Root-knot nematodes infect the fresh root tissues and have intricate host-parasite relationships that involve biochemical interactions between nematode saliva and plant amino acids. This creates a nutritional and metabolic sink for the nematodes, but interferes with the uptake and translocation of nutrients and water to other plant parts. It also causes changes in the activity of toxic metal uptake. Investigations were thus carried out to address these issues using the root-knot nematode, Meloidogyne graminicola infecting rice as a model in experiments carried out at IARI, New Delhi.