Candidate Genes for Metabolite Profiling of Strawberry NIL Collection

Phenolic compounds are natural products present in fruits and plants. They arise from the Shikimate pathway and include a wide variety of metabolites including Anthocyanins, Flavonoids (Flavan-3-ols and Flavonols), Flavanones and Hidroxycinnamic acid derivatives.  Strawberries are very rich in phenolic compounds and are involved in important biological functions like UV-light protection, defense response and resistance to stress and Anthocyanins are responsible for the attractive red fruit color. Near isogenic lines (NIL) collection in diploid strawberry (F. vesca) as a simplified model to map complex traits in strawberry have previously developed.  We have characterized the phenolic composition and content by liquid chromatography attached to gas spectrometry (LC-MS) to map mQTLs in the F. vesca NILs collection.

Among the observed 936 putative metabolites, we unambiguously identified 24, three anthocyanins, five flavonols, six flavan-3-ols, two flavanones, five hydroxycinnamic acid derivatives and ellagic acid, 4-hydroxy-2,5-dimethyl-3(2H)-furanyl glucoside and citric acid all of them described in strawberry. The accumulation of the metabolites was quantified by the genotype and the environment effect and their interaction. In total we mapped 72 mQTL for 20 different compounds and 4 chemical families distributed among all 7 LG.

Some interesting candidate genes were found in the mQTL enclosed regions. We extract genes from strawberry genome annotated as enzymes in the phenolic pathway and other genes. 250 candidate genes spread in all chromosomes colocalize with a specific mQTL. These results are a starting point to detect candidate genes responsible for phenolic accumulation in strawberry.