Biosynthesis of barley wax β-diketones: a type-III polyketide synthase condensing two fatty acyl units.

ABSTRACT: The surface coatings of cereal plants are dominated by waxy β-diketones crucial for drought resistance and, therefore, grain yield. Here, barley (Hordeum vulgare) wax analyses reveal β-diketone and associated 2-alkanol ester profiles suggesting a common C₁₆ 3-ketoacid precursor. Isotope analysis further shows that the major (C₃₁) diketone is synthesized from two plastidial C₁₆ acyl units. Previous studies identified a gene cluster encoding enzymes responsible for β-diketone formation in barley, but left their biochemical functions unknown. Various assays now characterize one of these enzymes as a thioesterase producing long-chain (mainly C₁₆) 3-ketoacids, and another one as a polyketide synthase (PKS) condensing the 3-ketoacids with long-chain (m

SUBMITTER: Sun Y 

PROVIDER: S-EPMC10638390 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature