The super line 03-04-034, which results from a cross between Pyrus bretchneideri cv Jingbaili and P.ussuriensis cv Yali, is highly resistant to pear scab.Specimens were inoculated with Venturia nashicola to generate a database of expressed sequence tags(ESTs) to be used as resources for transcripts induced in inoculated and uninoculated leaves. After performing subtractive suppression hybridization using cDNA of the inoculated and uninoculated leaves harvested 51 h after inoculation, 100 clones from the uninoculated and 100 clones from the inoculated cDNA library were selected and sequenced. BLASTN searches of each cDNA library against GenBank revealed eight unique sequences associated with the defense response, comprising four ESTs from the uninoculated cDNA library(ubiquitin extension protein, subtilisin-like protease, basic helix-loop-helix(bHLH) transcription factor and aspartic endopeptidase) and four ESTs from the inoculated cDNA library(S-adenosylmethionine synthase(SAMS), heat shock factor(HSF) domain class transcription factor, RNA-binding protein and polyphenol oxidase 5 precursor).Quantitative fluorescence real-time polymerase chain analysis revealed that the transcripts for SAMS and subtilisin-like protease were highly expressed in the incompatible interaction. The SAMS gene was more highly expressed in inoculated leaves than uninoculated leaves, while the reverse was true for subtilisin-like protease. The SAMS and subtilisin-like protease genes have been found to be associated with plant defense mechanisms. Further studies of greater detail are required to understand how these genes are expressed and regulated during infection with V.nashicola. The super line 03-04-034, which results from a cross between Pyrus bretchneideri cv Jingbaili and P. ussuriensis cv Yali, is highly resistant to pear scab. Specimens were inoculated with Venturia nashicola to generate a database of expressed sequence tags (ESTs) to be used as resources for transcripts induced inoculated and uninoculated leaves. After performing subtractive suppression hybridization using cDNA of the inoculated and uninoculated leaves harvested 51 h after inoculation, 100 clones from the inoculated and 100 clones from the inoculated cDNA library were selected and sequenced . BLASTN searched of each cDNA library against GenBank revealed eight unique sequences associated with the defense response, comprising four ESTs from the uninoculated cDNA library (ubiquitin extension protein, subtilisin-like protease, basic helix-loop-helix (bHLH) transcription factor and aspartic endopeptidase) and four ESTs from the inoculated cDNA library (S-adenosylmethionine synthase (SAMS), heat shock factor (HSF) domain class transcription factor, RNA-binding protein and polyphenol oxidase 5 precursor. Quantitative real-time polymerase chain analysis revealed that the transcripts for SAMS and subtilisin-like protease were highly expressed in the incompatible interaction. The SAMS gene was more highly expressed in in leaves than uninoculated leaves, while the reverse was true for subtilisin-like protease. The SAMS and subtilisin-like protease genes have been found to be associated with plant defense mechanisms. Further studies of greater detail are required to understand how these genes are expressed and regulated during infection with V. nashicola.