New cytokinin metabolites in IPT transgenic Arabidopsis thaliana plants

Werner, Tomáš; Hanuš, Jan; Holub, Jan; Schmülling, T.; Onckelen, H. V.; Strnad, Miroslav
PHYSIOLOGIA PLANTARUM 118 [1]: 127-137, 2009

Klíčová slova: transgenic Arabidopsis thaliana * cytokinin * zeatin-O-glucoside
Abstrakt: Two novel cytokinin metabolites were identified in transgenic Arabidopsis thaliana (L.) Heynh. plants containing the bacterial IPT gene under the transcriptional control of a heat-regulated promoter. After cyclic heat-shock treatment, the endogenous cytokinin concentrations were elevated up to 100-fold compared to the wild-type plants. More then 20 different cytokinin metabolites were found, with zeatin-type cytokinins being the most abundant. The metabolic inactivation of these compounds occurred predominantly through N-glucosylation. No significant accumulation of isopentenyladenine-type cytokinins, and only a small increase in dihydrozeatin metabolites, was observed. Subsequent studies of the abundant, unidentified conjugates revealed the presence of zeatin and dihydrozeatin diglucoside conjugates. Structural analysis, utilizing electrospray-liquid tandem mass spectrometry, identified these as a zeatin-O-glucoside-9-glucoside and dihydrozeatin-O-glucoside-9-glucoside, respectively. A third unknown metabolite, was tentatively identified as a phosphorylated form of zeatin-9-glucoside.
Autoři z ÚEB: Miroslav Strnad