High-order mutants reveal an essential requirement for peroxidases but not laccases in Casparian strip lignification.

Details

Serval ID
serval:BIB_D25F07AB3F66
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
High-order mutants reveal an essential requirement for peroxidases but not laccases in Casparian strip lignification.
Journal
Proceedings of the National Academy of Sciences of the United States of America
Author(s)
Rojas-Murcia N., Hématy K., Lee Y., Emonet A., Ursache R., Fujita S., De Bellis D., Geldner N.
ISSN
1091-6490 (Electronic)
ISSN-L
0027-8424
Publication state
Published
Issued date
17/11/2020
Peer-reviewed
Oui
Volume
117
Number
46
Pages
29166-29177
Language
english
Notes
Publication types: Journal Article
Publication Status: ppublish
Abstract
Lignin has enabled plants to colonize land, grow tall, transport water within their bodies, and protect themselves against various stresses. Consequently, this polyphenolic polymer, impregnating cellulosic plant cell walls, is the second most abundant polymer on Earth. Yet, despite its great physiological, ecological, and economical importance, our knowledge of lignin biosynthesis in vivo, especially the polymerization steps within the cell wall, remains vague-specifically, the respective roles of the two polymerizing enzymes classes, laccases and peroxidases. One reason for this lies in the very high numbers of laccases and peroxidases encoded by 17 and 73 homologous genes, respectively, in Arabidopsis Here, we have focused on a specific lignin structure, the ring-like Casparian strips (CSs) within the root endodermis. By reducing candidate numbers using cellular resolution expression and localization data and by boosting stacking of mutants using CRISPR-Cas9, we mutated the majority of laccases in Arabidopsis in a nonuple mutant-essentially abolishing laccases with detectable endodermal expression. Yet, we were unable to detect even slight defects in CS formation. By contrast, we were able to induce a complete absence of CS formation in a quintuple peroxidase mutant. Our findings are in stark contrast to the strong requirement of xylem vessels for laccase action and indicate that lignin in different cell types can be polymerized in very distinct ways. We speculate that cells lignify differently depending on whether lignin is localized or ubiquitous and whether cells stay alive during and after lignification, as well as the composition of the cell wall.
Keywords
Casparian strip, cell wall, endodermis, lignin, roots
Pubmed
Open Access
Yes
Create date
09/11/2020 9:04
Last modification date
23/11/2020 6:24
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