Rerouting of the lignin biosynthetic pathway by inhibition of cytosolic shikimate recycling in transgenic hybrid aspen.
RNA-seq
heterologous expression
lignocellulose
metabolome
phenolic metabolites
saccharification efficiency
shikimate pathway
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:
04 2022
04 2022
Historique:
received:
12
09
2021
accepted:
10
01
2022
pubmed:
20
1
2022
medline:
29
4
2022
entrez:
19
1
2022
Statut:
ppublish
Résumé
Lignin is a phenolic polymer deposited in the plant cell wall, and is mainly polymerized from three canonical monomers (monolignols), i.e. p-coumaryl, coniferyl and sinapyl alcohols. After polymerization, these alcohols form different lignin substructures. In dicotyledons, monolignols are biosynthesized from phenylalanine, an aromatic amino acid. Shikimate acts at two positions in the route to the lignin building blocks. It is part of the shikimate pathway that provides the precursor for the biosynthesis of phenylalanine, and is involved in the transesterification of p-coumaroyl-CoA to p-coumaroyl shikimate, one of the key steps in the biosynthesis of coniferyl and sinapyl alcohols. The shikimate residue in p-coumaroyl shikimate is released in later steps, and the resulting shikimate becomes available again for the biosynthesis of new p-coumaroyl shikimate molecules. In this study, we inhibited cytosolic shikimate recycling in transgenic hybrid aspen by accelerated phosphorylation of shikimate in the cytosol through expression of a bacterial shikimate kinase (SK). This expression elicited an increase in p-hydroxyphenyl units of lignin and, by contrast, a decrease in guaiacyl and syringyl units. Transgenic plants with high SK activity produced a lignin content comparable to that in wild-type plants, and had an increased processability via enzymatic saccharification. Although expression of many genes was altered in the transgenic plants, elevated SK activity did not exert a significant effect on the expression of the majority of genes responsible for lignin biosynthesis. The present results indicate that cytosolic shikimate recycling is crucial to the monomeric composition of lignin rather than for lignin content.
Substances chimiques
Alcohols
0
Phenylalanine
47E5O17Y3R
Lignin
9005-53-2
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Langues
eng
Sous-ensembles de citation
IM
Pagination
358-376Informations de copyright
© 2022 Society for Experimental Biology and John Wiley & Sons Ltd.
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