Genetic characterization of the Pto locus of tomato: semi-dominance and cosegregation of resistance to Pseudomonas syringae pathovar tomato and sensitivity to the insecticide Fenthion

• Published in: Molecular & general genetics Vol. 239; no. 1-2; p. 17
• Main Authors: Carland, F.M. (California Univ., Berkeley, CA (USA). Dept. Plant Pathology), Staskawicz, B.J
• Format: Journal Article
• Language: English
• Published: Germany 01.05.1993
• Subjects: ADN; Base Sequence; Biomarkers; CARTE GENETIQUE; DNA, Single-Stranded; Drug Resistance; Fenthion - pharmacology; GENE; Gene-for-gene resistance; GENES; Genes, Dominant; Genes, Plant; Genetic Linkage; Genetic mapping; Immunity, Innate - genetics; INSECTICIDAS; INSECTICIDE; Kinetics; LYCOPERSICON ESCULENTUM; MAPAS GENETICOS; Molecular Sequence Data; Plant disease resistance genes; Plant Diseases - genetics; Plant Diseases - microbiology; Plants - drug effects; Plants - genetics; Plants - microbiology; POLIMORFISMO GENETICO; POLYMORPHISME GENETIQUE; Pseudomonas - drug effects; Pseudomonas - genetics; Pseudomonas - pathogenicity; PSEUDOMONAS SYRINGAE; Random amplified polymorphic DNA; RAPD; RESISTANCE AUX MALADIES; RESISTENCIA A LA ENFERMEDAD
• ISSN: 0026-8925; 1432-1874
• DOI: 10.1007/BF00281596

The Pto locus governs resistance to bacterial speck disease in tomato caused by race O strains of Pseudomonas syringae pathovar tomato (Pst). Large populations segregating for the Pto locus were generated and genetically characterized. Analysis of the locus has revealed that Pto acts in a semi-dominant manner and cosegrates with sensitivity to an organophosphorous insecticide, Fenthion, suggesting that Pto may be a complex locus responsible for both phenotypes. Its map position on chromosome five of the classical genetic map was redefined and its position was assigned on the molecular map, thus facilitating the alignment of the two genetic maps of the short arm of chromosome five of tomato. Furthermore, were screened random amplified polymorphic (RAPD) markers for their ability to differentiate near-isogenic lines that differ only with respect to Pto and have identified and mapped seven of these markers. These results suggest that Pto may be located in a euchromatic region on chromosome five which will be advantageous for the cloning of this locus by one of several molecular strategies.