No abstract

A series of 21 multiplex (MP) polymerase chain reactions containing simple sequence repeat (SSR) markers spanning most of the apple genome has been developed. Eighty-eight SSR markers, well distributed over all 17 linkage groups (LGs), have been selected. Eighty-four of them were included in 21 different MPs while four could not be included in any MPs. The 21 MPs were then used to genotype approximately 2,000 DNA samples from the European High-quality Disease-Resistant Apples for a Sustainable agriculture project. Two SSRs (CH01d03 and NZAL08) were discarded at an early stage as they did not produce stable amplifications in the MPs, while the scoring of the multilocus (ML) SSR Hi07d11 and CN44794 was too complex for large-scale genotyping. The testing of the (2) the size range of the alleles amplified; (3) the identification of additional unmapped loci of some ML SSRs; (4) the development of methods to assign alleles to the different loci of ML SSRs and (5) conditions at which an SSR previously described as ML would amplify alleles of a single locus to be determined. These data resulted in the selection of 75 SSRs out of the 80 that are well suited and recommended for large genotyping projects.

Apple scab resistance is one of the most wellcharacterized plant-pathogen interactions in a woody plant species. While the HcrVf2 gene from the wild apple Malus floribunda 821 has proved capable of conferring scab resistance to the susceptible cv. Gala after genetic transformation, its identification represents only the first step in understanding the molecular mechanisms and, hence, the network of genes underlying the defence response. We used a PCR-based suppression subtractive hybridization to identify apple genes that are differentially expressed after Venturia inaequalis inoculation. Subtractive hybridization was performed between cDNA from challenged leaves of HcrVf2-resistant transgenic Gala and susceptible cv. Gala plants. A library of 523 unigenes was constructed and characterized by assigning a putative function via comparison with public databases. This set of pathogen-modulated apple genes includes many defence-related genes and is therefore an important source of information for understanding the molecular basis of the Malus-V. inaequalis interaction.

Background Most birch pollen-allergic patients develop allergic cross-reactions to the major allergen found in apples Mal d1, known as pollen-related food allergy (prFA). This is due to a strong clinically relevant homology between the major allergen in birch Bet v 1 and Mal d 1. Daily apple consumption induces oral tolerance in prFA, but its effect on the inhalational allergy has not been investigated. Objectives As continuous apple consumption might also mitigate the inhalational allergy, this study aimed to uncover apple cultivars suitable for treatment of birch pollen rhinoconjunctivitis and apple allergy in a controlled and established dosage. Methods Patients (n = 52) with birch pollen allergy and prFA to apples were subjected to a prick-to-prick test (SPT) with 23 cultivars (red-fleshed, old traditional and new commercial). By SPT, the apple parts flesh, peel equatorial and peel apical near the stalk were compared for their reactivity. One apple cultivar of each allergenicity class (low, middle and high) was subsequently tested in an oral provocation test (OPT). Results According to the SPTs, we provide a ranking of all 23 cultivars. Red-fleshed apples displayed the lowest reactivity, followed by old and new cultivars. Four cultivars showed disagreement from their allergenicity class: Santana and Pink Ladyâ, new cultivars that provoked only low to moderate. In contrast, White Rosemary and Goldparm€ ane, two old cultivars, induced strong reactions. Skin reactivity increased from flesh to peel to stalk, and SPT results could predict the severity of prFA of each allergenicity class. Conclusions Herein, we propose a treatment protocol for allergen immunotherapy to birch pollen and prFA with daily apple consumption. Red-fleshed, old and the new cultivars Santana and Pink Ladyâ provoke less allergic reactions and are suitable for initial induction. After a controlled and well-tolerated increase of intake, also moderate and finally high allergenic apple cultivars should be integrated into treatment of birch pollen allergenic patients.