Molecular orchestration of malate and citrate metabolism: regulatory networks governing organic acid dynamics and fruit quality attributes

Abstract

In most fleshy fruit, malate and citrate represent the predominant organic acids, serving as key determinants of flavor and nutritional quality. Their concentrations undergo dynamic changes driven by complex biosynthetic pathways and multilayered genetic regulation. Beyond their impact on taste, these organic acids have pleiotropic effects, influencing secondary metabolism and postharvest performance. This review synthesizes current knowledge on the molecular mechanism governing malate and citrate metabolism, including genes responsible for biosynthesis, catabolism, and transport, as well as regulatory networks orchestrated by transcription factors, environmental factors, and phytohormones such as ethylene, abscisic acid (ABA), auxin, gibberellin (GA), and salicylic acid (SA) during fruit development and ripening. We also explored how the dynamics of citrate and malate interact with critical quality attributes, including starch metabolism, textural properties, and postharvest performance, while highlighting domestication-selected genes that influence acidity. Finally, we propose an integrative model delineates the multifactorial regulation of organic acid metabolism in fleshy fruits.

Acknowledgements

This work was supported by National Natural Science Foundation of China (U23A20188), Natural Science Foundation of Fujian Province (2025 J01561), and Special Fund for Science and Technology Innovation of Fujian Agriculture and Forestry University (KFb22111XA).

Authors contributions

B.L.F. and L.Y.C. conceived this review. B.L.F. wrote original draft. L.Y.C. revised the manuscript.

Data availability

No datasets were generated or analyzed during the current study.

Conflicts of interest statement

The authors declare no conflict of interest.

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