Abstract
In higher plant cells, it is well known hypotheses that cortical microtubules regulate direction of cellulose microfibril deposition in the cell wall, and that the direction of cellulose microfibrils forms and maintains the cell shape, however, the mechanisms how the cellulose microfibril deposition pattern is regulated are still unclear. Previously, from chemical genetic approach we had identified a novel inhibitor, cobtorin, that perturbed the parallel alignment between the cortical microtubules and the cellulose microfibrils. In this study, we analyze a target of cobtorin by genetic resistant line screening from Arabidopsis FOX hunting library. From the screening, three cobtorin resistant genes were obtained; a lectin family protein, a polygalacturonase and a pectin methylesterase. Also addition of polygalacturonase rescued the cobtorin phenotype. On the other hand, overexpression of pectin synthase elevated the sensitivity to cobtorin. Furthermore cobtorin treatment induced abnormal pectin distribution. These data may indicate that the target of cobtorin is pectin or pectin related-compound in cell wall. We will discuss the role of pectin on cellulose microfibril deposition.
