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

根与周围土壤环境之间的界面以根细胞壁中亲脂性生物聚合物木质素的沉积为特征。根系的退化调节水和溶解化合物（如营养物质）的运输，在与非生物（干旱、渗透胁迫、盐胁迫）和生物（土传病原体）环境的相互作用中具有重要意义。化学上，拟南芥由线性长链羟基化脂肪酸组成，范围从C16到C24。尽管我们对木素的化学成分和基本功能有所了解，但我们对木素生物合成的了解仍然非常有限。利用对拟南芥的反向遗传学方法，我们令人信服地证明了脂肪酸细长ase1样基因家族的成员是亚糖蛋白形成过程所必需的。因此，该项目扩展到分析p450单加氧酶基因家族的成员，导致长链脂肪族亚蛋白单体的羟基化。因此，本项目将分析p450 -单加氧酶对木素生物合成的贡献以及与脂肪酸延长酶的相互作用，最终对木素生物合成所需的生物合成网络有一个大致的了解。深入了解甜菜素在根系中的生物合成，有助于提高作物对非生物和生物环境胁迫因子的耐受性。

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.