Jasmonate Metabolism and Its Relationship with Abscisic Acid During Strawberry Fruit Development and Ripening

The plant hormone jasmonoyl-isoleucine (JA-Ile) is involved in stress response, development, and secondary metabolite production, although its role in fruit development and ripening remains unknown. The aim of this study is to describe variations of endogenous jasmonate (JAs) contents and JA metabolism-related genes in order to associate these to the evolution of abscisic acid (ABA) content during development and ripening of strawberry (Fragaria x ananassa Duch. cv. Aromas) fruit. A quantitative analysis of phytohormones and gene expression was carried out using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and quantitative reverse transcription PCR (RT-qPCR) assays, respectively. The expression of genes encoding for JA metabolism enzymes exhibited a significant decrease concomitant to reduction of JAs and an increment of ABA levels from flowering to ripening stages. Exogenous application of methyl jasmonate (MeJA) triggered anthocyanin accumulation along with an increase in JA-Ile, JA, and MeJA levels, and a concomitant decrease in ABA. Together, these results provide insights into JAs homeostasis during strawberry fruit development, suggesting that MeJA-induced anthocyanin accumulation could be mediated by the activation of the JA signaling pathway. Furthermore, we propose an antagonistic relationship from the JA to the ABA pathway during non-climacteric strawberry fruit development and ripening.