Functional diversity of Toll/interleukin-1 receptor domains in flowering plants and its translational potential

Across the Tree of Life, innate immunity and cell death mechanisms protect hosts from potential pathogens. In prokaryotes, animals, and flowering plants, these functions are often mediated by Toll/interleukin-1 receptor (TIR) domain proteins. Here, we discuss recent analyses of TIR biology in flowering plants, revealing (i) TIR functions beyond pathogen recognition, e.g. in the spatial control of immunity, and (ii) the existence of at least two pathways for TIR signaling in plants. Also, we discuss TIR-based strategies for crop improvement and argue for a need to better understand TIR functions outside of commonly studied dicot pathways for future translational work. Opinions of experts on emerging topics in basic and translational plant TIR research are presented in supplementary video interviews.