Elucidating The Genetics Of Flavour Formation In Tomato

Traditionally the most important targets in fruit and vegetable breeding are producer traits, such as yield, disease resistance and shelf life. In the past decade, however, the importance of consumer-driven quality traits, such as flavour, nutritional value and appearance have been increasingly recognised. This is not only due to growing consumer demands for more healthy food with an excellent quality, but also to the availability of various omics tools, which make it possible to study complex, multifactorial traits, such as flavour and health. These quality traits are to a large extent determined by the phytochemical composition of our food products. Tomato is one of the most important vegetable crops worldwide and an important model for fleshy fruits. We evaluated a collection of 94 tomato cultivars and several breeding populations for variation in taste and metabolite content and linked this to high-resolution genotypic information. This led to the identification of mQTLs underlying important flavour traits. We observed a close correlation between the presence of phenylpropanoid-derived volatiles and a “smoky” flavour, linked to a QTL on chromosome 9. The release of these volatiles is determined by their storage form as glycoside conjugates. Using a combined genetic, metabolomic and transcriptomic approach the underlying glycosyltransferase gene was isolated and its role in the conjugation of phenylpropanoid volatiles was confirmed through expression studies in E. coli and transgenic plants. Regulation of volatile emission through glycoconjugation can pave the way to new strategies for controlling tomato fruit flavor and taste.

 This research was funded by the Dutch NWO genomics initiative Centre for Biosystems Genomics and the EU  project EUSOL (PL-016214).