1
|
Bae SH, Lee MH, Lee JH, Yu Y, Lee J, Kim TH. The Genome of the Korean Island-Originated Perilla citriodora 'Jeju17' Sheds Light on Its Environmental Adaptation and Fatty Acid and Lipid Production Pathways. Genes (Basel) 2023; 14:1898. [PMID: 37895247 PMCID: PMC10606934 DOI: 10.3390/genes14101898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Perilla is a key component of Korean food. It contains several plant-specialized metabolites that provide medical benefits. In response to an increased interest in healthy supplement food from the public, people are focusing on the properties of Perilla. Nevertheless, unlike rice and soybeans, there are few studies based on molecular genetics on Perilla, so it is difficult to systematically study the molecular breed. The wild Perilla, Perilla citriodora 'Jeju17', was identified a decade ago on the Korean island of Jeju. Using short-reads, long-reads, and Hi-C, a chromosome-scale genome spanning 676 Mbp, with high contiguity, was assembled. Aligning the 'Jeju17' genome to the 'PC002' Chinese species revealed significant collinearity with respect to the total length. A total of 31,769 coding sequences were predicted, among which 3331 were 'Jeju17'-specific. Gene enrichment of the species-specific gene repertoire highlighted environment adaptation, fatty acid metabolism, and plant-specialized metabolite biosynthesis. Using a homology-based approach, genes involved in fatty acid and lipid triacylglycerol biosynthesis were identified. A total of 22 fatty acid desaturases were found and comprehensively characterized. Expression of the FAD genes in 'Jeju17' was examined at the seed level, and hormone signaling factors were identified. The results showed that the expression of FAD genes in 'Jeju17' at the seed level was high 25 days after flowering, and their responses of hormones and stress were mainly associated with hormone signal transduction and abiotic stress via cis-elements patterns. This study presents a chromosome-level genome assembly of P. citriodora 'Jeju17', the first wild Perilla to be sequenced from the Korean island of Jeju. The analyses provided can be useful in designing ALA-enhanced Perilla genotypes in the future.
Collapse
Affiliation(s)
- Seon-Hwa Bae
- Genomics Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Republic of Korea;
| | - Myoung Hee Lee
- Upland Crop Breeding Research Division, Department of Southern Area Crop Science, Rural Development Administration (RDA), Miryang 50424, Republic of Korea;
| | - Jeong-Hee Lee
- SEEDERS Inc., 118, Jungang-ro, Jung-gu, Daejeon 34912, Republic of Korea;
| | - Yeisoo Yu
- DNACARE Co., Ltd., 48, Teheran-ro 25-gil, Gangnam-gu, Seoul 06126, Republic of Korea;
| | - Jundae Lee
- Department of Horticulture, College of Agriculture and Life Sciences, Jeonbuk National University, Jeonju 54896, Republic of Korea
| | - Tae-Ho Kim
- Genomics Division, Department of Agricultural Biotechnology, National Institute of Agricultural Sciences, Rural Development Administration, Jeonju 54874, Republic of Korea;
| |
Collapse
|
2
|
Hu C, Song J, Jin W, Wang W, Bai H, Wu C, Shen L. Lipidomics characterized TAG biosynthesis of developing kernels in three walnut cultivars in Xinjiang region. Food Chem 2023; 416:135808. [PMID: 36893647 DOI: 10.1016/j.foodchem.2023.135808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/19/2023] [Accepted: 02/25/2023] [Indexed: 03/07/2023]
Abstract
Walnut oil with very high proportion of polyunsaturated fatty acids exhibits many health beneficial effects. We hypothesized that the oil composition is led by a special pattern/mechanism for triacylglycerol (TAG) biosynthesis as well as accumulation in walnut kernel during embryo development. To test this hypothesis, shotgun lipidomics was performed for class-targeted lipid analysis (including TAG, phosphatidylcholine, phosphatidylethanolamine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, and lysophosphatidylcholine species) in walnut kernels from three cultivar collected at three critical stages of embryo development. The results indicated that TAG synthesis in the kernel happened before 84 days after flowering (DAF) and was significantly enhanced between 84 and 98 DAF. Moreover, TAG profile was changing along with DAFs due to the increased composition of 18:1 FA in TAG pool. Moreover, lipidomics also demonstrated that the enhanced acyl editing was responsible for the flux of FA through phosphatidylcholine for eventual TAG synthesis. Therefore, TAG biosynthesis in walnut kernel was characterized directly from lipid metabolism.
Collapse
Affiliation(s)
- Changfeng Hu
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, 548 Binwen Road, Hangzhou, Zhejiang, 310053, China
| | - Jingyi Song
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, 548 Binwen Road, Hangzhou, Zhejiang, 310053, China
| | - Wumeng Jin
- College of Basic Medical Sciences, Zhejiang Chinese Medical University, 548 Binwen Road, Hangzhou, Zhejiang, 310053, China
| | - Wenqiang Wang
- College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Hongjin Bai
- College of Horticulture and Forestry, Tarim University, Alar, 843300, China
| | - Cuiyun Wu
- College of Horticulture and Forestry, Tarim University, Alar, 843300, China
| | - Lirong Shen
- College of Biosystems Engineering and Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
| |
Collapse
|
3
|
Wang Y, Zeng F, Zhao Z, He L, He X, Pang H, Huang F, Chang P. Transmembrane Protein 68 Functions as an MGAT and DGAT Enzyme for Triacylglycerol Biosynthesis. Int J Mol Sci 2023; 24:ijms24032012. [PMID: 36768334 PMCID: PMC9916437 DOI: 10.3390/ijms24032012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
Triacylglycerol (TG) biosynthesis is an important metabolic process for intracellular storage of surplus energy, intestinal dietary fat absorption, attenuation of lipotoxicity, lipid transportation, lactation and signal transduction in mammals. Transmembrane protein 68 (TMEM68) is an endoplasmic reticulum (ER)-anchored acyltransferase family member of unknown function. In the current study we show that overexpression of TMEM68 promotes TG accumulation and lipid droplet (LD) formation in a conserved active sites-dependent manner. Quantitative targeted lipidomic analysis showed that diacylglycerol (DG), free fatty acid (FFA) and TG levels were increased by TMEM68 expression. In addition, TMEM68 overexpression affected the levels of several glycerophospholipids, such as phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, as well as sterol ester contents. TMEM68 exhibited monoacylglycerol acyltransferase (MGAT) and diacylglycerol acyltransferase (DGAT) activities dependent on the conserved active sites in an in vitro assay. The expression of lipogenesis genes, including DGATs, fatty acid synthesis-related genes and peroxisome proliferator-activated receptor γ was upregulated in TMEM68-overexpressing cells. These results together demonstrate for the first time that TMEM68 functions as an acyltransferase and affects lipogenic gene expression, glycerolipid metabolism and TG storage in mammalian cells.
Collapse
|
4
|
Lee Y, Park R, Miller SM, Li Y. Genetic compensation of triacylglycerol biosynthesis in the green microalga Chlamydomonas reinhardtii. Plant J 2022; 111:1069-1080. [PMID: 35727866 PMCID: PMC9545326 DOI: 10.1111/tpj.15874] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 06/10/2022] [Accepted: 06/16/2022] [Indexed: 06/14/2023]
Abstract
Genetic compensation has been proposed to explain phenotypic differences between gene knockouts and knockdowns in several metazoan and plant model systems. With the rapid development of reverse genetic tools such as CRISPR/Cas9 and RNAi in microalgae, it is increasingly important to assess whether genetic compensation affects the phenotype of engineered algal mutants. While exploring triacylglycerol (TAG) biosynthesis pathways in the model alga Chlamydomonas reinhardtii, it was discovered that knockout of certain genes catalyzing rate-limiting steps of TAG biosynthesis, type-2 diacylglycerol acyltransferase genes (DGTTs), triggered genetic compensation under abiotic stress conditions. Genetic compensation of a DGTT1 null mutation by a related PDAT gene was observed regardless of the strain background or mutagenesis approach, for example, CRISPR/Cas 9 or insertional mutagenesis. However, no compensation was found in the PDAT knockout mutant. The effect of PDAT knockout was evaluated in a Δvtc1 mutant, in which PDAT was upregulated under stress, resulting in a 90% increase in TAG content. Knockout of PDAT in the Δvtc1 background induced a 12.8-fold upregulation of DGTT1 and a 272.3% increase in TAG content in Δvtc1/pdat1 cells, while remaining viable. These data suggest that genetic compensation contributes to the genetic robustness of microalgal TAG biosynthetic pathways, maintaining lipid and redox homeostasis in the knockout mutants under abiotic stress. This work demonstrates examples of genetic compensation in microalgae, implies the physiological relevance of genetic compensation in TAG biosynthesis under stress, and provides guidance for future genetic engineering and mutant characterization efforts.
Collapse
Affiliation(s)
- Yi‐Ying Lee
- Institute of Marine and Environmental TechnologyUniversity of Maryland Center for Environmental ScienceBaltimoreMD21202USA
| | - Rudolph Park
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMD21250USA
| | - Stephen M. Miller
- Department of Biological SciencesUniversity of Maryland, Baltimore CountyBaltimoreMD21250USA
| | - Yantao Li
- Institute of Marine and Environmental TechnologyUniversity of Maryland Center for Environmental ScienceBaltimoreMD21202USA
- Department of Marine BiotechnologyUniversity of Maryland, Baltimore CountyBaltimoreMD21202USA
| |
Collapse
|
5
|
Gomez-Cano F, Chu YH, Cruz-Gomez M, Abdullah HM, Lee YS, Schnell DJ, Grotewold E. Exploring Camelina sativa lipid metabolism regulation by combining gene co-expression and DNA affinity purification analyses. Plant J 2022; 110:589-606. [PMID: 35064997 DOI: 10.1111/tpj.15682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
Camelina (Camelina sativa) is an annual oilseed plant that is gaining momentum as a biofuel cover crop. Understanding gene regulatory networks is essential to deciphering plant metabolic pathways, including lipid metabolism. Here, we take advantage of a growing collection of gene expression datasets to predict transcription factors (TFs) associated with the control of Camelina lipid metabolism. We identified approximately 350 TFs highly co-expressed with lipid-related genes (LRGs). These TFs are highly represented in the MYB, AP2/ERF, bZIP, and bHLH families, including a significant number of homologs of well-known Arabidopsis lipid and seed developmental regulators. After prioritizing the top 22 TFs for further validation, we identified DNA-binding sites and predicted target genes for 16 out of the 22 TFs tested using DNA affinity purification followed by sequencing (DAP-seq). Enrichment analyses of targets supported the co-expression prediction for most TF candidates, and the comparison to Arabidopsis revealed some common themes, but also aspects unique to Camelina. Within the top potential lipid regulators, we identified CsaMYB1, CsaABI3AVP1-2, CsaHB1, CsaNAC2, CsaMYB3, and CsaNAC1 as likely involved in the control of seed fatty acid elongation and CsaABI3AVP1-2 and CsabZIP1 as potential regulators of the synthesis and degradation of triacylglycerols (TAGs), respectively. Altogether, the integration of co-expression data and DNA-binding assays permitted us to generate a high-confidence and short list of Camelina TFs involved in the control of lipid metabolism during seed development.
Collapse
Affiliation(s)
- Fabio Gomez-Cano
- Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, Room 212, Biochemistry Building, East Lansing, MI, 48824-6473, USA
| | - Yi-Hsuan Chu
- Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, Room 212, Biochemistry Building, East Lansing, MI, 48824-6473, USA
| | - Mariel Cruz-Gomez
- Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, Room 212, Biochemistry Building, East Lansing, MI, 48824-6473, USA
| | - Hesham M Abdullah
- Department of Plant Biology, Michigan State University, 612 Wilson Road, Room 166, East Lansing, MI, 48824-1312, USA
- Biotechnology Department, Faculty of Agriculture, Al-Azhar University, Cairo, 11651, Egypt
| | - Yun Sun Lee
- Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, Room 212, Biochemistry Building, East Lansing, MI, 48824-6473, USA
| | - Danny J Schnell
- Department of Plant Biology, Michigan State University, 612 Wilson Road, Room 166, East Lansing, MI, 48824-1312, USA
| | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, Room 212, Biochemistry Building, East Lansing, MI, 48824-6473, USA
| |
Collapse
|
6
|
Pollard M, Shachar-Hill Y. Kinetic complexities of triacylglycerol accumulation in developing embryos from Camelina sativa provide evidence for multiple biosynthetic systems. J Biol Chem 2022; 298:101396. [PMID: 34774796 PMCID: PMC8715117 DOI: 10.1016/j.jbc.2021.101396] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/28/2021] [Accepted: 11/05/2021] [Indexed: 11/19/2022] Open
Abstract
Quantitative flux maps describing glycerolipid synthesis can be important tools for rational engineering of lipid content and composition in oilseeds. Lipid accumulation in cultured embryos of Camelina sativa is known to mimic that of seeds in terms of rate of lipid synthesis and composition. To assess the kinetic complexity of the glycerolipid flux network, cultured embryos were incubated with [14C/13C]glycerol, and initial and steady state rates of [14C/13Cglyceryl] lipid accumulation were measured. At steady state, the linear accumulations of labeled lipid classes matched those expected from mass compositions. The system showed an apparently simple kinetic precursor-product relationship between the intermediate pool, dominated by diacylglycerol (DAG) and phosphatidylcholine (PC), and the triacylglycerol (TAG) product. We also conducted isotopomer analyses on hydrogenated lipid class species. [13C3glyceryl] labeling of DAG and PC, together with estimates of endogenous [12C3glyceryl] dilution, showed that each biosynthetically active lipid pool is ∼30% of the total by moles. This validates the concept that lipid sub-pools can describe lipid biosynthetic networks. By tracking the kinetics of [13C3glyceryl] and [13C2acyl] labeling, we observed two distinct TAG synthesis components. The major TAG synthesis flux (∼75%) was associated with >95% of the DAG/PC intermediate pool, with little glycerol being metabolized to fatty acids, and with little dilution from endogenous glycerol; a smaller flux exhibited converse characteristics. This kinetic heterogeneity was further explored using postlabeling embryo dissection and differential lipid extractions. The minor flux was tentatively localized to surface cells across the whole embryo. Such heterogeneity must be recognized in order to construct accurate gene expression patterns and metabolic networks describing lipid biosynthesis in developing embryos.
Collapse
Affiliation(s)
- Mike Pollard
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA.
| |
Collapse
|
7
|
Avidan O, Malitsky S, Pick U. Fatty Acid Production and Direct Acyl Transfer through Polar Lipids Control TAG Biosynthesis during Nitrogen Deprivation in the Halotolerant Alga Dunaliella tertiolecta. Mar Drugs 2021; 19:368. [PMID: 34202376 DOI: 10.3390/md19070368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 12/31/2022] Open
Abstract
The aims of this work were to evaluate the contribution of the free fatty acid (FA) pool to triacylglyceride (TAG) biosynthesis and to try to characterize the mechanism by which FA are assimilated into TAG in the green alga Dunaliella tertiolecta. A time-resolved lipidomic analysis showed that nitrogen (N) deprivation induces a redistribution of total lipidome, particularly of free FA and major polar lipid (PL), in parallel to enhanced accumulation of polyunsaturated TAG. The steady-state concentration of the FA pool, measured by prolonged 14C-bicarbonate pre-labeling, showed that N deprivation induced a 50% decrease in total FA level within the first 24 h and up to 85% after 96 h. The abundance of oleic acid increased from 50 to 70% of total free FA while polyunsaturated FA (PUFA) disappeared under N deprivation. The FA flux, measured by the rate of incorporation of 14C-palmitic acid (PlA), suggests partial suppression of phosphatidylcholine (PC) acyl editing and an enhanced turnover of the FA pool and of total digalactosyl-diacylglycerol (DGDG) during N deprivation. Taken together, these results imply that FA biosynthesis is a major rate-controlling stage in TAG biosynthesis in D. tertiolecta and that acyl transfer through PL such as PC and DGDG is the major FA assimilation pathway into TAG in that alga and possibly in other green microalgae. Increasing the availability of FA could lead to enhanced TAG biosynthesis and to improved production of high-value products from microalgae.
Collapse
|
8
|
Ma H, Wu X, Wei Z, Zhao L, Li Z, Liang Q, Zheng J, Wang Y, Li Y, Huang L, Hu Q, Han D. Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis. J Exp Bot 2021; 72:510-524. [PMID: 33005924 PMCID: PMC7853605 DOI: 10.1093/jxb/eraa451] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 10/05/2020] [Indexed: 05/03/2023]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final committed step in triacylglycerol biosynthesis in eukaryotes. In microalgae, the copy number of DGAT genes is extraordinarily expanded, yet the functions of many DGATs remain largely unknown. This study revealed that microalgal DGAT can function as a lysophosphatidic acyltransferase (LPAAT) both in vitro and in vivo while losing its original function as DGAT. Among the five DGAT-encoding genes identified and cloned from the green microalga Haematococcus pluvialis, four encoded HpDGATs that showed triacylglycerol synthase activities in yeast functional complementation analyses; the exception was one of the type II DGAT encoding genes, HpDGTT2. The hydrophobic recombinant HpDGTT2 protein was purified in soluble form and was found to function as a LPAAT via enzymatic assay. Introducing this gene into the green microalga Chlamydomonas reinhardtii led to retarded cellular growth, enlarged cell size, and enhanced triacylglycerol accumulation, identical to the phenotypes of transgenic strains overexpressing CrLPAAT. This study provides a framework for dissecting uncharacterized DGATs, and could pave the way to decrypting the structure-function relationship of this large group of enzymes that are critical to lipid biosynthesis.
Collapse
Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoying Wu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Ziwang Wei
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhongze Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qing Liang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jie Zheng
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu Wang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Linfei Huang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Algae Biomass, SDIC Biotech Investment Corporation, Beijing, China
- Correspondence: or
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Correspondence: or
| |
Collapse
|
9
|
Xu Y, Caldo KMP, Falarz L, Jayawardhane K, Chen G. Kinetic improvement of an algal diacylglycerol acyltransferase 1 via fusion with an acyl-CoA binding protein. Plant J 2020; 102:856-871. [PMID: 31991039 DOI: 10.1111/tpj.14708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/26/2019] [Accepted: 01/21/2020] [Indexed: 05/03/2023]
Abstract
Microalgal oils in the form of triacylglycerols (TAGs) are broadly used as nutritional supplements and biofuels. Diacylglycerol acyltransferase (DGAT) catalyzes the final step of acyl-CoA-dependent biosynthesis of TAG, and is considered a key target for manipulating oil production. Although a growing number of DGAT1s have been identified and over-expressed in some algal species, the detailed structure-function relationship, as well as the improvement of DGAT1 performance via protein engineering, remain largely untapped. Here, we explored the structure-function features of the hydrophilic N-terminal domain of DGAT1 from the green microalga Chromochloris zofingiensis (CzDGAT1). The results indicated that the N-terminal domain of CzDGAT1 was less disordered than those of the higher eukaryotic enzymes and its partial truncation or complete removal could substantially decrease enzyme activity, suggesting its possible role in maintaining enzyme performance. Although the N-terminal domains of animal and plant DGAT1s were previously found to bind acyl-CoAs, replacement of CzDGAT1 N-terminus by an acyl-CoA binding protein (ACBP) could not restore enzyme activity. Interestingly, the fusion of ACBP to the N-terminus of the full-length CzDGAT1 could enhance the enzyme affinity for acyl-CoAs and augment protein accumulation levels, which ultimately drove oil accumulation in yeast cells and tobacco leaves to higher levels than the full-length CzDGAT1. Overall, our findings unravel the distinct features of the N-terminus of algal DGAT1 and provide a strategy to engineer enhanced performance in DGAT1 via protein fusion, which may open a vista in generating improved membrane-bound acyl-CoA-dependent enzymes and boosting oil biosynthesis in plants and oleaginous microorganisms.
Collapse
Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Kethmi Jayawardhane
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| |
Collapse
|
10
|
Zhao X, Qiu X. Very Long Chain Polyunsaturated Fatty Acids Accumulated in Triacylglycerol Are Channeled From Phosphatidylcholine in Thraustochytrium. Front Microbiol 2019; 10:645. [PMID: 30972054 PMCID: PMC6446058 DOI: 10.3389/fmicb.2019.00645] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 03/14/2019] [Indexed: 11/13/2022] Open
Abstract
Thraustochytrium is a marine protist that can accumulate a large amount of very long chain polyunsaturated fatty acids (VLCPUFA) in triacylglycerols (TAG). How these freshly synthesized VLCPUFAs are channeled into TAG remains unknown. In this study, the glycerolipid profile of Thraustochytrium at log and stationary growth stages was first analyzed by lipidomic tools, and then 14C-acetate and 14C-glycerol were used to trace the flux of fatty acids and backbone in glycerolipids. Lipidomic analysis showed that VLCPUFAs were mostly allocated to phosphatidylcholine (PC) and TAG. PC possessed a relatively stable profile of VLCPUFAs, whereas TAG carrying VLCPUFAs were significantly increased at the stationary phase. 14C-acetate labeled VLCPUFAs were predominately incorporated into PC initially but were mostly found in TAG at later time of labeling. Positional analysis showed that PC had either one VLCPUFA at its sn-2 position (PC1) or two VLCPUFAs (PC2), while TAG incorporated VLCPUFAs almost exclusively at the sn-2 position. Similarly, 14C-glycerol was more efficiently incorporated into PC1 than TAG initially but was mostly found in TAG at later time of labeling, and diacylglycerol and PC1 shared a similar incorporation pattern. These results indicate that VLCPUFAs in TAG are mainly channeled from PC likely through diacylglycerol as the intermediate.
Collapse
Affiliation(s)
- Xianming Zhao
- Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| | - Xiao Qiu
- Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada
| |
Collapse
|
11
|
Xu Y, Falarz L, Chen G. Characterization of Type-2 Diacylglycerol Acyltransferases in the Green Microalga Chromochloris zofingiensis. J Agric Food Chem 2019; 67:291-298. [PMID: 30543104 DOI: 10.1021/acs.jafc.8b05755] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step of the acyl-CoA-dependent TAG biosynthesis and thus is a key target for manipulating oil production in microalgae. The microalga Chromochloris zofingiensis can accumulate substantial amounts of triacylglycerol (TAG) and represents a promising source of algal lipids. In this study, C. zofingiensis DGAT2s (CzDGAT2s) were characterized with in silico, in vivo (yeast), and in vitro assays. Putative CzDGAT2s were identified, and their functional motifs and evolutionary relationship with other DGAT2s were analyzed. When CzDGAT2s were individually expressed in a TAG-deficient Saccharomyces cerevisiae strain, only CzDGAT2C could restore the TAG biosynthesis. Further in vitro assays indicated that CzDGAT2C displayed typical DGAT activity, which was fitted to the Michaelis-Menten equation, and N- and C-terminals were important for the enzyme activity. In addition, membrane yeast two-hybrid assay revealed a possible DGAT2 activity modulation via the formation of homodimer/heterodimer among different DGAT2 isoforms.
Collapse
Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
- Department of Biological Sciences , University of Manitoba , Winnipeg , Manitoba , Canada R3T 2N2
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
- Department of Biological Sciences , University of Manitoba , Winnipeg , Manitoba , Canada R3T 2N2
| |
Collapse
|
12
|
Caldo KMP, Shen W, Xu Y, Hanley-Bowdoin L, Chen G, Weselake RJ, Lemieux MJ. Diacylglycerol acyltransferase 1 is activated by phosphatidate and inhibited by SnRK1-catalyzed phosphorylation. Plant J 2018; 96:287-299. [PMID: 30003607 DOI: 10.1111/tpj.14029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/23/2018] [Accepted: 06/26/2018] [Indexed: 05/06/2023]
Abstract
Diacylglycerol acyltransferase 1 (DGAT1) catalyzes the final and committed step in the Kennedy pathway for triacylglycerol (TAG) biosynthesis and, as such, elucidating its mode of regulation is critical to understand the fundamental aspects of carbon metabolism in oleaginous crops. In this study, purified Brassica napus diacylglycerol acyltransferase 1 (BnaDGAT1) in n-dodecyl-β-d-maltopyranoside micelles was lipidated to form mixed micelles and subjected to detailed biochemical analysis. The degree of mixed micelle fluidity appeared to influence acyltransferase activity. BnaDGAT1 exhibited a sigmoidal response and eventual substrate inhibition with respect to increasing concentrations of oleoyl-CoA. Phosphatidate (PA) was identified as a feed-forward activator of BnaDGAT1, enabling the final enzyme in the Kennedy pathway to adjust to the incoming flow of carbon leading to TAG. In the presence of PA, the oleoyl-CoA saturation plot became more hyperbolic and desensitized to substrate inhibition indicating that PA facilitates the transition of the enzyme into the more active state. PA may also relieve possible autoinhibition of BnaDGAT1 brought about by the N-terminal regulatory domain, which was shown to interact with PA. Indeed, PA is a key effector modulating lipid homeostasis, in addition to its well recognized role in lipid signaling. BnaDGAT1 was also shown to be a substrate of the sucrose non-fermenting-1-related kinase 1 (SnRK1), which catalyzed phosphorylation of the enzyme and converted it to a less active form. Thus, this known regulator of carbon metabolism directly influences TAG biosynthesis.
Collapse
Affiliation(s)
- Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Wei Shen
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Linda Hanley-Bowdoin
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| |
Collapse
|
13
|
Abstract
The halotolerant green alga Dunaliella tertiolecta accumulates starch and triacylglycerol (TAG) amounting to 70% and 10-15% of total cellular carbon, respectively, when exposed to nitrogen (N) deprivation. The purpose of this study was to clarify the inter-relationships between the biosynthesis of TAG, starch, and polar lipids (PLs) in this alga. Pulse labeling with [14C]bicarbonate was utilized to label starch and [14C]palmitic acid (PlA) to label lipids. Transfer of 14C into TAG was measured and used to calculate rates of synthesis. About two-thirds of the carbon in TAG originates from starch, and one-third is made de novo by direct CO2 assimilation. The level made from degradation of pre-formed PLs is estimated to be very small. Most of the de novo synthesis involves fatty acid transfer through PLs made during the first day of N deprivation. The results suggest that starch made by photosynthetic carbon assimilation at the early stages of N deprivation is utilized for synthesis of TAG. Trans-acylation from PLs is the second major contributor to TAG biosynthesis. The utilization of starch for TAG biosynthesis may have biotechnological applications to optimize TAG biosynthesis in algae.
Collapse
Affiliation(s)
- Uri Pick
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
- Correspondence:
| | - Omri Avidan
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| |
Collapse
|
14
|
Chen G, Xu Y, Siloto RMP, Caldo KMP, Vanhercke T, Tahchy AE, Niesner N, Chen Y, Mietkiewska E, Weselake RJ. High-performance variants of plant diacylglycerol acyltransferase 1 generated by directed evolution provide insights into structure function. Plant J 2017; 92:167-177. [PMID: 28755522 DOI: 10.1111/tpj.13652] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/27/2017] [Accepted: 07/24/2017] [Indexed: 05/08/2023]
Abstract
Diacylglycerol acyltransferase 1 (DGAT1) catalyzes the acyl-CoA-dependent biosynthesis of triacylglycerol, the predominant component of seed oil. In some oil crops, including Brassica napus, the level of DGAT1 activity can have a substantial effect on triacylglycerol production. Structure-function insights into DGAT1, however, remain limited because of the lack of a three-dimensional detailed structure for this membrane-bound enzyme. In this study, the amino acid residues governing B. napus DGAT1 (BnaDGAT1) activity were investigated via directed evolution, targeted mutagenesis, in vitro enzymatic assay, topological analysis, and transient expression of cDNA encoding selected enzyme variants in Nicotiana benthamiana. Directed evolution revealed that numerous amino acid residues were associated with increased BnaDGAT1 activity, and 67% of these residues were conserved among plant DGAT1s. The identified amino acid residue substitution sites occur throughout the BnaDGAT1 polypeptide, with 89% of the substitutions located outside the putative substrate binding or active sites. In addition, cDNAs encoding variants I447F or L441P were transiently overexpressed in N. benthamiana leaves, resulting in 33.2 or 70.5% higher triacylglycerol content, respectively, compared with native BnaDGAT1. Overall, the results provide novel insights into amino acid residues underlying plant DGAT1 function and performance-enhanced BnaDGAT1 variants for increasing vegetable oil production.
Collapse
Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| | - Rodrigo M P Siloto
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| | | | | | | | - Yongyan Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| | - Elzbieta Mietkiewska
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton Alberta, Canada, T6G 2P5
| |
Collapse
|
15
|
Sato T, Akimoto N, Takahashi A, Ito A. Triptolide suppresses ultraviolet B-enhanced sebum production by inhibiting the biosynthesis of triacylglycerol in hamster sebaceous glands in vivo and in vitro. Exp Ther Med 2017; 14:361-366. [PMID: 28672939 DOI: 10.3892/etm.2017.4461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 02/24/2017] [Indexed: 12/21/2022] Open
Abstract
Ultraviolet B (UVB) irradiation causes alterations in cutaneous barrier function, including excessive production of sebum in sebaceous glands, which is associated with the aggravation of acne. This study aimed to evaluate the inhibitory effects of triptolide, a diterpenoid triepoxide from Tripterygium wilfordii Hook F, on sebocytic lipogenesis in UVB-irradiated hamster skin in vivo and in vitro. Topical application of triptolide decreased the UVB-enhanced sebum accumulation in the sebaceous glands of hamster skin. The level of triacylglycerol (TG), a major sebum component, on the skin surface was reduced by triptolide treatment in UVB-irradiated hamsters, whereas there was no change in that of free-fatty acids and cholesterol, which are minor sebum components. UVB irradiation significantly enhanced TG production (P<0.01 in extracellular lipids, P<0.05 in intracellular lipids), and the activity of acyl coenzyme A/diacylglycerol acyltransferase (DGAT), a rate-limiting enzyme of TG synthesis, in differentiated hamster sebocytes (P<0.05 at 6 h and UVB of 0.62 kJ/m2, P<0.001 at 24 h and UVB 0.37 or 0.62 kJ/m2). Furthermore, triptolide significantly inhibited UVB-enhanced TG production (P<0.05 at 28 nM and P<0.01 at 56 and 112 nM triptolide) and DGAT activity (P<0.01 at 28 nM and P<0.001 at 56 and 112 nM triptolide) in differentiated hamster sebocytes. These results provide novel evidence that triptolide decreases UVB-enhanced sebum production by inhibiting DGAT-dependent TG biosynthesis in differentiated hamster sebocytes. These findings may be applicable to the prevention of acne aggravation.
Collapse
Affiliation(s)
- Takashi Sato
- Department of Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Noriko Akimoto
- Department of Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Aiko Takahashi
- Department of Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Akira Ito
- The Institute for Social Medicine, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| |
Collapse
|
16
|
Yao QY, Huang H, Tong Y, Xia EH, Gao LZ. Transcriptome Analysis Identifies Candidate Genes Related to Triacylglycerol and Pigment Biosynthesis and Photoperiodic Flowering in the Ornamental and Oil-Producing Plant, Camellia reticulata (Theaceae). Front Plant Sci 2016; 7:163. [PMID: 26941748 PMCID: PMC4763035 DOI: 10.3389/fpls.2016.00163] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 01/30/2016] [Indexed: 05/19/2023]
Abstract
Camellia reticulata, which is native to Southwest China, is famous for its ornamental flowers and high-quality seed oil. However, the lack of genomic information for this species has largely hampered our understanding of its key pathways related to oil production, photoperiodic flowering process and pigment biosynthesis. Here, we first sequenced and characterized the transcriptome of a diploid C. reticulata in an attempt to identify genes potentially involved in triacylglycerol biosynthesis (TAGBS), photoperiodic flowering, flavonoid biosynthesis (FlaBS), carotenoid biosynthesis (CrtBS) pathways. De novo assembly of the transcriptome provided a catalog of 141,460 unigenes with a total length of ~96.1 million nucleotides (Mnt) and an N50 of 1080 nt. Of them, 22,229 unigenes were defined as differentially expressed genes (DEGs) across five sequenced tissues. A large number of annotated genes in C. reticulata were found to have been duplicated, and differential expression patterns of these duplicated genes were commonly observed across tissues, such as the differential expression of SOC1_a, SOC1_b, and SOC1_c in the photoperiodic flowering pathway. Up-regulation of SAD_a and FATA genes and down-regulation of FAD2_a gene in the TAGBS pathway in seeds may be relevant to the ratio of monounsaturated fatty acid (MUFAs) to polyunsaturated fatty acid (PUFAs) in seed oil. MYBF1, a transcription regulator gene of the FlaBS pathway, was found with great sequence variation and alteration of expression patterns, probably resulting in functionally evolutionary differentiation in C. reticulata. MYBA1_a and some anthocyanin-specific biosynthetic genes in the FlaBS pathway were highly expressed in both flower buds and flowers, suggesting important roles of anthocyanin biosynthesis in flower development. Besides, a total of 40,823 expressed sequence tag simple sequence repeats (EST-SSRs) were identified in the C. reticulata transcriptome, providing valuable marker resources for further basic and applied researches on this economically important Camellia plant.
Collapse
Affiliation(s)
- Qiu-Yang Yao
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- University of Chinese Academy of SciencesBeijing, China
| | - Hui Huang
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Yan Tong
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - En-Hua Xia
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- University of Chinese Academy of SciencesBeijing, China
| | - Li-Zhi Gao
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- *Correspondence: Li-Zhi Gao
| |
Collapse
|
17
|
Pan X, Chen G, Kazachkov M, Greer MS, Caldo KMP, Zou J, Weselake RJ. In Vivo and in Vitro Evidence for Biochemical Coupling of Reactions Catalyzed by Lysophosphatidylcholine Acyltransferase and Diacylglycerol Acyltransferase. J Biol Chem 2015; 290:18068-18078. [PMID: 26055703 DOI: 10.1074/jbc.m115.654798] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Indexed: 11/06/2022] Open
Abstract
Seed oils of flax (Linum usitatissimum L.) and many other plant species contain substantial amounts of polyunsaturated fatty acids (PUFAs). Phosphatidylcholine (PC) is the major site for PUFA synthesis. The exact mechanisms of how these PUFAs are channeled from PC into triacylglycerol (TAG) needs to be further explored. By using in vivo and in vitro approaches, we demonstrated that the PC deacylation reaction catalyzed by the reverse action of acyl-CoA:lysophosphatidylcholine acyltransferase (LPCAT) can transfer PUFAs on PC directly into the acyl-CoA pool, making these PUFAs available for the diacylglycerol acyltransferase (DGAT)-catalyzed reaction for TAG production. Two types of yeast mutants were generated for in vivo and in vitro experiments, respectively. Both mutants provide a null background with no endogenous TAG forming capacity and an extremely low LPCAT activity. In vivo experiments showed that co-expressing flax DGAT1-1 and LPCAT1 in the yeast quintuple mutant significantly increased 18-carbon PUFAs in TAG with a concomitant decrease of 18-carbon PUFAs in phospholipid. We further showed that after incubation of sn-2-[(14)C]acyl-PC, formation of [(14)C]TAG was only possible with yeast microsomes containing both LPCAT1 and DGAT1-1. Moreover, the specific activity of overall LPCAT1 and DGAT1-1 coupling process exhibited a preference for transferring (14)C-labeled linoleoyl or linolenoyl than oleoyl moieties from the sn-2 position of PC to TAG. Together, our data support the hypothesis of biochemical coupling of the LPCAT1-catalyzed reverse reaction with the DGAT1-1-catalyzed reaction for incorporating PUFAs into TAG. This process represents a potential route for enriching TAG in PUFA content during seed development in flax.
Collapse
Affiliation(s)
- Xue Pan
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Guanqun Chen
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Michael Kazachkov
- National Research Council Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
| | - Michael S Greer
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Jitao Zou
- National Research Council Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
| | - Randall J Weselake
- Alberta Innovates Phytola Centre, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
| |
Collapse
|
18
|
El Tahchy A, Petrie JR, Shrestha P, Vanhercke T, Singh SP. Expression of Mouse MGAT in Arabidopsis Results in Increased Lipid Accumulation in Seeds. Front Plant Sci 2015; 6:1180. [PMID: 26834753 PMCID: PMC4714628 DOI: 10.3389/fpls.2015.01180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/09/2015] [Indexed: 05/10/2023]
Abstract
Worldwide demand for vegetable oil is projected to double within the next 30 years due to increasing food, fuel, and industrial requirements. There is therefore great interest in metabolic engineering strategies that boost oil accumulation in plant tissues, however, efforts to date have only achieved levels of storage lipid accumulation in plant tissues far below the benchmark to meet demand. Monoacylglycerol acyltransferase (MGAT) is predominantly associated with lipid absorption and resynthesis in the animal intestine where it catalyzes monoacylglycerol (MAG) to form diacylglycerol (DAG), and then triacylglycerol (TAG). In contrast plant lipid biosynthesis routes do not include MGAT. Rather, DAG and TAG are either synthesized from glycerol-3-phosphate by a series of three subsequent acylation reactions, or originated from phospholipids via an acyl editing pathway. Mouse MGATs 1 and 2 have been shown to increase oil content transiently in Nicotiana benthamiana leaf tissue by 2.6 fold. Here we explore the feasibility of this approach to increase TAG in Arabidopsis thaliana seed. The stable MGAT2 expression resulted in a significant increase in seed oil content by 1.32 fold. We also report evidence of the MGAT2 activity based on in vitro assays. Up to 3.9 fold increase of radiolabeled DAG were produced in seed lysate which suggest that the transgenic MGAT activity can result in DAG re-synthesis by salvaging the MAG product of lipid breakdown. The expression of MGAT2 therefore creates an independent and complementary TAG biosynthesis route to the endogenous Kennedy pathway and other glycerolipid synthesis routes.
Collapse
Affiliation(s)
- Anna El Tahchy
- CSIRO Agriculture, Canberra, ACTAustralia
- CSIRO Food and Nutrition, Canberra, ACTAustralia
- *Correspondence: Anna El Tahchy,
| | - James R. Petrie
- CSIRO Agriculture, Canberra, ACTAustralia
- CSIRO Food and Nutrition, Canberra, ACTAustralia
| | - Pushkar Shrestha
- CSIRO Agriculture, Canberra, ACTAustralia
- CSIRO Food and Nutrition, Canberra, ACTAustralia
| | - Thomas Vanhercke
- CSIRO Agriculture, Canberra, ACTAustralia
- CSIRO Food and Nutrition, Canberra, ACTAustralia
| | - Surinder P. Singh
- CSIRO Agriculture, Canberra, ACTAustralia
- CSIRO Food and Nutrition, Canberra, ACTAustralia
| |
Collapse
|
19
|
Deng XD, Cai JJ, Fei XW. Involvement of phosphatidate phosphatase in the biosynthesis of triacylglycerols in Chlamydomonas reinhardtii. J Zhejiang Univ Sci B 2013; 14:1121-31. [PMID: 24302712 PMCID: PMC3863370 DOI: 10.1631/jzus.b1300180] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 10/18/2013] [Indexed: 12/22/2022]
Abstract
Lipid biosynthesis is essential for eukaryotic cells, but the mechanisms of the process in microalgae remain poorly understood. Phosphatidic acid phosphohydrolase or 3-sn-phosphatidate phosphohydrolase (PAP) catalyzes the dephosphorylation of phosphatidic acid to form diacylglycerols and inorganic orthophosphates. This reaction is integral in the synthesis of triacylglycerols. In this study, the mRNA level of the PAP isoform CrPAP2 in a species of Chlamydomonas was found to increase in nitrogen-free conditions. Silencing of the CrPAP2 gene using RNA interference resulted in the decline of lipid content by 2.4%-17.4%. By contrast, over-expression of the CrPAP2 gene resulted in an increase in lipid content by 7.5%-21.8%. These observations indicate that regulation of the CrPAP2 gene can control the lipid content of the algal cells. In vitro CrPAP2 enzyme activity assay indicated that the cloned CrPAP2 gene exhibited biological activities.
Collapse
Affiliation(s)
- Xiao-dong Deng
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Jia-jia Cai
- Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Xiao-wen Fei
- School of Science, Hainan Medical College, Haikou 571101, China
| |
Collapse
|
20
|
Bourgis F, Kilaru A, Cao X, Ngando-Ebongue GF, Drira N, Ohlrogge JB, Arondel V. Comparative transcriptome and metabolite analysis of oil palm and date palm mesocarp that differ dramatically in carbon partitioning. Proc Natl Acad Sci U S A 2011; 108:12527-32. [PMID: 21709233 PMCID: PMC3145713 DOI: 10.1073/pnas.1106502108] [Citation(s) in RCA: 232] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Oil palm can accumulate up to 90% oil in its mesocarp, the highest level observed in the plant kingdom. In contrast, the closely related date palm accumulates almost exclusively sugars. To gain insight into the mechanisms that lead to such an extreme difference in carbon partitioning, the transcriptome and metabolite content of oil palm and date palm were compared during mesocarp development. Compared with date palm, the high oil content in oil palm was associated with much higher transcript levels for all fatty acid synthesis enzymes, specific plastid transporters, and key enzymes of plastidial carbon metabolism, including phosphofructokinase, pyruvate kinase, and pyruvate dehydrogenase. Transcripts representing an ortholog of the WRI1 transcription factor were 57-fold higher in oil palm relative to date palm and displayed a temporal pattern similar to its target genes. Unexpectedly, despite more than a 100-fold difference in flux to lipids, most enzymes of triacylglycerol assembly were expressed at similar levels in oil palm and date palm. Similarly, transcript levels for all but one cytosolic enzyme of glycolysis were comparable in both species. Together, these data point to synthesis of fatty acids and supply of pyruvate in the plastid, rather than acyl assembly into triacylglycerol, as a major control over the storage of oil in the mesocarp of oil palm. In addition to greatly increasing molecular resources devoted to oil palm and date palm, the combination of temporal and comparative studies illustrates how deep sequencing can provide insights into gene expression patterns of two species that lack genome sequence information.
Collapse
Affiliation(s)
- Fabienne Bourgis
- Université de Bordeaux Ségalen, Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France
- Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France
| | - Aruna Kilaru
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824
| | - Xia Cao
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824
| | - Georges-Frank Ngando-Ebongue
- Centre de Recherches sur le Palmier à Huile de la Dibamba, Institut de Recherche Agricole pour le Développement, BP243 Douala, Cameroon; and
| | - Noureddine Drira
- Laboratoire de Biotechnologie Végétale, Faculté des Sciences de Sfax, Sfax 3038, Tunisia
| | - John B. Ohlrogge
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824
| | - Vincent Arondel
- Université de Bordeaux Ségalen, Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France
- Centre National de la Recherche Scientifique, Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, F-33000 Bordeaux, France
| |
Collapse
|