Abstract
In plants, fatty acids are de novo synthesized predominantly in plastids from acetyl-coenzyme A. Although fatty acid biosynthesis has been biochemically well studied, little is known about the regulatory mechanisms of the pathway. Here, we show that overexpression of the Arabidopsis (Arabidopsis thaliana) LEAFY COTYLEDON1 (LEC1) gene causes globally increased expression of fatty acid biosynthetic genes, which are involved in key reactions of condensation, chain elongation, and desaturation of fatty acid biosynthesis. In the plastidial fatty acid synthetic pathway, over 58% of known enzyme-coding genes are up-regulated in LEC1-overexpressing transgenic plants, including those encoding three subunits of acetyl-coenzyme A carboxylase, a key enzyme controlling the fatty acid biosynthesis flux. Moreover, genes involved in glycolysis and lipid accumulation are also up-regulated. Consistent with these results, levels of major fatty acid species and lipids were substantially increased in the transgenic plants. Genetic analysis indicates that the LEC1 function is partially dependent on ABSCISIC ACID INSENSITIVE3, FUSCA3, and WRINKLED1 in the regulation of fatty acid biosynthesis. Moreover, a similar phenotype was observed in transgenic Arabidopsis plants overexpressing two LEC1-like genes of Brassica napus. These results suggest that LEC1 and LEC1-like genes act as key regulators to coordinate the expression of fatty acid biosynthetic genes, thereby representing promising targets for genetic improvement of oil production plants.
Highlights
In plants, fatty acids are de novo synthesized predominantly in plastids from acetyl-coenzyme A
We found that overexpression of the Arabidopsis transcription factor gene LEAFY COTYLEDON1 (LEC1) resulted in elevated expression of a large number of genes in the fatty acid biosynthesis pathway
Consistent with this observation, the accumulation of major fatty acid species and lipids was substantially increased in LEC1-OXi transgenic plants
Summary
Fatty acids are de novo synthesized predominantly in plastids from acetyl-coenzyme A. In the plastidial fatty acid synthetic pathway, over 58% of known enzyme-coding genes are up-regulated in LEC1-overexpressing transgenic plants, including those encoding three subunits of acetyl-coenzyme A carboxylase, a key enzyme controlling the fatty acid biosynthesis flux. 2001), ABI3 (Giraudat et al, 1992), and FUS3 (Luerssen et al, 1998) all belong to the plant-specific B3 transcription factor family, and LEC1 is an NFY-B-type or CCAAT-binding factor-type transcription factor (Lotan et al, 1998) Both LEC1 and LEC2 act as positive regulators upstream of ABI3 and FUS3, which, in turn, function partially redundantly to control the expression of seed storage protein (SSP) genes (Baud et al, 2002; Kroj et al, 2003; Kagaya et al, 2005b; To et al, 2006). A more recent study revealed that LEC2 directly regulated WRI1, which, in turn, controlled the expression of a subset of genes involved in late glycolysis and fatty acid biosynthesis as well as the biosynthesis of biotin and lipoic acids (Baud et al, 2007a)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
