Why do you think your paper is highly cited?

Cytokinins are essential plant hormones that have long been known to control diverse processes of plant growth and development, but the mechanisms underlying the actions of cytokinins have largely remained elusive.  Our paper is highly cited probably because, for the first time, we were able to decipher a core cytokinin signaling pathway in its entirety from putative receptors to a target nuclear gene.

  Does it describe a new discovery or a new methodology that's useful to others?

The paper establishes a valuable framework for examining the actions of cytokinin during plant development.  The physiological single-cell protoplast system we developed will provide useful tools to elucidate other signaling pathways mediated by two-component circuitry in plants.

  What were some of the circumstances that led you to do this research?

The implication of the putative histidine kinases in cytokinin signaling and the finding of cytokinin-inducible response regulator genes led us to test the possibility that a two-component system may activate cytokinin signal transduction in plants.  However, most of all, the completion of the Arabidopsis genome sequence had enabled us to test the hypothesis by performing efficient functional analysis of the two-component regulators.

  Could you summarize the significance of your paper in layman's terms?

Our research has revealed how the plant hormone cytokinin regulates plant growth and development at the molecular level. Plants use a short signaling circuitry to mediate cytokinin signaling from the plasma membrane to the nucleus.  This pathway consists of receptors, shuttle proteins, and nuclear transcriptional factors, and appears to be central in controlling diverse cytokinin functions in cell division, shoot initiation, leaf formation and senescence in most plant species.  It is now possible to manipulate the genes involved in cytokinin signaling to generate desirable traits in cereal and horticultural crops, including high productivity and prolonged shelf life.

Ildoo Hwang
Assistant Professor
Department of Life Science 
Pohang University of Science and Technology
Pohang, Korea