Salicylic acid and induces resistance
In this study the effect of different concentrations of salicylic acid (0, 200, 400 and 600 mg/l) on fungal growth and induction of resistance in wheat against Fusarium graminearum causl agent of head blight at 0, 24, 72 and 120 h after inoculation was investigated. Then the treated plants were inoculated with spore suspension ( at concentration of 106 spore/mL) by injection into the lower part of spikelet.The activity of antioxidant enzymes, total phenolic content and oxalate oxidase and β- 1,3- glucanase gene expression as indicators of resistance was assayed. The results showed that the highest rate of enzyme and total phenol production was related to concentration of 400 ppm and 72 hours post-infection. The analysis of genes expression by Real time-PCR showed that in72 hours after infection the concentration of 400 ppm had the most influence on the expression of both genes. The β- 1,3- glucanase gene in the same concentration had higher than oxalate oxidase. Effect of salicylic acid on inhibition of mycelium growth showed that the inhibitory effect was increased by increasing concentration and concentration of 600 mg/l absolutely prevent mycelium growth. According to the results it can be concluded that salicylic acid may be useful in the induction of resistance to head bligh.