PpSnRK1α-PpNAC6/PpNAC36 module mediates nitrogen-regulated biosynthesis of γ-decalactone in peach fruit

Abstract

Flavor-related compounds, particularly γ-decalactone—the key contributor to the characteristic ‘peach-like’ aroma—serve as essential indicators of peach fruit quality and strongly influence consumer purchasing decisions. However, excessive application of N fertilizers has led to a significant decline in the flavor quality of peaches, posing a major obstacle to the sustainable development of the peach industry. Although this remains a critical challenge, the molecular mechanisms linking N to flavor compound biosynthesis are still not well characterized. In this study, we discovered that excessive N application reduced the biosynthesis of γ-decalactone in peach, based on multi-year field observations. Correlation analysis and expression profiling under N treatments revealed that two NAC (NAM-ATAF1/2-CUC2) transcription factors (TFs), PpNAC6 and PpNAC36, were involved in regulating γ-decalactone biosynthesis in response to N signaling. Genetic analyses indicated that PpNAC6 and PpNAC36 positively regulated the accumulation of γ-decalactone. Both yeast one-hybrid (Y1H) assays and dual-luciferase reporter assays consistently showed that PpNAC6 and PpNAC36 directly interact with the promoter regions of γ-decalactone biosynthesis-related genes (PpAAT2, PpAAT3, PpLOX1, PpLOX6, and PpFAD3) and significantly enhance their transcriptional activity. Furthermore, transgene verification demonstrated that the α subunit of peach SNF-related Kinase 1 (PpSnRK1α) suppresses γ-decalactone biosynthesis. Notably, we found that PpSnRK1α interacts with PpNAC6/PpNAC36 and selectively phosphorylates PpNAC36 in response to N, thus regulating γ-decalactone production. Our study uncovers the transcriptional regulatory network involved in PpSnRK1α-mediated phosphorylation of PpNAC6/PpNAC36, linking N signaling to γ-decalactone synthesis in peach, and provides insights for molecular breeding and precision fertilization to enhance peach flavor.

Acknowledgements

This work is supported by China Agricultural Research System (No. CARS-30-2-02), the grants from the Agricultural Improved Variety Engineering Program of Shandong Province (2024LZGCQY021), project ZR2024MC193 supported by Shandong Provincial Natural Science Foundation and project ZR2022QC019 supported by Shandong Provincial Natural Science Foundation. The authors thank TopEdit (www.topeditsci.com) for its linguistic assistance during the preparation of this manuscript.

Authors contributions

F.P. and Y.G. conceived the research project. J.L. performed the majority of the experiments and analyzed the data. X.Z., X.W., Z.W., Z.L. conducted the experiments. F.P., Y.G. and J.L. wrote the manuscript. Q.C., Y.X., J.G., J.L., and H.G. discussed the article.

Data availability

Data are available in figures of the article and its supplementary materials.

Conflicts of interest statement

The authors declare no conflict of interest.

Supplementary material

Supplementary material is available at Horticulture Research online.

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