Beyond R genes: dissecting disease-resistance pathways using genomics and proteomics

Breeding for disease resistance in crops has mainly been accomplished by incorporating single resistance (R) genes. There are advantages to quantitative resistance in terms of durability but breeding for this type of resistance is difficult. New technologies in genomics and proteomics are providing insights into disease-resistance pathways. Structural genomics can identify genomic regions that carry genes controlling these pathways and provide a means for identifying and cloning the genes involved. High-throughput molecular breeding can be used to rapidly assess a large number of lines and select for multiple-resistance quantitative trait loci. This makes breeding for complex resistance types feasible. Functional genomics can identify genes involved in the resistance pathway. By merging structural and functional genomics it will be possible to correlate complex patterns of gene expression with genomic regions and identify key elements that control entire pathways. To fully understand the pathways it is necessary to took at post-translational modification of proteins, as this is a fundamental mechanism involved in transducing the signal from the cell membrane to the nucleus to activate the resistance. Phosphoproteomics will help to discover proteins involved in the signalling pathways.