Batsale Marguerite, Alonso Marie, Pascal Stéphanie, Thoraval Didier, Haslam Richard P, Beaudoin Frédéric, Domergue Frédéric, Joubès Jérôme
Univesity of Bordeaux, CNRS, LBM, UMR 5200, Villenave d'Ornon, France.
University of Bordeaux, INRAE, BFP, UMR 1332, Villenave d'Ornon, France.
Front Plant Sci. 2023 Jan 25;14:1107333. doi: 10.3389/fpls.2023.1107333. eCollection 2023.
Very-long-chain fatty acids (VLCFA) are precursors for various lipids playing important physiological and structural roles in plants. Throughout plant tissues, VLCFA are present in multiple lipid classes essential for membrane homeostasis, and also stored in triacylglycerols. VLCFA and their derivatives are also highly abundant in lipid barriers, such as cuticular waxes in aerial epidermal cells and suberin monomers in roots. VLCFA are produced by the fatty acid elongase (FAE), which is an integral endoplasmic reticulum membrane multi-enzymatic complex consisting of four core enzymes. The 3-ketoacyl-CoA synthase (KCS) catalyzes the first reaction of the elongation and determines the chain-length substrate specificity of each elongation cycle, whereas the other three enzymes have broad substrate specificities and are shared by all FAE complexes. Consistent with the co-existence of multiple FAE complexes, performing sequential and/or parallel reactions to produce the broad chain-length-range of VLCFA found in plants, twenty-one KCS genes have been identified in the genome of . Using CRISPR-Cas9 technology, we established an expression platform to reconstitute the different Arabidopsis FAE complexes in yeast. The VLCFA produced in these yeast strains were analyzed in detail to characterize the substrate specificity of all KCS candidates. Additionally, Arabidopsis candidate proteins were transiently expressed in leaves to explore their activity and localization . This work sheds light on the genetic and biochemical redundancy of fatty acid elongation in plants.
极长链脂肪酸（VLCFA）是多种脂质的前体，在植物中发挥着重要的生理和结构作用。在整个植物组织中，VLCFA存在于多种对膜稳态至关重要的脂质类别中，也储存在三酰甘油中。VLCFA及其衍生物在脂质屏障中也高度丰富，例如地上表皮细胞中的角质蜡和根中的木栓质单体。VLCFA由脂肪酸延长酶（FAE）产生，FAE是一种内质网整合膜多酶复合体，由四种核心酶组成。3-酮酰基辅酶A合酶（KCS）催化延长反应的第一步，并决定每个延长循环的链长底物特异性，而其他三种酶具有广泛的底物特异性，为所有FAE复合体所共有。与多种FAE复合体共存一致，它们进行顺序和/或平行反应以产生植物中发现的广泛链长范围的VLCFA，在[植物名称]的基因组中已鉴定出21个KCS基因。利用CRISPR-Cas9技术，我们建立了一个表达平台，以在酵母中重组不同的拟南芥FAE复合体。对这些酵母菌株中产生的VLCFA进行了详细分析，以表征所有KCS候选物的底物特异性。此外，在[植物名称]叶片中瞬时表达拟南芥候选蛋白，以探索它们的活性和定位。这项工作揭示了植物中脂肪酸延长的遗传和生化冗余性。
