S04 - Session O1 - New diphenylurea-derived cytokinin oxidase/dehydrogenase inhibitors for plant tissue culture

Authors: Stefaan Werbrouck *, Nino Murvanidze, Jaroslav Nisler

One of the mechanisms regulating local cytokinin homeostasis in in vitro plants is their degradation by cytokinin oxidase/dehydrogenase (CKX). Recently, a new class of potent inhibitors of these enzymes was developed, mainly derived from diphenyl urea. The range of derivatives synthesised was very broad. Before applying them in micropropagation systems, they were first tested on CKX isoforms from maize and Arabidopsis. The best compounds showed IC50 values in the concentration range of 10-8 M. We showed that these compounds, unlike TDZ or CPPU do not possess intrinsic cytokinin activity, but only protect isoprenoid cytokinins from oxidation. The success of their application in vitro depends on the compound and the plant species. A number of early results will be demonstrated, ranging from shoot meristem induction to somatic embryogenesis. They appear to be promising new tools for use in plant tissue culture and biotechnology.