Development of pre-isogenic lines for rice blast-resistance by marker-aided selection from a recombinant inbred population

Abstract

To increase the available set of near-isogenic lines (NILs) for blast-resistance in rice, we have developed a general method for establishing NILs from populations of fixed recombinants that have been used for gene mapping. We demonstrated the application of this method by the selection of lines carrying genes from the rice cultivar Moroberekan. Moroberekan is a West African japonica cultivar that is considered to have durable resistance to rice blast. Multiple genes from Moroberekan conferring complete and partial resistance to blast have previously been mapped using a recombinant inbred (RI) population derived from a cross between Moroberekan and the highly and broadly susceptible indica cultivar CO39. To analyze individual blast-resistance genes, it is desirable to transfer them individually into a susceptible genetic background. This RI population, and the associated data sets on blast reaction and restriction fragment length polymorphism (RFLP) genotypes, were used for selection of lines likely to carry individual blast-resistance genes and a minimum number of chromosomal segments from Moroberekan. Because skewed segregation in the RI population favored CO39 (indica) alleles, resistant lines carrying 8.7-17.5% of Moroberekan alleles (the proportion expected after two or three backcrosses) could be selected. We chose three RI lines carrying different complete resistance genes to blast and two RI lines carrying partial resistance genes to blast as potential parents for the development of NILs. These lines were subjected to genetic analysis, which allowed clarification of some issues that could not be resolved during the initial gene-mapping study.

The Broad-Spectrum Blast Resistance Gene Pi9 Encodes a Nucleotide-Binding Site–Leucine-Rich Repeat Protein and Is a Member of a Multigene Family in Rice

“…For example, 5 blast R genes have been identified at the Pi-k locus of chromosome 11 (Kiyosawa 1989;Inukai et al 1994). Pi-ta and Pi-ta 2 are allelic or at least very close to each other in the centromere region of chromosome 12 (Rybka et al 1997), while Pi5(t) and Pi3(t) map at the same location on rice chromosome 5 (Inukai et al 1996;Jeon et al 2003). To date, only 2 blast R genes, Pib (Wang et al 1999) and Pi-ta , have been cloned.…”

Use of Pi5(t) markers in marker-assisted selection to screen for cultivars with resistance to Magnaporthe grisea

“…Genetic analysis indicates that Pi5(t) is allelic or closely linked to Pi3(t) and that Pi3(t) is closely linked to Pii(t) (Inukai et al 1994(Inukai et al , 1996. Additional disease assays have shown that the Pii(t), Pi3(t), and Pi5(t) genes display a similar reaction when tested against 16 M. grisea isolates (Imbe et al 2000;S.-S. Han et al unpublished data).…”

“…Analysis of their genetic linkage and resistance profiles has suggested that these three genes might be allelic or closely linked (Inukai et al 1994(Inukai et al , 1996Imbe et al 2000). Most recently, fine mapping has demonstrated that all three loci are tightly linked on chromosome 9 (Jeon et al 2003;Pan et al 2003).…”

“…This analysis revealed that the three markers were present only in those lines carrying Pi5(t), Pi3(t), or Pii(t). It has been previously demonstrated that the Pi5(t) locus is allelic to Pi3(t) and that both loci are physically identical (Inukai et al 1996;Jeon et al 2003). Therefore, using the three markers, we analyzed two monogenic lines, IRBL5-M and IRBL3-CP4, by DNA gel-blot analysis (Fig.…”

Characterization of Recombinant Inbred Lines Derived from Crosses in Melon (Cucumis melo L.), 'PMAR No. 5'*'Harukei No. 3'

“…The RI lines are useful for producing near-isogenic lines (Inukai et al 1996), for genetic analysis of quantitative traits and for mapping (Welsh et al 1995, Mansur et al 1996, Xiao et al 1996, Schiantarelli et al 2001. Perin et al (2002) constructed and integrated genetic linkage maps using RI lines of melon.…”