Project Title:

The function and evolution of the D14L receptor in arbuscular mycorrhizal symbiosis 

Project Summary:

Arbuscular mycorrhizal (AM) symbiosis is an ancient endosymbiosis that facilitates nutrient transfer between land plants and AM fungi. For this underground resource exchange to occur, AM fungi penetrate the root and spread inter- and intracellularly within the root cortex. A signal transduction pathway called the common symbiosis signalling pathway (CSSP) is conserved across the land plants and regulates gene expression required for fungal accommodation. Despite extensive research into the role of CSSP components in the establishment of AM symbiosis, the fact that characterised CSSP mutants can nevertheless establish fungal contacts means that other signalling pathways must be active. In contrast to the weaker phenotypes of CSSP mutants, loss of the alpha/beta hydrolase receptor DWARF14-LIKE (D14L) completely blocks AM symbiosis in angiosperms. However, a detailed functional explanation for the severity of the d14l phenotype is lacking and the broader relevance of the receptor, both in terms of its evolutionary significance in AM symbiosis and how it ties together with the CSSP, remains unclear. This PhD project sets out to investigate whether D14L operates upstream of the CSSP in pre-symbiosis signalling, and to assess whether D14L has evolved functional specificity for its role in AM symbiosis.