Late blight, caused by Phytophthora infestans is an important foliar disease of potato worldwide. Relatively little is known about the mechanisms of interaction between potato and this fungal pathogen. In the present work, expression of beta-tubulin (TUB) gene was monitored in resistant and susceptible potato cultivars at four early points of infection using quantitative real-time PCR (qPCR). Data showed significant variation in the expression patterns of the TUB gene during potato- P. infestans interactions as compared to the non-inoculated controls. It also shows that β- tubulin gene has a higher expression and faster induction in the resistant cultivar (0.9-fold) as compared with the susceptible one (0.11-fold), 24 hours post inoculation (hpi). However, the maximum expressions were 1.85 –folds in the resistant, and 1.3 –folds in the susceptible one 48 and 72 hpi, respectively. Increased potato TUB expression could be due to plant cytoskeleton rearrangement in response to P. infestans up to 72 hpi, and the subsequent decrease in its expression at 96hpi could be due to plant cell disruption resulting from tissue damage during necrosis. The information obtained from this study highlights crucial remarks into the signaling pathway that accounts for TUB gene expression changes elicited during potato- P. infestans interactions, which can provide testable hypotheses that will need direct future tests to determine how TUB changes may be specified in the defense system.
Key words: Solanum tuberosum L., Phytophthora infestans, β- tubulin expression, real time PCR