Abstract：Adopting SSH technology，this paper studied on the difference expressive genes of downy
mildew resistant cucumber inbred line‘ M801-3-1’ before and after the infection of downy mildew．Diseaseresistant
cucumber material vaccinated downy mildew and unvaccinated cDNA library was constructed using
SSH technology．Forty-eight positive clones were obtained by reverse Northern blot hybridization detection，
and 14 UniESTs were obtained including 8 singletons and 6 contigs via molecular biology software．The
SSH-EST genes function analysis indicated that oxidative stress resistance and chloroplast reconstruction
and protection mechanisms had very important role on disease resistance．At the same time，the paper
put forward that Clpb，HSP70，HSP22 and peptidyl-prolyl cis-trans isomerase might be involved in the R
gene-mediated defense reaction，and smHSP might be the‘ defending target’ of R protein，responsible for
monitoring intracellular exception．This study has provided a key evidence for revealing the relations between
active oxygen mechanism and R gene mediate protection mechanism．
