[The effect of okadaic acid on root morphology of Arabidopsis thaliana and microtubule organization in its cells].

To investigate the functional role of protein hyperphosphorylation in plant cells the general morphology of Arabidopsis thaliana primary roots and structural-functional property of cortical microtubules were studied after treatment with okadaic acid, specific inhibitor of protein phosphatases PPI and PP2A. It has been estimated that okadaic acid affects microtubule organization in a different manner depending from the type of the cells and functional zones of the primary root. It was found that the microtubules in epidermis and cortex cells of distal elongation zone which depolymerized after inhibitor treatment were the most sensitive to 0, 1, 1 and 10 nM okadaic acid concentrations. In trichoblasts, antichoblasts and cortex cells of differentiation zone treatment with okadaic acid caused the microtubules stabilization. Okadaic acid influences were particularly evident in root hair morphology, root hairs swelling and branching as a result of abnormal microtubules orientation observed. According to the data obtained, we can suggest that induction of protein hyperphosphorylation as a result of protein phosphatase inhibition plays crucial key in plant cell microtubule organization.