By manipulating the CHLORAD pathway, scientists can modify how plants respond to their environment. For example, the plant's ability to tolerate stresses such as high salinity can be improved.
The researchers hope that their results, published in Science, will open the way to new crop improvement strategies, which will be vital as we face the prospect of delivering food security for a population that is projected to reach nearly 10 billion by 2050.
The CHLORAD pathway helps to regulate structures inside plant cells called chloroplasts. Chloroplasts are the organelles that define plants. Along with many other metabolic, developmental and signalling functions, chloroplasts are responsible for photosynthesis - the process whereby sunlight energy is harnessed to power the cellular activities of life.
Consequently, chloroplasts are essential, not only for plants but also for the myriad ecosystems that depend on plants, and for agriculture.
Chloroplasts are composed of thousands of different proteins, most of which are made elsewhere in the cell and imported by the organelle. These proteins must all be very carefully regulated to ensure that the organelle keeps functioning properly. The CHLORAD pathway works by removing and disposing of unnecessary or damaged chloroplast proteins; hence the name CHLORAD, which stands for "chloroplast-associated protein degradation".
Professor Paul Jarvis, lead researcher, said: 'Two decades on from the identification of the chloroplast protein import machinery - which delivers new proteins to chloroplasts - our discovery of the CHLORAD pathway reveals for the first time how individual, unwanted proteins are removed from chloroplasts.'
Researcher, Dr Qihua Ling, said: 'Our previous studies showed that proteins in the chloroplast membranes are digested by a protein degradation system outside of chloroplasts. So, the key question was: How are chloroplast proteins extracted from the membrane to enable this to happen? Our discovery of the CHLORAD system answers this question, and we identified two novel proteins that act in the process.'
Co-researcher, Dr William Broad, added: 'Chloroplasts are eukaryotic organelles that originated more than a billion years ago from photosynthetic bacteria, by a process called endosymbiosis. Remarkably, the CHLORAD system contains a mix of components of eukaryotic origin and bacterial origin. This provides a fascinating example of how eukaryotic host cells have evolved gradually, co-opting available tools in novel ways, to govern their endosymbiotic organelles.'
Peter Burlinson, Frontier Bioscience Lead at the Biotechnology and Biological Sciences Research Council, said: 'The discovery of this biochemical pathway is a good example of how insights from fundamental plant biology research can reveal potential new strategies to develop crops that are more productive and resilient. This helps illustrate the value of basic science in contributing to addressing key global challenges including a rising global population, environmental stresses and an increased demand to deliver food security.'
By the year 2050, the current level of food production must increase by at least 70% to meet the demands of a growing world population and shifting dietary preferences towards more animal products, while 38% of the world's land and 70% of fresh water are already used for agriculture. Abiotic stresses, including drought, high and low temperatures, soil salinity, nutrient deficiencies, and toxic metals, are the leading cause of yield loss, decreasing crop productivity by 50-80% depending on the crop and geographical location.
Thus, developing stress-resistant crops that can have stable yields under stress conditions is an important strategy to ensure future food security. This need is particularly urgent considering the increased frequency of extreme weather conditions that accompany global climate change, which cause more severe environmental stresses, more frequent plant disease outbreaks, and reduced yield and harvest quality.
Oxford University Innovation (OUI), the University's research commercialisation arm, is managing the technology.
For more information and interview requests please contact the University of Oxford press office at email@example.com / 01865 280730.
After the embargo lifts the paper will be available here: http://science.
Please contact the Science press package team at 202-326-6440 or firstname.lastname@example.org to receive an official version of the paper.
Notes to editors
About Oxford University
Oxford University has been placed number 1 in the Times Higher Education World University Rankings for the third year running, and at the heart of this success is our ground-breaking research and innovation.
Oxford is world-famous for research excellence and home to some of the most talented people from across the globe. Our work helps the lives of millions, solving real-world problems through a huge network of partnerships and collaborations. The breadth and interdisciplinary nature of our research sparks imaginative and inventive insights and solutions.
Through its research commercialisation arm, Oxford University Innovation, Oxford is the highest university patent filer in the UK and is ranked first in the UK for university spinouts, having created more than 170 new companies since 1988. Over a third of these companies have been created in the past three years.
About Oxford University Innovation
Oxford University Innovation supports innovation activities across all University Divisions, managing technology transfer and consulting activities, and creating a world-leading innovation ecosystem, with Oxford University at its heart.
We provide access to technology from Oxford researchers through intellectual property licensing, spinout company formation and material sales, and to academic expertise through our Consulting Services team. The New Venture Support & Funding team supports investors or donors with an interest in early-stage ventures, and manages the Oxford Angels Network.
Our Startup Incubator supports members and ex-members of the University who wish to start or grow entrepreneur-driven ventures that are not University spinouts.
Oxford University Innovation is the highest university patent filer in the UK and is ranked 1st in the UK for university spinouts, having created over 170 new companies since 1988. In the 2016/17 financial year we completed more than 50 licenses and consulting agreements every month. For updates on innovations from Oxford, follow Oxford University Innovation on LinkedIn and Twitter or subscribe at http://innovation.