Rhizophagus clarus controls Meloidogyne javanica and enhances the activity of defense-related enzymes in tomato

ABSTRACT Root-knot nematodes (Meloidogyne spp.) cause severe damage to tomato crop. This study aimed to investigate the biocontrol potential of the arbuscular mycorrhizal fungus Rhizophagus clarus compared with that of the fungi Trichoderma harzianum and Pochonia chlamydosporia against Meloidogyne javanica in tomato and assess the activity of defense-related enzymes in mycorrhizal roots. Three experiments were carried out to evaluate mycorrhizal colonization, nematode penetration, development, and reproduction, plant growth, and enzyme activity in mycorrhizal roots. We observed that R. clarus colonization of tomato roots increased with time. Although R. clarus did not prevent nematode penetration or development in roots, it was efficient in reducing total nematode numbers. R. clarus, T. harzianum and P. chlamydosporia treatments reduced nematode reproduction by 56.5, 54.4, and 56.9%, respectively, compared with the control. Moreover, R. clarus increased tomato shoot weight and phenylalanine ammonia-lyase and peroxidase activities.