Identification of the blast resistance genes in three elite restorer lines of hybrid rice

Abstract

AbstractHybrid rice has the advantage to pyramid multiple resistance (R) genes because a hybrid rice cultivar is developed from the cross of a sterile line with a restorer line that can harbor different R genes. Thus, knowing the R genes in an elite line will help the combination of different R genes into a hybrid rice cultivar. Here, we identified the blast R genes in Shu Hui 548 (SH548), Shu Hui 882 (SH882), and Wu Shan Si Miao (WSSM), three elite restorer lines of hybrid rice that showed resistance to the rice blast fungus in the disease nurseries. At controlled laboratory conditions, the three elite restorer lines exhibited resistance to more than 20 China Rice Blast strains that harbor different avirulence genes, indicating their broad-spectrum resistance to blast disease. Expression analyses detected the transcripts of multiple known blast R genes. Sequencing of the expressed R genes indicated that, besides Pid2, SH548 also contains Pi2 and Ptr, SH882 and WSSM also contain Pikm and Pi9-Type5, respectively. Pi9-Type5 is a novel functional allele of Pi9. Therefore, SH548, SH882, and WSSM can be exploited in combination with the sterile lines containing other R genes, and they can be used as blast resistance donors in disease-resistance breeding programs.