Impact of 1-MCP and Controlled Atmosphere on Physiological Disorders in Stored Pome Fruit: Biochemical Signatures of Oxidative Stress Metabolism

在气调贮藏中，梨果的代谢活性通过控制氧气和二氧化碳的分压而降低，作为温度降低的补充。最佳条件是以下各项之间的折衷：（i）保持硬度/质量;（ii）在复温期间促进均匀成熟;以及（iii）使生理储存障碍的发生率最小化，所述生理储存障碍例如可导致经济损失的褐变和内部布朗宁。CA条件可导致细胞水平上氧化和还原（氧化还原）过程之间的失衡，以及内源性抗氧化剂（例如抗坏血酸盐、NADPH）的损失和氧化应激代谢物（如γ-氨基丁酸盐（GABA）和γ-羟基丁酸盐（GHB））的积累。 在这个建议中，我们打算调查是否在氧化还原和GABA代谢的变化与外部损伤和果肉布朗宁在控制气氛条件下储存的梨和苹果时间相关。 此外，梨果与预存储化学品，如1-甲基环丙烯或1-MCP，旨在通过抑制乙烯介导的成熟，以保持水果品质的处理可能会影响氧化应激代谢。 将通过反相HPLC、GC-质谱法和UV/维斯分光光度法测定氧化还原对和强制降解代谢物作为储存时间和1-MCP处理的函数。此外，我们打算调查GHB生产的相对重要性，作为一个前体的生理障碍，在苹果果实中使用的快速开花线与GHB形成酶，glyxoylate/琥珀酸半醛还原酶的RNAi结构转化。该项目应导致更好地理解的机制负责在存储的苹果和梨的生理障碍，并可能有助于改善存储协议，以保持产品质量，和诊断/技术的发展，以评估损伤的潜力和基因工程策略，以改善存储过程中的生理障碍。

In controlled atmosphere (CA) storage, the metabolic activity of pome fruit is decreased by controlling the oxygen and carbon dioxide partial pressures, as a supplement to a reduction in temperature. The optimal conditions are a compromise among: (i) maintaining firmness/quality; (ii) promoting uniform ripeness during re-warming; and, (iii) minimizing the incidence of physiological storage disorders such as scald and internal browning which can cause economic loss. CA conditions can result in an imbalance between oxidative and reductive (redox) processes at the cellular level and in the loss of endogenous antioxidants (e.g. ascorbate, NADPH) and accumulation of oxidative stress metabolites, like gamma-aminobutyrate (GABA) and gamma-hydroxybutyrate (GHB). In this proposal, we intend to investigate whether the shifts in redox and GABA metabolism are temporally associated with external injury and flesh browning in pears and apples stored under controlled atmosphere conditions. In addition, treatment of pome fruit with pre-storage chemicals, such as 1-methylcyclopropene or 1-MCP, aimed at preserving fruit quality via inhibition of ethylene mediated ripening may influence oxidative stress metabolism. The redox pairs and stress metabolites will be determined as a function of storage time and 1-MCP treatment via reverse-phase HPLC, GC-mass spectrometry, and with UV/Vis spectrophotometry. Also, we intend to investigate the relative importance of GHB production as a precursor to physiological disorders in apple fruit using a rapid-flowering line transformed with RNAi constructs of the GHB-forming enzyme, glyxoylate/succinic semialdehyde reductase. This project should lead to improved understanding of the mechanisms responsible for physiological disorders in stored apples and pears, and could contribute to improved storage protocols for maintaining quality of product, and the development of diagnostics/technologies for assessing injury potential and genetic engineering strategies for ameliorating physiological disorders during storage.