PpAPRR2 regulates chlorophyll biosynthesis and chloroplast development during early fruit development in peach.

Abstract

Key message: PpAPRR2 promotes chlorophyll accumulation in peach fruit, and its overexpression enhances fruitgreening in tomato. Fruit peel color represents an important quality trait in peach (Prunus persica L.), determined by the dynamic balance between chlorophyll and anthocyanin metabolism. While the regulatory networks controlling anthocyanin regulation have been well documented, the molecular mechanisms governing chlorophyll accumulation and peel greening remain less understood. Here, we identified nine ARR-B family transcription factors in peach and found that PpAPRR2 was predominantly expressed during early fruit development, showing a strong positive correlation with chlorophyll levels. Subcellular localization assays revealed that PpAPRR2 was localized in the nucleus. Functional analysis using virus-induced gene silencing (VIGS) in peach fruit reduced chlorophyll content and downregulation of photosynthesis-related genes. In contrast, heterologous overexpression of PpAPRR2 in tomato resulted in darker green fruits, enhanced chlorophyll content, and increased expression of chlorophyll biosynthesis genes. Transcriptome analysis further confirmed promotion of photosynthetic pathways and suppression of chlorophyll degradation in PpAPRR2-overexpressing tomato fruits. Together, these results demonstrate that PpAPRR2 acts as a regulator promoting chlorophyll accumulation and chloroplast development in peach fruit. This study provides novel insights into the genetic control of fruit peel coloration and offers a potential molecular target for improving fruit quality through genetic engineering.