title: Oxidative metabolism is associated with physiological disorders in fruits stored under multiple environmental stresses.
abstract: In combination with low temperature, controlled atmosphere storage and 1-methylcyclopropene (ethylene antagonist) application are used to delay senescence of many fruits and vegetables. Controlled atmosphere consists of low O2 and elevated CO2. When sub-optimal partial pressures are used, these practices represent multiple abiotic stresses that can promote the development of physiological disorders in pome fruit, including flesh browning and cavities, although there is some evidence for genetic differences in susceptibility. In the absence of surface disorders, fruit with flesh injuries are not easily distinguished from asymptomatic fruit until these are consumed. Oxidative stress metabolites tend to accumulate (e.g., γ-aminobutyrate) or rapidly decline (e.g., ascorbate and glutathione) in vegetative tissues exposed to hypoxic and/or elevated CO2 environments. Moreover, these phenomena can be associated with altered energy and redox status. Biochemical investigations of Arabidopsis and tomato plants with genetically-altered levels of enzymes associated with the γ-aminobutyrate shunt and the ascorbate-glutathione pathway indicate that these metabolic processes are functionally related and critical for dampening the oxidative burst in vegetative and fruit tissues, respectively. Here, we hypothesize that γ-aminobutyrate accumulation, as well energy and antioxidant depletion are associated with the development of physiological injury in pome fruit under multiple environmental stresses. An improved understanding of this relationship could assist in maintaining the quality of stored fruit.
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Rd E., Guelph, ON N1 G 2W1 Canada.
authors.forename: Geoffrey B
authors.initials: GB
authors.lastname: Lum
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Rd E., Guelph, ON N1 G 2W1 Canada.
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Shelp
authors.affiliation: Ontario Ministry of Agriculture and Food, Box 587, 1283 Blueline Rd. at Highway 3, Simcoe, Ontario N3Y 4N5 Canada.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: DeEll
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Rd E., Guelph, ON N1 G 2W1 Canada. Electronic address: gbozzo@uoguelph.ca.
authors.forename: Gale G
authors.initials: GG
authors.lastname: Bozzo
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D004734:Energy Metabolism; D005638:Fruit / Q000378:metabolism* / Q000502:physiology*; D008954:Models, Biological; D010084:Oxidation-Reduction; D013312:Stress, Physiological
chemical_list: D000975:Antioxidants
keywords: 1-Methylcylcopropene; Ascorbate; Controlled atmosphere; Glutathione; Oxidative stress; γ-Aminobutyrate