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 upregulates PpPIF3 expression. The resulting increase in PpPIF3 expression level negatively regulates structural genes (PpPSY2, PpPDS, PpZDS, PpLCYE, PpCYB1, PpHYB, PpHYE) expression. Bagging promoted the increase of zeaxanthin and the decrease of xanthophyll, β-cryptoxanthin, α-carotene, β-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.

中文翻译：

---

套袋遮光对桃果肉中类胡萝卜素积累的影响

为了阐明套袋遮光对桃果肉中类胡萝卜素积累的影响，对两个黄肉桃品种（3D-8和C18）在50℃套袋处理（黄黑色双层袋）后的果实进行了分析。盛开后的几天。套袋处理显着降低了类胡萝卜素含量。这种减少的原因可能是由于装袋导致的黑暗条件上调了 PpPIF3 表达。由此产生的 PpPIF3 表达水平的增加负向调节结构基因（PpPSY2、PpPDS、PpZDS、PpLCYE、PpCYB1、PpHYB、PpHYE）的表达。套袋促进了玉米黄质的增加和叶黄素、β-隐黄质、α-胡萝卜素、β-胡萝卜素的减少，最终降低了总类胡萝卜素的含量。然而，装袋对与类胡萝卜素切割相关的基因表达的影响很小。