Kiwifruit (Actinidia arguta) is an economically important horticultural crop worldwide with remarkably high nutritional value. However, the dynamic metabolic changes underlying fruit quality during kiwifruit ripening remain poorly understood. In this study, integrated metabolomic and transcriptomic analyses were conducted to explore the molecular basis of fruit quality across three ripening stages in three A. arguta varieties with distinct flesh characteristics: ‘Kokuwa’ (full-green flesh), ‘Xianziguang’ (red flesh), and ‘Qinghuang’ (yellow flesh). A total of 371 differentially accumulated metabolites and their coexpressed genes were classified into six distinct metabolite vs gene modules. Several metabolites, including five sugars, eight organic acids, four volatile compounds, and seventeen flavonoids, such as anthocyanins, procyanidins, and flavones, were further identified as key contributors to fruit quality formation. By integrating gene coexpression network analysis with metabolomic data, we identified a range of ripening-related genes and transcription factors involved in the biosynthesis of sugars, organic acids, anthocyanins, and the L-ascorbic acid metabolic pathway. Notably, thirteen structural genes involved in anthocyanin biosynthesis—anthocyanidin reductase (2), dihydroflavonol 4-reductase (4), flavonol synthase (5), and phenylalanine ammonia-lyase (2), were strongly correlated with multiple transcription factors, indicating that a complex regulatory network governed anthocyanin biosynthesis in A. arguta. This study provides new insights into the molecular basis of metabolite variation in kiwifruit and highlights the potential of genetic information for improving fruit quality.
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Funding
National Natural Science Foundation of China(32300314)
Shaanxi Science and Technology Co-ordination and Innovation Project of China(2022K-09)
Key Science and Technology Program of Shaanxi Province(2023-JC-QN-0253)
RIGHTS & PERMISSIONS
The Author(s)
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