title: Shifting from priming of salicylic acid- to jasmonic acid-regulated defences by Trichoderma protects tomato against the root knot nematode Meloidogyne incognita.
abstract: Beneficial root endophytes such as Trichoderma spp. can reduce infections by parasitic nematodes through triggering host defences. Little is currently known about the complex hormone signalling underlying the induction of resistance. In this study, we investigated whether Trichoderma modulates the hormone signalling network in the host to induce resistance to nematodes. We investigated the role and the timing of the jasmonic acid (JA)- and salicylic acid (SA)-regulated defensive pathways in Trichoderma-induced resistance to the root knot nematode Meloidogyne incognita. A split-root system of tomato (Solanum lycopersicum) was used to study local and systemic induced defences by analysing nematode performance, defence gene expression, responsiveness to exogenous hormone application, and dependence on SA and JA signalling of Trichoderma-induced resistance. Root colonization by Trichoderma impeded nematode performance both locally and systemically at multiple stages of the parasitism, that is, invasion, galling and reproduction. First, Trichoderma primed SA-regulated defences, which limited nematode root invasion. Then, Trichoderma enhanced JA-regulated defences, thereby antagonizing the deregulation of JA-dependent immunity by the nematodes, which compromised galling and fecundity. Our results show that Trichoderma primes SA- and JA-dependent defences in roots, and that the priming of responsiveness to these hormones upon nematode attack is plastic and adaptive to the parasitism stage.
authors: Plant-Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
authors: Ainhoa
authors: A
authors: Martínez-Medina
authors: Plant-Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
authors: Ivan
authors: I
authors: Fernandez
authors: Plant-Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
authors: Gerrit B
authors: GB
authors: Lok
authors: Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, Granada, 18008, Spain.
authors: María J
authors: MJ
authors: Pozo
authors: Plant-Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
authors: Corné M J
authors: CM
authors: Pieterse
authors: Plant-Microbe Interactions, Department of Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
authors: Saskia C M
authors: SC
authors: Van Wees
mesh_terms: D000818:Animals; D003517:Cyclopentanes / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000276:immunology* / Q000469:parasitology*; D008954:Models, Biological; D010058:Oviposition / Q000502:physiology; D054883:Oxylipins / Q000378:metabolism*; D010935:Plant Diseases / Q000469:parasitology*; D018517:Plant Roots / Q000469:parasitology*; D010941:Plant Tumors / Q000469:parasitology; D012098:Reproduction; D020156:Salicylic Acid / Q000378:metabolism*; D015398:Signal Transduction; D014242:Trichoderma / Q000502:physiology*; D014431:Tylenchoidea / Q000472:pathogenicity* / Q000502:physiology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; C011006:jasmonic acid; D020156:Salicylic Acid
keywords: 
  Trichoderma
  ; belowground; hormones; induced defences; jasmonic acid (JA); parasitic nematode; priming; salicylic acid (SA)