Developing and testing new biotechnological tools to increase seed oil yield: a key to the production of hydrocarbon chains in oleaginous crop species. – SOLAR

Project aims:
Oil from seeds constitutes a key component of both human and livestock diets, which consumption is steeply increasing worldwide. Then, fatty acids composing triacylglycerols (TAGs) accumulated in plant seeds are structurally similar to long chain hydrocarbons and consequently represent logical and competitive alternatives to hydrocarbon-based products for the production of detergents, paints, plastics and lubricants (green chemistry).
The increasing demand of plant oils for such industrial and nutritional applications highlights the urgent need to develop new methodologies to increase seed oil content when only little progress has been made by conventional breeding over the last decade. The successful engineering of domesticated high yielding oil crop species now requires a full elucidation of the mechanisms controlling the production of fatty acids and their assembly into TAGs.
The TAG biosynthetic network comprises two blocks of reactions: block A is composed of plastidial enzymes involved in fatty acid synthesis, while block B of reactions is composed of acylating enzymes involved in TAG assembly in the ER. So far, most biotechnological approaches aimed at increasing seed oil content have put the focus on block B, thought to contain the few metabolic bottlenecks limiting seed oil production. However, metabolic control analysis experiments have recently shown that control of flux is exerted both by block A and block B. Within each of these blocks, metabolic control is then further shared between several enzymatic steps. Thus, it is essential to elucidate the regulation of block A to find out new biotechnological tools able to efficiently stimulate fatty acid synthesis.
Recent data indicate that block A is highly regulated at the transcriptional level and that a coordinated activation of most genes encoding enzymes of block A is necessary to stimulate the rate of fatty acid production. This is the reason why this project is focused on the transcriptional regulation of block A.

Work plan:
This project aims to elucidate the transcriptional regulation of fatty acid biosynthesis in the model plant Arabidopsis and to provide us with new ways to modify seed filling in the support of sustainable agriculture. Our project has three major objectives:
- The first is to isolate an original set of transcription factors involved in the control of fatty acid synthesis in Arabidopsis.
- The second is to provide a deep understanding of the regulatory complex controlling the transcription of lipogenic genes.
- The third is to exploit this knowledge to boost fatty acid production in seeds in the frame of a biotechnological approach.

Expected results:
- The main outcome of the project will consist in original knowledge about the regulation of fatty acid biosynthesis in plants.
- The expected results of the project are mainly fundamental, even though biotechnological tools will be developed in the model species Arabidopsis as a proof of concept. Tools and strategies tested in this project may then be applied to the improvement of oil yields on oilcrops such as Brassica napus and the generation of new varieties of bioeconomic interest.