Plant pigments have a vital role in plant pollination, aesthetic appeal, and quality of the fruit. Naturally occurring major plant pigments include anthocyanins, carotenoids, and chlorophyll. In addition to their coloration, these pigments possess additional beneficial properties, which is why they are often referred to as bioactive compounds. Moreover, they exhibit strong antioxidant and antimicrobial properties. The pigments, particularly beta-carotene (a precursor to vitamin A), a type of carotenoid, are crucial for maintaining good vision. They can help reduce the risk of age-related macular degeneration and improve overall eye health. The antioxidants found in fruit pigments may improve cognitive function and reduce neurodegeneration. This review article explores the processes involved in the biosynthesis of essential pigments in fruits, emphasizing their biological significance and various applications, including effects on human health and economic value. Understanding these mechanisms can improve the color and quality of fruits, resulting in high consumer acceptance and higher market demand. The numerous benefits of plant pigments have sparked growing interest in incorporating them into our food. However, in-depth research is required to explore the biological significance of fruit pigments, as well as their role in human food and nutrition. Studies have shown that these bioactive compounds can help prevent and manage chronic degenerative diseases. Further research is necessary in both fundamental and applied areas to enhance pigment levels in fruit to a degree sufficient for disease prevention. Comprehensive research into the genetic regulation of pigment biosynthesis could illuminate pathways for enhancing pigmentation through genetic engineering or traditional breeding methods. Genome editing technologies like CRISPR could be employed to improve specific pathways related to pigment biosynthesis in fruits. Further promising opportunities for the application of these pigments beyond the food industry should be investigated, focusing on their potential contributions in cosmetics, textiles, medicine, agriculture, and other sectors.

Low temperature is among the most restrictive factors to limit the yield and distribution of pear. Pyrus hopeiensis is a valuable wild resource. PCA showed that P. hopeiensis had strong cold resistance. In this study, the mRNA and metabolome sequencing of P. hopeiensis flower organs exposed to different low temperatures were performed to identify changes of genes and metabolites in response to low-temperature stress. A total of 4 851 differentially expressed genes (DEGs) were identified. Trend analysis showed that these DEGs were significantly enriched in profiles 19, 18, 7, 14, 1, 4 and 11. And the KEGG enrichment analysis showed that the DEGs in profile 18 were significantly enriched in flavone and flavonol biosynthesis. Besides, the expressed trends as well as GO and KEGG functional enrichment analyses of DEGs under cold and freezing stress showed significantly difference. Analyses of flavonoid-related pathways indicated that flavonoid structural genes had undergone significant changes. Correlation analysis showed that bHLH and MYB TFs may affect flavonoid biosynthesis by regulating structural gene expression. And PhMYB308 and PhMYB330 were likely candidate repressors of flavonoid biosynthesis by binding to a specific site in bHLH proteins. In total, 92 differentially accumulated metabolites (DAMs) were identified in P. hopeiensis flowers including 12 flavonoids. WGCNA results showed that coral 1, pink and brown 4 modules were closely associated with flavonoids and 11 MYBs and 15 bHLHs among the three modules may activate or inhibit the expression of 23 structural genes of flavonoid biosynthesis. Taken together, the results of this study provided a theoretical basis for further exploration of the molecular mechanisms of flavonoid biosynthesis and cold resistance of P. hopeiensis flower organs and our findings laid a foundation for further molecular breeding in cold-resistant pear varieties.