Peach fruit PpNAC1 activates transcription to provide -3 fatty acids for the synthesis of short-chain flavor volatiles.

Volatile organic compounds (VOCs) derived from fatty acids are major contributors to fruit flavor and affect human preferences. The -3 fatty acid linolenic acid 3 (18:3) serves as an important precursor for synthesis of ()-2-hexenal and ()-3-hexenol. These short-chain C6 VOCs provide unique fresh notes in multiple fruit species. Metabolic engineering to improve fruit aroma requires knowledge of the regulation of fatty acid-derived VOCs. Here, we determined that ripe fruit-specific expression of contributes to 18:3 synthesis in peach fruit. However, no significant increases in ()-2-hexenal and ()-3-hexenol were detected after overexpressing . Interestingly, overexpressing the transcription factor increased the content of 18:3 and enhanced the production of its derived volatiles. Moreover, induced expression of genes responsible for downstream VOC synthesis was observed for transgenic tomato fruit overexpressing , but not for transgenic fruit overexpressing . Electrophoretic mobility shift and ChIP-Seq assays showed that PpNAC1 activated expression via binding to its promoter. Therefore, plays an important role in modulating fatty acid flux to produce fruit flavor-related VOCs. In addition to PpNAC1, expression was also associated with epigenetic modifications during peach fruit ripening. Taken together, our results provide new insights into the molecular mechanisms regulating biosynthesis of fatty acid and short-chain VOCs in fruit.