Quantitative Trait Locus Mapping for Fire Blight Resistance in an F2 Population of Malus fusca MAL0045 Uncovers Novel Resistance Loci.
Phytopathology
; 113(12): 2222-2229, 2023 Dec.
Article
em En
| MEDLINE
| ID: mdl-37856693
ABSTRACT
Several fire blight resistance loci in Malus genotypes map on different linkage groups (LGs) representing chromosomes of the domesticated apple. Prior genetics studies primarily focused on F1 populations. A strong resistance quantitative trait locus (QTL) explained up to 66% of phenotypic variance in an F1 progeny derived from crossing the highly resistant wild apple genotype Malus fusca MAL0045 and the highly susceptible apple cultivar 'Idared', which was previously mapped on LG10 (Mfu10) of MAL0045. Strains of the causative bacterial pathogen Erwinia amylovora, notably those that show a single nucleotide polymorphism in the avrRpt2EA effector protein sequence at position 156 (e.g., Ea3049), are more virulent and overcome some known fire blight resistance donors and their QTLs. However, MAL0045 is resistant to Ea3049 and Mfu10 is not overcome, but most of the F1 progeny were highly susceptible to this strain. This phenomenon led to the assumption that other putative resistance factors not segregating in the F1 progeny might be present in the genome of MAL0045. Here, we crossed F1 progeny together to obtain 135 F2 individuals. Facilitated by genotyping-by-sequencing and phenotypic assessments, we identified and mapped two novel resistance QTLs in these F2 individuals on LGs 4 and 15, which were not identified in the F1. To our knowledge, these are the first resistance QTLs mapped in F2 progeny in Malus. In addition, we report that neither MAL0045 nor Mfu10 is broken down by a highly aggressive U.S. strain, LA635, after analyses in the original F1 individuals. [Formula see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Malus
/
Erwinia amylovora
Limite:
Humans
Idioma:
En
Revista:
Phytopathology
Assunto da revista:
BOTANICA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Alemanha