(A) Relationships between lesion lengths on rice lines
IRBB7 (Xa7) and IR24 induced by strains of
Xoo haplotype C-01, races 9a, 9b and 9c, that were
recovered from IRBB7 and IR24 over 3 years. Xoo strains
that were more adapted to Xa7 (race 9a and 9c) were less
aggressive (caused shorter lesions) on IR24 than the less adapted
strains (race 9b). The lesions induced on IRBB7 by 9a and 9c strains
were shorter than those induced on IR24 by the 9b strains.
(B) DNA blot analysis of Xoo strains
recovered from IRBB7 that represent the different haplotypes and
virulence groups (haplotype C-01 contains race 9a, 9b, and 9c, and
haplotype C-05 contains race 9d). A 4.2-kb BamHI
fragment that hybridizes to the avrXa10 gene corresponds
to all but 0.17 kb of the avrXa7 gene.