مطالعه تأثیر نماتود مولد گره ریشه( Meloidogyne javanica ) بر فعالیت آنزیم فنیل آلانین آمونیالیاز در ریشه گوجه‌فرنگی در تعامل با قارچ عامل پژمردگی آوندی گوجه‌فرنگی Fusarium oxysporum f.sp. lycopersici

This research was conducted to study the effect of nematode (Meloidogyne javanica) on severity of tomato Fusarium wilt (Fusarium oxysporum f.sp. lycopersici race 1) and changes in Phenylalanine ammonia lyase (PAL) activity in split-root assays to show the possibility of systemic induced susceptibility caused by nematode to the fungus by local nematode infection. The results showed that the activity of nematode in one part of root confered susceptibility to Fusarium wilt in other part of the plant root and subsequently disease symptoms increased significantly in comparison to the control (without nematode inoculation). PAL specific activity showed a significant decrease in one half of split-root inoculated with fungus when the other half was inoculated with nematode as compared with the control (without nematode inoculation). Based on the results obtained in this study, nematode infection in one part of tomato plant root resulted in suppression of tomato defenses in all parts of the root, reduced tolerance or resistance to the fungus (as secondary pathogen) and intensified the fungal disease.