Reveal the lignification of ginkgo after click chemistry by novel monolignol analogs

Lignin is one of the abundant natural resources in the world, but most of it is discarded as waste. So, understanding the deposition and structure of lignin plays an important role lignin valorization. In order to avoid changing the side chain structure of lignin monomers to make negligible influence on lignin deposition process, propargyl group was introduced at 2/6 position of benzene ring to explore deposition mechanism of lignin in plants by polymerization of alkynyl-labeled lignin precursors (H_ALK, G_ALK) in vivo and in vitro. The results showed that H_ALK and G_ALK were biocompatibility, could participate in the polymerization of lignin in plants. With the growth of plants, the content of lignin increased, while deposition pattern of lignin hardly changed, but the content of structural units (such as β-β, β-O-4) changed. In Ginkgo biloba L. (ginkgo), alkynyl-labeled lignin was mainly formed in cambium, while more natural lignin was found in xylem, and there are also small amounts of lignin deposits in phloem and epidermal. Through understanding of deposition and structure of lignin, it provides a strong theoretical basis for the lignification dynamics of plant cell wall.