Recent advances in fruit development and ripening: an overview.

This article provides an overview of the Journal of Experimental Botany Special Issue on Fruit Development and Ripening. It reports that significant progress is being made in identifying genes controlling the development of dry dehiscent fruits in the model plant species Arabidopsis thaliana. In plants with fleshy fruits, a major focus has been the dissection of biochemical and genetic regulatory cascades controlling ripening, using tomato as a model species. Intermediates of the ethylene-signalling cascade, potential cross-talk between ethylene and auxin signals, and the role of ethylene-independent signals have all been described in this climacteric fruit. The recent isolation of the NOR and LeMADS-RIN genes, which participate in ethylene-independent signalling in tomato, and the discovery that a homologue of the RIN gene is expressed in strawberry, a non-climacteric fruit, suggests that common regulatory cascades may operate in all fruits. Transcriptional profiling during the development and ripening of both climacteric (tomato) and non-climacteric (strawberry) fruit has supported these observations, and also identified a number of novel genes involved in the biochemistry of fruit development and ripening. The use of phylogenies based on chloroplast gene sequences has allowed an insight into the evolution of fruit forms and fruit biochemistry, which may be useful for the manipulation of commercial species. Several molecular approaches, including positional cloning, QTL mapping and genetic engineering, are helping to define the biochemical and molecular bases of texture, flavour, colour, and aroma. As the understanding of the biology of fruit ripening has improved, so has the ability to improve the organoleptic and nutritional qualities of fruits through crop management, breeding or biotechnology.