title: Phosphite shifts physiological and hormonal profile of Monterey pine and delays Fusarium circinatum progression.
abstract: Fusarium circinatum is the causal agent of pitch canker disease affecting Pinus spp. and Pseudotsuga menziesii worldwide. Under strict quarantine measures, alternative approaches for disease control are necessary. Phosphite (Phi) salts are known for their fungicidal activity and as plant resistance elicitors; however, its potential is yet to be acknowledged in the Pinus-F. circinatum model. The main aim of this study was to assess whether the application of a Phi-based commercial formulation would delay the progression of the pitch canker on Pinus radiata plants, and on the in vitro fungal growth. In vitro assays were performed using different Phi concentrations (1% and 4%) and a non-treated control (0%), and repeated in vivo using inoculated and non-inoculated plants. Plant physiological parameters and hormonal content were evaluated. Phi was effective at inhibiting in vitro mycelial growth in a dose dependent manner. Regardless of fungal inoculation, Phi application induced positive effects on plant performance, despite phytotoxic effects found at 4%. Fusarium circinatum infection led to a reduction in gas exchange and chlorophyll fluorescence (Fv/Fm and φPSII), while proline and hormone (JA, ABA and SA) levels increased. Phi was effective in delaying disease symptom development in a dose dependent manner, concurrent with in vitro observations: gas exchange and chlorophyll fluorescence (Fv/Fm) were unaffected; proline, MDA and ABA decreased; electrolyte leakage and total soluble sugars increased. This suggests a direct (pathogen growth inhibition) and indirect (host defense priming) action of Phi, showing that Phi represents a potential strategy to control F. circinatum infection.
authors.affiliation: Department of Biology, CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Andreia
authors.initials: A
authors.lastname: Cerqueira
authors.affiliation: Department of Biology, CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Artur
authors.initials: A
authors.lastname: Alves
authors.affiliation: Department of Biology, CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Helder
authors.initials: H
authors.lastname: Berenguer
authors.affiliation: Department of Biology, CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Barbara
authors.initials: B
authors.lastname: Correia
authors.affiliation: Universitat Jaume I, Departamento de Ciencias Agrarias y del Medio Natural, 12071 Castelló de la Plana, Spain.
authors.forename: Aurelio
authors.initials: A
authors.lastname: Gómez-Cadenas
authors.affiliation: Sustainable Forest Management Research Institute, University of Valladolid - INIA, Avenida de Madrid 44, Palencia, Spain; Department of Plant Production and Forest Resources, University of Valladolid, Avenida de Madrid 44, Palencia, Spain.
authors.forename: Julio Javier
authors.initials: JJ
authors.lastname: Diez
authors.affiliation: Department of Biology, CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Monteiro
authors.affiliation: Department of Biology, CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. Electronic address: gpinto@ua.pt.
authors.forename: Glória
authors.initials: G
authors.lastname: Pinto
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D004305:Dose-Response Relationship, Drug; D004573:Electrolytes / Q000378:metabolism; D005453:Fluorescence; D005670:Fusarium / Q000472:pathogenicity*; D015227:Lipid Peroxidation / Q000187:drug effects; D017905:Phosphites / Q000008:administration & dosage / Q000494:pharmacology*; D028223:Pinus / Q000187:drug effects* / Q000254:growth & development / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000187:drug effects; D054046:Plant Stomata / Q000187:drug effects; D017680:Potassium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D011392:Proline / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000872:Anthocyanins; D004573:Electrolytes; D017905:Phosphites; D017680:Potassium Compounds; C056591:potassium phosphite; D002734:Chlorophyll; D002338:Carotenoids; D011392:Proline; D000077194:Chlorophyll A
keywords: Elicitors; Forestry disease management; Hormones; Pine pitch canker disease; Pinus radiata; Plant performance