title: Tobacco as a production platform for biofuel: overexpression of Arabidopsis DGAT and LEC2 genes increases accumulation and shifts the composition of lipids in green biomass.
abstract: When grown for energy production instead for smoking, tobacco can generate a large amount of inexpensive biomass more efficiently than almost any other agricultural crop. Tobacco possesses potent oil biosynthesis machinery and can accumulate up to 40% of seed weight in oil. In this work, we explored two metabolic engineering approaches to enhance the oil content in tobacco green tissues for potential biofuel production. First, an Arabidopsis thaliana gene diacylglycerol acyltransferase (DGAT) coding for a key enzyme in triacylglycerol (TAG) biosynthesis, was expressed in tobacco under the control of a strong ribulose-biphosphate carboxylase small subunit promoter. This modification led to up to a 20-fold increase in TAG accumulation in tobacco leaves and translated into an overall of about a twofold increase in extracted fatty acids (FA) up to 5.8% of dry biomass in Nicotiana tabacum cv Wisconsin, and up to 6% in high-sugar tobacco variety NC-55. Modified tobacco plants also contained elevated amounts of phospholipids. This increase in lipids was accompanied by a shift in the FA composition favourable for their utilization as biodiesel. Second, we expressed in tobacco Arabidopsis gene LEAFY COTYLEDON 2 (LEC2), a master regulator of seed maturation and seed oil storage under the control of an inducible Alc promoter. Stimulation of LEC2 expression in mature tobacco plants by acetaldehyde led to the accumulation of up to 6.8% per dry weight of total extracted FA. The obtained data reveal the potential of metabolically modified plant biomass for the production of biofuel.
authors.affiliation: Biotechnology Foundation Laboratories, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Vyacheslav
authors.initials: V
authors.lastname: Andrianov
authors.forename: Nikolai
authors.initials: N
authors.lastname: Borisjuk
authors.forename: Natalia
authors.initials: N
authors.lastname: Pogrebnyak
authors.forename: Anita
authors.initials: A
authors.lastname: Brinker
authors.forename: Joseph
authors.initials: J
authors.lastname: Dixon
authors.forename: Sergei
authors.initials: S
authors.lastname: Spitsin
authors.forename: John
authors.initials: J
authors.lastname: Flynn
authors.forename: Paulina
authors.initials: P
authors.lastname: Matyszczuk
authors.forename: Karolina
authors.initials: K
authors.lastname: Andryszak
authors.forename: Marilyn
authors.initials: M
authors.lastname: Laurelli
authors.forename: Maxim
authors.initials: M
authors.lastname: Golovkin
authors.forename: Hilary
authors.initials: H
authors.lastname: Koprowski
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D056804:Biofuels; D018533:Biomass; D051048:Diacylglycerol O-Acyltransferase / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D014280:Triglycerides / Q000096:biosynthesis*
chemical_list: D029681:Arabidopsis Proteins; D056804:Biofuels; D005227:Fatty Acids; C504240:LEC2 protein, Arabidopsis; D018749:RNA, Plant; D014157:Transcription Factors; D014280:Triglycerides; D051048:Diacylglycerol O-Acyltransferase