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Title: Flavonol rhamnosylation indirectly modifies the cell wall defects of RHAMNOSE BIOSYNTHESIS1 mutants by altering rhamnose flux
Summary

Rhamnose is required inArabidopsis thalianafor synthesizing pectic polysaccharides and glycosylating flavonols.RHAMNOSE BIOSYNTHESIS1(RHM1) encodes aUDPl‐rhamnose synthase, andrhm1mutants exhibit many developmental defects, including short root hairs, hyponastic cotyledons, and left‐handed helically twisted petals and roots. It has been proposed that the hyponastic cotyledons observed inrhm1mutants are a consequence of abnormal flavonol glycosylation, while the root hair defect is flavonol‐independent. We have recently shown that the helical twisting ofrhm1petals results from decreased levels of rhamnose‐containing cell wall polymers. In this study, we found that flavonols indirectly modify therhm1helical petal phenotype by altering rhamnose flux to the cell wall. Given this finding, we further investigated the relationship between flavonols and the cell wall inrhm1cotyledons. We show that decreased flavonol rhamnosylation is not responsible for the cotyledon phenotype ofrhm1mutants. Instead, blocking flavonol synthesis or rhamnosylation can suppressrhm1defects by divertingUDPl‐rhamnose to the synthesis of cell wall polysaccharides. Therefore, rhamnose is required in the cell wall for normal expansion of cotyledon epidermal cells. Our findings suggest a broad role for rhamnose‐containing cell wall polysaccharides in the morphogenesis of epidermal cells.

 
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PAR ID:
10056271
Author(s) / Creator(s):
 ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
The Plant Journal
Volume:
94
Issue:
4
ISSN:
0960-7412
Page Range / eLocation ID:
p. 649-660
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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