title: Genetic analysis of metabolites in apple fruits indicates an mQTL hotspot for phenolic compounds on linkage group 16.
abstract: Apple (Malus×domestica Borkh) is among the main sources of phenolic compounds in the human diet. The genetic basis of the quantitative variations of these potentially beneficial phenolic compounds was investigated. A segregating F₁ population was used to map metabolite quantitative trait loci (mQTLs). Untargeted metabolic profiling of peel and flesh tissues of ripe fruits was performed using liquid chromatography-mass spectrometry (LC-MS), resulting in the detection of 418 metabolites in peel and 254 in flesh. In mQTL mapping using MetaNetwork, 669 significant mQTLs were detected: 488 in the peel and 181 in the flesh. Four linkage groups (LGs), LG1, LG8, LG13, and LG16, were found to contain mQTL hotspots, mainly regulating metabolites that belong to the phenylpropanoid pathway. The genetics of annotated metabolites was studied in more detail using MapQTL®. A number of quercetin conjugates had mQTLs on LG1 or LG13. The most important mQTL hotspot with the largest number of metabolites was detected on LG16: mQTLs for 33 peel-related and 17 flesh-related phenolic compounds. Structural genes involved in the phenylpropanoid biosynthetic pathway were located, using the apple genome sequence. The structural gene leucoanthocyanidin reductase (LAR1) was in the mQTL hotspot on LG16, as were seven transcription factor genes. The authors believe that this is the first time that a QTL analysis was performed on such a high number of metabolites in an outbreeding plant species.
authors.affiliation: Wageningen UR Plant Breeding, Wageningen University and Research Centre, 6708 PB Wageningen, The Netherlands.
authors.forename: Sabaz Ali
authors.initials: SA
authors.lastname: Khan
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Chibon
authors.forename: Ric C H
authors.initials: RC
authors.lastname: de Vos
authors.forename: Bert A
authors.initials: BA
authors.lastname: Schipper
authors.forename: Evert
authors.initials: E
authors.lastname: Walraven
authors.forename: Jules
authors.initials: J
authors.lastname: Beekwilder
authors.forename: Thijs
authors.initials: T
authors.lastname: van Dijk
authors.forename: Richard
authors.initials: R
authors.lastname: Finkers
authors.forename: Richard G F
authors.initials: RG
authors.lastname: Visser
authors.forename: Eric W
authors.initials: EW
authors.lastname: van de Weg
authors.forename: Arnaud
authors.initials: A
authors.lastname: Bovy
authors.forename: Alessandro
authors.initials: A
authors.lastname: Cestaro
authors.forename: Riccardo
authors.initials: R
authors.lastname: Velasco
authors.forename: Evert
authors.initials: E
authors.lastname: Jacobsen
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Schouten
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D005638:Fruit / Q000235:genetics* / Q000378:metabolism*; D017343:Genes, Plant / Q000235:genetics; D008040:Genetic Linkage; D005838:Genotype; D006801:Humans; D006863:Hydrogen-Ion Concentration; D027845:Malus / Q000235:genetics* / Q000378:metabolism*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D010636:Phenols / Q000378:metabolism*; D040641:Quantitative Trait Loci / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
chemical_list: D010636:Phenols; D014157:Transcription Factors