Identification of powdery mildew resistance QTL in strawberry (Fragaria × ananassa)

Abstract

Key Message Powdery mildew resistance in two strawberry mapping populations is controlled by both stable and transient novel QTL of moderate effect. Some low transferability of QTL across wider germplasm was observed. Abstract The obligate biotrophic fungus Podosphaera aphanis is the causative agent of powdery mildew on cultivated strawberry (Fragaria × ananassa). Genotypes from two bi-parental mapping populations ‘Emily’ × ‘Fenella’ and ‘Redgauntlet’ × ‘Hapil’ were phenotyped for powdery mildew disease severity in a series of field trials. Here, we report multiple QTL associated with resistance to powdery mildew, identified in ten phenotyping events conducted across different years and locations. Six QTL show a level of stable resistance across multiple phenotyping events; however, many other QTL were represented in a single phenotyping event and therefore must be considered transient. Subsequent screening of identified QTL across a validation set determined whether identified QTL remained closely linked to the associated resistance gene in the wider germplasm. Furthermore, a preliminary association analysis identified a novel conserved locus for further investigation. Our data suggest that resistance is highly complex and that multiple, primarily additive, sources of quantitative resistance to powdery mildew exist across strawberry germplasm. Utilisation of the reported markers in marker-assisted breeding or genomic selection would lead to improved powdery mildew-resistant strawberry cultivars, particularly where the studied parents, progeny and close pedigree material are included in breeding germplasm.Electronic supplementary materialThe online version of this article (10.1007/s00122-018-3128-0) contains supplementary material, which is available to authorized users.

Salicylic acid-primed defence response in octoploid strawberry ‘Benihoppe’ leaves induces resistance against Podosphaera aphanis through enhanced accumulation of proanthocyanidins and upregulation of pathogenesis-related genes

“…Overexpression of AtELP3 and AtELP4 in diploid strawberry conferred enhanced resistance to P. aphanis, suggesting that ELP genes may confer resistance against PM [24]. Recent advances in our understanding of resistance against P. aphanis have revealed that it is polygenic and quantitatively inherited [25]. Despite these efforts, little research has focused on the molecular resistance mechanisms of the octoploid strawberry.…”

Defining Strawberry Uniformity using 3D Imaging and Genetic Mapping

“…Crosslink was used to generate linkage maps- a program developed specifically for polyploid plant species 30 . The map orders from 5 populations were combined to make the consensus map as detailed in the study of Harrison et al 31 . Fragaria × ananassa chromosome number is denoted by 1-7 and the sub-genome number is represented by A-D as specified in 32 .…”

Genetic and phenotypic associations between root architecture, arbuscular mycorrhizal fungi colonisation and low phosphate tolerance in strawberry (Fragaria × ananassa)

“…QTL mapping of phenotypic traits was performed through Kruskal-Wallis analysis on mean genotype trait values to identify focal single nucleotide polymorphisms (SNPs). The most significant marker was selected for each QTL and then combined into selection through a stepwise linear regression model using a stepwise regression function [54]. Interval mapping and MQM mapping was conducted in MapQTL® [55].…”