P-408 - Evolution of receptor (D14L) signalling specificity for symbiosis and development

The DWARF14-LIKE (D14L) signalling pathway is important for arbuscular mycorrhizal (AM) symbiosis development. In rice, D14L plays a dual role in regulating both developmental processes and symbiosis competence. Specifically, activation of D14L facilitates the degradation of the negative regulator SMAX1, leading to de-repression of symbiosis signalling and thereby promoting symbiosis development. While D14L is relevant for proper symbiotic regulation in angiosperms, its apparent lack of involvement in AM symbiosis in early-diverging land plants suggests that this function is a derived trait in later plant evolution. This project aims to reconstruct the evolutionary trajectory of the D14L signalling pathway and to identify key determinants of its recruitment into symbiotic signalling. To achieve this, a high-resolution metagenomics approach was employed to identify potential components associated with symbiosis signalling either upstream of the D14L pathway, via conserved cis-regulatory motifs, or downstream, using relevant differential transcriptomic data obtained from mutants of the D14L complex. After obtaining a comprehensive list of candidate genes using this approach, the future goal is to functionally characterise them in both rice and Marchantia paleacea, offering comparative insights into the molecular evolution and regulation of plant–fungal interactions across both early and late-diverging plant lineages.