Several groups in RSB, spanning all three Divisions, work on topics at the interface between microbes and their host. The School has expertise in both plant and animal hosts, pathogenic, parasitic and symbiotic microbes and projects investigating host-microbe interactions at the genomic, cellular, organismal and ecological level. Fundamental knowledge about the interactions between microbes and their hosts is critical for understanding natural ecosystems and their evolution, improving plant biomass for food production and development of vaccines and drugs for the treatment of infectious diseases.