The rhythm of life: researching circadian clocks
Issued: Mon, 07 Nov 2011 08:28:00 GMT
From ensuring the perfect bouquets on Mother's Day to maximising the harvesting period of potatoes, Professor Hugh Nimmo's research on the circadian clock is set to help us adapt to our ever-changing environment.
Life has evolved on a rotating Earth with alternating periods of light and darkness. As a result, most organisms have circadian clocks that allow them not only to respond to environmental changes but to anticipate them as well. While humans experience effects of the circadian clock through jet lag and shift work, plants also have an internal timekeeper, which helps them to effectively carry out their daily processes, as Professor Nimmo explains:
'Plants need to be ready to start photosynthesis as soon as the sun comes up in the morning, when the light comes on. To do this a plant has to get ready for photosynthesis during the dark. It has to “know” that the light is going to come on and that's what the circadian clock allows. It provides a timing device, which the cell can then use to control what it is doing.'
Until now it has been widely accepted that all plant cells contain essentially identical circadian clocks, all synchronised in the same way by light but running independently of each other, with no communication between different cells or organs. However, by studying mature plant roots and shoots separately, Professor Nimmo and his team have recently disproved this theory.
The study shows that in plant roots the clock mechanism is surprisingly different from that in shoots, with the period of the root clock being about 1.5 hours longer than the period of the shoot clock. In constant conditions created in the laboratory the roots lag progressively further behind the shoots. However, under normal day/night conditions, the shoots send a daily signal that synchronises the root clock, so the plant is properly coordinated.
Professor Nimmo's advances in the understanding of circadian clocks could help support the agricultural industry in developing techniques to improve crop yields in changing growing conditions:
'Given that we are in the age of global environmental change, I think it is pretty certain that the relation between temperature, day length and rainfall is going to change quite remarkably over the next 10 to 50 years. As a result, the information from basic science has to be used in plant breeding to get the right combination of properties into plants that will allow them to maximise their potential at any particular geographic location.'
An example of how ability to manipulate the circadian clock in plants could prove advantageous commercially is in potatoes. The growth of a tuber, the part of the potato we eat, follows a similar process to flowering in plants. Ancestral potatoes originally came from the Andes, and as a result tend only to tuberise in short-day environments. In order to expand this range, an understanding of how to alter a potato's circadian clock is required.
Professor Nimmo is collaborating with a group studying potatoes at the James Hutton Institute and is also in the process of applying for funding from the Biotechnology & Biological Sciences Research Council, with backing from the British Potato Council, to further this research, which could be of major benefit to the agricultural industry.