Differential cDNA-AFLP screening of transcripts associated with brown planthopper resistance in rice (Oryza sativa L.)

We have previously constructed a pyramid line, in which two major BPH resistance genes, Bph1 and Bph2 on the long arm of rice chromosome 12, were introgressed into a susceptible japonica cultivar, Tsukushibare. To identify transcripts that are derived from the introgressed chromosomal segments carrying the resistance genes, we analyzed mRNA profiles using amplified fragment length polymorphism-based mRNA fingerprinting (cDNA-AFLP). After this differential screening using 423 primer combinations, 41 polymorphic fragments were selected that were specific either to the pyramid line or Tsukushibare. Among them, 10 fragments expressed only in the pyramid line were cloned and sequenced. According to the genome database, at least two were from the proximity of the introgressed Bph1 locus. Our results suggest that cDNA-AFLP screening of differentially expressed fragments is a useful means to identify BPH resistance and/or infestation associated genes.