The objectives of this project were to develop the tools and methodologies for positional cloning of genes in tomato and apply them for the cloning a Fusarium resistance gene - I2.. The feasibility of positional cloning of disease resistance genes was demonstrated for Pto which confers resistance to pseudomonas (Martin et al. 1993). The Fusarium resistance gene was mapped genetically and physically and was found to be in close proximity to TG 105 (Segal et al. 1992). To obtain fine mapping of gene I2, and additional target genes in future projects, a high density linkage map was developed (Tanksley et al. 1992; Broun and Tanksley 1993). In addition two permanent mapping populations were constructed: a recombinant inbred (Paran et al. 1995; Zamir et al. 1993) and an introgression line population (Eshed et al. 1992; Eshed and Zamir 1994). Using these resources we determined that the I2 locus shows complete co-segregation, down to a resolution of a few Kb, with SL8 which shows architectural similarity with other plant resistance genes. Transformation and complementation analysis is in progress (Ori et al. in preparation).
Expression of the Fusarium
resistance gene I-2
colocalizes with the site of fungal containment
