EFFECT OF BETA-AMINOBUTYRIC ACID ON ACTIVITY OF PEROXIDASE AND POLYPHENOL OXIDASE ENZYMES IN CUCUMBER INFECTED WITH NEMATODE MELOIDOGYNE JAVANICA

Beta-amino-butyric acid is introduced as an inducer of resistance in plants against plant pathogens. In this research, the induction of some defensive compounds including peroxidase and polyphenol oxidase enzymes by this compound against the rootstock node-producing nematode Meloidogyne javanica in cucumber was investigated. The results showed that inoculation of cucumber roots infected with root-knot nematode with the chemical composition of BABA from the first day after inoculation increased the activity of peroxidase enzyme and reached its maximum on the fourth day of this activity. Induction of the activity of polyphenol oxidase enzyme showed a gradual increase with a significant difference in comparison to the control and healthy plants and reached the maximum on the fourth day. The electrophoresis of peroxidase isozymes showed that isozyme peroxidase forms in cucumber roots induced by BABA were much more potent than pathogen-induced isozymes. In plants treated with nematode plus BABA, two isozymes were Rf = 00.31 and Rf = 34/0, which were stronger than control (inoculated with nematode).