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Effect of NaHCO 3 treatments on the activity of cell‐wall‐degrading enzymes produced by Penicillium digitatum during the pathogenesis process on grapefruit
Author(s) -
Venditti Tullio,
D'hallewin Guy,
Ladu Gianfranca,
Petretto Giacomo L,
Pintore Giorgio,
Labavitch John M
Publication year - 2018
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.9025
Subject(s) - pectinase , penicillium digitatum , pectin , pectin lyase , chemistry , enzyme , biochemistry , pectate lyase , esterase , sodium bicarbonate , lyase , food science , microbiology and biotechnology , botany , biology , citrus fruit , organic chemistry
BACKGROUND This study was performed to clarify the strategies of Penicillium digitatum during pathogenesis on citrus, assessing, on albedo plugs, the effects of treatment with sodium bicarbonate (NaHCO 3 ), at two different pH values (5 and 8.3), on cell‐wall‐degrading enzyme activity over a period of 72 h. RESULTS Treatment with NaHCO 3 , under alkaline pH, delayed the polygalacturonase activity for 72 h, or 48 h in the case of the pectin lyase, compared with the control or the same treatment at pH 5. In contrast, pectin methyl esterase activity rapidly increased after 24 h, in plugs dipped in the same solution. In this case, the activity remained higher than untreated or pH 5‐treated plugs up to 72 h. CONCLUSION The rapid increase in pectin methyl esterase activity under alkaline conditions is presumably the strategy of the pathogen to lower the pH, soon after the initiation of infection, in order to restore an optimal environment for the subsequent polygalacturonase and pectin lyase action. In fact, at the same time, a low pH delayed the enzymatic activity of polygalacturonase and pectin lyase, the two enzymes that actually cleave the α‐1,4‐linkages between the galacturonic acid residues. © 2018 Society of Chemical Industry