The Panicle blast resistance Mechanism of qPbm11 in the rice cultivar miyazaki-mochi is independent from that of Pb1

Abstract

Understanding the mechanism of disease resistance is critical for combating rice blast disease that causes the most deleterious effects on rice yield, and for evolving successful blast tolerance breeding programs using blast resistance (R) genes. The qPbm11 locus in the blast resistant cultivar Miyazaki- mochi exerts panicle resistance similar to the well-known quantitative panicle resistance gene Pb1. qPbm11 and Phi show similarity in panicle blast resistance, quantitative resistance, and proximity of loci on the rice genome. Pb1 resistance is dependent on the expression of transcription factor WRKY45. To identify the resistance mechanism of the qPbm11 locus, we downregulated WRKY45 in the cultivar Miyazaki-mochi through an Agrobacterium-mediated transformation and surveyed its panicle resistance. WRKY45 RNAi transgenic Miyazaki-mochi plants exhibited similar levels of panicle resistance compared to WT, indicating that the qPbm11 locus is independent of the Pb1 resistance pathway. Our results suggested that cloning the genes responsible for qPbm11-mediated resistance along with Pb1 using pyramiding technology could enhance panicle resistance in rice.