ISHS Acta Horticulturae 789: XV Meeting of the EUCARPIA Tomato Working Group
COMPARISON BETWEEN OL-2 AND MLO LOCI CONFERRING RESISTANCE TO OIDIUM IN TOMATO AND BARLEY, RESPECTIVELY |
| Authors: | C. Lotti, R. Panstruga, K. Theres, F. Ciccarese, C. De Giovanni, L. Ricciardi |
| Keywords: | resistance genes, powdery mildew, Arabidopsis, EST, bulk segregant analysis |
| Abstract:
Powdery mildew is a common fungal disease of tomato. The pathogen can cause severe damage both on glasshouse-grown tomatoes and on field crops, especially when high humidity occurs. A recessive gene named ol-2 conferring resistance against the pathogen was found in an accession of Lycopesicon esculentum var. cerasiforme. Previous studies, performed by means of BSA analysis on resistant (R28 accession) and susceptible parents (cv. Super Marmande) and on a F2 segregant population, have allowed us to identify molecular markers linked to ol-2 and localized on chromosome 4. The main objective of the present work was to characterize the chromosome region in which ol-2 lies. To this end, a comparative sequence analysis based both on knowledge of well-characterized resistance genes in barley and Arabidopsis and on similarities among resistance gene families was performed to identify an EST of tomato homologous to mlo barley and Atmlo2 Arabidopsis mutants in the Solanaceae database. On the basis of the nucleotide sequence, a set of primers was drawn to amplify mRNA and genomic DNA of the two parents used in the bulk segregant analysis. Molecular characterization of the cDNA and the genomic region in which ol-2 lies was performed using different primer combinations in order to establish molecular diversity between resistant and susceptible parents. | |
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