Investigation of the Jasmonate ZIM-Domain Family Reveals PavJAZ8 Regulates Fruit Aroma Traits in Sweet Cherry (Prunus avium L.).

Jasmonate ZIM-domain (JAZ) family genes, which belong to TIFY family, are plant-specific transcriptional repressors. As key regulators of the jasmonic acid signaling pathway, JAZ proteins play crucial roles in various aspects of plant biology. However, the identification and functional characterization of JAZ genes in sweet cherry (Prunus avium L.) fruit remain unknown. In the present study, we identified nine JAZ members in the sweet cherry genome. We systematically analyzed the gene structures, protein domains, evolutionary relationships, and physicochemical properties of these members and also evaluated their expression levels across different fruit developmental stages, as well as under methyl jasmonate (MeJA) treatment. Among these members, our results revealed a previously uncharacterized JAZ member, PavJAZ8, as a crucial regulator of fruit aroma traits. Specifically, RT-qPCR analysis showed that PavJAZ8 overexpression modulates the expression of genes involved in the biosynthesis of aroma volatiles, such as PavLOX2, PavLOX3, PavHPL1, PavADH1.1, PavADH1.2, and PavADH7, which are involved in the synthesis of aldehydes and alcohols. Consistent with the gene expression data, analysis of volatile metabolites revealed that PavJAZ8 overexpression significantly inhibited the accumulation of several related aldehydes and alcohols, including hexanal, geraniol, and benzyl alcohol. Furthermore, PavJAZ8 expression was highly responsive to phytohormone treatments, such as abscisic acid (ABA) and MeJA. Further analysis showed that PavJAZ8 interacts with PavMYC2, thereby mediating JA signal transduction. Our results highlight PavJAZ8 as a novel regulator of fruit aroma quality, offering a valuable genetic target for sweet cherry improvement.