Drought, plant symbionts and silicon - improving crop water relations under future climate change scenarios

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Food security is threatened by the adverse effects of drought on crop yields.Droughts are increasing in both frequency and severity, and much of globalfood production relies on rain-fed agriculture, so sustainable approaches toincreasing crop resilience to drought are urgently needed. Silicon, which manycrops accumulate to high levels, has been shown to protect plants againstdrought stress. The mechanisms responsible remain unclear, but onepossibility is strengthened root cell walls leading to better soil penetration,water uptake and transport.Arbuscular mycorrhizal fungi (AMF) form a symbiotic relationship with themajority of land plants including most agriculturally important crop species, andmay confer a number of benefits to their host plant, including improved waterrelations. They have also been shown to increase silicon uptake. However, theabundance and diversity of AMF has declined under intensive farming methods;if the remaining species are the ones which have the greatest beneficialimpacts on silicon uptake and plant water relations is completely unknown. Theinteracting effects of AMF colonisation, rhizosphere microbial community andsilicon supply on resistance to drought stress have also not yet been studied.This project would address this knowledge gap using innovative newtechniques to study the way silicon is deposited in plant roots, the effect thishas on plant water relations and crop yields, and how this process is affected bythe presence of AMF. It will also test whether different species of AMF affectsilicon uptake differently, and how AMF influence other components of themicrobial community and the effect of this on Si uptake.The successful student will join a project with the potential for real worldimpact in terms of improved food security and protecting crops from theeffects of climate change through novel sustainable approaches. They willbenefit from training in plant biology and ecophysiology, as well as state-of-the-art analytical and imaging techniques, including portable X-ray florescencespectroscopy, novel stable isotope tracking techniques and microbialcommunity analysis. They will also benefit from collaboration with University ofCalifornia which will use 13Carbon stable isotopes and Nano-Scale Imaging MassSpectrometry to track carbon movement through the individual members ofthe rhizosphere community. This will provide novel insights into how droughtaffects carbon allocation below ground, which components of the soil microbialcommunity benefit from this increased carbon and the implications for nutrientacquisition dynamics and carbon cycling in crop systems.