Seminars

Bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo), bacterial streak caused by X. oryzae pv. oryzicola (Xoc), and fungal blast caused by Magnaporthe grisea are devastating diseases of rice worldwide. Application of host resistance to these pathogens is the most economical and environment-friendly approach to solve this problem. Quantitative resistance conferred by quantitative trait loci (QTLs) is presumably valuable sources for broad-spectrum disease resistance. However, molecular evidence that supports this hypothesis is rare. Resistance QTLs are also only identified genetic resources from rice against Xoc. Although a large number of QTLs against these rice diseases have been identified, these sources have not been used effectively in rice improvement because of the complex genetic control of quantitative resistance and because of the genes underlying most of resistance QTLs being unknown. To isolate disease resistance QTLs, we established a strategy of validation and functional analysis of the QTL. We have isolated several rice resistance QTLs using this strategy. Functional characterization of the encoding proteins of these resistance QTLs indicates that these genes belong to defense-responsive genes group. These QTLs can mediate broad-spectrum resistance and can be used in breeding programs by manipulating their expression.

Related references
1, Kou Y, Wang S (2010) Broad-spectrum and durability: understanding of quantitative disease resistance. Curr. Opin. Plant Biol. 13:181-185.
2, Hu K, Qiu D, Shen X, Li X, Wang S (2008) Isolation and manipulation of quantitative trait loci for disease resistance in rice using a candidate gene approach. Mol. Plant 1:786-793.