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Article|08 Nov 2019|OPEN
Genetic analysis of stilbenoid profiles in grapevine stems reveals a major mQTL hotspot on chromosome 18 associated with disease-resistance motifs
Soon L. Teh1,2, Bety Rostandy1,3, Mani Awale4,5, James J. Luby1, Anne Fennell4 & Adrian D. Hegeman1,
1Department of Horticultural Science, University of Minnesota, Saint Paul, MN 55108, USA
2Present address: Tree Fruit Research and Extension Center, Department of Horticulture, Washington State University, Wenatchee, WA 98801, USA
3Present address: Department of Mathematics and Statistics, University of North Carolina, Greensboro, NC 27412, USA
4Agronomy, Horticulture and Plant Science Department, South Dakota State University, Brookings, SD 57007, USA
5Present address: Grape and Wine Institute, University of Missouri, Columbia, MO 65211, USA

Horticulture Research 6,
Article number: 19121 (2019)
doi: 10.1038/hortres.2019.121
Views: 46

Received: 26 Apr 2019
Revised: 24 Sep 2019
Accepted: 01 Oct 2019
Published online: 08 Nov 2019

Abstract

Grapevine (Vitis spp.) contains a wealth of phytochemicals that have received considerable attention due to health-promoting properties and biological activities as phytoalexins. To date, the genetic basis of the quantitative variations for these potentially beneficial compounds has been limited. Here, metabolic quantitative trait locus (mQTL) mapping was conducted using grapevine stems of a segregating F2 population. Metabolic profiling of grapevine stems was performed using liquid chromatography–high-resolution mass spectrometry (LC-HRMS), resulting in the detection of 1317 ions/features. In total, 19 of these features matched with literature-reported stilbenoid masses and were genetically mapped using a 1449-SNP linkage map and R/qtl software, resulting in the identification of four mQTLs. Two large-effect mQTLs that corresponded to a stilbenoid dimer and a trimer were mapped on chromosome 18, accounting for phenotypic variances of 29.0% and 38.4%. Functional annotations of these large-effect mQTLs on the VitisNet network database revealed a major hotspot of disease-resistance motifs on chromosome 18. This 2.8-Mbp region contains 48 genes with R-gene motifs, including variants of TIR, NBS, and LRR, that might potentially confer resistance to powdery mildew, downy mildew, or other pathogens. The locus also encompasses genes associated with flavonoid and biosynthetic pathways that are likely involved in the production of secondary metabolites, including phytoalexins. In addition, haplotype dosage effects of the five mQTLs further characterized the genomic regions for differential production of stilbenoids that can be applied in resistance breeding through manipulation of stilbenoid production in planta.