Xa21 is another dominant bacterial blight gene, which was originally discovered in wild rice specie Oryza longistaminata (Ikeda et al. [1990]).
Kogyoku carries a bacterial blight gene Xa1, which was introduced into a susceptible cultivar IR24 background by backcrossing to develop an isogenic line IRBB1 (Ogawa et al. 1991).
Our findings indicate that effector genomics enables discovery and functional profiling of late blight R genes and Avr genes at an unprecedented rate and promises to accelerate the engineering of late blight resistant potato varieties.
An introgression rice line mainly in MH725 genetic background, designed as WH6725, has been developed to contain bacterial blight resistance genes Xa4, Xa21 and Xa27, blast resistance gene Pi9, submergence tolerance gene Sub1A and fragrance gene badh2.1 through MAS and gene pyramiding.
Several late blight resistance genes, including both race-specific and race-non-specific genes, have been cloned in recent years [4], [5], [38], [39], [40], [41].
The PIN184 population has been genotyped among others with the nuclear marker CosA, two allele specific markers derived from the R3a and R3b late blight resistance genes and SNPs at position 691 and 692 of the StAOS2 gene, which were associated with field resistance to late blight [ 56].
The presence of such bands in the near-isogenic lines, having different bacterial blight resistance genes probably suggests that these microsatellite loci may be associated with disease resistance genes.
Pyramided lines carrying two, three or four bacterial blight resistance genes showed broad-spectrum and higher resistance than the lines with a single resistance gene (Gu et al.2005; Jeung et al.2006; Kim et al.2009; Singh et al.2001; Suh et al.2009a).2009a
First, the specificity spectrum of novel late blight R genes cannot be assessed in the absence of diagnostic pathogen races making it impossible to discriminate between genes with similar functional activities.
Integration of molecular markers to the backcross breeding was highly effective for transfer of three bacterial blight resistance genes.
