Systemic resistance induction against cucumber marginal leaf blight disease by sodium silicate application

Induction of systemic resistance to cucumber against marginal leaf blight disease caused by Pseudomonas marginalis using silicon application (as 1 &2 mM of sodium silicate) was studied under greenhouse conditions. Results indicated that application of 2 mM of sodium silicate remarkably increased resistance in cucumber against the pathogen. According to the results, disease severity in plants treated with 2mM sodium silicate was reduced to 62% comparied to the control plants. One of the systemic resistance induction mechanisms by sodium silicate is stimulating the production of pathogenesis related proteins in plants which are indicator of systemic acquired resistance (SAR). We assayed the activity of chitinase and β- 1, 4 glucanaseenzymes for induced resistance in plants treated with 1 and 2 Mm sodium silicate in 0, 24, 48 and 96h after inoculation by P. marginalis. Results showed that the highest activity of chitinase and β- 1, 4 glucanase enzymes were scored 96 h after treating plants with sodium silicate. β- 1, 4 glucanase activity was 0.025 U/mg proteinand chitinase activity was 0.0085 U/mg protein. These results suggested the importance of the chemical elicitor role for induction of systemic resistance to cucumber against P. marginalis