Cambridge plant scientists say the circadian clock genes, which allow plants to measure daily and seasonal rhythms, should be targeted in agriculture and plant breeding for higher yields and more sustainable farming.
Like humans, plants have an “internal clock” that monitors the rhythms of their environment. The authors of a study published today say that now the genetic basis of this circadian system is well understood and that there are improved genetic tools to modify it, the clock should be harnessed in agriculture – a process they qualify as “ chronoculture ” – to contribute to global food security.
“We live on a rotating planet, and this has a huge impact on our biology – and on the biology of plants. We have found that plants grow much better when their internal clock is adapted to the environment in which they are growing.” said Professor Alex Webb, chair of cell signaling in the Department of Plant Sciences at the University of Cambridge and lead author of the report.
A plant’s circadian clock plays an important role in regulating many functions that affect yield, including flowering time, photosynthesis, and water use. The genes controlling the circadian rhythm are similar in all major crop plants – making them a potential target for breeders wishing to gain more control over these functions.
Chronoculture could also be applied by adapting cultural practices to the optimum time of day, in order to reduce the resources required. The study is published today in the journal Science.
The simplest and easiest approach, scientists say, would be to use knowledge of a crop’s internal clock to apply water, herbicides or pesticides at the most efficient time of day. day or night. Low-cost technologies, including drones and sensors, could collect information around the clock on the growth and health of plant crops. Farmers could then receive advice on the best time to apply treatments to their specific crop, for their precise location and weather conditions.
“We know from laboratory experiments that watering plants or applying pesticides can be more effective at certain times of the day, which means farmers could use less of these resources. It’s a simple victory that could save money and contribute to sustainability, ”says Webb.
He added: “Using water more efficiently is an important sustainability goal for agriculture.”
Webb says that indoor “vertical farming” could also be improved by using time-cultivation. The approach, mainly used for leafy greens today, grows crops under highly controlled light and temperature conditions, but can also be very energy intensive. With knowledge of a plant’s internal clock and the ability to change it through genetic modification, the lighting and heating cycles could be tailored to the plant for highly efficient growth.
“In vertical agriculture, time-cultivation could give full control over the crop. We could select specific crop plants with internal clocks suitable for indoor growing, and optimize the light and temperature cycles for them,” explains Webb.
A third potential application of time culture is postharvest, when plants slowly deteriorate and continue to be eaten by pests. There is good evidence that pest damage can be reduced by maintaining the internal rhythms of harvested plants.
“Plant responses to pests are optimized – they are more resistant to pests at the time of day when the pests are active,” explains Webb. “So just a simple light in the refrigeration truck on and off to mimic the day / night cycle would use the plant’s internal clock to help improve storage and reduce waste.”
Researchers say that by selecting plants with special characteristics such as late flowering for higher yield, crop breeders have already unwittingly chosen plants with the most appropriate internal clock. A new understanding of the genes involved in the clock could make this type of selection much more targeted and efficient.
Webb says there are plenty of opportunities for time farming to make food production more sustainable. The specifics would be different for each location and each culture, and this is where more research is needed now. He is convinced that this approach can be part of the solution to sustainably feed our growing population.
It has been estimated that we will have to produce more food over the next 35 years has never been produced in human history, given the projected increases in the world’s population and the change in diets as incomes increase.
A similar idea is now being applied in human medicine: “Chronomedicine” discovers that drugs are most effective when taken at a specific time of day.