Abstract Phospholipase D (PLD) is a key enzyme involved in membrane lipid catabolism. Hexanal, a C6 volatile aldehyde is a strong PLD -inhibitor, and has been observed to enhance the shelf life and quality of horticultural produce. In the present study, the effect of hexanal vapor exposure on the postharvest quality and ripening response of bell pepper fruit was evaluated. Hexanal exposure for a minimum of 6 h was found to be essential to delay ripening in bell pepper fruit. Quantification of head space hexanal levels in the presence of pepper fruit revealed a gradual decrease in concentration, while it remained relatively steady close to the peak value in the absence of pepper fruit. Hexanal treated bell peppers subjected to 21 d of postharvest storage evolved higher levels of aroma volatiles than untreated peppers. Hexanal vapor treatment induced significant alterations in the transcript accumulation and expression of genes involved in the carotenoid biosynthetic pathway, antioxidant enzyme systems, and the LOX pathway in stored pepper fruit. Real time PCR analysis also confirmed the near-complete downregulation of expression of genes encoding PLD α, β, δ and ζ isoforms in hexanal vapor treated peppers. The results suggest that hexanal vapor treatment can beneficially influence the expression of genes in multiple biochemical pathways, which could ultimately result in enhancing the shelf life and quality of horticultural produce.

中文翻译：

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暴露于己醛蒸气的甜椒的成熟反应、果实品质和磷脂酶 D 基因表达

摘要 磷脂酶 D (PLD) 是参与膜脂分解代谢的关键酶。己醛是一种 C6 挥发性醛，是一种强 PLD 抑制剂，已被观察到可提高园艺产品的保质期和质量。在本研究中，评估了己醛蒸气暴露对甜椒果实采后品质和成熟反应的影响。发现至少 6 小时的己醛暴露对于延迟甜椒果实的成熟至关重要。存在辣椒果实时顶部空间己醛水平的定量显示浓度逐渐降低，而在没有辣椒果实的情况下它保持相对稳定接近峰值。收获后储存 21 天的己醛处理的甜椒比未处理的辣椒产生更高水平的香气挥发物。己醛蒸汽处理诱导了储存辣椒果实中类胡萝卜素生物合成途径、抗氧化酶系统和 LOX 途径相关基因的转录积累和表达的显着改变。实时 PCR 分析还证实了在己醛蒸汽处理的辣椒中编码 PLD α、β、δ 和 ζ 同种型的基因表达几乎完全下调。结果表明，己醛蒸汽处理可以有益地影响多种生化途径中基因的表达，最终可以提高园艺产品的保质期和质量。实时 PCR 分析还证实了在己醛蒸汽处理的辣椒中编码 PLD α、β、δ 和 ζ 同种型的基因表达几乎完全下调。结果表明，己醛蒸汽处理可以有益地影响多种生化途径中基因的表达，最终可以提高园艺产品的保质期和质量。实时 PCR 分析还证实了在己醛蒸汽处理的辣椒中编码 PLD α、β、δ 和 ζ 同种型的基因表达几乎完全下调。结果表明，己醛蒸汽处理可以有益地影响多种生化途径中基因的表达，最终可以提高园艺产品的保质期和质量。