Possible mechanisms for the generation of phenyl glycoside-type lignin-carbohydrate linkages in lignification with monolignol glucosides.
cell wall
lignin-carbohydrate complex
lignin-carbohydrate linkage
monolignol glucoside
nuclear magnetic resonance
phenyl glycoside
Journal
The Plant journal : for cell and molecular biology
ISSN: 1365-313X
Titre abrégé: Plant J
Pays: England
ID NLM: 9207397
Informations de publication
Date de publication:
09 2020
09 2020
Historique:
received:
04
10
2019
revised:
17
06
2020
accepted:
24
06
2020
pubmed:
6
7
2020
medline:
23
4
2021
entrez:
6
7
2020
Statut:
ppublish
Résumé
The existence and formation of covalent lignin-carbohydrate (LC) linkages in plant cell walls has long been a matter of debate in terms of their roles in cell wall development and biomass use. Of the various putative LC linkages proposed to date, evidence of the native existence and formation mechanism of phenyl glycoside (PG)-type LC linkages in planta is particularly scarce. The present study aimed to explore previously overlooked mechanisms for the formation of PG-type LC linkages through the incorporation of monolignol glucosides, which are possible lignin precursors, into lignin polymers during lignification. Peroxidase-catalyzed lignin polymerization of coniferyl alcohol in the presence of coniferin and syringin in vitro resulted in the generation of PG-type LC linkages in synthetic lignin polymers, possibly via nucleophilic addition onto quinone methide (QM) intermediates formed during polymerization. Biomimetic lignin polymerization of coniferin via the β-glucosidase/peroxidase system also resulted in the generation of PG-type as well as alkyl glycoside-type LC linkages. This occurred via non-enzymatic QM-involving reactions and also via enzymatic transglycosylations involving β-glucosidase, which was demonstrated by in-depth structural analysis of the synthetic lignins by two-dimensional NMR. We collected heteronuclear single-quantum coherence (HSQC) NMR for native cell wall fractions prepared from pine (Pinus taeda), eucalyptus (Eucalyptus camaldulensis), acacia (Acacia mangium), poplar (Populus × eurarnericana) and bamboo (Phyllostachys edulis) wood samples, which exhibited correlations, albeit at low levels, that were well matched with those of the PG-type LC linkages in synthetic lignins incorporating monolignol glucosides. Overall, our results provide a molecular basis for feasible mechanisms for the generation of PG-type LC linkages from monolignol glucosides and further substantiates their existence in planta.
Substances chimiques
Glucosides
0
Glycosides
0
Lignin
9005-53-2
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
156-170Informations de copyright
© 2020 Society for Experimental Biology and John Wiley & Sons Ltd.
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