July 25, 2017
Joint research by RIKEN CSRS and Nagoya University has revealed a new plant hormone transport mechanism for plant growth.
Cytokinins play an important role in root-to-shoot long-distance signaling. It was believed that trans-zeatin-riboside, a cytokinin precursor, is a major translocation form via xylem and its action depends on metabolic conversion to active form trans-zeatin in proximity to the site of action
Researchers found that both forms of cytokinin—precursor and active—are transported and controls different set of shoot traits. Specifically, root-to-shoot translocation of trans-zeatin mainly controls leaf size, whereas that of trans-zeatin riboside is sufficient for regulating leaf size and also rate of leaf formation. They also found the transport ratio of these two forms can be changed in response to nitrogen nutritional condition in the rhizosphere.
Because this dual signaling system allows plants to fine-tune the manner of shoot growth to adapt to fluctuating environments such as nitrogen levels, these findings are expected to contribute to production technologies for environmentally resilient crops that will provide full yields even when fertilizer application has been reduced.
Nature Plants doi:10.1038/nplants.2017.112
A. Osugi, M. Kojima, Y. Takebayashi, N. Ueda, T. Kiba, H. Sakakibara,
"Systemic transport of trans-zeatin and its precursor have differing roles in Arabidopsis shoots".
Hitoshi Sakakibara: Group Director
Takatoshi Kiba: Research Scientist
Plant Productivity Systems Research Group