Unravelling the Plant Cell Cycle in Nematode Induced Feeding Sites

Abstract

Cell cycle activation is a key component of host plant manipulation by sedentary nematodes. It is generally believed that root-knot nematodes induce giant cells by repeated cycles of acytokinetic mitosis accompanied by endocycles while cyst nematodes induce extra rounds of DNA synthesis. Microscopic expression analysis of genes that encode key regulators of the cell cycle and the use of cell cycle inhibitors demonstrate that endoreduplication cycles may play a role in both giant cell and syncytium formation, while mitosis is essential for giant cell development and syncytium expansion (via fusion of neighbouring cells). When mitosis is blocked, gall development is completely inhibited, indicating that cycles of endoreduplication or other means of DNA amplification are insufficient to drive giant cell expansion. DNA synthesis is required for both gall and syncytium development.