Communication Dans Un Congrès Année : 2022

Elucidating the functional redundancy of Very Long Chain Fatty Acid Elongation enzymes in Arabidopsis thaliana

Résumé

Very-long-chain fatty acids (VLCFA) are important molecules with crucial physiological and structural roles in plants. With acyl chains of 20 carbons and longer, VLCFA can be modified and derivatized into flexible components and precursors of various important lipids such as phospholipids and sphingolipids mainly in plasma and vacuolar membranes, cuticular waxes in epidermis, suberin in roots or triacylglycerols (TAGs) in seeds. Plant VLCFA are therefore precursors of abundant lipids involved in different mechanisms allowing plants to grow and adjust to their ever-changing environment (membrane trafficking, cell division and differentiation, non-stomatal water loss prevention, energy storage). Their structural, protective, nutritive and energetic properties have already led to several reports on their synthesis and functions in plants. VLCFA are produced by the fatty acid elongase (FAE complex), an integral ER membrane enzymatic complex containing four distinct enzymes (KCS, KCR, HCD and ECR). Studies, including photoperiod and chemical inhibition of elongase activities, initially raised the idea for existence of multiple elongase complexes, with a distinct chain-length specificity that perform sequential and/or parallel reactions to produce the broad chain-length-range of VLCFA found in plants. The KCR, HCD and ECR enzymes are thought to have broad substrate specificity and may be shared by all FAE complexes. In contrast, KCS enzymes determine the chain-length substrate specificity of each elongation reaction. Consistent with the co-existence of multiple FAE complexes, 21 KCS genes have been identified in Arabidopsis thaliana. In order to further characterize the substrate specificities of all 21 Arabidopsis KCS candidates, we established an expression platform in yeast to reconstitute the different Arabidopsis FAE complexes and compare the resulting VLCFA profiles. Moreover, Arabidopsis candidate genes have been transiently expressed in Nicotiana benthamiana leaves to explore their localization and activity in plants. This full functional characterization led us to highlight the activity of half of Arabidopsis KCS family and allowed us to further study critical residues involved in their substrate specificity.

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hal-05261996 , version 1 (15-09-2025)

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  • HAL Id : hal-05261996 , version 1

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Marguerite Batsale, Marie Alonso, Stéphanie Pascal, Didier Thoraval, Frédéric Domergue, et al.. Elucidating the functional redundancy of Very Long Chain Fatty Acid Elongation enzymes in Arabidopsis thaliana. 25th International Symposium on Plant Lipids, Jul 2022, Grenoble, France. ⟨hal-05261996⟩
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