title: Induced systemic resistance by beneficial microbes.
abstract: Beneficial microbes in the microbiome of plant roots improve plant health. Induced systemic resistance (ISR) emerged as an important mechanism by which selected plant growth-promoting bacteria and fungi in the rhizosphere prime the whole plant body for enhanced defense against a broad range of pathogens and insect herbivores. A wide variety of root-associated mutualists, including Pseudomonas, Bacillus, Trichoderma, and mycorrhiza species sensitize the plant immune system for enhanced defense without directly activating costly defenses. This review focuses on molecular processes at the interface between plant roots and ISR-eliciting mutualists, and on the progress in our understanding of ISR signaling and systemic defense priming. The central role of the root-specific transcription factor MYB72 in the onset of ISR and the role of phytohormones and defense regulatory proteins in the expression of ISR in aboveground plant parts are highlighted. Finally, the ecological function of ISR-inducing microbes in the root microbiome is discussed.
authors.affiliation: Plant-Microbe Interactions, Institute of Environmental Biology, Department of Biology, Faculty of Science, Utrecht University, 3508 TB Utrecht, The Netherlands; email: C.M.J.Pieterse@uu.nl , C.Zamioudis@uu.nl , R.L.Berendsen@uu.nl , S.VanWees@uu.nl , P.A.H.M.Bakker@uu.nl.
authors.forename: Corné M J
authors.initials: CM
authors.lastname: Pieterse
authors.forename: Christos
authors.initials: C
authors.lastname: Zamioudis
authors.forename: Roeland L
authors.initials: RL
authors.lastname: Berendsen
authors.forename: David M
authors.initials: DM
authors.lastname: Weller
authors.forename: Saskia C M
authors.initials: SC
authors.lastname: Van Wees
authors.forename: Peter A H M
authors.initials: PA
authors.lastname: Bakker
mesh_terms: D018407:Bacterial Physiological Phenomena; D005658:Fungi / Q000502:physiology*; D010937:Plant Growth Regulators / Q000502:physiology; D010944:Plants / Q000382:microbiology*
chemical_list: D010937:Plant Growth Regulators
keywords: defense priming; plant growth–promoting microbes; plant immunity; rhizosphere microbiome; root signaling