Study Shows Plants Regulate Growth-Inhibiting Hormones to Survive

Scientists from Nagoya University have, for the first time, observed one of the natural mechanisms in the regulation of the levels of growth inhibiting hormone in plants. Previously observed in bacteria, its discovery in plants will enable novel ways of increasing crop productivity globally. Using rice plants, the research team discovered that a process called "allosteric regulation" is involved in maintaining the phytohormonal balance in plants. Their research findings could significantly advance the research on plant growth and development, providing a potential solution for food security.

Lead scientist Professor Miyako Ueguchi-Tanaka of Nagoya University explains that they used X-ray crystallography. They found that, as molecules of the enzymes (gibberellin 2-oxidase 3 [GA2ox3], and auxin dioxygenase [DAO]) bind to gibberellin and auxin (respectively), they interact among themselves and form 'multimeric' structures, comprising four and two units, respectively. As the amounts of gibberellin and auxin increase, so does the rate of multimerization of the enzymes. And multimerization enhances the activity of the enzymes, enabling greater degradation of gibberellin and auxin. She adds that synchronous structural changes and activity enhancement are typical of allosteric-regulation events.

The research team further carried out "phylogenetic" analysis of GA2ox3 and DAO, and they discovered that plants independently developed this hormone regulation mechanism at three separate time-points over the course of the evolutionary process.

For more details, read the news article on the Nagoya University website.