Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 31, 2000
Publication Date: N/A
Interpretive Summary: This manuscript reviews basic concepts of the genetics of plant resistance to disease and the genetics of pathogens' abilities to cause disease. Much work and experience has shown that major genes for resistance are effective only for a limited time in many cases. Ways to improve the durability of resistance are reviewed, as are the more recent developments in the isolation and characterization of resistance genes at the molecular level. Strategies to use resistance gene sequence information to breed resistant crops are discussed, as are the inherent pitfalls of such approaches. An integration of breeding, pathology, molecular genetics, agronomy, and ecology will provide the greatest hope for sustained agricultural production in the face of plant pathogens.
Technical Abstract: Recent focus on transgenic approaches to engineering disease resistance in crops has obscured the power and efficiency of improving disease resistance by manipulating the natural disease resistance genes in crops through traditional breeding and genetics. Plant breeders and molecular biologists prefer to work with simply-inherited disease resistances, but these are often unstable because of the potentially rapid evolution of virulence in many pathogen populations. A transgene that confers resistance to a disease when initially released is not guaranteed to do so in the future. More durable alternatives include pyramiding multiple disease resistance genes into a single genotype; developing multiline cultivars with several different resistance alleles; or breeding for partial resistance. New approaches are expected to develop in the near future, as we learn much more about the composition, genomic organization, allelic diversity, and biochemical function of genes and gene products in disease resistance pathways. Better understanding of how DNA sequence variation in resistance genes results in specific disease resistance, combined with the use of chimeraplasty techniques that can modify DNA sequences without introducing foreign DNA into the crop, may be exploited to enhance crop disease resistance in the future. Reliance on major-gene resistances alone, whether naturally- or transgenically-derived, will likely result in unstable resistance. Integration of genetic forms of resistance with total system approaches to disease management based on agroecological considerations will promote durability of resistance and sustainability of production.