This project will use double-haploid lines of wheat derived from a mapping population of over 500 lines in which the parents have contrasting phenotype for arbuscular mycorrhiza (AM) competence, to determine the effect of wheat mycorrhiza on rhizosphere microbial populations, AM-inducible defences and soil quality (soil organic matter content, macroaggregate stability, soil porosity and water holding capacity).

Intensive modern arable farming methods combined with selection of less AM-competent wheat is hypothesised to have contributed to the loss of soil structure and organic matter content that now is a major constraint on crop productivity, especially under conditions of inadequate or too much rainfall.

AM fungi have been shown to be vital players in soil aggregate stability and contribute to soil organic matter storage but to date the possibility of actively selecting wheat varieties and agronomic management practices to synergistically harness the benefits of AM fungi and associated Plant Growth Promoting Rhizobacteria (PGPR) for sustainable soil quality has not been considered.

We will resolve the basis of mycorrhiza inducible defences against major wheat fungal pathogens- take all and Septoria, and the potentialy synergistic interactions between mycorrhiza and PGPR. We will use wheat lines with contrasting mycorrhizal competence, but otherwise genetically very similar, selected from the mapping population. In the field we will establish a sequential trial of the wheat lines on plots under conventional tillage and no-tillage management, with and without addition of commercially available mycorrhizal inoculum.

In addition a grass ley will be established and planted with the wheat lines after 3 years- to assess how this traditional way of rebuilding soil quality compares to the other management treatments.

The work will quantify mycorrhizosphere carbon fluxes into aggregates using 14C and conduct metagenomic analyses of mycorrhizosphere communities.