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Article|01 Aug 2020|OPEN
Major-effect candidate genes identified in cultivated strawberry (Fragaria × ananassa Duch.) for ellagic acid deoxyhexoside and pelargonidin-3-O-malonylglucoside biosynthesis, key polyphenolic compounds
Jahn Davik1 , , Kjersti Aaby2 , Matteo Buti3 , Muath Alsheikh4,5 , Nada Surbanovski6 , Stefan Martens7 and Dag Røen4 , Daniel James Sargent,8
1Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research, Ås N-1433, Norway
2NOFIMA AS, Norwegian Institute of Food Fisheries and Aquaculture Research, Ås N-1433, Norway
3Department of Agriculture, Food, Environment and Forestry, University of Florence, Florence, Italy
4Graminor Breeding Ltd., N-2322 Ridabu, Norway
5Department of Plant Sciences, Norwegian University of Life Sciences, Ridabu N-1432 Ås, Norway
6NIAB-EMR, East Malling, ME19 6BJ Kent, UK
7Department of Food Quality and Nutrition, Fondazione Edmund Mach, Centro Ricerca e Innovazione, Via E. Mach 1, 38010 San Michele all’Adige, TN, Italy
8Department of Genetics, Genomics and Breeding, NIAB-EMR, East Malling, ME19 6BJ Kent, UK
*Corresponding author. E-mail: jahn.davik@nibio.no

Horticulture Research 7,
Article number: 125 (2020)
doi: https://doi.org/10.1038/s41438-020-00347-4
Views: 958

Received: 07 Apr 2020
Revised: 27 May 2020
Accepted: 31 May 2020
Published online: 01 Aug 2020

Abstract

Strawberries are rich in polyphenols which impart health benefits when metabolized by the gut microbiome, including anti-inflammatory, neuroprotective, and antiproliferative effects. In addition, polyphenolic anthocyanins contribute to the attractive color of strawberry fruits. However, the genetic basis of polyphenol biosynthesis has not been extensively studied in strawberry. In this investigation, ripe fruits from three cultivated strawberry populations were characterized for polyphenol content using HPLC-DAD-MSn and genotyped using the iStraw35k array. GWAS and QTL analyses identified genetic loci controlling polyphenol biosynthesis. QTL were identified on four chromosomes for pelargonidin-3-O-malonylglucoside, pelargonidin-3-O-acetylglucoside, cinnamoyl glucose, and ellagic acid deoxyhexoside biosynthesis. Presence/absence of ellagic acid deoxyhexoside and pelargonidin-3-O-malonylglucoside was found to be under the control of major gene loci on LG1X2 and LG6b, respectively, on the F. × ananassa linkage maps. Interrogation of gene predictions in the F. vesca reference genome sequence identified a single candidate gene for ellagic acid deoxyhexoside biosynthesis, while seven malonyltransferase genes were identified as candidates for pelargonidin-3-O-malonylglucoside biosynthesis. Homologous malonyltransferase genes were identified in the F. × ananassa ‘Camarosa’ genome sequence but the candidate for ellagic acid deoxyhexoside biosynthesis was absent from the ‘Camarosa’ sequence. This study demonstrated that polyphenol biosynthesis in strawberry is, in some cases, under simple genetic control, supporting previous observations of the presence or absence of these compounds in strawberry fruits. It has also shed light on the mechanisms controlling polyphenol biosynthesis and enhanced the knowledge of these biosynthesis pathways in strawberry. The above findings will facilitate breeding for strawberries enriched in compounds with beneficial health effects.