Characterization of Arabidopsis thaliana mutant ror-1 (roscovitine-resistant) and its utilization in understanding of the role of cytokinin N-glucosylation pathway in plants

Dwivedi S., Vaňková R., Motyka V., Herrera C., Žižková E., Auer C.

Klíčová slova: cytokinin metabolism, N-glucosyltransferase, GRAM domain, aromatic cytokinins, roscovitine
Abstrakt: Cytokinin analogue roscovitine exhibits a strong inhibitory effect on cytokinin N-glucosylation, one of the most important pathways of cytokinin inactivation in plants. Roscovitine-resistant mutant. (ror-1) was isolated using TDNA tagged lines of Arabidopsis thaliana (L.) Heynh in order to find a gene putatively involved in cytokinin N-glucosylation. The amount of cytokinin N-glucosides of transzeatin- and isopentenyladenine-type was elevated by 20% in ror-1 mutant compared to WT. The cytokinin oxidase/ dehydrogenase activity exhibited a mild elevation in ror-1 compared to WT in basal media. Additionally, ror-1 plants showed slightly enhanced resistance to exogenously supplied aromatic cytokinins (benzyladenine). Incubation with exogenous cytokinin (5 lM BA for 24 h) resulted in significant up-regulation of ROR-1 gene expression in ror-1 mutant. In silico analysis showed that ROR-1 gene encoded for a protein consisting of GRAM (Glycosyltransferases Rab-like GTPase activators and Myotubularins) and C2 domains. Here, we report on the role of ROR-1 gene in metabolism of bioactive cytokinins in the plants.
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