ABSTRACT
Fruit ripening is a highly coordinated developmental process that coincides with seed maturation. Regulated expression of thousands of genes controls fruit softening as well as accumulation of pigments, sugars, acids, and volatile compounds that increase attraction to animals. A combination of molecular tools and ripening-affected mutants has permitted researchers to establish a framework for the control of ripening. Key to crop improvement is a deeper understanding of the processes underlying fruit ripening. In tomato, mutations blocking the transition to ripe fruits have provided insights into the role of ethylene and its associated molecular networks involved in the control of ripening. However, the role of other plant hormones is still poorly understood. Translation of information from tomato to other eshy-fruited species indicates that regulatory networks are conserved across a wide spectrum of angiosperm fruit morphologies. In this chapter, we describe how plant hormones, transcription factors, and epigenetic changes are intimately related to provide tight control of the ripening process. These discoveries are likely to have a major impact on strategies for crop improvement through genetic manipulation of ripening regulatory genes in fruit-bearing species. The ndings from comparative genomics and system biology approaches are also discussed. Recent developments in the sequencing of angiosperm genomes have provided the foundation for a step change in crop improvement through the understanding and harnessing of genome-wide genetic and epigenetic variation.
