Solid-State ¹³C NMR Delineates the Architectural Design of Biopolymers in Native and Genetically Altered Tomato Fruit Cuticles

Abstract

Plant cuticles on outer fruit and leaf surfaces are natural macromolecular composites of waxes and polyesters that ensure mechanical integrity and mitigate environmental challenges. They also provide renewable raw materials for cosmetics, packaging, and coatings. To delineate the structural framework and flexibility underlying the versatile functions of cutin biopolymers associated with polysaccharide-rich cell-wall matrices, solid-state NMR spectra and spin relaxation times were measured in a tomato fruit model system, including different developmental stages and surface phenotypes. The hydrophilic–hydrophobic balance of the cutin ensures compatibility with the underlying polysaccharide cell walls; the hydroxy fatty acid structures of outer epidermal cutin also support deposition of hydrophobic waxes and aromatic moieties while promoting the formation of cell-wall cross-links that rigidify and strengthen the cuticle composite during fruit development. Fruit cutin-deficient tomato mutants with compromised microbial resistance exhibit less efficient local and collective biopolymer motions, stiffening their cuticular surfaces and increasing their susceptibility to fracture.

An Ionic Liquid Extraction That Preserves the Molecular Structure of Cutin Shown by Nuclear Magnetic Resonance

“…of the hydrolysable constituents), while providing insights on its biosynthesis (Bakan and Marion, 2017) but not of their structural molecular organisation, which remains largely unknown (Fich et al, 2016;Bakan and Marion, 2017). To advance our understanding of important cutinrelated questions such as cutin/cell wall polymers interactions or the role of cutin in defence to pathogens (Chatterjee et al, 2016), a better insight into the structure of cutin in its native state is highly required.…”

The glycerol-3-phosphate acyltransferase GPAT6 from tomato plays a central role in fruit cutin biosynthesis

“…Following their synthesis in the endoplasmic reticulum, cutin monomers are transported across the plasmalemma and polysaccharide cell wall to the hydrophobic cuticle layer. The monomers are then assembled into a network of linear and branched cutin polymers (Chatterjee et al, 2016;Philippe et al, 2016) by cutin synthases (Girard et al, 2012;Yeats et al, 2012b;Fich et al, 2016).…”

An Anthracene Excimer Fluorescence Probe on Mesoporous Silica for Dual Functions of Detection and Adsorption of Mercury (II) and Copper (II) with Biological In Vivo Applications

“…Both the materials SiO 2 @NH 2 and SiO 2 @PBATPA shows three peaks at 12, 24, and 45 ppm in 13 C CP (MAS) NMR spectrum ( Figure A) which can be assigned to three methylene groups, (CH 2 ) 3  . Some additional peaks between 92–162 and 180 ppm in SiO 2 @PBATPA are due to the presence of arene and carbonyl carbons, respectively . The 29 Si CP (MAS) NMR (Figure B) shows Q n type signals (−94, −102, −110 ppm) for silanol group in all the three compounds and T n type signals (−50 to −70 ppm) for SiO 2 @NH 2 and SiO 2 @PBATPA due to silicon atoms of the organic linker 3‐APTES …”