title: Peroxidase-Generated Apoplastic ROS Impair Cuticle Integrity and Contribute to DAMP-Elicited Defenses.
abstract: Cuticular defects trigger a battery of reactions including enhanced reactive oxygen species (ROS) production and resistance to necrotrophic pathogens. However, the source of ROS generated by such impaired cuticles has remained elusive. Here, we report the characterization ofArabidopsis thaliana ohy1mutant, aPeroxidase 57(PER57) - overexpressing line that demonstrates enhanced defense responses that result both from increased accumulation of ROS and permeability of the leaf cuticle. Theohy1mutant was identified in a screen ofA. thalianaseedlings for oligogalacturonides (OGs) insensitive/hypersensitive mutants that exhibit altered growth retardation in response to exogenous OGs. Mutants impaired in OG sensitivity were analyzed for disease resistance/susceptibility to the necrotrophic phytopathogensBotrytis cinereaandPectobacterium carotovorum. In theohy1line, the hypersensitivity to OGs was associated with resistance to the tested pathogens. ThisPER57overexpressing line exhibited a significantly more permeable leaf cuticle than wild-type plants and this phenotype could be recapitulated by overexpressing other class III peroxidases. Such peroxidase overexpression was accompanied by the suppressed expression of cutin biosynthesis genes and the enhanced expression of genes associated with OG-signaling. Application of ABA completely removed ROS, restored the expression of genes associated with cuticle biosynthesis and led to decreased permeability of the leaf cuticle, and finally, abolished immunity toB. cinerea. Our work demonstrates that increased peroxidase activity increases permeability of the leaf cuticle. The loss of cuticle integrity primes plant defenses to necrotrophic pathogens via the activation of DAMP-responses.
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Mantas
authors.initials: M
authors.lastname: Survila
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Pär R
authors.initials: PR
authors.lastname: Davidsson
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Ville
authors.initials: V
authors.lastname: Pennanen
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Tarja
authors.initials: T
authors.lastname: Kariola
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Martin
authors.initials: M
authors.lastname: Broberg
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Sipari
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Heino
authors.affiliation: Division of Genetics, Viikki Plant Science Centre, Department of Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki Helsinki, Finland.
authors.forename: Erkki T
authors.initials: ET
authors.lastname: Palva
keywords: Arabidopsis; Peroxidase 57 (PER57); cutin biosynthesis; necrotrophs; oligogalacturonides (OGs); reactive oxygen species (ROS)