Cloning and characterization of an esophageal-gland-specific chorismate mutase from the phytoparasitic nematode Meloidogyne javanica

Root-knot nematodes are obligate plant parasites that alter plant cell grow th and development by inducing the formation of giant feeder cells. It is t hought that nematodes inject secretions from their esophageal glands into p lant cells while feeding, and that these secretions cause giant cell format ion. To elucidate the mechanisms underlying the formation of giant cells, a strategy was developed to clone esophageal gland genes from the root-knot nematode Meloidogyne javanica. One clone, shown to be expressed in the nema tode's esophageal gland, codes for a potentially secreted chorismate mutase (CM), Chi is a key branch-point regulatory enzyme in the shikimate pathway and converts chorismate to prephenate, a precursor of phenylalanine and ty rosine, The shikimate pathway is not found in animals, but in plants, where it produces aromatic amino acids and derivative compounds that play critic al roles in growth and defense, Therefore, we hypothesize that this CM is i nvolved in allowing nematodes to parasitize plants.