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

Abstract

Key message: DzERF94 correlates with DzLCYE and lutein in pale-yellow durian; dual-luciferase and EMSA assays show it binds and activates the DzLCYE promoter, altering carotenoid production in tomato. 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. Kathoei Nueakhao, a pale-yellow cultivar, was the only cultivar in which both DzERF94 and DzLCYE remained expressed at the ripe stage, and it also accumulated the highest lutein content. 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, and an electrophoretic mobility shift assay (EMSA) showed that DzERF94 binds the DzLCYE promoter in vitro. 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.