Articles
Development of SNP molecular markers targeting the major apple scab resistance gene Rvi14
Article number
1412_46
Pages
307 – 312
Language
English
Abstract
Scab (Venturia inaequalis) is the most damaging disease on apple tree, requiring 15 to 25 phytosanitary treatments per year.
More than 18 major resistance genes have been discovered but so far, only the Rvi6 gene has been widely introgressed into commercial cultivars.
Due to the increase of major resistance gene breakdown by new virulent strains, many apple-breeding programs aim to pyramid other genetic sources (major genes and QTLs) to improve resistance durability.
In this context, the Rvi14 scab resistance gene was previously detected on linkage group LG06 of the German cultivar ‘Dülmener Rosenapfel’. Cultivars pyramiding Rvi6 and Rvi14 could offer a durable level of resistance against the majority of V. inaequalis strains.
However, the precise location of the gene is so far unknown.
Additionally, only few SSR molecular markers were identified to target Rvi14 and SSR markers are more expensive and have a lower genotyping throughput than SNP. The present work describes the method used to identify and validate new SNP molecular markers targeting Rvi14. To do so, recombinant individuals around the targeted locus, derived from a cross between ‘Gala’ and ‘Dülmener Rosenapfel’, were genotyped using the Illumina 20K and Affymetrix-Axiom 480K chips.
Genotypic data were correlated with phenotypic scores obtained after grafted plants were inoculated with scab in the greenhouse.
In addition, candidate SNP markers were tested on a large and diverse panel of ~200 individuals from the INRAE/Novadi breeding program.
Validated SNP markers will be used for Marker Assisted Breeding and for further fine mapping of the gene.
More than 18 major resistance genes have been discovered but so far, only the Rvi6 gene has been widely introgressed into commercial cultivars.
Due to the increase of major resistance gene breakdown by new virulent strains, many apple-breeding programs aim to pyramid other genetic sources (major genes and QTLs) to improve resistance durability.
In this context, the Rvi14 scab resistance gene was previously detected on linkage group LG06 of the German cultivar ‘Dülmener Rosenapfel’. Cultivars pyramiding Rvi6 and Rvi14 could offer a durable level of resistance against the majority of V. inaequalis strains.
However, the precise location of the gene is so far unknown.
Additionally, only few SSR molecular markers were identified to target Rvi14 and SSR markers are more expensive and have a lower genotyping throughput than SNP. The present work describes the method used to identify and validate new SNP molecular markers targeting Rvi14. To do so, recombinant individuals around the targeted locus, derived from a cross between ‘Gala’ and ‘Dülmener Rosenapfel’, were genotyped using the Illumina 20K and Affymetrix-Axiom 480K chips.
Genotypic data were correlated with phenotypic scores obtained after grafted plants were inoculated with scab in the greenhouse.
In addition, candidate SNP markers were tested on a large and diverse panel of ~200 individuals from the INRAE/Novadi breeding program.
Validated SNP markers will be used for Marker Assisted Breeding and for further fine mapping of the gene.
Authors
A. Petiteau, B. Petit, C. Denancé, M. Cournol, F. Lebreton, C.E. Durel, F. Laurens, H. Muranty
Keywords
apple, Venturia inaequalis, Rvi14, molecular assisted breeding, genetic mapping
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