Steroidal glycoalkaloids (SGAs) are a class of cholesterol-derived anti-nutritional defense compound that are produced in species of the genus Solanum, such as tomato (S. lycopersicum), potato (S. tuberosum), and eggplant (S. melongena). However, the regulation of defense-related metabolites in eggplant remains underexplored. In tomato and potato, the JASMONATE-RESPONSIVE ETHYLENE RESPONSE FACTOR 4 (JRE4) transcription factor positively regulates a large number of genes involved in SGA biosynthesis. Here, we report that the overexpression of eggplant JRE4 (SmJRE4) induces numerous metabolic genes involved in SGA biosynthesis in leaves. We demonstrate the jasmonate-dependent induction of SmJRE4 and its downstream metabolic genes and show that ethylene treatment attenuates this induction. Our findings thus provide molecular insights into SGA biosynthesis and its regulation in this major crop.
Keywords: eggplant; ethylene; jasmonate; steroidal glycoalkaloids; transcription factor.