Nitrogen (N) and phosphorous (P) are essential for all aspects of plant growth. Paradoxically, they are poorly available in soils, leading to extensive use of fertilisers to fulfil the demand of a growing population. However, their synthesis and application in agricultural practices harms the environment. The synthesis of N fertilizers alone consumes 3-5% of the world’s annual natural gas demand, which is equivalent to 1-2% of the world's annual energy consumption. The application of N fertilizers to soils can impair phosphate-natural resources and increase soil and water pollution as well as global warming through emissions of nitrous oxide. In this context, lowering fertiliser inputs and breeding crops with better P and N use efficiency are important goals for sustainable agriculture and food security at a time of rapidly growing population in the current climate change.
The use of plant-symbiotic microorganisms such as nitrogen-fixing bacteria and phosphate-delivering mycorrhizal fungi in agricultural practices can overcome this problem by providing these nutrients to the plants in an environmentally sustainable manner. The success of root symbioses relies on the molecular dialogue between symbionts and plants. After plant-microorganism recognition, the bacteria/fungi colonize the plant root, forming specific structures known as nodules (nitrogen-fixing bacteria) and arbuscules (phosphate-delivering fungi) where the microorganisms live and provide N or P to the plant.
In our lab, we are developing novel strategies to enhancing these symbiotic interactions for their application in agricultural practices. For that, during the ‘EASY-CROPS project’, we developed a line in the model legume Medicago truncatula (EASY line) with increased root symbioses. We study whether the enhanced symbiotic interactions in the EASY line could benefit plant performance and nutrient content of the plant under different soil conditions. Furthermore, we investigated whether the enhanced symbiotic performance of the EASY line is correlated with a higher growth and nitrogen content of the plant under nutrient-depleted conditions.
Cereal crops can interact with arbuscular mycorrhiza fungi, but not with nitrogen-fixing bacteria. Bread wheat is an agriculturally important crop species for UK and EU markets. For this project, the EASY mutation was identified in Cadenza and Kronos wheat cultivars in a collection developed at the John Innes Centre (Norwich, UK). We investigated the arbuscular mycorrhiza symbiosis phenotype in the wheat EASY lines.
The EASY mutation was identified in a protein relevant for the recognition of the plant-symbiotic microorganisms. To better understand the mechanistic role of the EASY mutation during symbiosis, we aimed to determine the structure of this protein. This is a high-risk objective as the structure of these type of proteins have not been determined yet in plants.
