Scientists throw light on the mechanism of plants' ticking clock

Jul 28, 2014
Scientists throw light on the mechanism of plants’ ticking clock

Scientists from the University of York are part of an international team of researchers who have made a significant step in discovering the genetic mechanisms that plants use to fight for light.

In a study published in the journal eLife they pinpoint a protein that plays a key role in the way the Circadian Clock – the internal mechanism which governs plants' daily cycles—can anticipate dark and light intensity and duration of light.

These internal clocks control how multiple genes are switched 'on' or 'off' at different times in every 24-hour period. Because light and ambient temperatures also vary with time of day, many organisms, including humans, use these external signals as cues to reset their own internal clocks. As daylight hours and temperature vary around the world, and with the seasons, plants and animals must be able to change how these external signals influence their internal clocks to enable them to stay in tune with the day/night cycle. However, it is not clear how they do this.

The researchers, from the Department of Biology at York working with colleagues from Max Plank Institute for Plant Breeding Research, explored this question by growing plants that were from a cross between two types of the model plant Arabidopsis thaliana from different environments—one from Germany, and the other from Tajikistan in Central Asia.

These offspring were also genetically engineered so that an enzyme that could give off light was produced under the control of the internal clock. The scientists found that the plants continued to glow and fade with an almost daily rhythm even after external cues, such as changes in temperature or light, had been removed.

Various offspring plants glowed and faded with different rhythms with some having, for example, a 21-hour day and others a 28-hour day. These distinctions were caused by many genes that differed from the original German and Tajikistan parent plants, and the researchers "mapped" one of these genetic differences to a single gene.

Offspring that inherited a version of a gene called ELF3 from the Tajikistan parent had internal clocks that ran faster when the plant was under the light. These plants also gradually stopped glowing as brightly as the German parent when they were kept in the dark, suggesting that their internal clocks were "ticking more softly". It was already known that the ELF3 gene affected the in plants, and the research team concluded that the plants with Tajikistan version of this gene—ELF3-Sha—were also less able to reset their to synchronize in response to .

The researchers also showed that the normal ELF3 protein is more likely to be found in the nucleus of a plant cell than the ELF3-Sha version, which might suggest that this protein is involved in switching genes off. Further research is now needed to uncover exactly how the ELF3 protein does this to keep the plant's internal clock "ticking" correctly.

One of the research team, Professor Seth Davis, of the Department of Biology at York and formerly of the Max Plank Institute for Plant Breeding Research, said: "The challenge now is to convert this fundamental research to change clock genes in crop plants so they can better respond to different environmental influences and mitigate the forces of climate change."

Explore further: Mycologist promotes agarikon as a possibility to counter growing antibiotic resistance

add to favorites email to friend print save as pdf

Related Stories

Internal clock, external light regulate plant growth

Jul 09, 2007

Most plants and animals show changes in activity over a 24-hour cycle. Now, for the first time, researchers have shown how a plant combines signals from its internal clock with those from the environment to show a daily rhythm ...

Plants tell time

Jun 04, 2013

Scientist Peter Freeman is managing a project that is probing the clock and metabolism of plants, called TiMet. Partners to the project include star biologists in the Germany, Spain, Switzerland and the UK, all working to gai ...

Recommended for you

YEATS protein potential therapeutic target for cancer

Oct 23, 2014

Federal Express and UPS are no match for the human body when it comes to distribution. There exists in cancer biology an impressive packaging and delivery system that influences whether your body will develop cancer or not.

Precise and programmable biological circuits

Oct 23, 2014

A team led by ETH professor Yaakov Benenson has developed several new components for biological circuits. These components are key building blocks for constructing precisely functioning and programmable bio-computers.

User comments : 0