The Importance of Plant Hormone Cytokinin “QUALITY” Revealed

November 26, 2013

Side-Chain Modification of Cytokinin defines the Function

A research group at the RIKEN CSRS revealed that the function of the plant hormone cytokinin depends not only on changes in quantity but also in quality, which is generated by side-chain modification of cytokinins.

Cytokinins, a class of plant hormones, are central regulators of plant growth and development. The group was searching for enzyme genes responsible for making the side-chain modifications to synthesize trans-zeatin (tZ)-type cytokinins. They succeeded in identifying CYP735A1 and CYP735A2 as such genes. Analysis of a mutant of CYP735A activity, which is deficient in tZ-type cytokinins, revealed that the tZ-type cytokinins promote shoot growth, whereas cytokinins without sid- chain modification do not. These results show that the side-chain modification of cytokinin is crucial for shoot growth regulation in plants.

Elucidation of this new mechanism is expected to pave the way for development of novel technologies to increase crop harvests and biomass production.

Original article
Developmental Cell
T. Kiba, K. Takei, M. Kojima, H. Sakakibara,
"Side-chain Modification of Cytokinins Control Shoot Growth in Arabidopsis".
Hitoshi Sakakibara: Group Director
Takatoshi Kiba: Research Scientist
Plant Productivity Systems Research Group