Understanding symbiosis signalling in barley for enhanced recruitment of beneficial soil bacteria

The rapid population increase and high demand for food production raise immense concerns about an upcoming global food crisis.

Low soil nutrient levels are a key factor limiting crop yields, and farmers currently rely on extensive application of chemical fertilisers, which have severe negative environmental effects.

The implementation of beneficial soil microbes with nutrient-sequestering functions has therefore become a mainstream interest, aimed at increasing crop productivity while reducing the ecological footprint of current agricultural systems.The Common Symbiosis Signalling Pathway (CSSP) plays a pivotal role in orchestrating symbiotic relationships between plants and arbuscular mycorrhiza fungi, as well as leguminous plants and nitrogen-fixing bacteria.

These symbioses are vital for optimal plant nutrient acquisition, particularly nitrogen and phosphorus.

While the functions of CSSP genes in arbuscular mycorrhizal symbiosis in cereals are well-documented, their impact on other beneficial microbiota, such as nitrogen-fixing bacteria, remains unknown.

Unraveling these interactions is crucial for addressing contemporary environmental challenges related to crop nutrient limitations and organic fertiliser development.In the proposed project, we employ barley CSSP mutants and perform microbiome profiling, transcriptomics, and metabolomics approaches to elucidate the influence of CSSP genes on bacterial assembly, uncover genes involved in the interaction with beneficial bacteria, and identify CSSP-dependent root metabolites that govern plant-microbe signalling.Preliminary data showed that barley CSSP mutations significantly alter bacterial assembly, particularly reducing the colonisation by bacterial orders known for hosting plant growth-promoting isolates.A comprehensive assessment of cereal interactions with beneficial soil bacteria will provide the groundwork for future engineering endeavours aimed at addressing current environmental challenges.