A Receptor-like Kinase Mediates the Response of Arabidopsis Cells to the Inhibition of Cellulose Synthesis
Abstract
A major challenge is to understand how
the walls of expanding plant cells are correctly assembled
and remodeled, often in the presence of walldegrading
micro-organisms. Plant cells, like yeast, react
to cell-wall perturbations as shown by changes in gene
expression, accumulation of ectopic lignin, and growth
arrest caused by the inhibition of cellulose synthesis.
Results:Wehave identified a plasma-membrane-bound
receptor-like kinase (THESEUS1), which is present in
elongating cells. Mutations in THE1 and overexpression
of a functional THE1-GFP fusion protein did not affect
wild-type (WT) plants but respectively attenuated and
enhanced growth inhibition and ectopic lignification in
seedlings mutated in cellulose synthase CESA6 without
influencing the cellulose deficiency. A T-DNA insertion
mutant for THE1 also attenuated the growth defect
and ectopic-lignin production in other but not all cellulose-
deficient mutants. The deregulation of a small number
of genes in cesA6 mutants depended on the presence
of THE1. Some of these genes are involved in
pathogen defense, in wall crosslinking, or in protecting
the cell against reactive oxygen species.
Conclusions: The results show that THE1 mediates the
response of growing plant cells to the perturbation of
cellulose synthesis and may act as a cell-wall-integrity
sensor.