This project aims to characterise I-7 resistance by digital gene expression analysis. We also aim to map I-7 and develop PCR-based markers for marker-assisted breeding of I-7.
The tomato I-7 gene confers resistance to Fusarium wilt caused by the fungus Fusarium oxysporum f. sp. lycopersici. To determine the nature of the resistance response conferred by I-7, we are using Illumina sequencing to conduct an RNAseq analysis of transcripts expressed in resistant and susceptible plants challenged with Fusarium. This will enable the identification of defence genes activated by I-7 and, given that I-7 has been introgressed from a wild relative of tomato, will also enable the identification of SNPs (single nucleotide polymorphisms) in transcripts encoded by genes linked to I-7. This will in turn enable the genetic mapping of I-7 and the development of a robust PCR-based marker for use in the marker-assisted breeding of I-7 by tomato breeders. This project is funded by an ARC Linkage grant in collaboration with Mr Des McGrath of the Queensland Department of Primary Industries and Fisheries.