Objective Carotenoid content is an important factor affecting the color and taste of tomato (Solanum lycopersicum) fruit. This study aims to investigate the effect of jasmonic acid on carotenoid accumulation during tomato ripening,

Method Tomato fruits at 38 days after pollination were harvested, treated with exogenous hormones and their inhibitors and cultivated for five days. The carotenoid content was measured, and the expression changes of carotenoid synthesis genes during tomato ripening were systematically analyzed using qRT-PCR technology. The effects of jasmonic acid, ethylene and their inhibitors on the expression of these genes were studied.

Result The results showed that methyl jasmonate and ethylene treatments increased the carotenoid mass concentrations to 1.65-fold and 1.73-fold of the control, respectively, and upregulated the expression levels of carotenoid synthesis-related genes SlCRTISO and SlPSY1. In addition, the expression levels of ethylene biosynthesis pathway genes SlACS1, SlACS2, SlACS3, SlACO1, SlACO2, SlACO3, SlACO5 and SlACO6, and ethylene signal transduction pathway genes SlERF.B3 and SlEIL2 were up-regulated. The expression of the core gene SlMYC2 of the jasmonic acid signal transduction pathway was also up-regulated.

Conclusion Methyl jasmonate positively regulates carotenoid accumulation in tomato fruits, and affects the synthesis and signal transduction of ethylene, the key hormone controlling fruit ripening. This study provides important clues for understanding jasmonic acid-mediated regulation of carotenoid synthesis, with implications for controlling tomato fruit ripening.