1
|
Wang Y, Wang J, Yang S, Liang Q, Gu Z, Wang Y, Mou H, Sun H. Selecting a preculture strategy for improving biomass and astaxanthin productivity of Chromochloris zofingiensis. Appl Microbiol Biotechnol 2024; 108:117. [PMID: 38204137 PMCID: PMC10781847 DOI: 10.1007/s00253-023-12873-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/05/2023] [Accepted: 10/17/2023] [Indexed: 01/12/2024]
Abstract
Chromochloris zofingiensis is a potential source of natural astaxanthin; however, its rapid growth and astaxanthin enrichment cannot be achieved simultaneously. This study established autotrophic, mixotrophic, and heterotrophic preculture patterns to assess their ameliorative effect on the C. zofingiensis heterotrophic growth state. In comparison, mixotrophic preculture (MP) exhibited the best improving effect on heterotrophic biomass concentration of C. zofingiensis (up to 121.5 g L-1) in a 20 L fermenter, reaching the global leading level. The astaxanthin productivity achieved 111 mg L-1 day-1, 7.4-fold higher than the best record. The transcriptome and 13C tracer-based metabolic flux analysis were used for mechanism inquiry. The results revealed that MP promoted carotenoid and lipid synthesis, and supported synthesis preference of low unsaturated fatty acids represented by C18:1 and C16:0. The MP group maintained the best astaxanthin productivity via mastering the balance between increasing glucose metabolism and inhibition of carotenoid synthesis. The MP strategy optimized the physiological state of C. zofingiensis and realized its heterotrophic high-density growth for an excellent astaxanthin yield on a pilot scale. This strategy exhibits great application potential in the microalgae-related industry. KEY POINTS: • Preculture strategies changed carbon flux and gene expression in C. zofingiensis • C. zofingiensis realized a high-density culture with MP and fed-batch culture (FBC) • Astaxanthin productivity achieved 0.111 g L-1 day-1 with MP and FBC.
Collapse
Affiliation(s)
- Yuxin Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China
| | - Jia Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China
| | - Shufang Yang
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Qingping Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China
| | - Ziqiang Gu
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China
| | - Ying Wang
- Marine Science research Institute of Shandong Province, Qingdao, 266003, China.
| | - Haijin Mou
- College of Food Science and Engineering, Ocean University of China, Qingdao, 266003, China.
| | - Han Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China.
| |
Collapse
|
2
|
Liu PY, Wu JJ, Li G, Lin CB, Jiang S, Liu S, Wan X. The Biosynthesis of Astaxanthin Esters in Schizochytrium sp. is Mediated by a Bifunctional Diacylglycerol Acyltransferase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:3584-3595. [PMID: 38344823 DOI: 10.1021/acs.jafc.3c09086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Astaxanthin esters are a major form of astaxanthin found in nature. However, the exact mechanisms of the biosynthesis and storage of astaxanthin esters were previously unknown. We found that Schizochytrium sp. synthesized both astaxanthin and docosahexaenoic acid (DHA)-enriched lipids. The major type of astaxanthin produced was free astaxanthin along with astaxanthin-DHA monoester and other esterified forms. DHA accounted for 41.0% of the total fatty acids from astaxanthin monoesters. These compounds were deposited mainly in lipid droplets. The biosynthesis of the astaxanthin esters was mainly carried out by a novel diacylglycerol acyltransferase ScDGAT2-1, while ScDGAT2-2 was involved only in the production of triacylglycerol. We also identified astaxanthin ester synthases from the astaxanthin-producing algae Haematococcus pluvialis and Chromochloris zofingiensis, as well as a thraustochytrid Hondaea fermentalgiana with an unknown carotenoid profile. This investigation enlightens the application of thraustochytrids for the production of both DHA and astaxanthin and provides enzyme resources for the biosynthesis of astaxanthin esters in the engineered microbes.
Collapse
Affiliation(s)
- Peng-Yang Liu
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Jun-Jie Wu
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Gang Li
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Chu-Bin Lin
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
- Wuhan Polytechnic University, Wuhan 430048, China
| | - Shan Jiang
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Shuang Liu
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
- Wuhan Polytechnic University, Wuhan 430048, China
| | - Xia Wan
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, China
| |
Collapse
|
3
|
Pan Y, Zhang W, Wang X, Jouhet J, Maréchal E, Liu J, Xia XQ, Hu H. Allele-dependent expression and functionality of lipid enzyme phospholipid:diacylglycerol acyltransferase affect diatom carbon storage and growth. PLANT PHYSIOLOGY 2024; 194:1024-1040. [PMID: 37930282 DOI: 10.1093/plphys/kiad581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/06/2023] [Accepted: 10/11/2023] [Indexed: 11/07/2023]
Abstract
In the acyl-CoA-independent pathway of triacylglycerol (TAG) synthesis unique to plants, fungi, and algae, TAG formation is catalyzed by the enzyme phospholipid:diacylglycerol acyltransferase (PDAT). The unique PDAT gene of the model diatom Phaeodactylum tricornutum strain CCMP2561 boasts 47 single nucleotide variants within protein coding regions of the alleles. To deepen our understanding of TAG synthesis, we observed the allele-specific expression of PDAT by the analysis of 87 published RNA-sequencing (RNA-seq) data and experimental validation. The transcription of one of the two PDAT alleles, Allele 2, could be specifically induced by decreasing nitrogen concentrations. Overexpression of Allele 2 in P. tricornutum substantially enhanced the accumulation of TAG by 44% to 74% under nutrient stress; however, overexpression of Allele 1 resulted in little increase of TAG accumulation. Interestingly, a more serious growth inhibition was observed in the PDAT Allele 1 overexpression strains compared with Allele 2 counterparts. Heterologous expression in yeast (Saccharomyces cerevisiae) showed that enzymes encoded by PDAT Allele 2 but not Allele 1 had TAG biosynthetic activity, and 7 N-terminal and 3 C-terminal amino acid variants between the 2 allele-encoded proteins substantially affected enzymatic activity. P. tricornutum PDAT, localized in the innermost chloroplast membrane, used monogalactosyldiacylglycerol and phosphatidylcholine as acyl donors as demonstrated by the increase of the 2 lipids in PDAT knockout lines, which indicated a common origin in evolution with green algal PDATs. Our study reveals unequal roles among allele-encoded PDATs in mediating carbon storage and growth in response to nitrogen stress and suggests an unsuspected strategy toward lipid and biomass improvement for biotechnological purposes.
Collapse
Affiliation(s)
- Yufang Pan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wanting Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG-LPCV, Grenoble Cedex 9 38054, France
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG-LPCV, Grenoble Cedex 9 38054, France
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xiao-Qin Xia
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanhua Hu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| |
Collapse
|
4
|
Li J, Chen H, Chang L, Wu C, Zhang H, Chen YQ, Chen W. Functions and substrate selectivity of diacylglycerol acyltransferases from Mortierella alpina. Appl Microbiol Biotechnol 2023; 107:5761-5774. [PMID: 37498333 DOI: 10.1007/s00253-023-12694-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/07/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023]
Abstract
Mortierella alpina produces various polyunsaturated fatty acids in the form of triacylglycerols (TAG). Diacylglycerol acyltransferase (DGAT) catalyzes the binding of acyl-CoA to diacylglycerol to form TAG and is the key enzyme involved in TAG synthesis. A variety of DGATs are present in M. alpina; however, comparative analysis of the functional properties and substrate selectivity of these DGATs is insufficient. In this study, DGAT1 (MaDGAT1A/1B/1C) and DGAT2 (MaDGAT2A/2B) isoforms from M. alpina were analyzed and heterologously expressed in S. cerevisiae H1246. The results showed that MaDGAT1A/1B/2A/2B were able to restore TAG synthesis, and the corresponding TAG content in recombinant yeasts was 2.92 ± 0.42%, 3.62 ± 0.22%, 0.86 ± 0.34%, and 0.18 ± 0.09%, respectively. In S. cerevisiae H1246, MaDGAT1A preferred C16:1 among monounsaturated fatty acids, MaDGAT1B preferred C16:0 among saturated fatty acids (SFAs), and MaDGAT2A/2B preferred C18:0 among SFAs. Under exogenous addition of polyunsaturated fatty acids (PUFAs), MaDGAT1A and 2A preferentially assembled linoleic acid into TAG, and MaDGAT2B had substrate selectivity for eicosapentaenoic and linoleic acids in ω-6 PUFAs. In vitro, MaDGAT1A showed no obvious acyl-CoA selectivity and MaDGAT1B preferred C20:5-CoA. MaDGAT1A/1B preferred C18:1/C18:1-DAG compared with C20:4/C20:4-DAG. This study indicates that MaDGATs have the potential to be used in the production of LA/EPA-rich TAG and provide a reference for improving the production of TAGs in oleaginous fungi. KEY POINTS: • MaDGAT1A preferred C16:1 among MUFAs, MaDGAT1B and MaDGAT2A/2B preferred C16:0 and C18:0 among SFAs, respectively • MaDGAT1A/2A preferentially assembled linoleic acid into TAG, and MaDGAT2B has substrate selectivity for eicosapentaenoic acid and linoleic acid in ω-6 PUFAs • MaDGAT1A showed no obvious acyl-CoA selectivity, and MaDGAT1B preferred C20:5-CoA. MaDGAT1A/1B preferred to select C18:1/C18:1-DAG compared with C20:4/C20:4-DAG.
Collapse
Affiliation(s)
- Jun Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
| | - Lulu Chang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Chen Wu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA
| | - Wei Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| |
Collapse
|
5
|
Senousy HH, El-Sheekh MM, Khairy HM, El-Sayed HS, Mahmoud GAE, Hamed AA. Biodiesel Production from the Marine Alga Nannochloropsis oceanica Grown on Yeast Wastewater and the Effect on Its Biochemical Composition and Gene Expression. PLANTS (BASEL, SWITZERLAND) 2023; 12:2898. [PMID: 37631110 PMCID: PMC10459201 DOI: 10.3390/plants12162898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 07/24/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023]
Abstract
Microalgae-based biodiesel synthesis is currently not commercially viable due to the high costs of culture realizations and low lipid yields. The main objective of the current study was to determine the possibility of growing Nannochloropsis oceanica on Saccharomyces cerevisiae yeast wastewater for biodiesel generation at an economical rate. N. oceanica was grown in Guillard F/2 synthetic medium and three dilutions of yeast wastewater (1, 1.25, and 1.5%). Biodiesel properties, in addition to carbohydrate, protein, lipid, dry weight, biomass, lipid productivity, amino acids, and fatty acid methyl ester (FAMEs) content, were analyzed and the quality of the produced biodiesel is assessed. The data revealed the response of N. oceanica to nitrogen-deficiency in the three dilutions of yeast wastewater. N. oceanica in Y2 (1.25%) yeast wastewater dilution exhibited the highest total carbohydrate and lipid percentages (21.19% and 41.97%, respectively), and the highest lipid productivity (52.46 mg L-1 day -1) under nitrogen deficiency in yeast wastewater. The fatty acids profile shows that N. oceanica cultivated in Y2 (1.25%) wastewater dilution provides a significant level of TSFA (47.42%) and can be used as a feedstock for biodiesel synthesis. In addition, N. oceanica responded to nitrogen shortage in wastewater dilutions by upregulating the gene encoding delta-9 fatty acid desaturase (Δ9FAD). As a result, the oleic and palmitoleic acid levels increased in the fatty acid profile of Y2 yeast wastewater dilution, highlighting the increased activity of Δ9FAD enzyme in transforming stearic acid and palmitic acid into oleic acid and palmitoleic acid. This study proved that the Y2 (1.25%) yeast wastewater dilution can be utilized as a growth medium for improving the quantity of specific fatty acids and lipid productivity in N. oceanica that affect biodiesel quality to satisfy global biodiesel requirements.
Collapse
Affiliation(s)
- Hoda H. Senousy
- Botany and Microbiology Department, Faculty of Science, Cairo University, Giza 12613, Egypt;
| | | | - Hanan M. Khairy
- National Institute of Oceanography and Fisheries (NIOF), Cairo 11516, Egypt; (H.M.K.); (H.S.E.-S.)
| | - Heba S. El-Sayed
- National Institute of Oceanography and Fisheries (NIOF), Cairo 11516, Egypt; (H.M.K.); (H.S.E.-S.)
| | | | - Amal A. Hamed
- Botany and Microbiology Department, Faculty of Science, Cairo University, Giza 12613, Egypt;
| |
Collapse
|
6
|
Liu K, Li J, Xing C, Yuan H, Yang J. Characterization of Auxenochlorella protothecoides acyltransferases and potential of their protein interactions to promote the enrichment of oleic acid. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:69. [PMID: 37085915 PMCID: PMC10120206 DOI: 10.1186/s13068-023-02318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/10/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND After centuries of heavy reliance on fossil fuel energy, the world suffers from an energy crisis and global warming, calling for carbon emission reduction and a transition to clean energy. Microalgae have attracted much attention as a potential feedstock for biofuel production due to their high triacylglycerol content and CO2 sequestration ability. Many diacylglycerol acyltransferases (DGAT) species have been characterized, which catalyze the final committed step in triacylglycerol biosynthesis. However, the detailed structure-function features of DGATs and the role of the interactions among DGAT proteins in lipid metabolism remained largely unknown. RESULTS In this study, the three characterized DGATs of Auxenochlorella protothecoides 2341 showed distinct structural and functional conservation. Functional complementation analyses showed that ApDGAT1 had higher activity than ApDGAT2b in yeast and model microalgae, and ApDGAT2a had no activity in yeast. The N-terminus was not essential to the catalysis function of ApDGAT1 but was crucial to ApDGAT2b as its enzyme activity was sensitive to any N-terminus modifications. Similarly, when acyl-CoA binding proteins (ACBPs) were fused to the N-terminus of ApDGAT1 and ApDGAT2b, zero and significant activity changes were observed, respectively. Interestingly, the ApACBP3 + ApDGAT1 variant contributed to higher oil accumulation than the original DGAT1, and ApACBP1 + ApDGAT1 fusion boosted oleic acid content in yeast. Overexpression of the three DGATs and the variation of ApACBP3 + ApDGAT1 increased the content of C18:1 of Chlamydomonas reinhardtii CC-5235. Significantly, ApDGAT1 interacted with itself, ApDGAT2b, and ApACBP1, which indicated that these three lipid metabolic proteins might have been a part of a dynamic protein interactome that facilitated the enrichment of oleic acid. CONCLUSIONS This study provided new insights into the functional and structural characteristics of DGATs and elucidated the importance of these physical interactions in potential lipid channeling.
Collapse
Affiliation(s)
- Kui Liu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinyu Li
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chao Xing
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Hongli Yuan
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinshui Yang
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
| |
Collapse
|
7
|
Satpati GG, Dikshit PK, Mal N, Pal R, Sherpa KC, Rajak RC, Rather SU, Raghunathan S, Davoodbasha M. A state of the art review on the co-cultivation of microalgae-fungi in wastewater for biofuel production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:161828. [PMID: 36707000 DOI: 10.1016/j.scitotenv.2023.161828] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/29/2022] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
The microalgae have a great potential as the fourth generation biofuel feedstock to deal with energy crisis, but the cost of production and biomass harvest are the major hurdles in terms of large scale production and applications. Using filamentous fungi to culture targeted alga for biomass accumulation and eventually harvesting is a sustainable way to mitigate environmental impacts. Microalgal co-culture method could be an alternative to overcome limitations and increase biomass yield and lipid accumulation. It was found to be the high feasibility for the production of biofuels from fungi and microalgae using wastewater. This article aimed to state the synergistic approaches, their culture protocols, harvesting procedure and their potential biotechnological applications. Additionally, algal-fungal consortia could digest cellulosic biomass, potentially reducing operating costs as part of industrial need. As a result of co-cultivation, biofuel production could be economically feasible owing to its excellent ability to treat wastewater and be eco-friendly. The implications of the innovative co-cultivation technology have demonstrated the potential for further development based on the policies that have been supported and implemented.
Collapse
Affiliation(s)
- Gour Gopal Satpati
- Department of Botany, Bangabasi Evening College, University of Calcutta, 19, Rajkumar Chakraborty Sarani, Kolkata 700009, West Bengal, India.
| | - Pritam Kumar Dikshit
- Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Vaddeswaram 522302, Andhra Pradesh, India
| | - Navonil Mal
- Phycology Laboratory, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Ruma Pal
- Phycology Laboratory, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Knawang Chhunji Sherpa
- Microbial Process and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, Kerala, India
| | - Rajiv Chandra Rajak
- Department of Botany, Marwari College, Ranchi University, Ranchi, Jharkhand, India
| | - Sami-Ullah Rather
- Department of Chemical and Materials Engineering, King Abdulaziz University, P.O. Box, 80204, Jeddah 21589, Saudi Arabia
| | - Sathya Raghunathan
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai 600048, India
| | - MubarakAli Davoodbasha
- School of Life Sciences, B.S. Abdur Rahman Crescent Institute of Science and Technology, Chennai 600048, India.
| |
Collapse
|
8
|
Peng Z, Zheng L, Tian H, Wang J, Liu W, Meng J, Zhang J, Li X, Wan S. Newly identified essential amino acids affecting peanut ( Arachis hypogaea L.) DGAT2 enzyme activity. Heliyon 2023; 9:e12878. [PMID: 36711321 PMCID: PMC9876841 DOI: 10.1016/j.heliyon.2023.e12878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 12/26/2022] [Accepted: 01/05/2023] [Indexed: 01/19/2023] Open
Abstract
Triacylglycerols is the major storage lipid in most crop seeds. As the key enzyme catalyzing the final step of triacylglycerols biosynthesis, the activity of diacylglycerol acyltransferases directly related to oil content. It has been shown that certain amino acids are very important for enzyme activity, one amino acid variation will greatly change the enzyme activity. In this study, we identified three amino acid point mutations that affect the Arachis hypogaea diacylglycerol acyltransferase 2 enzyme activity, T107M, K251R and L316P. According to the three amino acid variations, three single-nucleotide-mutant sequences of Arachis hypogaea diacylglycerol acyltransferase 2a were constructed and transformed into yeast strain H1246 for function verification. Results showed that T107M and K251R could change the fatty acid content and composition of the transformed yeast strains, whereas L316P led to the loss of enzyme activity. By analyzing the 2D and 3D structures of the three variants, we found that the changes of spatial structure of T107M, K251R and L316P caused the changes of the enzyme activity. Our study could provide a theoretical basis for changing the enzyme activity of DGAT by genetic engineering, and provide a new idea for increasing the oil content of the crops.
Collapse
Affiliation(s)
- Zhenying Peng
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Science, Jinan, 250100, China
- Corresponding author.
| | - Ling Zheng
- College of Life Science, Shandong Normal University, Jinan, 250014, China
| | - Haiying Tian
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Science, Jinan, 250100, China
| | - Jianguo Wang
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Science, Jinan, 250100, China
| | - Wenwen Liu
- College of Life Science, Shandong Normal University, Jinan, 250014, China
| | - Jingjing Meng
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Science, Jinan, 250100, China
| | - Jialei Zhang
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Science, Jinan, 250100, China
| | - Xinguo Li
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Science, Jinan, 250100, China
- Corresponding author.
| | - Shubo Wan
- Shandong Academy of Agricultural Science, Jinan, 250100, China
- Corresponding author.
| |
Collapse
|
9
|
Sahoo S, Dehury B, Narang PK, Raina V, Misra N, Suar M. Comprehensive sequence and structure analysis of algal lipid catabolic enzyme Triacylglycerol lipase: an in silico study to vitalize the development of optimum engineered strains with high lipid productivity. J Biomol Struct Dyn 2022; 40:11989-12007. [PMID: 34415234 DOI: 10.1080/07391102.2021.1967194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Microalgae as an alternative renewable resource for biofuel production have captured much significance. Nonetheless, its economic viability is a field of major concern for researchers. Unraveling the lipid catabolic pathway and gaining insights into the sequence-structural features of its primary functioning enzyme, Triacylglycerol lipase, will impart valuable information to target microalgae for augmented lipid content. In the present study, a genome-wide comparative study on putative Triacylglycerol lipase (TAGL) enzyme from algal species belonging to varied phylogenetic lineages was performed. The comprehensive sequence analysis revealed that TAGL comprises of three distinct conserved domains, such as, Patatin, Class III Lipase, and Abhydro_lipase, and also confirmed the ubiquitous presence of GXSXG motif in the sequences analyzed. In the absence of a crystal structure of algal TAGL till date, we developed the first 3D model of patatin domain of TAGL from an oleaginous microalga, Phaedactylum tricornutum, employing homology modeling, docking and molecular dynamic simulations methods. The domain-substrate complex having the low-ranking docking score revealed the binding of palmitic acid to the TAGL patatin domain surface with strong hydrogen bond interactions. The simulation results implied that the substrate-complexed patatin domain and the free enzyme adopted a more stable conformation after 40 ns. This is the first ever attempt to provide in-silico insights into the structural and dynamical insights on catalytic mechanism of the TAGL patatin domain. Subsequently, these findings aided our understanding on their structural stability, folding mechanism and protein-substrate interactions, which could be further utilized to design site-specific mutagenic experiments for engineering microalgal strains.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Susrita Sahoo
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India
| | - Budheswar Dehury
- Department of Chemistry, Technical University of Denmark, Lyngby, Denmark
| | - Parminder Kaur Narang
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India.,SGTB Khalsa College, Delhi University, Delhi, India
| | - Vishakha Raina
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India
| | - Namrata Misra
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India.,KIIT-Technology Business Incubator (KIIT-TBI), Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India
| | - Mrutyunjay Suar
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India.,KIIT-Technology Business Incubator (KIIT-TBI), Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, India
| |
Collapse
|
10
|
Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
Collapse
Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
| |
Collapse
|
11
|
Shi M, Yu L, Shi J, Liu J. A conserved MYB transcription factor is involved in regulating lipid metabolic pathways for oil biosynthesis in green algae. THE NEW PHYTOLOGIST 2022; 235:576-594. [PMID: 35342951 DOI: 10.1111/nph.18119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Green algae can accumulate high levels of triacylglycerol (TAG), yet knowledge remains fragmented on the regulation of lipid metabolic pathways by transcription factors (TFs). Here, via bioinformatics and in vitro and in vivo analyses, we revealed the roles of a myeloblastosis (MYB) TF in regulating TAG accumulation in green algae. CzMYB1, an R2R3-MYB from Chromochloris zofingiensis, was transcriptionally upregulated upon TAG-inducing conditions and correlated well with many genes involved in the de novo fatty acid synthesis, fatty acid activation and desaturation, membrane lipid turnover, and TAG assembly. Most promoters of these genes were transactivated by CzMYB1 in the yeast one-hybrid assay and contained the binding elements CNGTTA that were recognized by CzMYB1 through the electrophoretic mobility shift assay. CrMYB1, a close homologue of CzMYB1 from Chlamydomonas reinhardtii that recognized similar elements for binding, also transcriptionally correlated with many lipid metabolic genes. Insertional disruption of CrMYB1 severely suppressed the transcriptional expression of CrMYB1, as well as of key lipogenic genes, and impaired TAG level considerably under stress conditions. Our results reveal that this MYB, conserved in green algae, is involved in regulating global lipid metabolic pathways for TAG biosynthesis and accumulation.
Collapse
Affiliation(s)
- Meicheng Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Lihua Yu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jianan Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| |
Collapse
|
12
|
Ma H, Zheng J, Li Y, Zhao L, Zou S, Hu Q, Han D. A Novel Bifunctional Wax Ester Synthase Involved in Early Triacylglycerol Accumulation in Unicellular Green Microalga Haematococcus pluvialis Under High Light Stress. Front Bioeng Biotechnol 2022; 9:794714. [PMID: 35111735 PMCID: PMC8802113 DOI: 10.3389/fbioe.2021.794714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 11/20/2022] Open
Abstract
The bulk of neutral lipids, including astaxanthin esters and triacylglycerols (TAGs), are accumulated in the green microalga Haematococcus pluvialis under high light (HL) stress. In this study, a novel bifunctional wax ester synthase (WS) gene was cloned from H. pluvialis upon HL stress. The overexpression of HpWS restored the biosynthesis of wax esters and TAGs in neutral lipid-deficient yeast mutant Saccharomyces cerevisiae H1246 fed with C18 alcohol and C18:1/C18:3 fatty acids, respectively. Under HL stress, HpWS was substantially upregulated at the transcript level, prior to that of the type I diacylglycerol:acyl-CoA acyltransferase encoding gene (HpDGAT1). HpDGAT1 is the major TAG synthase in H. pluvialis. In addition, the application of xanthohumol (a DGAT1/2 inhibitor) in the H. pluvialis cells did not completely eliminate the TAG biosynthesis under HL stress at 24 h. These results indicated that HpWS may contribute to the accumulation of TAGs in H. pluvialis at the early stage under HL stress. In addition, the overexpression of HpWS in Chlamydomonas reinhardtii bkt5, which is engineered to produce free astaxanthin, enhanced the production of TAGs and astaxanthin. Our findings broaden the understanding of TAG biosynthesis in microalgae and provide a new molecular target for genetic manipulation in biotechnological applications.
Collapse
Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Haiyan Ma,
| | - 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
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Song Zou
- 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
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - 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
| |
Collapse
|
13
|
Bai F, Yu L, Shi J, Li-Beisson Y, Liu J. Long-chain acyl-CoA synthetases activate fatty acids for lipid synthesis, remodeling and energy production in Chlamydomonas. THE NEW PHYTOLOGIST 2022; 233:823-837. [PMID: 34665469 DOI: 10.1111/nph.17813] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Long-chain acyl-CoA synthetases (LACSs) play many roles in mammals, yeasts and plants, but knowledge on their functions in microalgae remains fragmented. Here via genetic, biochemical and physiological analyses, we unraveled the function and roles of LACSs in the model microalga Chlamydomonas reinhardtii. In vitro assays on purified recombinant proteins revealed that CrLACS1, CrLACS2 and CrLACS3 all exhibited bona fide LACS activities toward a broad range of free fatty acids. The Chlamydomonas mutants compromised in CrLACS1, CrLACS2 or CrLACS3 did not show any obvious phenotypes in lipid content or growth under nitrogen (N)-replete condition. But under N-deprivation, CrLACS1 or CrLACS2 suppression resulted in c. 50% less oil, yet with a higher amount of chloroplast lipids. By contrast, CrLACS3 suppression impaired oil remobilization and cell growth severely during N-recovery, supporting its role in fatty acid β-oxidation to provide energy and carbon sources for regrowth. Transcriptomics analysis suggested that the observed lipid phenotypes are likely not due to transcriptional reprogramming but rather a shift in metabolic adjustment. Taken together, this study provided solid experimental evidence for essential roles of the three Chlamydomonas LACS enzymes in lipid synthesis, remodeling and catabolism, and highlighted the importance of lipid homeostasis in cell growth under nutrient fluctuations.
Collapse
Affiliation(s)
- Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Lihua Yu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jianan Shi
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Yonghua Li-Beisson
- CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Aix Marseille Université, Saint Paul-Lez-Durance, 13108, France
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| |
Collapse
|
14
|
Metabolic engineering of the oleaginous alga Nannochloropsis for enriching eicosapentaenoic acid in triacylglycerol by combined pulling and pushing strategies. Metab Eng 2021; 69:163-174. [PMID: 34864212 DOI: 10.1016/j.ymben.2021.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/20/2021] [Accepted: 11/30/2021] [Indexed: 11/23/2022]
Abstract
The marine alga Nannochloropsis oceanica has been considered as a promising photosynthetic cell factory for synthesizing eicosapentaenoic acid (EPA), yet the accumulation of EPA in triacylglycerol (TAG) is restricted to an extreme low level. Poor channeling of EPA to TAG was observed in N. oceanica under TAG induction conditions, likely due to the weak activity of endogenous diacylglycerol acyltransferases (DGATs) on EPA-CoA. Screening over thirty algal DGATs revealed potent enzymes acting on EPA-CoA. Whilst overexpressing endogenous DGATs had no or slight effect on EPA abundance in TAG, introducing selected DGATs with strong activity on EPA-CoA, particularly the Chlamydomonas-derived CrDGTT1, which resided at the outermost membrane of the chloroplast and provided a strong pulling power to divert EPA to TAG for storage and protection, led to drastic increases in EPA abundance in TAG and TAG-derived EPA level in N. oceanica. They were further promoted by additional overexpression of an elongase gene involved in EPA biosynthesis, reaching 5.9- and 12.3-fold greater than the control strain, respectively. Our results together demonstrate the concept of applying combined pulling and pushing strategies to enrich EPA in algal TAG and provide clues for the enrichment of other desired fatty acids in TAG as well.
Collapse
|
15
|
Li J, Cao J, Chen H, Tang X, Zhang H, Chen W. Functional characterization of two diacylglycerol acyltransferase 1 genes in Mortierella alpina. Lett Appl Microbiol 2021; 74:194-203. [PMID: 34755357 DOI: 10.1111/lam.13597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 11/30/2022]
Abstract
Diacylglycerol acyltransferase (DGAT) is a crucial enzyme in the triacylglycerol (TAG) biosynthesis pathway. The oleaginous fungus Mortierella alpina can accumulate large amounts of arachidonic acid (ARA, C20:4) in the form of TAG. Therefore, it is important to study the functional characteristics of its DGAT. Two putative genes MaDGAT1A/1B encoding DGAT1 were identified in M. alpina ATCC 32222 genome by sequence alignment. Sequence alignment with identified DGAT1 homologs showed that MaDGAT1A/1B contain seven conserved motifs that are characteristic of the DGAT1 subfamily. Conserved domain analysis showed that both MaDGAT1A and MaDGAT1B belong to the Membrane-bound O-acyltransferases superfamily. The transforming with MaDGAT1A/1B genes could increase the accumulation of TAG in Saccharomyces cerevisiae to 4·47 and 7·48% of dry cell weight, which was 7·3-fold and 12·3-fold of the control group, respectively, but has no effect on the proportion of fatty acids in TAG. This study showed that MaDGAT1A/1B could effectively promote the accumulation of TAG and therefore may be used in metabolic engineering aimed to increase TAG production of oleaginous fungi.
Collapse
Affiliation(s)
- J Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China
| | - J Cao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China
| | - H Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China
| | - X Tang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China
| | - H Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, P.R. China.,Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi, P.R. China
| | - W Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, P.R. China.,School of Food Science and Technology, Jiangnan University, Wuxi, P.R. China
| |
Collapse
|
16
|
Bai F, Zhang Y, Liu J. A bZIP transcription factor is involved in regulating lipid and pigment metabolisms in the green alga Chlamydomonas reinhardtii. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
17
|
Wu T, Yu L, Zhang Y, Liu J. Characterization of fatty acid desaturases reveals stress-induced synthesis of C18 unsaturated fatty acids enriched in triacylglycerol in the oleaginous alga Chromochloris zofingiensis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:184. [PMID: 34535156 PMCID: PMC8447527 DOI: 10.1186/s13068-021-02037-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/07/2021] [Indexed: 05/16/2023]
Abstract
BACKGROUND The green microalga Chromochloris zofingiensis is capable of producing high levels of triacylglycerol rich in C18 unsaturated fatty acids (UFAs). FA desaturation degree is regulated by FA desaturases (FADs). Nevertheless, it remains largely unknown regarding what FADs are involved in FA desaturations and how these FADs collaborate to contribute to the high abundance of C18 UFAs in triacylglycerol in C. zofingiensis. RESULTS To address these issues, we firstly determined the transcription start sites of 11 putative membrane-bound FAD-coding genes (CzFADs) and updated their gene models. Functional validation of these CzFADs in yeast and cyanobacterial cells revealed that seven are bona fide FAD enzymes with distinct substrates. Combining the validated functions and predicted subcellular compartments of CzFADs and the FA profiles of C. zofingiensis, the FA desaturation pathways in this alga were reconstructed. Furthermore, a multifaceted lipidomic analysis by systematically integrating thin-layer chromatography, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry techniques was conducted, unraveling profiles of polar membrane lipids in C. zofingiensis and major desaturation steps occurring in these lipids. By correlating transcriptional patterns of CzFAD genes and changes of lipids upon abiotic stress conditions, our results highlighted collaboration of CzFADs for C18 UFA synthesis and supported that both de novo FA synthesis and membrane lipid remodeling contributed C18 UFAs to triacylglycerol for storage. CONCLUSIONS Taken together, our study for the first time elucidated the pathways of C18 FA desaturations and comprehensive profiles of polar membrane lipids in C. zofingiensis and shed light on collaboration of CzFADs for the synthesis and enrichment of C18 UFAs in triacylglycerol.
Collapse
Affiliation(s)
- Tao Wu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Lihua Yu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| |
Collapse
|
18
|
Shi Y, Liu M, Pan Y, Hu H, Liu J. Δ6 Fatty Acid Elongase is Involved in Eicosapentaenoic Acid Biosynthesis Via the ω6 Pathway in the Marine Alga Nannochloropsis oceanica. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:9837-9848. [PMID: 34414763 DOI: 10.1021/acs.jafc.1c04192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nannochloropsis oceanica represents a promising sunlight-driven alga for producing eicosapentaenoic acid (EPA, 20:5Δ5,8,11,14,17), a value-added very long-chain polyunsaturated fatty acid (VLC-PUFA). Here, we unraveled the function and roles of a Δ6 fatty acid elongase (NoΔ6-FAE) in N. oceanica. Heterologous expression of NoΔ6-FAE in yeast confirmed its function in elongating C18 Δ6-PUFAs rather than others. Subcellular localization experiments suggested that NoΔ6-FAE resides in the chloroplast endoplasmic reticulum. NoΔ6-FAE knockdown attenuated C20:3Δ8,11,14, C20:4Δ5,8,11,14, and EPA yet enhanced C18:3Δ6,9,12, leading to overall decreases in total fatty acids, triacylglycerol, diacylglycerol, free fatty acids, and polar membrane lipids. In contrast, NoΔ6-FAE overexpression in N. oceanica caused nearly opposite phenotypes. Moreover, N. oceanica lacked detectable C18:3Δ9,12,15, C18:4Δ6,9,12,15, and C20:4Δ8,11,14,17 even under NoΔ6-FAE knockdown or overexpression. Our results reveal the involvement of NoΔ6-FAE in EPA biosynthesis via the ω6 pathway in N. oceanica and highlight the potential of manipulating NoΔ6-FAE for improved lipid production.
Collapse
Affiliation(s)
- Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Meijing Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Hanhua Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| |
Collapse
|
19
|
Xu Y, Pan X, Lu J, Wang J, Shan Q, Stout J, Chen G. Evolutionary and biochemical characterization of a Chromochloris zofingiensis MBOAT with wax synthase and diacylglycerol acyltransferase activity. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5584-5598. [PMID: 34037747 DOI: 10.1093/jxb/erab236] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
Wax synthase (WS) catalyzes the last step in wax ester biosynthesis in green plants. Two unrelated sub-families of WS, including the bifunctional acyltransferase and plant-like WS have been reported, but the latter is largely uncharacterized in microalgae. Here, we functionally characterized a putative plant-like WS (CzWS1) from the emerging model green microalga Chromochloris zofingiensis. Our results showed that plant-like WS evolved under different selection constraints in plants and microalgae, with positive selection likely contributing to functional divergence. Unlike jojoba with high amounts of wax ester in seeds and a highly active WS enzyme, C. zofingiensis has no detectable wax ester but a high abundance of WS transcripts. Co-expression analysis showed that C. zofingiensis WS has different expression correlation with lipid biosynthetic genes from jojoba, and may have a divergent function. In vitro characterization indicated that CzWS1 had diacylglycerol acyltransferase activity along with WS activity, and overexpression of CzWS1 in yeast and Chlamydomonas reinhardtii affected triacylglycerol accumulation. Moreover, biochemical and bioinformatic analyses revealed the relevance of the C-terminal region of CzWS1 in enzyme function. Taken together, our results indicated a functional divergence of plant-like WS in plants and microalgae, and the importance of its C-terminal region in specialization of enzyme function.
Collapse
Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Xue Pan
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Junhao Lu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Juli Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Qiyuan Shan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
- School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jake Stout
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
20
|
Zhang Y, Ye Y, Bai F, Liu J. The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:119. [PMID: 33992124 PMCID: PMC8126118 DOI: 10.1186/s13068-021-01969-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/07/2021] [Indexed: 05/05/2023]
Abstract
The algal lipids-based biodiesel, albeit having advantages over plant oils, still remains high in the production cost. Co-production of value-added products with lipids has the potential to add benefits and is thus believed to be a promising strategy to improve the production economics of algal biodiesel. Chromochloris zofingiensis, a unicellular green alga, has been considered as a promising feedstock for biodiesel production because of its robust growth and ability of accumulating high levels of triacylglycerol under multiple trophic conditions. This alga is also able to synthesize high-value keto-carotenoids and has been cited as a candidate producer of astaxanthin, the strongest antioxidant found in nature. The concurrent accumulation of triacylglycerol and astaxanthin enables C. zofingiensis an ideal cell factory for integrated production of the two compounds and has potential to improve algae-based production economics. Furthermore, with the advent of chromosome-level whole genome sequence and genetic tools, C. zofingiensis becomes an emerging model for studying lipid metabolism and carotenogenesis. In this review, we summarize recent progress on the production of triacylglycerol and astaxanthin by C. zofingiensis. We also update our understanding in the distinctive molecular mechanisms underlying lipid metabolism and carotenogenesis, with an emphasis on triacylglycerol and astaxanthin biosynthesis and crosstalk between the two pathways. Furthermore, strategies for trait improvements are discussed regarding triacylglycerol and astaxanthin synthesis in C. zofingiensis.
Collapse
Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China.
| |
Collapse
|
21
|
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. JOURNAL OF EXPERIMENTAL BOTANY 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] [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
|
22
|
Xing G, Li J, Li W, Lam SM, Yuan H, Shui G, Yang J. AP2/ERF and R2R3-MYB family transcription factors: potential associations between temperature stress and lipid metabolism in Auxenochlorella protothecoides. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:22. [PMID: 33451355 PMCID: PMC7811268 DOI: 10.1186/s13068-021-01881-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/08/2021] [Indexed: 05/09/2023]
Abstract
BACKGROUND Both APETALA2/Ethylene Responsive Factor (AP2/ERF) superfamily and R2R3-MYB family were from one of the largest diverse families of transcription factors (TFs) in plants, and played important roles in plant development and responses to various stresses. However, no systematic analysis of these TFs had been conducted in the green algae A. protothecoides heretofore. Temperature was a critical factor affecting growth and lipid metabolism of A. protothecoides. It also remained largely unknown whether these TFs would respond to temperature stress and be involved in controlling lipid metabolism process. RESULTS Hereby, a total of six AP2 TFs, six ERF TFs and six R2R3-MYB TFs were identified and their expression profiles were also analyzed under low-temperature (LT) and high-temperature (HT) stresses. Meanwhile, differential adjustments of lipid pathways were triggered, with enhanced triacylglycerol accumulation. A co-expression network was built between these 18 TFs and 32 lipid-metabolism-related genes, suggesting intrinsic associations between TFs and the regulatory mechanism of lipid metabolism. CONCLUSIONS This study represented an important first step towards identifying functions and roles of AP2 superfamily and R2R3-MYB family in lipid adjustments and response to temperature stress. These findings would facilitate the biotechnological development in microalgae-based biofuel production and the better understanding of photosynthetic organisms' adaptive mechanism to temperature stress.
Collapse
Affiliation(s)
- Guanlan Xing
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Jinyu Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Wenli Li
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Hongli Yuan
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Jinshui Yang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| |
Collapse
|
23
|
Cui H, Zhao C, Xu W, Zhang H, Hang W, Zhu X, Ji C, Xue J, Zhang C, Li R. Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis. BMC PLANT BIOLOGY 2021; 21:20. [PMID: 33407140 PMCID: PMC7788937 DOI: 10.1186/s12870-020-02794-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/09/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. RESULTS Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. CONCLUSIONS Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.
Collapse
Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Hongjiang Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wei Hang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Xiaoli Zhu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| |
Collapse
|
24
|
Cui H, Xu W, Zhu X, Zhao C, Cui Y, Ji C, Zhang C, Xue J, Qin S, Jia X, Li R. Characterization of a Haematococcus pluvialis Diacylglycerol Acyltransferase 1 and Its Potential in Unsaturated Fatty Acid-Rich Triacylglycerol Production. FRONTIERS IN PLANT SCIENCE 2021; 12:771300. [PMID: 34950166 PMCID: PMC8688921 DOI: 10.3389/fpls.2021.771300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 05/17/2023]
Abstract
The unicellular green alga Haematococcus pluvialis has been recognized as an industry strain to produce simultaneously esterified astaxanthin (EAST) and triacylglycerol (TAG) under stress induction. It is necessary to identify the key enzymes involving in synergistic accumulation of EAST and TAG in H. pluvialis. In this study, a novel diacylglycerol acyltransferase 1 was systematically characterized by in vivo and in silico assays. The upregulated expression of HpDGAT1 gene was positively associated with the significant increase of TAG and EAST contents under stress conditions. Functional complementation by overexpressing HpDGAT1 in a TAG-deficient yeast strain H1246 revealed that HpDGAT1 could restore TAG biosynthesis and exhibited a high substrate preference for monounsaturated fatty acyl-CoAs (MUFAs) and polyunsaturated fatty acyl-CoAs (PUFAs). Notably, heterogeneous expression of HpDGAT1 in Chlamydomonas reinhardtii and Arabidopsis thaliana resulted in a significant enhancement of total oils and concurrently a high accumulation of MUFAs- and PUFAs-rich TAGs. Furthermore, molecular docking analysis indicated that HpDGAT1 contained AST-binding sites. These findings evidence a possible dual-function role for HpDGAT1 involving in TAG and EAST synthesis, demonstrating that it is a potential target gene to enrich AST accumulation in this alga and to design oil production in both commercial algae and oil crops.
Collapse
Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Xiaoli Zhu
- College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Yulin Cui
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Song Qin
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Xiaoyun Jia
- College of Life Sciences, Shanxi Agricultural University, Taigu, China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
- *Correspondence: Runzhi Li,
| |
Collapse
|
25
|
Sanya DRA, Onesime D, Kunze G, Neuveglise C, Crutz-Le Coq AM. The native acyltransferase-coding genes DGA1 and DGA2 affect lipid accumulation in Blastobotrys raffinosifermentans differently when overexpressed. FEMS Yeast Res 2020; 20:5989697. [PMID: 33206977 DOI: 10.1093/femsyr/foaa060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 11/16/2020] [Indexed: 12/19/2022] Open
Abstract
Blastobotrys raffinosifermentans is an ascomycetous yeast with biotechnological applications, recently shown to be an oleaginous yeast accumulating lipids under nitrogen limitation. Diacylglycerol acyltransferases (DGATs) act in the lipid storage pathway, in the last step of triacylglycerol biosynthesis. Two DGAT families are widespread in eukaryotes. We first checked that B. raffinosifermentans strain LS3 possessed both types of DGAT, and we then overexpressed the native DGAT-encoding genes, DGA1 and DGA2, separately or together. DGA2 (from the DGAT1 family) overexpression was sufficient to increase lipid content significantly in LS3, to up to 26.5% of dry cell weight (DCW), 1.6 times the lipid content of the parental strain (16.90% of DCW) in glucose medium under nitrogen limitation. By contrast, DGA1 (of the DGAT2 type) overexpression led to a large increase (up to 140-fold) in the amount of the corresponding transcript, but had no effect on overall lipid content relative to the parental strain. Analysis of the expression of the native genes over time in the parental strain revealed that DGA2 transcript levels quadrupled between 8 and 24 h in the N-limited lipogenic medium, whereas DGA1 transcript levels remained stable. This survey highlights the predominant role of the DGAT1 family in lipid accumulation and demonstrates the suitability of B. raffinosifermentans for engineering for lipid production.
Collapse
Affiliation(s)
- Daniel Ruben Akiola Sanya
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| | - Djamila Onesime
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| | - Gotthard Kunze
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Physiology and Cell Biology, Correnstr. 3, Gatersleben 06466, Germany
| | - Cécile Neuveglise
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| | - Anne-Marie Crutz-Le Coq
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| |
Collapse
|
26
|
Falarz LJ, Xu Y, Caldo KMP, Garroway CJ, Singer SD, Chen G. Characterization of the diversification of phospholipid:diacylglycerol acyltransferases in the green lineage. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:2025-2038. [PMID: 32538516 DOI: 10.1111/tpj.14880] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 05/03/2023]
Abstract
Triacylglycerols have important physiological roles in photosynthetic organisms, and are widely used as food, feed and industrial materials in our daily life. Phospholipid:diacylglycerol acyltransferase (PDAT) is the pivotal enzyme catalyzing the acyl-CoA-independent biosynthesis of triacylglycerols, which is unique in plants, algae and fungi, but not in animals, and has essential functions in plant and algal growth, development and stress responses. Currently, this enzyme has yet to be examined in an evolutionary context at the level of the green lineage. Some fundamental questions remain unanswered, such as how PDATs evolved in photosynthetic organisms and whether the evolution of terrestrial plant PDATs from a lineage of charophyte green algae diverges in enzyme function. As such, we used molecular evolutionary analysis and biochemical assays to address these questions. Our results indicated that PDAT underwent divergent evolution in the green lineage: PDATs exist in a wide range of plants and algae, but not in cyanobacteria. Although PDATs exhibit the conservation of several features, phylogenetic and selection-pressure analyses revealed that overall they evolved to be highly divergent, driven by different selection constraints. Positive selection, as one major driving force, may have resulted in enzymes with a higher functional importance in land plants than green algae. Further structural and mutagenesis analyses demonstrated that some amino acid sites under positive selection are critically important to PDAT structure and function, and may be central in lecithin:cholesterol acyltransferase family enzymes in general.
Collapse
Affiliation(s)
- Lucas J Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| | - Colin J Garroway
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Stacy D Singer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, T1J 4B1, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| |
Collapse
|
27
|
Kou Y, Liu M, Sun P, Dong Z, Liu J. High light boosts salinity stress-induced biosynthesis of astaxanthin and lipids in the green alga Chromochloris zofingiensis. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101976] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
28
|
Zhang Y, Ye Y, Ding W, Mao X, Li Y, Gerken H, Liu J. Astaxanthin Is Ketolated from Zeaxanthin Independent of Fatty Acid Synthesis in Chromochloris zofingiensis. PLANT PHYSIOLOGY 2020; 183:883-897. [PMID: 32385091 PMCID: PMC7333715 DOI: 10.1104/pp.20.00325] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 04/30/2020] [Indexed: 05/09/2023]
Abstract
The biosynthesis of astaxanthin, a high-value keto-carotenoid with broad industrial applications, remains unambiguous in algae. Here, we dissected the astaxanthin biosynthetic pathway and the coordination between astaxanthin and triacylglycerol (TAG) biosynthesis in the emerging model alga Chromochloris zofingiensis In vivo and in vitro experiments demonstrated that astaxanthin, utilizing the methylerythritol phosphate pathway-derived isopentenyl diphosphate as the building block, was synthesized from β-carotenoid ketolase-mediated ketolation of zeaxanthin rather than β-carotenoid hydroxylase-mediated hydroxylation of canthaxanthin, thus leading to the buildup of astaxanthin and canthaxanthin as end products in C. zofingiensis The synthesized astaxanthin, stored in TAG-filled lipid droplets, was esterified mainly with the fatty acid C18:1, which was not catalyzed by any acyltransferase previously proposed. Astaxanthin accumulated in a well-coordinated manner with TAG, supported by the coordinated up-regulation of both biosynthetic pathways at the transcriptional level. Nevertheless, astaxanthin and TAG showed no interdependence: inhibition of de novo fatty acid biosynthesis severely attenuated TAG biosynthesis but promoted the accumulation of astaxanthin, particularly in the diester form, leading to a fivefold increase in the astaxanthin/TAG ratio; however, inhibition of astaxanthin biosynthesis showed little effect on TAG accumulation. Our data suggest that an increase in astaxanthin accumulation following inhibition of de novo fatty acid biosynthesis, which is not regulated at the transcriptional level, is likely derived from the conversion of other carotenoids rather than from a shunt of carbon flux from lipid biosynthesis. Combined, these findings further our understanding of astaxanthin biosynthesis and provide a feasible strategy for promoting astaxanthin content and purity in algae.
Collapse
Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Wei Ding
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, Maryland 21202
| | - Henri Gerken
- Arizona Center for Algal Technology and Innovation, Arizona State University Polytechnic Campus, Mesa, Arizona 85212
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| |
Collapse
|
29
|
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. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 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] [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
|
30
|
Wu T, Fu Y, Shi Y, Li Y, Kou Y, Mao X, Liu J. Functional Characterization of Long-Chain Acyl-CoA Synthetase Gene Family from the Oleaginous Alga Chromochloris zofingiensis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:4473-4484. [PMID: 32208653 DOI: 10.1021/acs.jafc.0c01284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Long-chain acyl-coenzyme A (CoA) synthetase (LACS) catalyzes the formation of acyl-CoAs from free fatty acids, which is pivotal for lipid metabolism. Here, we confirmed the presence of six CzLACS genes in Chromochloris zofingiensis. Functional complementation and in vitro enzymatic assay indicated that CzLACS2 through CzLACS5 rather than CzLACS1 or CzLACS6 are bona fide LACS enzymes and they have overlapping yet distinct substrate preference. The results of the subcellular colocalization experiment and different expression patterns under three triacylglycerol (TAG)-inducing conditions showed that CzLACS2 through CzLACS4 reside at endoplasmic reticulum (ER) and are involved in TAG biosynthesis, while CzLACS5 resides in peroxisome and participates in fatty acid β-oxidation. The yeast one-hybrid assay using a library of 50 transcription factors (TFs) constructed in our study identified 12 TFs potentially involved in regulating the expression of CzLACSs. Moreover, heterologous expression of CzLACSs demonstrated their engineering potential for modulating TAG synthesis in yeast and algal cells.
Collapse
Affiliation(s)
- Tao Wu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Yunlei Fu
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yuelian Li
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Yaping Kou
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| |
Collapse
|
31
|
Mao X, Lao Y, Sun H, Li X, Yu J, Chen F. Time‑resolved transcriptome analysis during transitions of sulfur nutritional status provides insight into triacylglycerol (TAG) and astaxanthin accumulation in the green alga Chromochloris zofingiensis. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:128. [PMID: 32695224 PMCID: PMC7367374 DOI: 10.1186/s13068-020-01768-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/11/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Chromochloris zofingiensis, an oleaginous microalga, is a promising feedstock for the co-production of triacylglycerol (TAG)-based biodiesel and the high-value product astaxanthin. To reveal the molecular mechanism of TAG and astaxanthin biosynthesis during transitions of sulfur nutritional status, namely sulfur-starvation (SS) and sulfur-replenishment (SR), the physiological responses and the transcriptomic dynamics of C. zofingiensis were examined. RESULTS The results revealed a reversible TAG and astaxanthin accumulation under SS, which is correlated with the reduction of cell growth and protein content, indicating the reallocation of carbon. By correlating the data on the physiological and transcriptional responses to different sulfur nutritional status, a model for the underlying mechanism of TAG and astaxanthin accumulation in C. zofingiensis was postulated, which involved up-regulation of key genes including diacylglycerol acyltransferase (DGTT5) and beta-carotene ketolase (BKT1), increased energy and NADPH supply by elevating the tricarboxylic acid (TCA) cycle and the oxidative pentose phosphate (OPP) pathway, and the increased carbon precursors (pyruvate and acetyl-CoA) through central carbon metabolism. In addition, the net enhancement of the de novo biosynthesis of fatty acids and the re-direction of the terpenoid precursors toward the branch catalyzed by lycopene beta cyclase (LCYb) and BKT1 escalated the substrate availability for the biosynthesis of TAG and astaxanthin, respectively. CONCLUSIONS In this study, the time-resolved transcriptional analysis of C. zofingiensis under SS and SR conditions was reported for the first time to elucidate the regulatory roles of key enzymes, including DGTT5, BKT1 and LCYb, in the underlying mechanisms of TAG and astaxanthin accumulation.
Collapse
Affiliation(s)
- Xuemei Mao
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060 China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060 China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, 518060 China
| | - Yongmin Lao
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060 China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, 518060 China
| | - Han Sun
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060 China
| | - Xiaojie Li
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060 China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, 518060 China
| | - Jianfeng Yu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060 China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, 518060 China
| | - Feng Chen
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060 China
- Institute for Innovative Development of Food Industry, Shenzhen University, Shenzhen, 518060 China
| |
Collapse
|
32
|
Mao X, Zhang Y, Wang X, Liu J. Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:73. [PMID: 32322303 PMCID: PMC7161124 DOI: 10.1186/s13068-020-01714-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/09/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Chromochloris zofingiensis, a freshwater alga capable of synthesizing both triacylglycerol (TAG) and astaxanthin, has been receiving increasing attention as a leading candidate producer. While the mechanism of oleaginousness and/or carotenogenesis has been studied under such induction conditions as nitrogen deprivation, high light and glucose feeding, it remains to be elucidated in response to salt stress, a condition critical for reducing freshwater footprint during algal production processes. RESULTS Firstly, the effect of salt concentrations on growth, lipids and carotenoids was examined for C. zofingiensis, and 0.2 M NaCl demonstrated to be the optimal salt concentration for maximizing both TAG and astaxanthin production. Then, the time-resolved lipid and carotenoid profiles and comparative transcriptomes and metabolomes were generated in response to the optimized salt concentration for congruent analysis. A global response was triggered in C. zofingiensis allowing acclimation to salt stress, including photosynthesis impairment, ROS build-up, protein turnover, starch degradation, and TAG and astaxanthin accumulation. The lipid metabolism involved a set of stimulated biological pathways that contributed to carbon precursors, energy and reductant molecules, pushing and pulling power, and storage sink for TAG accumulation. On the other hand, salt stress suppressed lutein biosynthesis, stimulated astaxanthin biosynthesis (mainly via ketolation), yet had little effect on total carotenoid flux, leading to astaxanthin accumulation at the expense of lutein. Astaxanthin was predominantly esterified and accumulated in a well-coordinated manner with TAG, pointing to the presence of common regulators and potential communication for the two compounds. Furthermore, the comparison between salt stress and nitrogen deprivation conditions revealed distinctions in TAG and astaxanthin biosynthesis as well as critical genes with engineering potential. CONCLUSIONS Our multi-omics data and integrated analysis shed light on the salt acclimation of C. zofingiensis and underlying mechanisms of TAG and astaxanthin biosynthesis, provide engineering implications into future trait improvements, and will benefit the development of this alga for production uses under saline environment, thus reducing the footprint of freshwater.
Collapse
Affiliation(s)
- Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| |
Collapse
|
33
|
Wang X, Wei H, Mao X, Liu J. Proteomics Analysis of Lipid Droplets from the Oleaginous Alga Chromochloris zofingiensis Reveals Novel Proteins for Lipid Metabolism. GENOMICS PROTEOMICS & BIOINFORMATICS 2019; 17:260-272. [PMID: 31494267 PMCID: PMC6818385 DOI: 10.1016/j.gpb.2019.01.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/13/2018] [Accepted: 01/04/2019] [Indexed: 11/30/2022]
Abstract
Chromochloris zofingiensis represents an industrially relevant and unique green alga, given its capability of synthesizing triacylglycerol (TAG) and astaxanthin simultaneously for storage in lipid droplets (LDs). To further decipher lipid metabolism, the nitrogen deprivation (ND)-induced LDs from C. zofingiensis were isolated, purified, and subjected to proteomic analysis. Intriguingly, many C. zofingiensis LD proteins had no orthologs present in LD proteome of the model alga Chlamydomonas reinhardtii. Seven novel LD proteins (i.e., two functionally unknown proteins, two caleosins, two lipases, and one l-gulonolactone oxidase) and the major LD protein (MLDP), which were all transcriptionally up-regulated by ND, were selected for further investigation. Heterologous expression in yeast demonstrated that all tested LD proteins were localized to LDs and all except the two functionally unknown proteins enabled yeast to produce more TAG. MLDP could restore the phenotype of mldp mutant strain and enhance TAG synthesis in wild-type strain of C. reinhardtii. Although MLDP and caleosins had a comparable abundance in LDs, they responded distinctly to ND at the transcriptional level. The two lipases, instead of functioning as TAG lipases, likely recycled polar lipids to support TAG synthesis. For the first time, we reported that l-gulonolactone oxidase was abundant in LDs and facilitated TAG accumulation. Moreover, we also proposed a novel working model for C. zofingiensis LDs. Taken together, our work unravels the unique characteristics of C. zofingiensis LDs and provides insights into algal LD biogenesis and TAG synthesis, which would facilitate genetic engineering of this alga for TAG improvement.
Collapse
Affiliation(s)
- Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Hehong Wei
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China.
| |
Collapse
|
34
|
Wu T, Mao X, Kou Y, Li Y, Sun H, He Y, Chen F. Characterization of Microalgal Acetyl-CoA Synthetases with High Catalytic Efficiency Reveals Their Regulatory Mechanism and Lipid Engineering Potential. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9569-9578. [PMID: 31385495 DOI: 10.1021/acs.jafc.9b03370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Acetyl-CoA synthetase (ACS) plays a key role in microalgal lipid biosynthesis and acetyl-CoA industrial production. In the present study, two ACSs were cloned and characterized from the oleaginous microalga Chromochloris zofingiensis. In vitro kinetic analysis showed that the Km values of CzACS1 and CzACS2 for potassium acetate were 0.99 and 0.81 mM, respectively. Moreover, CzACS1 and CzACS2 had outstanding catalytic efficiencies (kcat/Km), which were 70.67 and 79.98 s-1 mM-1, respectively, and these values were higher than that of other reported ACSs. CzACS1 and CzACS2 exhibited differential expression patterns at the transcriptional level under various conditions. Screening a recombinant library of 52 transcription factors (TFs) constructed in the present study via yeast one-hybrid assay pointed to seven TFs with potential involvement in the regulation of the two ACS genes. Expression correlation analysis implied that GATA20 was likely an important regulator of CzACS2 and that ERF9 could regulate two CzACSs simultaneously.
Collapse
Affiliation(s)
| | | | | | | | - Han Sun
- Institute for Advanced Study , Shenzhen University , Shenzhen 518060 , China
| | | | - Feng Chen
- Institute for Advanced Study , Shenzhen University , Shenzhen 518060 , China
| |
Collapse
|
35
|
Liu J, Sun Z, Mao X, Gerken H, Wang X, Yang W. Multiomics analysis reveals a distinct mechanism of oleaginousness in the emerging model alga Chromochloris zofingiensis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1060-1077. [PMID: 30828893 DOI: 10.1111/tpj.14302] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Chromochloris zofingiensis, featured due to its capability to simultaneously synthesize triacylglycerol (TAG) and astaxanthin, is emerging as a leading candidate alga for production uses. To better understand the oleaginous mechanism of this alga, we conducted a multiomics analysis by systematically integrating time-resolved transcriptomes, lipidomes and metabolomes in response to nitrogen deprivation. The data analysis unraveled the distinct mechanism of TAG accumulation, which involved coordinated stimulation of multiple biological processes including supply of energy and reductants, carbon reallocation from protein and starch, and 'pushing' and 'pulling' carbon to TAG synthesis. Unlike the model alga Chlamydomonas, de novo fatty acid synthesis in C. zofingiensis was promoted, together with enhanced turnover of both glycolipids and phospholipids, supporting the drastic need of acyls for TAG assembly. Moreover, genomewide analysis identified many key functional enzymes and transcription factors that had engineering potential for TAG modulation. Two genes encoding glycerol-3-phosphate acyltransferase (GPAT), the first committed enzyme for TAG assembly, were found in the C. zofingiensis genome; in vivo functional characterization revealed that extrachloroplastic GPAT instead of chloroplastic GPAT played a central role in TAG synthesis. These findings illuminate distinct oleaginousness mechanisms in C. zofingiensis and pave the way towards rational manipulation of this alga to becone an emerging model for trait improvements.
Collapse
Affiliation(s)
- Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Zheng Sun
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Henri Gerken
- School of Sustainable Engineering and the Built Environment, Arizona State University Polytechnic campus, Mesa, AZ, 85212, USA
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Wenqiang Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| |
Collapse
|
36
|
Sun Z, Zhang Y, Sun LP, Liu J. Light Elicits Astaxanthin Biosynthesis and Accumulation in the Fermented Ultrahigh-Density Chlorella zofinginesis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:5579-5586. [PMID: 31038310 DOI: 10.1021/acs.jafc.9b01176] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The growth and astaxanthin production of Chlorella zofingiensis were examined under both heterotrophic and photoautotrophic conditions, and it was found that, in comparison to the photoautotrophic mode, the heterotrophic mode led to high algal densities but attenuated intracellular astaxanthin accumulation. Following the heterotrophy-photoautotrophy transition, a considerable increase in the astaxanthin content was observed, accompanied by the upregulation of key carotenogenic genes, including phytoene synthase (PSY), β-carotenoid hydroxylase (CHYb), β-carotenoid ketolase 1 (BKT1), and β-carotenoid ketolase 2 (BKT2). In contrast, the astaxanthin content and carotenogenic genes underwent an opposite change following the photoautotrophy-heterotrophy transition, suggesting the key role of light in stimulating astaxanthin biosynthesis. To improve the astaxanthin production by C. zofingiensis, a novel heterotrophy-photoinduction culture strategy without dilution was developed and evaluated. The astaxanthin content and productivity reached 2.7 mg g-1 of dry weight and 9.9 mg L-1 day-1, respectively, which were 4.0- and 2.5-fold higher than that obtained under the heterotrophic condition.
Collapse
Affiliation(s)
- Zheng Sun
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education; International Research Center for Marine Biosciences, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education , Shanghai Ocean University , Shanghai 201306 , People's Republic of China
| | - Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering , Peking University , Beijing 100871 , People's Republic of China
| | - Li-Ping Sun
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education; International Research Center for Marine Biosciences, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education , Shanghai Ocean University , Shanghai 201306 , People's Republic of China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering , Peking University , Beijing 100871 , People's Republic of China
| |
Collapse
|
37
|
Zhang Y, Shi M, Mao X, Kou Y, Liu J. Time-resolved carotenoid profiling and transcriptomic analysis reveal mechanism of carotenogenesis for astaxanthin synthesis in the oleaginous green alga Chromochloris zofingiensis. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:287. [PMID: 31890015 PMCID: PMC6913025 DOI: 10.1186/s13068-019-1626-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/04/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND Chromochloris zofingiensis is emerging as an industrially relevant alga given its robust growth for the production of lipids and astaxanthin, a value-added carotenoid with broad applications. Nevertheless, poor understanding of astaxanthin synthesis has limited engineering of this alga for rational improvements. RESULTS To reveal the molecular mechanism underlying astaxanthin accumulation in C. zofingiensis, here we conducted an integrated analysis by combining the time-resolved transcriptomes and carotenoid profiling in response to nitrogen deprivation (ND). A global response was triggered for C. zofingiensis to cope with the ND stress. Albeit the little variation in total carotenoid content, individual carotenoids responded differentially to ND: the primary carotenoids particularly lutein and β-carotene decreased, while the secondary carotenoids increased considerably, with astaxanthin and canthaxanthin being the most increased ones. The carotenogenesis pathways were reconstructed: ND had little effect on the carbon flux to carotenoid precursors, but stimulated astaxanthin biosynthesis while repressing lutein biosynthesis, thereby diverting the carotenoid flux from primary carotenoids to secondary carotenoids particularly astaxanthin. Comparison between C. zofingiensis and Haematococcus pluvialis revealed the distinctive mechanism of astaxanthin synthesis in C. zofingiensis. Furthermore, potential bottlenecks in astaxanthin synthesis were identified and possible engineering strategies were proposed for the alga. CONCLUSIONS Collectively, these findings shed light on distinctive mechanism of carotenogenesis for astaxanthin biosynthesis in C. zofingiensis, identify key functional enzymes and regulators with engineering potential and will benefit rational manipulation of this alga for improving nutritional traits.
Collapse
Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Meicheng Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yaping Kou
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| |
Collapse
|