PT  - JOURNAL ARTICLE
AU  - Li, Fu-Shuang
AU  - Phyo, Pyae
AU  - Jacobowitz, Joseph
AU  - Hong, Mei
AU  - Weng, Jing-Ke
TI  - The molecular structure of plant sporopollenin
AID  - 10.1101/415612
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 415612
4099  - http://biorxiv.org/content/early/2018/09/12/415612.short
4100  - http://biorxiv.org/content/early/2018/09/12/415612.full
AB  - Sporopollenin is a ubiquitous and extremely chemically inert biopolymer that constitutes the outer wall of all land-plant spores and pollen grains. Sporopollenin protects the vulnerable plant gametes against a wide range of environmental assaults, and is considered as a prerequisite for the migration of early plants onto land. Despite its importance, the chemical structure of plant sporopollenin has remained elusive. Using a newly developed thioacidolysis degradative method together with state-of-the-art solid-state NMR techniques, we determined the detailed molecular structure of pine sporopollenin. We show that pine sporopollenin is primarily composed of aliphatic-polyketide-derived polyvinyl alcohol units and 7-O-p-coumaroylated C16 aliphatic units, crosslinked through a distinctive m-dioxane moiety featuring an acetal. Naringenin was also identified as a minor component of pine sporopollenin. This discovery answers the long-standing question about the chemical makeup of plant sporopollenin, laying the foundation for future investigations of sporopollenin biosynthesis and for design of new biomimetic polymers with desirable inert properties.