Approaches for the protection of Solanum tuberosum from late blight through the regulation of inf1 and inf4 elicitin genes

Late blight is a disease affecting economically important crops, which is caused by the oomycete Phytophthora infestans. Mainly, fungicides are used against it, however they may harm the environment when used in large quantities. Spray-induced gene silencing (SIGS) can become an alternative to the classical fungicides in the fight against P. infestans. SIGS involves the treatment of plants with double-stranded RNA (dsRNA) which triggers the RNA interference mechanism to suppress translation of the target gene. So, it is possible to suppress the expression of genes. We have chosen two P. infestans genes, inf1 and inf4 involved in the different stages of the parasite development. For the production of dsRNA in E. coli HT115 two expression vectors were constructed on the basis of the L4440 plasmid, each carrying a cDNA fragment of these genes between two T7 phage promoters oriented in the opposition to each other. To evaluate the protective effect of the dsRNA potato explants were treated with a solution containing dsRNA of one of the genes or their combination. 24 hours later, phytophthora zoospores were inoculated with the registration of the effect after 5 days. According to the measurement results, the lesion area was significantly larger in plants treated with water than in the other three experimental groups that were treated with dsRNA.