ORIGINAL RESEARCH article
Front. Plant Sci.
Sec. Crop and Product Physiology
Rootstock Selection Shapes Melon Taste by Divergent Regulation of Sugar and Amino Acid Metabolism
Hao Zhang 1
Muhammad Mohsin Kaleem 2
Liang Qigan 1
Yinke Du 1
Maerhaba Paerhati 3
Tian Banlv 2
Haojie Zhang 2
Zhang Wenwei 2
Yuan Huang 2
Fu Xiaofa 1
Min Wang 4
Zhu Jingrong 3
Bin Liu 5
1. Breeding Station in Sanya, Hainan, Xinjiang Academy of Agricultural Sciences, Xinjiang Uygur Autonomous Region, Sanya,572000, China, Sanya, China
2. Huazhong Agricultural University, Wuhan, China
3. Key Laboratory of Functional Nutrition and Health of Characteristic Agricultural Products in Desert Oasis Ecological Region , Ministry of Agriculture and Rural Affairs Xinjiang China., Xinjiang, China
4. Vegetable Research Institute, Hainan Academy of Agricultural Sciences, Haikou, 570000, China, Haikou, China
5. Sanya Mingzhu Melon and Watermelon Variety Demonstration Evaluation and Research Center; Sanya，572000, China, Sanya, China
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Abstract
Melon (Cucumis melo L.) is a widely cultivated fruit, renowned for its nutritional value and culinary applications. This study explores the molecular mechanisms underlying flavor enhancement in melons grafted onto different rootstocks: Cucurbita moschata (QY1) and Cucumis metuliferus (ZM4). Transcriptomic and metabolomic analyses revealed significant genetic and metabolic adaptations in response to grafting. The two rootstocks exhibited different strategies: ZM4 activated genes related to carbohydrate metabolism, while QY1 activated energy metabolism. The ZM4 rootstock showed significant upregulation of sucrose-cleaving enzymes such as INV and bglX/bglB, correlating with the accumulation of glucose and fructose, while key nucleotide-sugar synthases (UGDH and GAE) expanded UDP-sugar precursors for glycosylation. These genetic changes led to enhanced anabolic flux, including the accumulation of cell wall polysaccharides such as mannan and glycosides like vanilloyl glucose. In contrast, ZM4/SG exhibited enhanced stress resilience by activating AKR1A1 and MIOX, leading to increased accumulation of xylitol and trehalose-6-phosphate. Furthermore, QY1/SG showed increased amino acid metabolism activity, with elevated expression of E3.2.1.21 and MIOX, promoting glycoside hydrolysis and NADPH regeneration, thus enhancing energy metabolism. This study highlights the coordinated gene expression of hydrolytic, biosynthetic, and stress-adaptive pathways in ZM4/SG, which is associated with a redirection of carbon flux towards structural polysaccharides and high-value glycosides. These findings provide valuable insights into and are consistent with a role for rootstock-mediated processes in quality related traits improvement in melons. Collectively, these discoveries outline a working model for future research aimed at elucidating the synergistic regulatory networks through which rootstocks influence fruit sweetness, which will be essential for advancing strategies toward precise quality modulation in melons.
Summary
Keywords
Cucumis metuliferus, Cucurbita moschata, Grafting, Metabolomics, rootstock, Transcriptomics
Received
05 November 2025
Accepted
17 February 2026
Copyright
© 2026 Zhang, Kaleem, Qigan, Du, Paerhati, Banlv, Zhang, Wenwei, Huang, Xiaofa, Wang, Jingrong and Liu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Zhu Jingrong
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