Genetic and metabolic effects of ripening mutations and vine detachment on tomato fruit quality

Authors: OSIRIO, SONIA - Cornell University; CARNERIA, RAPHAEL - Cornell University; LYTOVCHENKO, ANNA - Max Planck Institute For Biogeochemistry; MCQUINN, RYAN - Boyce Thompson Institute; SORENSON, IBEN - Cornell University; VALARINO, JOSE - Max Planck Institute For Biogeochemistry; Giovannoni, James; FERNIE, ALISDAIR - Max Planck Institute For Biogeochemistry; ROSE, JOCELYN - Cornell University

Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2019
Publication Date: 5/26/2019
Citation: Osirio, S., Carneria, R., Lytovchenko, A., Mcquinn, R., Sorenson, I., Valarino, J., Giovannoni, J.J., Fernie, A., Rose, J. 2019. Genetic and metabolic effects of ripening mutations and vine detachment on tomato fruit quality. Plant Biotechnology Journal. 18(1). https://doi.org/10.1111/pbi.13176.
DOI: https://doi.org/10.1111/pbi.13176

Interpretive Summary: When fleshy fruits such as tomato, peach and banana ripen, they typically undergo changes in color, flavor, aroma and texture, all of which promote their quality and ultimately consumption. In nature this is a means of facilitating seed dispersal while for humans, fruit are important contributors to nutritional and food security. Ripening processes are complex and associated with a broad range of metabolic pathways, including those that lead to the accumulation of sugars, organic acids and additional chemicals influencing flavor and nutrition. Natural ripening mutations are used to delay ripening which helps extend shelf-life and reduce product loss but comes at the expense of flavor and quality. Our research efforts addressed the chemical changes that occur during ripening of fruits carrying ripening mutations so as to better target genetic or post-harvest solutions to the reduced quality these mutations carry along. We also examined the influcen of ripening the fruit off versus on the vine which additionally impacts quality. The resulting determination of fruit chemical composition points to sugars and carotenoids as key compounds influenced by off vine ripening and ripening mutations. This information provides a foundation to begin to rectify these changes and attempt to improve fruit quality.

Technical Abstract: Tomato (Solanum lycopersicum) fruit ripening is regulated co-operatively by the action of ethylene and a hierarchy of transcription factors, including RIPENING INHIBITOR (RIN) and NONRIPENING (NOR). Mutations in these two genes have been adopted commercially to delay ripening, and accompanying textural deterioration, as a means to prolong shelf life. However, these mutations also affect desirable traits associated with colour and nutritional value, although the extent of this trade-off has not been assessed in detail. Here, we evaluated changes in tomato fruit pericarp primary metabolite and carotenoid pigment profiles, as well as the dynamics of specific associated transcripts, in the rin and nor mutants during late development and postharvest storage, as well of those of the partially ripening delayed fruit ripening (dfd) tomato genotype. These profiles were compared with those of the wild-type tomato cultivars Ailsa Craig (AC) and M82. We also evaluated the metabolic composition of M82 fruit ripened on or off the vine over a similar period. In general, the dfd mutation resulted in prolonged firmness and maintenance of quality traits without compromising key metabolites (sucrose, glucose/ fructose and glucose) and sectors of intermediary metabolism, including tricarboxylic acid cycle intermediates. Our analysis also provided insights into the regulation of carotenoid formation and highlighted the importance of the polyamine, putrescine, in extending fruit shelf life. Finally, the metabolic composition analysis of M82 fruit ripened on or off the vine provided insights into the import into fruit of compounds, such as sucrose, during ripening.