Apple scab, caused by the fungal pathogen Venturia inaequalis, is one of the most severe diseases of apple worldwide. It is the most studied plant-pathogen interaction involving a woody species using modern genetic, genomic, proteomic and bioinformatic approaches in both species. Although ‘Geneva’ apple was recognised long ago as a potential source of resistance to scab, this resistance has not been previously characterised. Differential interactions between various monoconidial isolates of V. inaequalis and six segregating F1 and F2 populations indicate the presence of at least five loci governing the resistance in ‘Geneva’. The 17 chromosomes of apple were screened using genotyping-by-sequencing, as well as single marker mapping to position loci controlling the V. inaequalis resistance on linkage group 4. Next, we fine-mapped a 5 cM region containing five loci conferring both dominant and recessive scab resistance to the distal end of the linkage group. This region corresponds to 2.2 Mbp (from 20.3 to 22.5 Mbp) on the physical map of ‘Golden Delicious’ containing nine candidate NBS-LRR resistance genes. This study increases our understanding of the complex genetic basis of apple scab resistance conferred by ‘Geneva’ as well as the gene-for-gene (GfG) relationships between the effector genes in the pathogen and resistance genes in the host.
There are no comments yet. You can post the first one!
Post a comment
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.