Genomics-assisted analysis of natural substances in carrots

Carrots contain many different natural substances such as anthocyanins, phenylpropanoids, polyacetylenes and terpenoids including carotenoids, which have numerous biological functions in the plant but may also positively impact human physiology and health. Daucus species with their typical taproots are exceptionally rich in terpenes including monoterpenes, sesquiterpenes, diterpenes and triterpenes. Volatile terpenes play a decisive role for carrot taste and aroma but may also influence off-taste such as bitterness. Breeding high-quality carrot cultivars would profit from a better understanding of the genetics of compounds involved in these effects. A combined approach of terpene metabolite profiling, genotyping-by-sequencing (GBS) and genome-wide association study (GWAS) was used to get insights into the genetic control of volatile terpene biosynthesis in carrots and to identify terpene synthase candidate genes. Another research project on secondary metabolites in carrots is focused on polyacetylenes (PAs). PAs of the falcarinol-type contribute to the bitter off-taste but can also have anti-microbial and anti-cancer effects. We are studying the PA formation in carrots by an interdisciplinary approach using a broad spectrum of bioinformatic, genetic, molecular and analytical methods; and present first results of this work.