Inhibition of monogalactosyldiacylglycerol synthesis by down-regulation of MGD1 leads to membrane lipid remodeling and enhanced triacylglycerol biosynthesis in Chlamydomonas reinhardtii
Tóm tắt
Membrane lipid remodeling involves regulating the physiochemical modification of cellular membranes against abiotic stress or senescence, and it could be a trigger to increase neutral lipid content. In algae and higher plants, monogalactosyldiacylglycerol (MGDG) constitutes the highest proportion of total membrane lipids and is highly reduced as part of the membrane lipid remodeling response under several abiotic stresses. However, genetic regulation of MGDG synthesis and its influence on lipid synthesis has not been studied in microalgae. For development of an industrial microalgae strain showing high accumulation of triacylglycerol (TAG) by promoting membrane lipid remodeling, MGDG synthase 1 (MGD1) down-regulated mutant of Chlamydomonas reinhardtii (Cr-mgd1) was generated and evaluated for its suitability for biodiesel feedstock. The Cr-mgd1 showed a 65% decrease in CrMGD1 gene expression level, 22% reduction in MGDG content, and 1.39 and 5.40 times increase in diacylglyceryltrimethylhomoserines (DGTS) and TAG, respectively. The expression levels of most genes related to the decomposition of MGDG (plastid galactoglycerolipid degradation1) and TAG metabolism (diacylglycerol O-acyltransferase1, phospholipid:diacylglycerol acyltransferase, and major lipid droplet protein) were increased. The imbalance of DGDG/MGDG ratio in Cr-mgd1 caused reduced photosynthetic electron transport, resulting in less light energy utilization and increased reactive oxygen species levels. In addition, endoplasmic reticulum stress was induced by increased DGTS levels. Thus, accelerated TAG accumulation in Cr-mgd1 was stimulated by increased cellular stress as well as lipid remodeling. Under high light (HL) intensity (400 µmol photons/m2/s), TAG productivity in Cr-mgd1–HL (1.99 mg/L/d) was 2.71 times higher than that in wild type (WT–HL). Moreover, under both nitrogen starvation and high light intensity, the lipid (124.55 mg/L/d), TAG (20.03 mg/L/d), and maximum neutral lipid (56.13 mg/L/d) productivity were the highest. By inducing lipid remodeling through the mgd1 gene expression regulation, the mutant not only showed high neutral lipid content but also reached the maximum neutral lipid productivity through cultivation under high light and nitrogen starvation conditions, thereby possessing improved biomass properties that are the most suitable for high quality biodiesel production. Thus, this mutant may help understand the role of MGD1 in lipid synthesis in Chlamydomonas and may be used to produce high amounts of TAG.
Tài liệu tham khảo
MacDougall KM, McNichol J, McGinn PJ, O’Leary SJ, Melanson JE. Triacylglycerol profiling of microalgae strains for biofuel feedstock by liquid chromatography-high-resolution mass spectrometry. Anal Bioanal Chem. 2011;401:2609–16.
Williams PJLB, Laurens LML. Microalgae as biodiesel & biomass feedstocks: review & analysis of the biochemistry, energetics & economics. Energy Environ Sci. 2010;3:554.
Lv S, Zhang J, Ni H, Wang X, Zhu Y, Chen L. Study on the coupling relationship of low temperature fluidity and oxidation stability of biodiesel. Appl Sci. 2020;10:1757.
Stournas S, Lois E, Serdari A. Effects of fatty acid derivatives on the ignition quality and cold flow of diesel fuel. J Am Oil Chem Soc. 1995;72:433–7.
Iwai M, Yamada-Oshima Y, Asami K, Kanamori T, Yuasa H, Shimojima M, et al. Recycling of the major thylakoid lipid MGDG and its role in lipid homeostasis in Chlamydomonas reinhardtii. Plant Physiol. 2021;187:1341–56.
Kobayashi K, Narise T, Sonoike K, Hashimoto H, Sato N, Kondo M, et al. Role of galactolipid biosynthesis in coordinated development of photosynthetic complexes and thylakoid membranes during chloroplast biogenesis in Arabidopsis. Plant J. 2013;73:250–61.
Awai K, Maréchal E, Block MA, Brun D, Masuda T, Shimada H, et al. Two types of MGDG synthase genes, found widely in both 16:3 and 18:3 plants, differentially mediate galactolipid syntheses in photosynthetic and nonphotosynthetic tissues in Arabidopsis thaliana. Proc Natl Acad Sci. 2001;98:10960–5.
Kobayashi K, Awai K, Takamiya K, Ohta H. Arabidopsis type B monogalactosyldiacylglycerol synthase genes are expressed during pollen tube growth and induced by phosphate starvation. Plant Physiol. 2004;134:640–8.
Aronsson H, Schottler MA, Kelly AA, Sundqvist C, Dormann P, Karim S, et al. Monogalactosyldiacylglycerol deficiency in Arabidopsis affects pigment composition in the prolamellar body and impairs thylakoid membrane energization and photoprotection in leaves. Plant Physiol. 2008;148:580–92.
Riekhof WR, Sears BB, Benning C. Annotation of genes involved in glycerolipid biosynthesis in Chlamydomonas reinhardtii: discovery of the betaine lipid synthase BTA1Cr. Eukaryot Cell. 2005;4:242–52.
Chen D, Wang S, Qi L, Yin L, Deng X. Galactolipid remodeling is involved in drought-induced leaf senescence in maize. Environ Exp Bot. 2018;150:57–68.
Bejaoui F, Salas JJ, Nouairi I, Smaoui A, Abdelly C, Martínez-Force E, et al. Changes in chloroplast lipid contents and chloroplast ultrastructure in Sulla carnosa and Sulla coronaria leaves under salt stress. J Plant Physiol. 2016;198:32–8.
Nishida I, Murata N. Chilling sensitivity in plants and cyanobacteria: the crucial contribution of membrane lipids. Annu Rev Plant Biol. 1996;47:541–68.
Legeret B, Schulz-Raffelt M, Nguyen HM, Auroy P, Beisson F, Peltier G, et al. Lipidomic and transcriptomic analyses of Chlamydomonas reinhardtii under heat stress unveil a direct route for the conversion of membrane lipids into storage lipids. Plant Cell Environ. 2016;39:834–47.
Bajhaiya AK, Dean AP, Zeef LA, Webster RE, Pittman JK. PSR1 is a global transcriptional regulator of phosphorus deficiency responses and carbon storage metabolism in Chlamydomonas reinhardtii. Plant Physiol. 2016;170:1216–34.
Sunshine H, Iruela-Arispe ML. Membrane lipids and cell signaling. Curr Opin Lipiol. 2017;28:408–13.
Yu L, Zhou C, Fan J, Shanklin J, Xu C. Mechanisms and functions of membrane lipid remodeling in plants. Plant J. 2021;107:37–53.
Du ZY, Lucker BF, Zienkiewicz K, Miller TE, Zienkiewicz A, Sears BB, et al. Galactoglycerolipid lipase PGD1 is involved in thylakoid membrane remodeling in response to adverse environmental conditions in Chlamydomonas. Plant Cell. 2018;30:447–65.
Li X, Moellering ER, Liu B, Johnny C, Fedewa M, Sears BB, et al. A galactoglycerolipid lipase is required for triacylglycerol accumulation and survival following nitrogen deprivation in Chlamydomonas reinhardtii. Plant Cell. 2012;24:4670–86.
Zäuner S, Jochum W, Bigorowski T, Benning C. A cytochrome b5-containing plastid-located fatty acid desaturase from Chlamydomonas reinhardtii. Eukaryot Cell. 2012;11:856–63.
Yang W, Wittkopp TM, Li X, Warakanont J, Dubini A, Catalanotti C, et al. Critical role of Chlamydomonas reinhardtii ferredoxin-5 in maintaining membrane structure and dark metabolism. Proc Natl Acad Sci. 2015;112:14978–83.
Yu CW, Lin YT, Li HM. Increased ratio of galactolipid MGDG:DGDG induces jasmonic acid overproduction and changes chloroplast shape. New Phytol. 2020;228:1327–35.
Cazzaniga S, Kim M, Bellamoli F, Jeong J, Lee S, Perozeni F, et al. Photosystem II antenna complexes CP26 and CP29 are essential for nonphotochemical quenching in Chlamydomonas reinhardtii. Plant Cell Environ. 2020;43:496–509.
Heredia-Martínez LG, Andrés-Garrido A, Martínez-Force E, Pérez-Pérez ME, Crespo JL. Chloroplast damage induced by the inhibition of fatty acid synthesis triggers autophagy in Chlamydomonas. Plant Physiol. 2018;178:1112–29.
Kim S, Kim H, Ko D, Yamaoka Y, Otsuru M, Kawai-Yamada M, et al. Rapid induction of lipid droplets in Chlamydomonas reinhardtii and Chlorella vulgaris by Brefeldin A. PLoS ONE. 2013;8: e81978.
Yamaoka Y, Shin S, Choi BY, Kim H, Jang S, Kajikawa M, et al. The bZIP1 transcription factor regulates lipid remodeling and contributes to ER stress management in Chlamydomonas reinhardtii. Plant Cell. 2019;31:1127–40.
Lee J-W, Shin S-Y, Kim H-S, Jin E, Lee H-G, Oh H-M. Lipid turnover between membrane lipids and neutral lipids via inhibition of diacylglyceryl N, N, N-trimethylhomoserine synthesis in Chlamydomonas reinhardtii. Algal Res. 2017;27:162–9.
Bonente G, Pippa S, Castellano S, Bassi R, Ballottari M. Acclimation of Chlamydomonas reinhardtii to different growth irradiances. J Biol Chem. 2012;287:5833–47.
Nogueira DPK, Silva AF, Araújo OQF, Chaloub RM. Impact of temperature and light intensity on triacylglycerol accumulation in marine microalgae. Biomass Bioenergy. 2015;72:280–7.
Nama S, Madireddi SK, Yadav RM, Subramanyam R. Non-photochemical quenching-dependent acclimation and thylakoid organization of Chlamydomonas reinhardtii to high light stress. Photosynth Res. 2019;139:387–400.
Rayati M, Rajabi Islami H, Shamsaie MM. light intensity improves growth, lipid productivity, and fatty acid profile of Chlorococcum oleofaciens (Chlorophyceae) for biodiesel production. Bioenergy Res. 2020;13:1235–45.
Ibanez-Salazar A, Rosales-Mendoza S, Rocha-Uribe A, Ramirez-Alonso JI, Lara-Hernandez I, Hernandez-Torres A, et al. Over-expression of Dof-type transcription factor increases lipid production in Chlamydomonas reinhardtii. J Biotechnol. 2014;184:27–38.
Rengel R, Smith RT, Haslam RP, Sayanova O, Vila M, León R. Overexpression of acetyl-CoA synthetase (ACS) enhances the biosynthesis of neutral lipids and starch in the green microalga Chlamydomonas reinhardtii. Algal Res. 2018;31:183–93.
Kim J, Kwak HS, Sim SJ, Jin E. Overexpression of malic enzyme isoform 2 in Chlamydomonas reinhardtii PTS42 increases lipid production. Bioresour Technol Rep. 2019;7: 100239.
Li Y, Han D, Hu G, Dauvillee D, Sommerfeld M, Ball S, et al. Chlamydomonas starchless mutant defective in ADP-glucose pyrophosphorylase hyper-accumulates triacylglycerol. Metab Eng. 2010;12:387–91.
De Luca M, Pappalardo I, Limongi AR, Viviano E, Radice RP, Todisco S, et al. Lipids from microalgae for cosmetic applications. Cosmetics. 2021;8:52.
Molnar A, Bassett A, Thuenemann E, Schwach F, Karkare S, Ossowski S, et al. Highly specific gene silencing by artificial microRNAs in the unicellular alga Chlamydomonas reinhardtii. Plant J. 2009;58:165–74.