Detection of novel blast resistance genes, Pi58(t) and Pi59(t), in a Myanmar rice landrace based on a standard differential system uri icon

abstract

  • The use of broad-spectrum R genes is an effective way to achieve durable resistance against rice blast (Magnaporthe oryzae Couch, anamorph: Pyricularia oryzae Cavara) in rice (Oryza sativa L.). We previously surveyed the diversity of blast resistance in 948 rice varieties and found a Myanmar rice landrace, Haoru (International Rice Research Institute genebank acc. no. IRGC33090), with broad-spectrum resistance against the standard differential blast isolates. Here, we examined the genetic basis of Haoru's broad-spectrum resistance by using the standard blast differential system consisting of the standard isolates and differential varieties. For genetic analysis, we used a BC1F1 population and BC1F2 lines derived from crosses of Haoru with a susceptible variety, US-2. Co-segregation analysis of the reaction pattern in the BC1F1 population against the 20 standard isolates suggested that Haoru harbors three R genes. By using bulk-segregant and linkage analysis, we mapped two of the three R genes on chromosomes 12 and 6, and designated them as Pi58(t) and Pi59(t), respectively. Pi58(t) and Pi59(t) were differentiated from other reported R genes using the standard differential system. The estimated resistance spectrum of Pi58(t) corresponded with that of Haoru, suggesting that Pi58(t) is primarily responsible for Haoru's broad-spectrum resistance. In addition, Pi59(t) and the third gene were also proven to be new and useful genetic resources for studying and improving blast resistance in rice.

publication date

  • 2013
  • 2013
  • 2013