Tackling functional redundancy of Arabidopsis fatty acid elongase complexes

Abstract

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 Arabidopsis thaliana. 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 Nicotiana benthamiana leaves to explore their activity and localization in planta. This work sheds light on the genetic and biochemical redundancy of fatty acid elongation in plants.

Decoding drought resilience: a comprehensive exploration of the cotton Eceriferum (CER) gene family and its role in stress adaptation

“…It consists of VLCFAs and derivatives [ 36 ]. Cuticular wax production is regulated by several genes, including CER [ 9 ], KCR (beta-ketoacyl-CoA reductase) [ 37 ], KCS [ 38 ], FAR (fatty acid CoA reductase) [ 39 ], CUT1 [ 40 ], FAE (fatty acid elongase) [ 41 ], and LACS [ 42 ]. The CER gene family contributes to the production of cuticle wax and has a vital function in stress mitigation [ 12 ].…”

Dynamic relationships among pathways producing hydrocarbons and fatty acids of maize silk cuticular waxes

“…Downstream of the fatty acid elongase system, within the decarbonylative hydrocarbon-forming pathway, Arabidopsis ECERIFERUM1 (CER1) and CER1-LIKE1 proteins each form unique reductase-decarbonylase complexes with CER3 and cytochrome b5, which sequentially convert VLCFA-CoAs to aldehydes and alkanes of different chain lengths ( Pascal et al 2019 ). These potential mechanisms for altering HC 2n-1:0 : FA 2n:0 ratios can be tested via heterologous expression of candidate genes within recently engineered yeast systems expressing the maize or Arabidopsis fatty acid elongase complexes ( Haslam et al 2012 , 2015 ; Campbell et al 2019 ; Stenback et al 2022 ; Batsale et al 2023 ).…”

Light and Methyl Jasmonate Impact in the Biosynthesis of Anthocyanins and VLCFAs in the <em>Euonymus maximowiczianus</em> Aril-Derived Long-Term Suspension-Cultured Cells

“…Next, four core enzymes of FAE complex perform sequential reactions, beginning with a condensation of a LC(n)acyl-CoA (as a primer) and malonyl-CoA (as a two-carbon donor) catalyzed by β-ketoacyl-CoA synthase (KCS) to give a β-keto-LC(n+2)-acyl-CoA, then function β-ketoacyl-CoA reductase, βhydroxyacyl-CoA dehydratase, and enoyl-CoA reductase to form a LC(n+2)-acyl-CoA, which can further elongated by repeated cycles [56,57]. Take note of KCS determines the chain-length substrate specificity of each elongation cycle [56][57][58].…”