Interaction between PpERF5 and PpERF7 enhances peach fruit aroma by upregulating PpLOX4 expression

Ethylene plays a critical role in peach (Prunus persica) fruit ripening; however, the molecular mechanism underlying ethylene-mediated aroma biosynthesis remains unclear. Here, we compared the difference in aroma-related volatiles and gene expression levels between melting-flesh (MF) and stony hard (SH) peach cultivars at S3, S4 I, S4 II, S4 III stages, and explored the relation between volatile biosynthesis related genes and ethylene response factor (ERF) genes. The concentration of fruity aromatic compounds such as lactones and terpenes increased significantly in MF peach during fruit ripening, while it was nearly undetectable in SH peach. LOX4 and FAD1 genes expressed concomitantly with ethylene emission and significantly downregulated by 1-MCP. Besides, 1-MCP treatment could sharply influence the fruity aromatic compounds, suggesting that these genes play key roles in volatile biosynthesis during fruit ripening. Furthermore, PpERF5 and PpERF7 could bind together to form a protein complex that enhanced the transcription of LOX4 more than each transcription factor individually. Overall, this work provides new insights into the transcriptional regulatory mechanisms associated with aroma formation during peach fruit ripening.