Crop production sustainability through the microbial lens

One of the current greatest societal challenges is to deliver more productive and sustainable agriculture to feed the World's growing population while also mitigating against climate change. The microbially-driven nitrification process has important environmental and economic consequences in agricultural soils, including substantial loss of nitrogen fertiliser and nitrous oxide production, a potent greenhouse gas1. One approach to solve this nitrogen use efficiency dilemma is to use the natural nitrification inhibition compounds produced by some plants2. This biological nitrification inhibition (BNI) process holds considerable promise for more productive and sustainable agriculture.
BNI has been demonstrated in a range of crops, and there is the suggestion (but no evidence yet) for a strong BNI potential in barley, which is the most cultivated cereal crop in Scotland. This project aims to understand the biological nitrification inhibition in barley with the following main objectives:
1) determine the BNI efficiency in several cultivated and barley landrace lines
2) reconstruct the historical origin of BNI potential in barley
3) characterise and isolate the molecules responsible for the BNI
The BNI efficiency of several cultivated and barley landrace lines will first be tested by determining their influence on nitrification3. Barley lines will be grown in the greenhouse on soil containing a diverse community of active nitrifiers. Nitrification rates, nitrifier abundance and community structure will be determined alongside plant growth.
Selection of both recent and ancient landraces of barley will enable reconstructing the evolution of BNI potential throughout the history of barley migration and development. Access to a unique collection of barley genotypes and populations with associated envirotypes and germplasm genetics will allow linking the historical origin of Barley BNI to plant genetics and environmental origin.
Chemical characterisation of BNI factors is generally highly limited, including in barley. The student will extract the BNI compounds from the root exudates of selected Barley lines and identify them by mass spectrometry molecular networking. The BNI efficiency of the isolated BNI molecules will be tested on a microbial culture collection of archaeal and bacterial nitrifiers. In addition, other natural products with related structures will be tested to determine the structure responsible for BNI in Barley.
Altogether, this project will advance knowledge on sustainable crop production, and the PhD student will join dynamic research groups with international reputations. The student will benefit from interdisciplinary training on microbiology, plant genetics and chemistry with a large scope for personal development.