Rice, rocks and the parasitic weed Striga: Increasing sustainable cereal production and protection in sub-Saharan Africa

The Grantham Centre for Sustainable Futures focuses on advancing sustainability research and connecting it with the policy debate around how humans can live in a more sustainable way.
grantham.sheffield.ac.uk

We are recruiting Scholars who will combine outstanding intellect with a strong commitment to public engagement, leadership and action. These ambitious individuals will complete interdisciplinary PhD research projects to help solve the challenges of sustainability. They will be supported by the Centre through a unique training programme, designed to equip them with the skills to become policy advocates and leaders in sustainability matters.

Your application for this studentship should be accompanied by a CV and a 200 word supporting statement. Your statement should outline your aspirations and motivation for studying in the Grantham Centre, outlining any relevant experience.

Please select ’Standard PhD’ and the Department of Animal and Plant Sciences. Fill in the title of your desired project and the name(s) of the supervisors’. The starting date of the PhD will be the start of the next academic year - 1 Oct 2017. The ’Funding stage’ on the form will be ’project studentship’.

The parasitic weed Striga devastates the yields of maize, sorghum and rain-fed rice in Africa. Striga species are difficult to control and innovative, sustainable solutions are urgently required. One possible strategy is to amend soils of degraded croplands with crushed silicate rocks to enhance the natural process of weathering. Plants enhance weathering of silicate rocks through acidification of the rhizosphere and by mycorrhization. Weathering of silicate rocks leads to the production of silicic acid, which can be taken up by some plants including rice. Uptake of silicic acid leads to increased resistance to some biotic stresses, due to mechanical strengthening of cell walls and/or to priming of biochemical and molecular defence pathways, both of which are key control points for molecular resistance against the parasitic weed Striga. This project aims to take a molecular genetic approach to accelerate the development of faster weathering rice varieties with enhanced resistance to Striga.

Following the Climate Change Conference (COP21), there is a commitment to seek innovative, sustainable solutions to increase crop yields whilst simultaneously sequestering atmospheric CO2. One strategy is to amend soils of degraded croplands with crushed silicate rocks to enhance the natural process of weathering and sequester anthropogenic carbon. Crop plants enhance weathering of silicate rocks through acidification of the rhizosphere and by mycorrhization. Benefits for food security arise through the production and uptake of silicic acid by some plants (including rice). This can lead to increased resistance to biotic stresses due to mechanical strengthening of cell walls and/or to priming of molecular defence pathways, both of which are key control points for resistance against the parasitic weed Striga. Striga causes devastating losses of cereal yields in sub Saharan Africa, worth over 7 billion US$ annually. This project aims to accelerate the development of faster weathering varieties of rain-fed rice with enhanced resistance to Striga. This will allow the development of a low cost, sustainable control strategy for resource poor farmers in Africa helping to improve food security whilst contributing to climate change mitigation. The student will determine how enhanced accumulation of silica increases resistance to Striga and exploit newly-available rice genetic resources to identify genes controlling the ability of roots to take up and silicic acid and exude protons and organic acids to accelerate weathering. The student will benefit from an exciting project that combines molecular genetic and biogeochemical expertise of the supervisors to deliver new breakthroughs in this field.

Key words:
Striga, parasitic weeds, weathering, silica, climate change, rice