Systemic Acquired Resistance (SAR) is a mechanism of induced defense in unaffected parts of the plant by inoculating with microorganisms or other stress as an inducer that confers long-lasting protection against a broad spectrum of microorganisms. This experiment tries to detect the presence of SAR to Puccinia sorghi causing common rust in corn. Common rust susceptible corn plants, in the greenhouse condition, were inoculated by Pseudomonas bacteria; Exserohilum turcicum causing northern corn leaf blight (NCLB); toxin produced by Pyrenophora tritici-repentis (PTR), causing tan spot in wheat; Actigard® 50WG, a selective, systemic compound inducing host-plant resistance (AGD) and a control treatment using water as an inducers. Challenger (P. sorghi) was inoculated one week after inducer. Disease assessment was carried out 13th day after inoculation with P. sorghi by enumerating pustules numbers. Percent area leaf death of inducer-injected leaf was 100% in plants injected with PTR toxin and more than 80% in NCLB treatments. In AGD, PST and water injected plants percentage of dead leaf area was below 55% except two plants in Actigard® treated which were above 80%. Unlike previous findings, PTR toxin significantly decreased the pustules number by 70.52% than control. AGD and PST did not develop systemic resistance and developed pustules numbers comparable to control (PST:~105, AGD: ~104, Control: ~138). Based on this experiment, it can be concluded that SAR can be activated in corn, however, widely adapted commercial like Benzothiadiazole may not be efficient against P. sorghi.
18 December, 2013
Getachew Zeleke: Dear All,
Thank you in advance for sharing your experiences. I'm plant protection expert helping small, medium and large scale farmers in Ethiopia. It is of high value to my career. Please send to me any thing that you think will be helpful to me in the field of plant protection.
With Best Regards