Study of the Changes in Quantitative Activity of Proxidase in Olive Cultivars during the Interaction between Verticillium dahliae and Meloidogyne javanica

The non-defoliant strain of Verticillium dahliae (SS-4) was isolated from olive groves showing disease symptoms in Toshan area of southern Gorgan city. Root-knot nematode, Meloidogyne javanica, was recovered from infested olive seedlings and following identification it was propagated on tomato seedlings cv. Rutgers. One-year-old seedlings of olive cultivars, Zard, Roghani, Koroneiki and Manzanilla, were transplanted to pots containing 2000g of sterilized sandy loam soil. The experiment was conducted in a completely randomized design of 32 treatments and five replications. The treatments included: control, nematode alone, fungus alone and fungus+nematode. Pots (containing 2000g of loam-sandy soil) were inoculated with J2 (2000, 3000, 4000 per pot) of nematode and/or microsclerotia (20000 per pot) of fungus according to the treatments for the cultivars. Pots were arranged on glasshouse benches with a temperature of 25-27°C, and under natural light. Quantitative activities of Soluble Peroxidase (SPOX) and ionically Cell-Wall-bound Peroxidase (CWPOX) were evaluated using guaiacol, as a substrate, and according to change in absorbance of the reaction mixture at 470 nm per minute per milligram of total protein on days 1, 10, 20 and 30 after inoculation. Results showed that SPOX and CWPOX activity increased in seedlings inoculated with only fungus reaching its maximum level at the 30th day in Koroneiki. The enzymes activity showed a significant increase in treatments inoculated with nematode and fungus until 20 days after inoculation and afterwards decrease until 30 days after inoculation as compared with the fungus alone treatments (p ? 0.05). Results indicated the nematode was able to limit induction of SPOX and CWPOX even against fungus.