title: Histolocalization and physico-chemical characterization of dihydrochalcones: Insight into the role of apple major flavonoids.
abstract: Flavonoids, like other metabolites synthesized via the phenylpropanoid pathway, possess a wide range of biological activities including functions in plant development and its interaction with the environment. Dihydrochalcones (mainly phloridzin, sieboldin, trilobatin, phloretin) represent the major flavonoid subgroup in apple green tissues. Although this class of phenolic compounds is found in very large amounts in some tissues (≈200mg/g of leaf DW), their physiological significance remains unclear. In the present study, we highlight their tissue-specific localization in young growing shoots suggesting a specific role in important physiological processes, most notably in response to biotic stress. Indeed, dihydrochalcones could constitute a basal defense, in particular phloretin which exhibits a strong broad-range bactericidal and fungicidal activity. Our results also indicate that sieboldin forms complexes with iron with strong affinity, reinforcing its antioxidant properties and conferring to this dihydrochalcone a potential for iron seclusion and/or storage. The importance of localization and biochemical properties of dihydrochalcones are discussed in view of the apple tree defense strategy against both biotic and abiotic stresses.
authors.affiliation: INRA, UMR1345 Institut de Recherche en Horticulture et Semences, F-49071 Angers, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Gaucher
authors.forename: Thomas
authors.initials: T
authors.lastname: Dugé de Bernonville
authors.forename: David
authors.initials: D
authors.lastname: Lohou
authors.forename: Sylvain
authors.initials: S
authors.lastname: Guyot
authors.forename: Thomas
authors.initials: T
authors.lastname: Guillemette
authors.forename: Marie-Noëlle
authors.initials: MN
authors.lastname: Brisset
authors.forename: James F
authors.initials: JF
authors.lastname: Dat
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D047188:Chalcones / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000737:chemistry*; D005658:Fungi / Q000187:drug effects* / Q000254:growth & development; D027845:Malus / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D018520:Plant Shoots / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D047188:Chalcones; D005419:Flavonoids; C015812:dihydrochalcone