Apoplastic polyesters in Arabidopsis surface tissues – A typical suberin and a particular cutin

• Published in: Phytochemistry (Oxford) Vol. 66; no. 22; pp. 2643 - 2658
• Main Authors: Franke, Rochus, Briesen, Isabel, Wojciechowski, Tobias, Faust, Andrea, Yephremov, Alexander, Nawrath, Christiane, Schreiber, Lukas
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.11.2005; Elsevier
• Subjects: Aliphatic polyester; Apoplastic biopolymers; apoplasts; Arabidopsis - chemistry; Arabidopsis - metabolism; Arabidopsis - ultrastructure; Arabidopsis thaliana; Biological and medical sciences; Brassicaceae; Catalysis; Cell Wall - chemistry; Cell Wall - metabolism; cell walls; chemical composition; Chemical constitution; Cutin; endodermis; fatty acid composition; Fundamental and applied biological sciences. Psychology; hydrolases; leaves; Lipids; long chain fatty acids; Membrane Lipids - chemistry; Membrane Lipids - metabolism; Microscopy, Electron, Transmission; plant biochemistry; plant cuticle; Plant Extracts; Plant Leaves - chemistry; Plant Leaves - metabolism; plant morphology; Plant physiology and development; Plant Roots - chemistry; Plant Roots - metabolism; Plastics - chemistry; Plastics - metabolism; polyesters; Polyesters - chemistry; Polyesters - metabolism; polysaccharides; root systems; spatial distribution; Spectrometry, Mass, Electrospray Ionization; Suberin; transmission electron microscopes; ultrastructure; Very long-chain fatty acids; Arabidopsis thaliana; Cutin; Suberin; Very long-chain fatty acids; Brassicaceae; Aliphatic polyester; Apoplastic biopolymers; Molecular structure; Ester polymer; Cuticle; Plant leaf; Cell wall; Cruciferae; Dicotyledones; Angiospermae; Isolation; Spermatophyta; Transgenic plant; Mutation
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2005.09.027

The aliphatic monomer composition of isolated Arabidopsis leaf cuticles and of suberin from Arabidopsis was determined by gas chromatography and mass spectrometry. A biosynthetic pathway is discussed. Cutinized and suberized cell walls form physiological important plant–environment interfaces as they act as barriers limiting water and nutrient loss and protect from radiation and invasion by pathogens. Due to the lack of protocols for the isolation and analysis of cutin and suberin in Arabidopsis, the model plant for molecular biology, mutants and transgenic plants with a defined altered cutin or suberin composition are unavailable, causing that structure and function of these apoplastic barriers are still poorly understood. Transmission electron microscopy (TEM) revealed that Arabidopsis leaf cuticle thickness ranges from only 22 nm in leaf blades to 45 nm on petioles, causing the difficulty in cuticular membrane isolation. We report the use of polysaccharide hydrolases to isolate Arabidopsis cuticular membranes, suitable for depolymerization and subsequent compositional analysis. Although cutin characteristic ω-hydroxy acids (7%) and mid-chain hydroxylated fatty acids (8%) were detected, the discovery of α,ω-diacids (40%) and 2-hydroxy acids (14%) as major depolymerization products reveals a so far novel monomer composition in Arabidopsis cutin, but with chemical analogy to root suberin. Histochemical and TEM analysis revealed that suberin depositions were localized to the cell walls in the endodermis of primary roots and the periderm of mature roots of Arabidopsis. Enzyme digested and solvent extracted root cell walls when subjected to suberin depolymerization conditions released ω-hydroxy acids (43%) and α,ω-diacids (24%) as major components together with carboxylic acids (9%), alcohols (6%) and 2-hydroxyacids (0.1%). This similarity to suberin of other species indicates that Arabidopsis roots can serve as a model for suberized tissue in general.