The metabolic grid of suberin biosynthesis in Arabidopsis - a multi-branched pathway appointing cytochrome P450 w-hydroxylases and fatty acid elongases

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The interface between roots and the surrounding soil environment is characterized by the deposition of the lipophilic biopolymer suberin in root cell walls. Suberization in roots regulates the transport of water and dissolved compounds (e.g. nutrients) and it is of major significance in the interaction with the abiotic (drought, osmotic stress, salt stress) and the biotic (soil-borne pathogens) environment. Chemically, Arabidopsis suberin is composed of linear, long-chain hydroxylated fatty acids ranging from C16 to C24. Despite our knowledge on the chemical composition and the fundamental function of suberin, our knowledge on suberin biosynthesis still is remarkably limited. Using a reverse genetics approach in Arabidopsis we convincingly showed that members of the FATTY ACID ELONGASE1-like gene family are required for the process of suberin formation. Consequently, this projects is expanded to analyse members of the gene family of P450-monooxygenases, leading to the hydroxylation of the long-chain aliphatic suberin monomers. Thus in this project the contribution of P450-monooxygenases to suberin biosynthesis and the interaction with fatty acid elongases will be analyzed, finally leading to a general understanding of the biosynthetic network needed for suberin biosynthesis. An improved knowledge of suberin biosynthesis in roots could help in future to improve stress tolerance of crop plants towards abiotic and biotic environmental stress factors.