Very high levels of sunlight can be hazardous to plants, overwhelming their ability to photosynthesise. This effect is exaggerated when there is a shortage of water or extreme temperatures. The resulting damage to the delicate photosynthetic membranes in the plant leads to impaired growth, cell destruction and, eventually, plant death. The scientists, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), have found that plants are able to turn unwanted absorbed light into heat by altering the structure of one of the proteins in these membranes. This unique nanoscale safety valve prevents plant damage by harmlessly dissipating the lethal excess radiation. This photoprotective process was found to be aided by a special carotenoid molecule called zeaxanthin and plants with higher levels of this molecule appear to be better protected.
Professor Peter Horton, research leader at the University of Sheffield, said, "Plants use a range of processes to adapt to harsh and potentially damaging environmental conditions. We are beginning to understand the mechanisms plants have at a molecular level to prevent damage from excess sunlight. We hope that this knowledge could be used to improve photosynthesis rates, and therefore productivity, in staple crops that feed millions in parts of the world where environmental conditions can be particularly harsh."
Professor Horton continued, "To fully apply this research to improving the productivity of crops we need to understand how these processes relate to plant growth and development in field conditions. Processes that may appear important in the laboratory may not be in the varied conditions of the field."
The researchers have been working with agricultural institutes in South America and the Asia to start to work out how their knowledge of the defence mechanisms in model plants such as Arabidopsis could be used to improve the photosynthesis rates of staple crops such as rice and the common bean.
Professor Julia Goodfellow, BBSRC Chief Executive, commented, "This demonstrates how research into fundamental biological processes has the potential to have a big impact on people's lives around the world. Many research projects supported by BBSRC provide fundamental information that can underpin improvements in staple crops both in the UK, as we face the effects of climate change, and overseas, where it can aid sustainable agriculture and improve food security."