title: Up-regulation of lipoxygenase, phospholipase, and oxylipin-production in the induced chemical defense of the red alga Gracilaria chilensis against epiphytes.
abstract: The red alga Gracilaria chilensis is commercially farmed for the production of agar hydrocolloids, but some susceptible algae in farms suffer from intense epiphyte growth. We investigated the induced chemical defense response of G. chilensis against epiphytes and demonstrated that an extract of an epiphyte-challenged alga can trigger a defense response. The hormonally active metabolites were purified by RP-HPLC. Treatment with the extract or the purified fraction changed the chemical profile of the alga and increased resistance against epiphyte spores. Semi-quantitative RT-PCR and enzyme assays demonstrated that this metabolic response occurs after an increase in lipoxygenase and phospholipase A2 activity. Although this suggests the involvement of regulatory oxylipins, neither jasmonic acid nor the algal metabolite prostaglandin E2 triggers comparable defense responses.
authors.affiliation: Station Biologique de Roscoff, UMR 7139 CNRS-UPMC & LIA-DIAMS, Roscoff, France.
authors.forename: Florian
authors.initials: F
authors.lastname: Weinberger
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lion
authors.forename: Ludovic
authors.initials: L
authors.lastname: Delage
authors.forename: Bernard
authors.initials: B
authors.lastname: Kloareg
authors.forename: Philippe
authors.initials: P
authors.lastname: Potin
authors.forename: Jessica
authors.initials: J
authors.lastname: Beltrán
authors.forename: Verónica
authors.initials: V
authors.lastname: Flores
authors.forename: Sylvain
authors.initials: S
authors.lastname: Faugeron
authors.forename: Juan
authors.initials: J
authors.lastname: Correa
authors.forename: Georg
authors.initials: G
authors.lastname: Pohnert
mesh_terms: D003517:Cyclopentanes / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D044724:Gracilaria / Q000201:enzymology*; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D054883:Oxylipins / Q000378:metabolism; D010741:Phospholipases A / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D057865:Plant Immunity / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation / Q000502:physiology
chemical_list: D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; C011006:jasmonic acid; D008084:Lipoxygenase; D010741:Phospholipases A; D015232:Dinoprostone