Science - October 4, 2017

Biological clock: from Nobel Prize to glasshouse plants

Text:
Albert Sikkema

The Nobel Prize in Physiology or Medicine has been awarded this week jointly to three American researchers who have elucidated the working of the biological clock. Plant physiologist Sander van der Krol teaches Wageningen students on this subject and uses knowledge of the clock to regulate the growth of plants in glasshouses.

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The American researchers Jeffrey C. Hall, Michael Rosbash and Michael W. Young were able to isolate a gene in fruit flies that regulates the body’s rhythm of day. But it’s a bit more complex than that, explains Van der Krol. ‘They have unravelled the mechanism of the biological clock in plants and animals. Thanks to their research into the fruit fly’s biological clock, we now also understand how that clock works in other organisms. They were the first to find a gene that forms part of the clock, and they have discovered a feedback mechanism in which this gene inhibits its own synthesis. Upon further investigation, they also found steps that delayed this feedback mechanism. These delays in the feedback are necessary to achieve a 24-hours cycle. In this, they have mapped the structure of the biological clock for all organisms.’

Jet lag
Like humans, plants have a biological clock which reacts to light and temperature, teaches Van der Krol. ‘When our body’s rhythm is disrupted by jet lag, due to travelling to Australia for example, the light cycle realigns our biological clock. The Nobel Prize laureates have set the foundation of knowledge about the way environmental factors influence the biological clock.’

Van der Krol recently finished a research project with 35 horticultural farms in which he demonstrated how disrupting the clock of plants in glasshouses can allow for control of their growth. The aim is to keep plants compact. A compact plant not only looks better, but is also easier to transport, as more plants can be stored per square metre of a truck.

Immune systeme
In the follow-up project, Van der Krol uses this knowledge to find new combinations of light and temperature that will lead to more efficient methods of keeping the glasshouse plants compact. ‘Meanwhile, we are also learning how the plants choose between investing in growth or their immune system through the clock. This means that we might also be able to improve the immunity of plants by influencing their biological clock.’ The best part of these treatments is that the effects are temporary and the plants go back to their normal patterns afterwards.

Lecture
This week, Van der Krol will be lecturing on the biological clock in plants and animals as part of the Ecofysiologie course. He uses movies that beautifully explain the research of the Nobel Prize laureates. Coincidentally, Van der Krol knows Michael Young, as he worked at Rockefeller University for four years, where Young is a professor. This is also the university where the research into the biological clock in plants had started years ago.

He fully agrees with the choice to award them the Nobel Prize. ‘They have found a fundamental mechanism that is of great importance for medicine, biology, ecology and agriculture.’


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