Genetic and epigenetic regulation of tomato fruit ripening

Tomato is one of the top consumed vegetables and an excellent model for studies on fleshy fruit ripening. In tomato, ripening is a complex process regulated by genetic and epigenetic mechanisms together with plant hormones. So far mostly one-on-one regulatory relationships between regulators and effectors were explored, but the true function of some major regulators is still not clear, as are the interactions of their spontaneous mutant alleles in ripening regulation. This thesis studies tomato fruit ripening regulation at the molecular level by focusing on the evaluation of the true function of major transcription factors (TFs), on the interaction of their spontaneous mutant alleles and on the effects of non-coding elements. To achieve that, CRISPR/Cas9-mutagenesis as well as crosses were used to obtain real knock-out mutants and genotypes with different and combined doses of spontaneous mutant alleles, followed by phenotyping and gene expression analysis to evaluate their functions in ripening. Moreover, some suggestions for future CRISPR mutagenesis experiments are proposed based on our observations. In conclusion, this thesis illustrates the function of some major TFs and interactions of their spontaneous mutant alleles in tomato ripening regulation, which enhances our knowledge, and points the way to future work on ripening regulation