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Cytokinin-Deficient Transgenic Arabidopsis Plants Show Multiple Developmental Alterations Indicating Opposite Functions of Cytokinins in the Regulation of Shoot and Root Meristem Activity
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SYSNO ASEP 0172358 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Ostatní články Title Cytokinin-Deficient Transgenic Arabidopsis Plants Show Multiple Developmental Alterations Indicating Opposite Functions of Cytokinins in the Regulation of Shoot and Root Meristem Activity Author(s) Werner, T. (DE)
Motyka, Václav (UEB-Q) RID, ORCID
Laucou, V. (FR)
Smets, R. (BE)
Onckelen, H. V. (BE)
Schmülling, T. (DE)Source Title Plant Cell. - : Oxford University Press - ISSN 1040-4651
Roč. 15, č. 11 (2003), s. 2532-2550Number of pages 19 s. Language eng - English Country US - United States Keywords Transgenic Arabidopsis Plants ; Cytokinins ; Root Meristem Activity Subject RIV EB - Genetics ; Molecular Biology R&D Projects IAA6038002 GA AV ČR - Academy of Sciences of the Czech Republic (AV ČR) CEZ AV0Z5038910 - UEB-Q Annotation Cytokinins are hormones that regulate cell division and development. As a result of a lack of specific mutants and biochemical tools, it has not been possible to study the consequences of cytokinin deficiency. Cytokinin-deficient plants are expected to yield information about processes in which cytokinins are limiting and that, therefore, they might regulate. We have engineered transgenic Arabidopsis plants that overexpress individually six different members of the cytokinin oxidase/dehydrogenase (AtCKX) gene family and have undertaken a detailed phenotypic analysis. Transgenic plants had increased cytokinin breakdown (30 to 45% of wild-type cytokinin content) and reduced expression of the cytokinin reporter gene ARR5:GUS (-glucuronidase). Cytokinin deficiency resulted in diminished activity of the vegetative and floral shoot apical meristems and leaf primordia, indicating an absolute requirement for the hormone. By contrast, cytokinins are negative regulators of root growth and lateral root formation. We show that the increased growth of the primary root is linked to an enhanced meristematic cell number, suggesting that cytokinins control the exit of cells from the root meristem. Different AtCKX-green fluorescent protein fusion proteins were localized to the vacuoles or the endoplasmic reticulum and possibly to the extracellular space, indicating that subcellular compartmentation plays an important role in cytokinin biology. Analyses of promoter:GUS fusion genes showed differential expression of AtCKX genes during plant development, the activity being confined predominantly to zones of active growth. Our results are consistent with the hypothesis that cytokinins have central, but opposite, regulatory functions in root and shoot meristems and indicate that a fine-tuned control of catabolism plays an important role in ensuring the proper regulation of cytokinin functions. Workplace Institute of Experimental Botany Contact David Klier, knihovna@ueb.cas.cz, Tel.: 220 390 469 Year of Publishing 2004
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