Adaptive evolution of fungal avirulence genes imposed by plant resistance genes

摘要

For many decades resistance (R) genes have been introduced into crop plants as a sustainable method to protect them against pathogens. However, as a result of selection pressure imposed by R genes pathogens are eventually able to overcome R genes resulting in outbreaks of epidemics known as the 'boom and bust' cycle. Resistant cultivars that were once booming eventually busted, forcing breeders to introduce anew R gene. Genetic studies on the model flax-Melampsora lini pathosystem by Flor has led tothe development of the gene-for-gene model, which states that for every dominant R gene in the plant there is a matching dominant avirulence (Avr) gene in the pathogen.