Genetic Engineering for Blast Disease Resistance in Rice, Using a Plant Defensin Gene from Brassica Species

Abstract

Rice (Oryza sativa L.) is one of the most important crops in the world, especially in Asia. Rice suffers serious damage from several pathogens, which reduce yield. One of the most devastating fungal diseases is rice blast (Magnaporthe grisea). Bacterial diseases are also important, especially bacterial leaf blight (Xanthomonas oryzae), which is one of the most serious diseases of rice in South-East Asia. Rice blast attacks the rice leaf and panicle. Because of the variability of the blast fungus’s host range and cultivar specificity, disease control through traditional breeding methods produces only partial success (Krishnamurthy et al., 2001). Several approaches based on molecular genetics have been developed to engineer high levels of rice blast resistance, including determination of genetic loci and analysis of the signal transduction pathways for the expression of disease resistance in cells (Michelmore & Meyers, 1998; Ellis et al., 2000; Dangl & Jones, 2001). Also, an increasing number of antifungal peptides are being discovered in animals, plants, insects, and other organisms (Yun et al., 1997; Zasloff, 2002).