Abstract: Total RNA was extracted from the leaves of the disease-resistant cucumber（Cucumis sativus L.）cultivar‘649’challenged by Pseudoperonospora cubensis using the modified SDS method. And then，a full-length cDNA library was constructed. The results showed that the primary titer of the constructed cDNA library was 5.5 × 106 pfu • mL-1，and titer of the amplified library was 6.5 × 109 pfu • mL-1. The recombination rate was about 99%. The size of inserted cDNA fragment ranged from 0.5 kb to 2.0 kb，majority at about 1.0 kb. Sequencing analysis showed that 2 507 unigenes，included 211 contigs and 2 296 singlets were identified in the 3 360 ESTs derived from the cDNA library. The result of the bioinformatics analysis indicated that there were 427 plant defense/resistance-related genes including two type resistance genes and programmed cell death related genes. The discovery of these genes provides an important reference for further studying cucumber disease resistance mechanism and cloning resistance related genes.

Key words: cucumber, Pseudoperonospora cubensis, RNA extraction, cDNA Library, resistance related genes