Key transcription factors regulate fruit ripening and metabolite accumulation in tomato

Huimin Jia, Yaping Xu, Yuanwei Deng, Yinhuan Xie, Zhongshan Gao, Zhaobo Lang, Qingfeng Niu

Plant Physiol.; 2024 Jun 28; 195(3):2256-2273. doi: 10.1093/plphys/kiae195.

Abstract

Fruit ripening is a complex process involving dynamic changes to metabolites and is controlled by multiple factors, including transcription factors (TFs). Several TFs are reportedly essential regulators of tomato (Solanum lycopersicum) fruit ripening. To evaluate the effects of specific TFs on metabolite accumulation during fruit ripening, we combined CRISPR/Cas9-mediated mutagenesis with metabolome and transcriptome analyses to explore regulatory mechanisms. Specifically, we generated various genetically engineered tomato lines that differed regarding metabolite contents and fruit colors. The metabolite and transcript profiles indicated that the selected TFs have distinct functions that control fruit metabolite contents, especially carotenoids and sugars. Moreover, a mutation to ELONGATED HYPOCOTYL5 (HY5) increased tomato fruit fructose and glucose contents by approximately 20% (relative to the wild-type levels). Our in vitro assay showed that HY5 can bind directly to the G-box cis-element in the Sugars Will Eventually be Exported Transporter (SWEET12c) promoter to activate expression, thereby modulating sugar transport. Our findings provide insights into the mechanisms regulating tomato fruit ripening and metabolic networks, providing the theoretical basis for breeding horticultural crops that produce fruit with diverse flavors and colors.

See https://pubmed.ncbi.nlm.nih.gov/38561990/

Figure 1. Phenotypes of mutant fruit and differences in the fruit ripening process between the mutants and “Ailsa Craig” (AC). A) Phenotypes of the mutant and AC fruit collected at 46 DPA. Scale bar, 1 cm. B) Carotenoid contents of the mutants and AC. C) Ethylene production in the mutants and AC at 46 DPA. Data are presented as the mean ± Sd (n = 3) in panels B and C. Lowercase letters indicate significantly differences by Duncan's multiple range test with P < 0.05.