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Article|04 Apr 2022|OPEN
Peach fruit PpNAC1 activates PpFAD3-1 transcription to provide ω-3 fatty acids for the synthesis of short-chain flavor volatiles
Zhengnan Jin1 , Jiaojiao Wang2 , Xiangmei Cao1 , Chunyan Wei1 , Jianfei Kuang3 , Kunsong Chen1 and Bo Zhang,1 ,
1Laboratory of Fruit Quality Biology, Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
2School of Agriculture and Biology, Shanghai Jiao Tong University, Minhang Campus, Shanghai 200240, China
3Guangdong Key Laboratory for Postharvest Science, College of Horticultural Science, South China Agricultural University, Guangzhou 510642, China
*Corresponding author. E-mail: bozhang@zju.edu.cn

Horticulture Research 9,
Article number: uhac085 (2022)
doi: https://doi.org/10.1093/hr/uhac085
Views: 20

Received: 16 Nov 2021
Accepted: 27 Mar 2022
Published online: 04 Apr 2022

Abstract

Volatile organic compounds (VOCs) derived from fatty acids are major contributors to fruit flavor and affect human preferences. The ω-3 fatty acid linolenic acid 3 (18:3) serves as an important precursor for synthesis of (E)-2-hexenal and (Z)-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 PpFAD3-1 contributes to 18:3 synthesis in peach fruit. However, no significant increases in (E)-2-hexenal and (Z)-3-hexenol were detected after overexpressing PpFAD3-1. Interestingly, overexpressing the PpNAC1 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 PpNAC1, but not for transgenic fruit overexpressing PpFAD3-1. Electrophoretic mobility shift and ChIP-Seq assays showed that PpNAC1 activated PpFAD3-1 expression via binding to its promoter. Therefore, PpNAC1 plays an important role in modulating fatty acid flux to produce fruit flavor-related VOCs. In addition to PpNAC1, PpFAD3-1 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.