Banana MaERF124 negatively modulates carotenoid accumulation during fruit ripening through repression of carotenogenesis genes

Abstract

Banana is an important source of carotenoids, and the fruit accumulate carotenoids during the ripening process. However, the regulatory mechanisms underlying carotenoid production in banana fruit have not been well studied. Here, we report that MaERF124 is a negative transcriptional regulator of carotenogenesis genes in banana. The reduced accumulation of MaERF124 was accompanied with the increased contents of carotenoids during the ripening of the four banana varieties, suggesting a negative role of MaERF124 in carotenoid production. Further assays showed that MaERF124 acts as a transcriptional repressor and directly targets the promoters of carotenoid biosynthetic genes including MaDXR, MaGGPS, MaCRTISO and MaLCYB1.2. Moreover, ectopic expression of MaERF124 in tomato fruit repressed the transcript levels of carotenoid formation genes to inhibit carotenoid production. Taken together, these findings reveal that MaERF124 negatively modulates carotenoid formation via transcriptional repression of key genes involved in carotenoid synthesis, which provides a regulatory machinery for improving the contents of carotenoids in banana fruit.