Location: Plant Physiology and Genetics ResearchTitle: The acyl desaturase CER17 is involved in producing wax unsaturated primary alcohols and cutin monomers
|YANG, XAINPENG - Chinese Academy Of Sciences|
|ZHAO, HUAYAN - Chinese Academy Of Sciences|
|KOSMA, DYLAN - University Of Nevada|
|LI, RONGJUN - Chinese Academy Of Sciences|
|LIU, XIULIN - Chinese Academy Of Sciences|
|PARSONS, EUGENE - Prairie State College|
|JENKS, MATTHEW - West Virginia University|
|LU, SHIYOU - Chinese Academy Of Sciences|
Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2017
Publication Date: 1/9/2017
Citation: Yang, X., Zhao, H., Kosma, D.K., Tomasi, P., Dyer, J.M., Li, R., Liu, X., Parsons, E.P., Jenks, M.A., Lu, S. 2017. The acyl desaturase CER17 is involved in producing wax unsaturated primary alcohols and cutin monomers. Plant Physiology. 173:1109-1124.
Interpretive Summary: The cuticle is a hydrophobic, protective barrier on the surface of plants that plays a major role in coordinating interactions between the plant and its environment. The cuticle is composed of a complex mixture of hydrocarbons, and while many genes have been identified that are involved in its production, there are also many steps that are not yet understood. In a collaborative effort between scientists at the Chinese Academy of Sciences in Wuhan, China, the University of Nevada, Reno, the ARS lab in Maricopa, Arizona, Prairie State College in Chicago Heights, Illinois, and West Virginia University in Morgantown, West Virginia, a new gene called “ADS4” was identified that plays a key role in the production of a previously unknown component in the cuticular lipids of plants. By using genetic, cellular, and biochemical studies, the scientists were able to determine not only the function of this gene, but also how it interacted with other genes in the cuticle-production pathway. These results provide an important piece to the puzzle that describes a complete picture of cuticle production in plants, and will be informative not only to scientists interested in understanding the basic aspects of cuticle synthesis, but also to breeders who are interested in improving drought tolerance of crops through directed modification of the cuticle production pathway.
Technical Abstract: We report here n-6 mono-unsaturated primary alcohols (the C26:1, C28:1, and C30:1 homologues) in the cuticular waxes of Arabidopsis inflorescence stem, a class of wax compound not previously reported in Arabidopsis. Further, we used mutation and transgenic complementation analyses to demonstrate that the ACYL-COENZYME A DESATURASE LIKE4 (ADS4) gene plays a principal role in directing the synthesis of these unsaturated waxes. The ads4 mutant (allelic to cer17) also displayed elevated saturated waxes and cutin monomers, and a thickened and irregular cuticle ultrastructure. The process whereby these saturated waxes and cutin monomers were elevated on ads4 is still unknown. However, we conclude that ADS4 is not necessary for desaturation of cutin monomers since unsaturated monomers on ads4 were elevated. The ads4 cuticle defect was more prominent in upper (distal) stems than lower (basal) stems, the ADS4 transcript was most abundant in the epidermis of upper stems, and the ADS4 protein localized to the endoplasmic reticulum. To elucidate possible ADS4 substrates, double mutants deficient in ADS4 and either LONG-CHAIN ACYL-COA SYNTHETASE1 (LACS1) or LACS2 proteins were examined. Genetic interaction of ADS4 with LACS1 was observed for upper but not lower stems, wherein the upper stem of the double mutant produced more cutin monomers and a thicker and more disorganized cuticle ultrastructure, and higher cuticle permeability, than observed for wild type or either mutant parent. Our findings demonstrate that ADS4 functions in production of mono-unsaturated waxes, and interacts with LACS1 to determine cutin monomer abundance, especially in the upper inflorescence stem.