Publication details

Antibody-mediated modulation of cytokinins in tobacco: organ-specific changes in cytokinin homeostasis

Authors

GELOVÁ Zuzana TEN HOOPEN Petra NOVÁK Ondřej MOTYKA Václav PERNISOVÁ Markéta DABRAVOLSKI Siarhei DIDI Vojtěch TILLACK Isolde OKLEŠŤKOVÁ Jana STRNAD Miroslav HAUSE Bettina HARUŠTIAKOVÁ Danka CONRAD Udo JANDA Lubomír HEJÁTKO Jan

Type Article in Periodical
Magazine / Source Journal of Experimental Botany
MU Faculty or unit

Central European Institute of Technology

Citation
Doi http://dx.doi.org/10.1093/jxb/erx426
Keywords antibody-mediated modulation; biosynthesis; CKX; cytokinin; homeostasis; organ specificity; tobacco.
Description Cytokinins comprise a group of phytohormones with an organ-specific mode of action. Although the mechanisms controlling the complex networks of cytokinin metabolism are partially known, the role of individual cytokinin types in the maintenance of cytokinin homeostasis remains unclear. Utilizing the overproduction of single-chain Fv antibodies selected for their ability to bind trans-zeatin riboside and targeted to the endoplasmic reticulum, we post-synthetically modulated cytokinin ribosides, the proposed transport forms of cytokinins. We observed asymmetric activity of cytokinin biosynthetic genes and cytokinin distribution in wild-type tobacco seedlings with higher cytokinin abundance in the root than in the shoot. Antibody-mediated modulation of cytokinin ribosides further enhanced the relative cytokinin abundance in the roots and induced cytokinin-related phenotypes in an organ-specific manner. The activity of cytokinin oxidase/dehydrogenase in the roots was strongly up-regulated in response to antibody-mediated formation of the cytokinin pool in the endoplasmic reticulum. However, we only detected a slight decrease in the root cytokinin levels. In contrast, a significant decrease of cytokinins occurred in the shoot. We suggest the roots as the main site of cytokinin biosynthesis in tobacco seedlings. Conversely, cytokinin levels in the shoot seem to depend largely on long-range transport of cytokinin ribosides from the root and their subsequent metabolic activation.
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