Recently, Horticultural Plant Journal published online a research paper by the fruit and vegetable storage and processing research team at Yangzhou University titled “Effects of 1-MCP on Proline, Polyamine, and Nitric Oxide Metabolism in Postharvest Peach Fruits under Chilling Stress“.
Peaches are sensitive to low temperatures, and prolonged storage below 8 °C can cause cold damage, resulting in flesh browning and a mealy texture, severely affecting fruit quality. Proline, polyamines, and nitric oxide are three active plant small molecules that participate in regulating the physiological processes of postharvest cold damage in fruits and inhibit cold damage occurrence. Since these three substances compete for the same synthetic substrates (as shown below), they are often studied together. 1-MCP is an efficient ethylene antagonist widely used in the preservation of fruits and vegetables, but the effects of 1-MCP on proline, polyamines, and nitric oxide remain unknown.
Figure 1. Competitive synthesis mechanism of proline, polyamines, and nitric oxide
The occurrence of cold damage in peach fruits is a complex physiological change process involving abnormal metabolism of reactive oxygen species, energy, cell walls, and other substances. Active small molecules in plants, such as proline, polyamines, and nitric oxide, actively participate in the physiological regulation of low-temperature stress, alleviating cold damage; however, their roles and metabolic mechanisms are not clear. This study explores how proline, polyamines, and nitric oxide participate in delaying the occurrence of cold damage in peach fruits and the effects of 1-MCP treatment on them.
To explore the regulatory effects of proline, polyamines, and nitric oxide on postharvest cold damage in peaches, and the impact of 1-MCP treatment on them, peaches were treated with 1-MCP (1 μL · L-1) and ethylene (1 μL · L-1), stored at 4 °C for 28 d, and then moved to 25 °C for 3 d to simulate shelf life. After 7 d of cold storage, peaches exhibited symptoms of cold damage, accompanied by increased conductivity and accumulation of malondialdehyde. Under cold stress, proline and polyamines in peaches were primarily synthesized from glutamic acid and arginine, respectively, with Δ’-pyrroline-5-carboxylate synthase (P5CS) and arginine decarboxylase (ADC) playing crucial roles. Compared to the control, the contents of proline and polyamines in peaches treated with 1-MCP increased, enhancing cold resistance. In comparison to the control, cold damage symptoms in peaches treated with ethylene were more severe, while nitric oxide content decreased and the activity of nitric oxide synthase weakened; however, nitric oxide may not be a direct active factor in 1-MCP induced cold resistance in peaches, as the nitric oxide content also decreased in peaches treated with 1-MCP. The activity of nitric oxide synthase also weakened. In summary, proline and polyamines significantly participate in the cold resistance induced by 1-MCP, while nitric oxide did not directly participate.
Fig. 7. Effects of 1-MCP and ethylene treatments on the NO contents (a) and NOS activity (b) of peach fruit under chilling stress.
This study explores the preservation mechanism of 1-MCP from the perspective of its effects on active small molecules (proline, polyamines, and nitric oxide). The results provide new insights into the mechanisms of cold damage occurrence in peaches and the preservation mechanisms of 1-MCP.
Qian Chunlu is the first author of this paper, with Qian Chunlu and Xiao Lixia as corresponding authors. The adversity physiology research team of horticultural crops at Yangzhou University also participated in this study.
Funding Introduction:
This research was funded by the Jiangsu Natural Science Foundation (BK20140483) and the China Postdoctoral Science Foundation (2014M560451).
Paper Link:
https://www.sciencedirect.com/science/article/pii/S246801412030131X
Journal Introduction:Horticultural Plant Journal is an English academic journal sponsored by the Chinese Society for Horticulture, the Vegetable and Flower Research Institute of the Chinese Academy of Agricultural Sciences, and the China Agricultural Science and Technology Press. It is currently indexed by international databases such as SCIE, Scopus, Biological Abstracts (BA) & BIOSIS Previews (BP), Directory of Open Access Journals (DOAJ), CABI Abstracts, Food Science and Technology Abstracts, CNKI Global, CSTPCD, etc.
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https://www.editorialmanager.com/hortpj/
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https://www.sciencedirect.com/journal/horticultural-plant-journal
