Cell-wall remodelling is an important process required for plant growth and morphogenesis. Yet, little is known about the mechanisms by which this process influences plant development. In their study, Kay Schneitz and co-workers investigated the consequences of treating plants with the herbicide isoxaben, which disrupts cell wall integrity by depleting cellulose synthases from the cell wall. They found that isoxaben reduces the expression of the Arabidopsis cell fate determinant STRUBBELIG (SUB) and alters the architecture of SUB complexes at the plasma membrane. Moreover, inhibition of cellulose biosynthesis with isoxaben promotes increased endocytosis of SUB in epidermal cells of the root meristem, thus removing it from potential target proteins. To test whether isoxaben treatment affects cell fate decisions in Arabidopsis, the authors analysed root hair patterning in seedlings. They found that isoxaben induces similar root hair patterning defects to a sub mutant and causes misexpression of a root hair patterning reporter construct. Moreover, isoxaben treatment causes floral meristem and ovule defects. Notably, ectopic expression of SUB alleviates the isoxaben-induced defects in root hair patterning and flower development. Collectively, these findings argue that STRUBBELIG is a key factor linking cell wall remodelling to cell fate decisions in Arabidopsis.
