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Fruit size is an important fruit quality trait that influences the production and commodity values of loquats (Eriobotrya japonica Lindl.). The Small Auxin Upregulated RNA (SAUR) gene family has proven to play a vital role in the fruit development of many plant species. However, it has not been comprehensively studied in a genome-wide manner in loquats, and its role in regulating fruit size remains unknown. In this study, we identified 95 EjSAUR genes in the loquat genome. Tandem duplication and segmental duplication contributed to the expansion of this gene family in loquats. Phylogenetic analysis grouped the SAURs from Arabidopsis, rice, and loquat into nine clusters. By analyzing the transcriptome profiles in different tissues and at different fruit developmental stages and comparing two sister lines with contrasting fruit sizes, as well as by functional predictions, a candidate gene (EjSAUR22) highly expressed in expanding fruits was selected for further functional investigation. A combination of Indoleacetic acid (IAA) treatment and virus-induced gene silencing revealed that EjSAUR22 was not only responsive to auxin, but also played a role in regulating cell size and fruit expansion. The findings from our study provide a solid foundation for understanding the molecular mechanisms controlling fruit size in loquats, and also provide potential targets for manipulation of fruit size to accelerate loquat breeding. [ABSTRACT FROM AUTHOR]

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. • Reduced expression of MaERF124 is inversely associated with carotenoid accumulation. • MaERF124 acts as a transcriptional repressor. • MaERF124 suppresses the transcription of carotenogenesis genes. • Overexpression of MaERF124 in tomato inhibits carotenoid production. [ABSTRACT FROM AUTHOR]