description
- As climate changes, many crops will be exposed to conditions of abiotic stress that will limit yield, and so compromise food security. Depedning on region, such stresses include more frequent high temperature, changing rainfall (leading to drought or flooding), increased salinity (due to sea level rise or the use of poor-quality irrigation water), and high light stress due altered cloud cover. Strategies for mitigating these effects of environmental change include conventional plant breeding and genetic manipulation. The former is generally slow while the latter, although potentially more rapid, remains unacceptable to the public in many parts of the world, include the UK and most EU countries. Thus, for food production in much of the EU, neither of these strategies is likely to deliver effective mitigation in the short-medium term. A third strategy is to exploit advances in the understanding of plant signalling in response to abiotic stress to develop new growth enhancers that are targeted specifically at improving crop responses to abiotic stress. This proposal is based on one such novel growth enhancer, the 'Alethea technology' developed by the industrial partner, Plant Impact Plc. Field data obtained by Plant Impacts plc shows that Alethea can significantly increase the yield of many crops growing under abiotic stress, including wheat grown under water deficits, tomatoes under elevated salinity and cherries grown under high-light stress (at altitude in the sub-tropics). Initially controlled environment studies conducted jointly by Plant Impact and LEC staff have begun to reveal some of the underlying mechanisms of Alethea action. Initial data for in situ gas exchanges show that Alethea protects photosynthesis in crops irrigated with saline irrigation water, with consistent significant improvements in both net photosynthesis and stomatal conductance, and improved water use efficiency. Plant Impact is now funding a post-doctoral researcher within LEC who is investigating the effects of Alethea on gene expression under salt stress, using tomato as a model crop. The project proposed here will build on these preliminary data, extending existing studies on salt to allow the student to consider the effects of Alethea treatment on plant responses to oxidative stress. Oxidative stress, the overproduction of reactive oxygen species (ROS) is a common mechanism of damage at the cellular and tissue scale in response to exposure to a range of abiotic stresses. We have initial evidence from tomato that Alethea enhances antioxidant metabolism in plants exposed to salt stress, but the student will examine this mechanism in detail. The initial focus will be the effects of Alethea on ROS production in response to excessive light (photosynthetic radiation (PAR) and ultraviolet radiation(UV)) which are the particular area of expertise of the pimary supervisor, Dr Nigel Paul. However, the student's supervisory committee will also include Dr Mike Roberts and Professor Bill Davies, who bring expertise in plant cell and molecular biology and plant water stress respectively as well as Mr David Marks, from Plant Impact Plc. This panel, and the ability to work closely alongside the post-doc funded by Plant Impact Plc, will provide the student with a broad-based support and the ability to find their own project focus within the broad areas defined here. The student will be trained in a range of techniques, across a range of scales of organisation. The concentrations and distribution of specific reactive oxygen species will be quantified in leaf tissues using dyes (leaf staining with nitroblue tetrazolium & diaminobenzidine) and image analysis, and this will be linked to measured of photosynthetic damage (using chlorophyll fluorescence and in situ gas exchange), antioxidant metabolism (using spectrophotometric and GC-MS analyses) and ultimately plant growth.