Giant cell formation in tomato roots caused by Meloidogyne incognita and Meloidogyne hapla (Nematoda) infection. A light and electron microscope study

Abstract

Light and electron microscope studies show the changes which occur during transformation of small thin-walled plant cells into greatly enlarged "giant cells," which act as nutrient sources for the developing nematodes. Proliferation of cytoplasm and organelles, lobing of nuclei, and development of irregularly thickened cell walls suggested an increased metabolic activity in these cells. Giant cells appear to be most actively synthesizing materials, including a crystalline form of storage protein, during the later stages of nematode development. Numerous spiny vesicles were present and thought to be associated with the production of storage protein. Shortly after maturation of the female nematode, there was a breakdown of giant cell structure, characterized by a loss of membrane clarity and eventual disappearance of organelles.