Effect of Treatments at Different Light Time on Coumarin Metabolism in Colored Layer of Pomelo Peri-carp
Pomelo,a significant fruit in southern regions,contains coumarin-rich pericarp highly influenced by the external environ-ment.However,the impact of light on coumarin metabolism remains unclear.This study conducted four light time treatments(12 h,24 h,36 h,and 48 h)to investigate light's effect on coumarin metabolism in the colored layer of pomelo pericarp.Gongshui white pomelo and dwarf-late pomelo were utilized as test materials,with 21 coumarins detected through targeted metabolomics.Following this,peri-carps were colored in control and treatment groups for comparative analysis of coumarin metabolic differences.The results indicated that bergamottin,aurapten and osthol were among the coumarins with high content and significant differences in the colored layer of Gongshui white pomelo and dwarf-late pomelo pericarps.Different light time significantly influenced the accumulation of bergamottin,aurapten,osthol and total coumarin in Gongshui white pericarp's colored layer.Additionally,osthenol,bergamottin,aurapten,osthol and total coumarin accumulation were notably affected in dwarf-late pomelo pericarp's colored layer.PCA analysis revealed distinct relative content of total coumarin in the colored layer of Gongshui white pomelo and dwarf-late pomelo treated with different light times.Overall,light treatment altered the coumarin accumulation characteristics in the colored layer of Gongshui white pomelo and dwarf-late pomelo,with dwarf-late pomelo showing higher osthenol and columbianetin accumulation compared to Gongshui white pomelo.These findings provide a basis for understanding the regulatory mechanism of light on citrus coumarin metabolism,it provides a new idea for improving the medicinal quality of citrus.