Transcription factor NOR and CNR synergistically regulate tomato fruit ripening and carotenoid biosynthesis

Abstract

Despite significant phenotypic variations between CNR spontaneous mutants and knockout mutants, ample genetic evidence has validated CNR's essential role in fruit ripening regulation (Manning et al. 2006; Wang et al., 2020; Gao et al. 2019; Lai et al. 2020). [...]CNR was chosen for further analysis. Asterisks above the bars indicate statistically significant differences (Student’s t test; *P < 0.05, **P < 0.01).g The proposed model of NOR and CNR in modulating tomato fruit ripening To assess the collaborative function of these two transcription factors, nor, cnr and nor/cnr mutants were created in the Ailsa Craig (AC) background using CRISPR/Cas9 gene editing technology. Additionally, dual-luciferase reporter assays demonstrated that NOR alone significantly enhanced DML2 transcription in tobacco leaves, while co-expression with CNR markedly boosted the transcription activity of NOR (Fig. 1d). [...]transient silencing of CNR in the NOR-OE genetic background substantially lowered DML2 expression levels (Fig. 1f). In this study, we uncovered that NOR interacts with CNR to enhance ethylene synthesis and tomato fruit ripening. [...]NOR/CNR-mediated DML2 expression feedback to regulate NOR/CNR gene expression.