The members of the casein kinase 1 (CK1) subfamily are distinguished by interspecific conservatism and an extensive set of phosphorylation substrates. Recently, appeared strong evidence that CK1 are able to phosphorylate tubulin directly. Thus, CK1 contribute to the tubulin code and functional specialization of microtubules. In this work, we present the results of studying the response of plant tubulin cytoskeleton to the treatment with the CK1-specific inhibitor D4476. It was demonstrated that D4476 shows a strong dose-dependent effect on Arabidopsis thaliana root growth and morphology. The experiments on the plants expressing chimeric gfp-map4 gene construct proved the relation of the observed morphological reactions with the spatial organization of microtubules caused by a selective inhibition of protein kinases CK1.