Histolocalization and physico-chemical characterization of dihydrochalcones: Insight into the role of apple major flavonoids

Matthieu Gaucher (1) , Thomas Duge de Bernonville (1) , David Lohou (1) , Sylvain Guyot (2) , Thomas Guillemette (1) , Marie-Noelle Brisset (1) , James Dat (1)

1 IRHS - Institut de Recherche en Horticulture et Semences
2 SRC - BFL - Station de Recherches Cidricoles et Biotransformation des Fruits et Légumes

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 (approximate to 200 mg/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. (C) 2013 Elsevier Ltd. All rights reserved.

Mots clés: Malus x domestica; Rosaceae; Histolocalization; Antimicrobial activity; Iron chelation; Dihydrochalcones; Phloridzin; Sieboldin; Phloretin; WILT DISEASE RESISTANCE; ANTIOXIDANT ACTIVITY; PHENOLIC-COMPOUNDS; ERWINIA-AMYLOVORA; LIPID-PEROXIDATION; SCAB RESISTANCE; VENTURIA-INAEQUALIS; OXIDATIVE STRESS; IRON COMPLEXES; FIRE BLIGHT

Domaines: Sciences du Vivant [q-bio]

Matthieu Gaucher, Thomas Duge de Bernonville, David Lohou, Sylvain Guyot, Thomas Guillemette, et al.. Histolocalization and physico-chemical characterization of dihydrochalcones: Insight into the role of apple major flavonoids. Phytochemistry, 2013, 90, pp.78 - 89. ⟨10.1016/j.phytochem.2013.02.009⟩. ⟨hal-01209908⟩