory Locus 1）, a gene encoding a conserved WD-protein that functions as a global regulator of sugar, stress, and hormone responses, in part by inhibition of SNFl-related protein kinases （SnRK1）. Consistent with the reported role of SnRK1 kinases in the phosphorylation and inactivation of the main regulatory enzyme of the MVA pathway （hydroxymethylglutaryl coenzyme-A reductase）, its activity but not transcript or protein levels was reduced in prll seedlings. However, the accumulation of MVA-derived end products （sterols） was unaltered in mutant seedlings. Sucrose supplementation to wild- type seedlings phenocopied the prll mutation in terms of isoprenoid metabolism, suggesting that the observed isoprenoid phenotypes result from the increased sugar accumulation in the prll mutant. In summary, PRL1 appears to coordinate isoprenoid metabolism with sugar, hormone, and stress responses.
基金This study was financially supported by National Natural Science Foundation of China(Grant no.21877111 and no.21922812)China Postdoctoral Science Foundation(199936).
文摘Current yeast metabolic engineering in isoprenoids production mainly focuses on rewiring of cytosolic metabolic pathway.However,the precursors,cofactors and the enzymes are distributed in various sub-cellular compartments,which may hamper isoprenoid biosynthesis.On the other side,pathway compartmentalization provides several advantages for improving metabolic flux toward target products.We here summarize the recent advances on harnessing sub-organelle for isoprenoids biosynthesis in yeast,and analyze the knowledge about the localization of enzymes,cofactors and metabolites for guiding the rewiring of the sub-organelle metabolism.This review may provide some insights for constructing efficient yeast cell factories for production of isoprenoids and even other natural products.
基金supported by the National Key Research and Development Program of China [2022YFF1100304 (2022YFF1100300), China]National Natural Science Foundation of China [82293682 (82293680), China]+1 种基金Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences (2021-RC350-009, China)the CAMS Innovation Fund for Medical Sciences (2021-I2M-1-029, China)。
文摘Metabolic engineering has been widely used for production of natural medicinal molecules.However, engineering high-yield platforms is hindered in large part by limited knowledge of complex regulatory machinery of metabolic network. N~6-Methyladenosine(m^(6)A) modification of RNA plays critical roles in regulation of gene expression. Herein, we identify 1470 putatively m^(6)A peaks within 1151 genes from the haploid Saccharomyces cerevisiae strain. Among them, the transcript levels of 94 genes falling into the pathways which are frequently optimized for chemical production, are remarkably altered upon overexpression of IME4(the yeast m^(6)A methyltransferase). In particular, IME4 overexpression elevates the mRNA levels of the methylated genes in the glycolysis, acetyl-CoA synthesis and shikimate/aromatic amino acid synthesis modules. Furthermore, ACS1 and ADH2, two key genes responsible for acetyl-CoA synthesis, are induced by IME4 overexpression in a transcription factor-mediated manner.Finally, we show IME4 overexpression can significantly increase the titers of isoprenoids and aromatic compounds. Manipulation of m^(6)A therefore adds a new layer of metabolic regulatory machinery and may be broadly used in bioproduction of various medicinal molecules of terpenoid and phenol classes.
