BIOLIPOL · Unraveling the biosynthesis of fatty acid-based lipid polymers in plants
FP7 — People (Marie Curie Actions)
- Duration
- 2008-05-01 → 2012-04-30
- EU contribution
- €100,000
- Participants
- 1
- Scheme
- MC-IRG
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Results in brief
Unraveling the biosynthesis of fatty acid-based lipid polymers in plants
Project context and objectives The aim of this project was to identify new enzymes involved in the biosynthesis of the plant protective lipid polyesters cutin and suberin, and gain insights into the acyl oxidation and acyltransfer reactions of the pathway. Work performed Twenty-one candidate genes have been tested by reverse genetics in the model plant Arabidopsis thaliana. Mutants for four candidate genes have been found to be essential for cutin synthesis and were characterised in detail. A major result was the discovery that the in-chain hydroxylase synthesizing 10,16-dihydroxypalmitate (a common cutin monomer in nature) was encoded by CYP77A6, a member of a P450 family with no previously ascribed in vivo function. It was demonstrated that CYP77A6 acts after the terminal hydroxylase CYP86A4 to produce 10,16-dihydroxypalmitate. Analysis of the mutants has also shown that the cutin polymer is central to the formation of petal nanoridges (Li-Beisson et al. 2009 PNAS 106:22008). In addition, it has been demonstrated that CYP77A4 is involved specifically in the synthesis of a trihydroxy acid found in cutins and is essential for seed germination under osmotic stress (PhD thesis of G. Verdier, 2010-2013, Aix-Marseille University). Gene overexpression studies have also been conducted in Arabidopsis and yeast. Several combinations of GPAT acyltransferases and fatty acid oxidases have been overexpressed. The combination GPAT5/CYP86B1 has allowed the production and secretion of very long chain hydroxyacids and diacids that are normally found in the suberin of roots. Main results The project has yielded important new insights into the identity and characteristics of the enzymes involved in the pathway of plant lipid polyester biosynthesis. The enzymes identified are potentially useful for biotechnological applications such as: - improving barrier functions in crops by genetically engineering the cutin polymer (resistance to pathogens, desiccation and/or salinity); - producing high amounts of oxidised fatty acids (omega-hydroxy fatty acids, fatty diols, dicarboxylic acids) in plants, which could replace petroleum-derived products for the synthesis of polymers and specialty chemicals.
Data: CORDIS, © European Union
Project objective
Cutin and suberin are plant-specific extracellular lipid polymers that are involved in critical water and pathogen barrier functions at the interface between plants and their environment. The biosynthesis of these glycerol- and fatty acid-based polymers remains largely unknown. Understanding how plant cells oxidize, activate, transfer and polymerize acyl chains in the pathway of biosynthesis of cutin and suberin would be helpful to manipulate the composition of plant hydrophobic barriers and obtain crops with higher resistance to pathogens or desiccation. In addition, the reactions of lipid polyester biosynthesis involving oxidized fatty acids are likely to be highly relevant to the bottlenecks that are currently limiting the production in plants of high amounts of omega-hydroxy fatty acids and dicarboxylic acids, which are biomolecules with potential to replace petroleum for the synthesis of polymers and specialty chemicals. The applicant and his colleagues at Michigan State University have identified the first mutant affected in suberin synthesis, characterized a family of glycerol acyltransferases involved in polyester biosynthesis in the model plant Arabidopsis thaliana and shown that these acyltransferases are key partners of P450 fatty acid oxidases for the production of oxidized fatty acids in plant cuticles. In order to further understand the acyl activation, acyl oxidation and acyltransfer reactions required for the biosynthesis of lipid polymers in plants and to identify more players in this pathway, the applicant proposes to: 1) Pursue a knock-out/overexpression approach in Arabidopsis on a larger scale. 2) Co-overexpress various combinations of these Arabidopsis enzymes in yeast in an attempt to characterize their activity and determine the minimal number of genes required to produce polyacylglycerols containing hydroxy-fatty acids and/or dicarboxylic acids. 3) Determine the subcellular location of the enzymes identified.
Original text from CORDIS.
Participants
- CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS · ParisCoordinatorFrance
Links
Data: CORDIS, © European Union