title: Indole-3-acetic acid (IAA) induced changes in oil content, fatty acid profiles and expression of four fatty acid biosynthetic genes in Chlorella vulgaris at early stationary growth phase.
abstract: Microalgae lipids and oils are potential candidates for renewable biodiesel. Many microalgae species accumulate a substantial amount of lipids and oils under environmental stresses. However, low growth rate under these adverse conditions account for the decrease in overall biomass productivity which directly influence the oil yield. This study was undertaken to investigate the effect of exogenously added auxin (indole-3-acetic acid; IAA) on the oil content, fatty acid compositions, and the expression of fatty acid biosynthetic genes in Chlorella vulgaris (UMT-M1). Auxin has been shown to regulate growth and metabolite production of several microalgae. Results showed that oil accumulation was highest on days after treatment (DAT)-2 with enriched levels of palmitic (C16:0) and stearic (C18:0) acids, while the linoleic (C18:2) and α-linolenic (C18:3n3) acids levels were markedly reduced by IAA. The elevated levels of saturated fatty acids (C16:0 and C18:0) were consistent with high expression of the β-ketoacyl ACP synthase I (KAS I) gene, while low expression of omega-6 fatty acid desaturase (ω-6 FAD) gene was consistent with low production of C18:2. However, the increment of stearoyl-ACP desaturase (SAD) gene expression upon IAA induction did not coincide with oleic acid (C18:1) production. The expression of omega-3 fatty acid desaturase (ω-3 FAD) gene showed a positive correlation with the synthesis of PUFA and C18:3n3.
authors.affiliation: School of Fundamental Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: malinna@umt.edu.my.
authors.forename: Malinna
authors.initials: M
authors.lastname: Jusoh
authors.affiliation: School of Marine Science and Environment, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: lohsh@umt.edu.my.
authors.forename: Saw Hong
authors.initials: SH
authors.lastname: Loh
authors.affiliation: School of Food Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: chuahts@umt.edu.my.
authors.forename: Tse Seng
authors.initials: TS
authors.lastname: Chuah
authors.affiliation: School of Food Science and Technology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: aaziz@umt.edu.my.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Aziz
authors.affiliation: School of Fundamental Sciences, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia; Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia. Electronic address: cha_ts@umt.edu.my.
authors.forename: Thye San
authors.initials: TS
authors.lastname: Cha
mesh_terms: D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000378:metabolism; D056804:Biofuels / Q000032:analysis; D048408:Chlorella vulgaris / Q000737:chemistry / Q000235:genetics*; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis / Q000096:biosynthesis*; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism; D019787:Linoleic Acid / Q000032:analysis; D058086:Microalgae / Q000737:chemistry; D006899:Mixed Function Oxygenases / Q000378:metabolism; D019301:Oleic Acid / Q000378:metabolism
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D007210:Indoleacetic Acids; D007527:Isoenzymes; D019301:Oleic Acid; C030737:indoleacetic acid; D019787:Linoleic Acid; D006899:Mixed Function Oxygenases; D044943:Fatty Acid Desaturases; C018747:acyl-(acyl-carrier-protein)desaturase; C078565:omega-3 fatty acid desaturase; C078182:beta-ketoacyl-acyl carrier protein synthase I; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase
keywords: Chlorella vulgaris; Chlorellaceae; Indole-3-acetic acid; Keto-acyl ACP synthase I; Microalgae; Omega-3 fatty acid desaturase; Omega-6 fatty acid desaturase; Stearoyl-ACP desaturase