Importance and Use of Resistance Gene Analogs

The identification, isolation and subsequent cloning of effective disease resistance genes for their use to enhance the protection level against various groups of pathogens in plants is an important aspect of crop improvement. Disease resistance genes (R-genes) have been characterized and cloned from many plant species. The resistance gene analogs (RGAs) are putative or tentative disease resistance genes which are identified on the basis of their structure. The RGAs are an efficient tool in identifying and isolating disease resistance genes and have got efficiency in building a durable resistance. In order to know the exact function of RGAs they need to be characterized and linked with the genes actually conferring resistance phenotype. Regions of amino acid conservation in resistance gene encoded proteins have facilitated the isolation of RGA sequences from genomic DNA in many crop plants using polymerase chain reaction based techniques.