The influence of root-knot nematodes (Meloidogyne javanica) on yield and on activity of sucrose synthase and invertase in roots of eggplants (Solanum melongena)

Infection of eggplants (Solanum melongena) with root-knot nematodes (Meloidogyne javanica) decreased total plant and fruit dry weight, increased sucrose synthase activity in galls an in the whole root system and also increased invertase activity in galls but not in the whole root system.

No sucrose synthase activity was detected in homogenates of infective larvae of M. javanica but sucrose hydrolysing activity was detected in these nematodes. Thus sucrose synthase activity appears to be associated only with plant tissue whereas sucrose hydrolysing activity may be associated with both plant and nematode. The starch and sucrose content of galls of infected plants were much lower than that of adjacent roots or of the roots of uninfected plants.