Combating plant diseases through transition metal allocation

Understanding how plants fend-off invading microbes is essential for food security and the economy of large parts of the world. Consequently, a sustained and dedicated effort has been directed at unveiling how plants protect themselves from invading microbes. Major defense hormone signaling pathways have been characterized, the identity of many immune response-triggering molecules as well as many of their receptors have been determined, and the mechanisms of pathogen-host arms race are being studied. In recent years, evidence for a new layer of plant innate immunity involving transition metals has been brought forward. This would link plant metal nutrition with plant immune responses and open up possible new strategies for pathogen control involving metal fertilizers instead of pesticides. In this review, we outline our current understanding of metal-mediated plant immune response and indicate the future avenues of exploration of this topic.