Effects of Shading by Bagging on Carotenoid Accumulation in Peach Fruit Flesh

To clarify the effects of shading by bagging on the carotenoid accumulation in peach fruit flesh, the fruits of two yellow-fleshed peach cultivars (3D-8 and C18) were analyzed after a bagging treatment (yellow-black double-layered bag) at 50 days after full bloom. The bagging treatment significantly decreased the carotenoid content. The reason for this decrease may be that dark conditions due to bagging upregulatesPpPIF3expression. The resulting increase inPpPIF3expression level negatively regulates structural genes (PpPSY2,PpPDS,PpZDS,PpLCYE,PpCYB1,PpHYB,PpHYE) expression. Bagging promoted the increase of zeaxanthin and the decrease of xanthophyll, beta-cryptoxanthin, alpha-carotene, beta-carotene, and finally reduced the content of total carotenoids. However, bagging minimally influenced the expression of genes related to carotenoid cleavage. Additionally, bagging decreased peach fruit quality and the total phenol content, but increased the reactive oxygen species content.

Automated summary

Bagging significantly decreases carotenoid content in peach fruit flesh, possibly due to upregulation of PpPIF3 expression under dark conditions. This leads to negative regulation of structural genes and ultimately reduces total carotenoid content. Bagging also has minimal effect on genes related to carotenoid cleavage, but decreases peach fruit quality and total phenol content while increasing reactive oxygen species content.