Thomas Thirkell

Molecular basis of the benefits of arbuscular mycorrhizal symbiosis for the nitrogen nutrition of crop plants

Nitrogen is the most commonly limiting nutrient to the growth of crop plants, which almost universally rely on the addition of nitrogen-rich fertilizers – the price of which is spiralling as fossil fuel prices rise.

As such, there is increasing demand  for sustainable crop production, with nutrient supply and soil management being of paramount concern. To this end, mycorrhizal fungi – soil fungi that are symbiotic with many crop plants – may provide a solution. A group of these fungi, known as Arbuscular Mycorrhizal fungi (AMF) are known to improve soil structure and water holding capacity and, while they are able to improve crop plant nitrogen uptake, quite how this is achieved is unclear. My project looks at the role of AMF in releasing nitrogen bound in organic matter in the soil, how this nitrogen is acquired by the fungus and subsequently transferred to the partner plant, as well as the ecological significance of this transfer for plant and fungus. Interactions between AMF and other soil microbes, and how they influence the efficacy of nutrient trade will also be investigated.”

The arbuscular mycorrhizal (AM) symbiosis is a mutualism between 80% of plant species and soil fungi whereby the plant provides the fungus with carbon in return for providing key nutrients such nitrogen (N). This project will use maize, a highly mycorrhizal crop, as a model to investigate the extent to which current management practices have impacted upon AM diversity in agricultural soils and resolve the mechanisms through which AM fungi can mobilise different chemical forms of soil N.