The regulatory role of DzERF94 in carotenoid biosynthesis during ripening in durian (Durio zibethinus) pulp

Durian pulp exhibits varying intensities of yellow color because of variations in carotenoid content and composition among cultivars. Carotenoid biosynthesis is regulated by multiple factors, including APETALA2 (AP2)/ethylene response factor (ERF) transcription factors. In this study, four durian cultivars with distinct yellow color intensities were analyzed. Expression profiling of carotenoid biosynthetic and AP2/ERF genes during fruit development and ripening identified the AP2/ERF transcription factor DzERF94, which was positively correlated with the transcript level of durian lycopene ε-cyclase (DzLCYE) and lutein content in the pale-yellow cultivar Kathoei Nueakhao. Transient expression of DzERF94 in tomatoes led to increased LCYE transcript levels and lutein content. Additionally, DzERF94 activated the DzLCYE promoter in a dual-luciferase assay. Transcriptome analysis of these transiently transformed tomatoes further suggested that DzERF94 influences carotenoid metabolism and ethylene and abscisic acid signaling pathways. These findings provide new insights into the role of AP2/ERF proteins in regulating carotenoid accumulation during durian fruit development and ripening across cultivars.