| 1. |
- Edwards, Kieron D., et al.
(författare)
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Circadian clock components control daily growth activities by modulating cytokinin levels and cell division-associated gene expression in Populus trees
- 2018
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Ingår i: Plant, Cell and Environment. - : John Wiley & Sons. - 0140-7791 .- 1365-3040. ; 41:6, s. 1468-1482
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Tidskriftsartikel (refereegranskat)abstract
- Trees are carbon dioxide sinks and major producers of terrestrial biomass with distinct seasonal growth patterns. Circadian clocks enable the coordination of physiological and biochemical temporal activities, optimally regulating multiple traits including growth. To dissect the clock's role in growth, we analysed Populus tremula x P. tremuloides trees with impaired clock function due to down-regulation of central clock components. late elongated hypocotyl (lhy-10) trees, in which expression of LHY1 and LHY2 is reduced by RNAi, have a short free-running period and show disrupted temporal regulation of gene expression and reduced growth, producing 30-40% less biomass than wild-type trees. Genes important in growth regulation were expressed with an earlier phase in lhy-10, and CYCLIN D3 expression was misaligned and arrhythmic. Levels of cytokinins were lower in lhy-10 trees, which also showed a change in the time of peak expression of genes associated with cell division and growth. However, auxin levels were not altered in lhy-10 trees, and the size of the lignification zone in the stem showed a relative increase. The reduced growth rate and anatomical features of lhy-10 trees were mainly caused by misregulation of cell division, which may have resulted from impaired clock function.
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| 2. |
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| 3. |
- Lakehal, Abdellah, et al.
(författare)
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ETHYLENE RESPONSE FACTOR 115 integrates jasmonate and cytokinin signaling machineries to repress adventitious rooting in Arabidopsis
- 2020
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Ingår i: New Phytologist. - : Wiley-Blackwell Publishing Inc.. - 0028-646X .- 1469-8137. ; 228, s. 1611-1626
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Tidskriftsartikel (refereegranskat)abstract
- Adventitious root initiation (ARI) is ade novoorganogenesis program and a key adaptive trait in plants. Several hormones regulate ARI but the underlying genetic architecture that integrates the hormonal crosstalk governing this process remains largely elusive. In this study, we use genetics, genome editing, transcriptomics, hormone profiling and cell biological approaches to demonstrate a crucial role played by the APETALA2/ETHYLENE RESPONSE FACTOR 115 transcription factor. We demonstrate that ERF115 functions as a repressor of ARI by activating the cytokinin (CK) signaling machinery. We also demonstrate thatERF115is transcriptionally activated by jasmonate (JA), an oxylipin-derived phytohormone, which represses ARI in NINJA-dependent and independent manners. Our data indicate that NINJA-dependent JA signaling in pericycle cells blocks early events of ARI. Altogether, our results reveal a previously unreported molecular network involving cooperative crosstalk between JA and CK machineries that represses ARI.
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| 4. |
- Parizkova, Barbora, et al.
(författare)
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iP & OEIP - Cytokinin Micro Application Modulates Root Development with High Spatial Resolution
- 2022
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Ingår i: Advanced Materials Technologies. - : Wiley. - 2365-709X. ; 7:10
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Tidskriftsartikel (refereegranskat)abstract
- State-of-the-art technology based on organic electronics can be used as a flow-free delivery method for organic substances with high spatial resolution. Such highly targeted drug micro applications can be used in plant research for the regulation of physiological processes on tissue and cellular levels. Here, for the first time, an organic electronic ion pump (OEIP) is reported that can transport an isoprenoid-type cytokinin, N-6-isopentenyladenine (iP), to intact plants. Cytokinins (CKs) are plant hormones involved in many essential physiological processes, including primary root (PR) and lateral root (LR) development. Using the Arabidopsis thaliana root as a model system, efficient iP delivery is demonstrated with a biological output - cytokinin-related PR and LR growth inhibition. The spatial resolution of iP delivery, defined for the first time for an organic compound, is shown to be less than 1 mm, exclusively affecting the OEIP-targeted LR. Results from the application of the high-resolution OIEP treatment method confirm previously published findings showing that the influence of CKs may vary at different stages of LR development. Thus, OEIP-based technologies offer a novel, electronically controlled method for phytohormone delivery that could contribute to unraveling cytokinin functions during different developmental processes with high specificity.
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