Recent Progress on the Variation of Blast Resistance and Cloning of the Resistance Genes in Rice

Using blast-resistant varieties for cultivation is one of the most effective, economical and environmentally friendly ways to prevent the disease on rice (Oryzae sativa L.). However, it has been noticed recently that the resistance of somedisease tolerant-rice being promoted for the purpose began to diminish or even disappear. The phenomenon was attributed to the disappearance of host resistance genes or the mutations on avirulence genes of the plants. This article reviews the relevant pathogenic mechanisms, possible cause(s) for the reduction or loss on the blast-resistance, potential remedies, and search for the avirulence genes for cloning and recoverying in an attempt to resolve the problem at hand.