Calcium chloride treatment modifies cell wall metabolism and activates defense responses in strawberry fruit ( Fragaria x ananassa , Duch)
LANGER, SILVIA E.; MARINA, MARÍA; BURGOS, JOSÉ L.; MARTÍNEZ, GUSTAVO A.; CIVELLO, PEDRO M.; VILLARREAL, NATALIA M.
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
JOHN WILEY & SONS LTD
BACKGROUND: Fruit dips in calcium ions solutions have been shown as an effective treatment to extend strawberries (Fragaria x ananassa, Duch) quality during storage. In the present work, strawberry fruit were treated with 1% (w/v) calcium chloride solution and treatment effects on cell wall enzymes activities and the expression of encoding genes, as well as enzymes involved in fruit defense responses was investigated.RESULTS: Calcium treatment activated pectin methylesterase activity while inhibited those corresponding to pectin hydrolases as polygalacturonase and β-galactosidase. Moreover, the expression of key genes for strawberry pectin metabolism (and fruit softening process) was up- (for FaPME1) and down- (for FaPG1, FaPLB, FaPLC, FaβGal1 and FaAra1) regulated by calcium dips. In agreement, a higher firmness levels and ionically-bound pectins (IBP) amount were detected in calcium treated fruit when compared with controls. The in vitro and in vivo growth rate of fungal pathogen Botrytis cinerea was limited by calcium treatment. Moreover, the activity of polyphenol oxidases, chitinases, peroxidases and β-1,3-glucanases was enhanced by calcium ions dips. CONCLUSIONS: New insights concerning the biochemical and molecular basis of cell wall preservation and resistance to fungal pathogens on calcium-treated strawberries are provided.