Co-inoculation of tomato with an arbuscular mycorrhizal fungus improves plant immunity and reduces root-knot nematode infection

Arbuscular mycorrhizal fungi are important for controlling soil-borne diseases and could be important for managements of root-knot disease. Effective co-inoculation of mycorrhiza (Rhizophagus irregularis) and root-knot nematode (Meloidogyne incognita) on plant growth, physiological and biochemical changes during root-knot nematode infection into tomato (Lycopersicon esculentum cv. PT-3) plants were studied. Experiments were conducted under controlled conditions and carried up to one month after nematode inoculation. Rhizophagus irregularis treated plants significantly enhanced plant growth and reduced nematode induced parameters. They also exhibited potent activity of phenolics and defensive enzymes i.e. peroxidase (PO), polyphenyloxidase (PPO) and superoxide dismutase (SOD) while a significant reduction was recorded in malondialdehyde (MDA) and hydrogen peroxide (H2O2) content. Both physiological and biochemical parameters were significantly improved in response to Rhizophagus irregularis. These finding indicates the importance of Rhizophagus irregularis as a potential biocontrol tool for the management of root-knot disease.