Unlocking the secret to fresh-cut apple freshness: Violet LED and transcription factors
image: Violet LED light increased the antioxidant capacity and decreased oxidative enzyme activities of fresh-cut apple fruit.
Credit: Horticulture Research
Fresh-cut apple browning is a significant quality issue, often reducing the fruit's marketability. Recent research reveals that violet light emitting diode (LED) light treatment effectively inhibits this process by increasing phenolic accumulation. The study identifies key transcription factors, MdHY5 and MdHYH, that play a crucial role in regulating phenolic metabolism. By activating the phenolic biosynthesis gene MdPAL and inhibiting the phenolic degradation genes MdPPO and MdPOD, violet LED light reduces enzymatic browning in apple slices. These findings provide valuable insights into enhancing fresh-cut apple quality and potentially extend to other fresh-cut fruits.
Enzymatic browning in fresh-cut fruits, particularly apples, significantly affects their appearance and shelf life. Various methods, including light treatments, have been explored to combat this issue. However, the molecular mechanisms behind how light inhibits browning have remained unclear. This study investigates the effects of violet light emitting diode (LED) light on fresh-cut apples, focusing on its impact on phenolic compounds and related transcription factors. By elucidating these pathways, the research aims to provide a deeper understanding of how light treatment can preserve fruit quality, with implications for postharvest handling in the fruit industry.
Based on these challenges, further research is needed to optimize light treatments for broader applications.
The study (DOI: 10.1093/hr/uhae276), published in Horticulture Research in September 2024, investigates the impact of violet LED light on fresh-cut apple browning. Researchers from Shenyang Agricultural University and Liaoning Agricultural Vocational and Technical College explored how this light treatment influences the phenolic content in apples. By using metabolomic and transcriptomic analyses, they identified key genes and transcription factors, particularly MdHY5 and MdHYH, that regulate phenolic accumulation and degradation. The findings offer valuable insights into improving fresh-cut apple quality through light-based interventions.
Violet LED light treatment significantly reduced the browning of fresh-cut apple slices by promoting phenolic accumulation and suppressing the activities of oxidative enzymes like polyphenol oxidase (MdPPO) and peroxidase (MdPOD). Metabolomic analysis revealed an increase in phenolic acids and flavonoids, key compounds responsible for the antioxidant activity of apples. Transcriptomic analysis identified that the violet light activated MdHY5 and MdHYH transcription factors, which directly regulate the expression of phenolic-related genes. Specifically, MdHY5 and MdHYH were found to suppress MdPPO and MdPOD expression while enhancing MdPALexpression, thus reducing phenolic degradation and boosting synthesis. Further experiments showed that when MdHY5 and MdHYH were silenced, the violet LED light no longer inhibited browning, highlighting their essential roles in the process. Additionally, the study found that MdHY5 and MdHYH form a positive feedback loop, activating each other's expression, which further strengthens their regulatory roles. This discovery provides new insights into the molecular mechanisms by which light treatments can be used to maintain the freshness and quality of cut fruit.
Dr. Hui Yuan, a key researcher in this study, commented: “Our findings underscore the significance of light treatment in reducing the enzymatic browning of fresh-cut apples. By understanding the molecular mechanisms involving MdHY5 and MdHYH, we can optimize light-based interventions to enhance the quality and shelf life of fresh-cut fruits. This research not only opens new doors for apple preservation but could also be applied to a wide range of other fresh-cut produce, benefiting both the food industry and consumers.”
The findings from this study have significant implications for the fruit industry. By utilizing violet LED light to regulate phenolic metabolism, the postharvest shelf life of fresh-cut apples can be extended, improving their marketability and reducing food waste. The discovery of MdHY5 and MdHYH[s role in this process opens up new avenues for genetic or environmental manipulation to enhance fruit quality. This approach could be expanded to other fruits, offering a simple, cost-effective solution to preserve fresh-cut produce. Further research into optimizing light treatments and exploring their impact on other quality parameters will be crucial for future applications in food preservation.
###
References
DOI
Original Source URL
https://doi.org/10.1093/hr/uhae276
Funding information
This work was supported by the National Key Research and Development Program of China (2022YFD2100105) and the National Natural Science Foundation of China (32125034).
About Horticulture Research
Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.