Increasing food security whilst simultaneously reducing environmental impacts and enhancing resilience to future climate are the key challenges facing agriculture. Agronomic sustainability can be facilitated by incorporating legume crops, such as peas and beans, into crop rotations. Legumes are able to fix atmospheric nitrogen through their symbiotic root-nodule bacteria (e.g. Rhizobia spp.), and thus reduce the need for synthetic fertiliser input. Successful root nodulation relies upon agricultural soils having a sufficiently high inoculum potential. However, intensively farmed soils are often lacking in populations of rhizobia due to the rotation of non-leguminous crops and high application rates of synthetic nitrogenous fertilisers. A strategy to combat this is to directly treat the seed with a concentrated inoculum of rhizobia, which ensures suitably high concentrations of root-nodule bacteria in the rhizosphere of the growing root. Because this technology is suitably advanced, there is now the opportunity to enhance and optimise this process by combining seed treatments that are able to simultaneously increase biological nitrogen fixation and induce disease resistance through the addition of plant growth-promoting rhizobacteria (PGPR) and resistance elicitors.
The mechanistic and physiological basis of such seed treatments however, needs critical evaluation in a sustainable agricultural context. Therefore, the focus of this studentship will be to develop novel legume-microbe seed treatments as either practical liquid, solid or seed coating formulations, and assess subsequent root nodulation, plant development and disease resistance in peas and faba bean, which are important agronomic legume species in both the UK and in the developing world. In addition to the benefits of legume seed treatments for European agricultural systems, this project will also explore how this technology can be transferred and adapted to local situations in developing countries for adoption by resource-poor farmers.
Specifically, the objectives of this project are to:
1. Characterise novel rhizobial isolates for improved inoculum longevity and improved N-fixing efficacy
2. Combine rhizobial isolates with other key symbionts such as PGPR and resistance elicitors (e.g. biomass-derived elicitors)
3. Determine the mechanistic and physiological basis of these novel seed treatments on different legume genotypes in terms of subsequent plant fitness, growth & yield
University of Stirling, Legume Technology Ltd., Processors and Growers Research Organisation (PGRO), and the James Hutton Institute.
Francesc Ferrando Molina - University of Stirling, 4 Union St, Stirling FK8 1NZ