Tomato fruit ripening is regulated by transcription factors (TFs), their downstream effector genes, and the ethylene biosynthesis and signalling pathway. Spontaneous non-ripening mutants ripening inhibitor (rin), non-ripening (nor) and Colorless non-ripening (Cnr) correspond with mutations in or near the TF-encoding genes MADS-RIN, NAC-NOR and SPL-CNR, respectively. Here, we produced heterozygous single and double mutants of rin, nor and Cnr and evaluated their functions and genetic interactions in the same genetic background. We showed how these mutations interact at the level of phenotype, individual effector gene expression, and sensory and quality aspects, in a dose-dependent manner. Rin and nor have broadly similar quantitative effects on all aspects, demonstrating their additivity in fruit ripening regulation. We also found that the Cnr allele is epistatic to rin and nor and that its pleiotropic effects on fruit size and volatile production, in contrast to the well-known dominant effect on ripening, are incompletely dominant, or recessive.

中文翻译：

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rin、nor 和 Cnr 自发突变以加性和上位方式抑制番茄果实成熟

番茄果实成熟受转录因子 (TF)、其下游效应基因以及乙烯生物合成和信号通路的调控。自发非成熟突变体成熟抑制剂 (rin)、非成熟 (nor) 和无色非成熟 (Cnr) 分别对应于 TF 编码基因 MADS-RIN、NAC-NOR 和 SPL-CNR 中或附近的突变。在这里，我们产生了 rin、nor 和 Cnr 的杂合单突变体和双突变体，并在相同的遗传背景下评估了它们的功能和遗传相互作用。我们展示了这些突变如何在表型、个体效应基因表达以及感官和质量方面以剂量依赖性方式相互作用。Rin 和 nor 在所有方面都具有广泛相似的定量影响，表明它们在果实成熟调控中的可加性。