Molecular mechanisms for pathogenic elicitor-induced cell cycle arrest at G2 checkpoint in synchronized tobacco BY-2 cells.

Abstract

Pathogenic signals affect growth and development in plants. However, the molecular links between cell cycle control and the regulation of defense responses including programmed cell death are largely unknown in plants. Using synchronized tobacco BY-2 cells, we analyzed the cell-cycle dependence of elicitor-induced defense responses. A proteinaceous elicitor, cryptogein, induced cell cycle arrest at G1 and G2 phases prior to the expression of defense-related genes and hypersensitive cell death (Plant J. (2004) 40: 131-; Plant Cell Physiol. (2005) 46: 156-). To analyze molecular mechanisms for the elicitor-induced cell cycle arrest at G2 checkpoint, we characterized the expression levels and activities of various cell cycle regulators such as cyclins and cyclin-dependent kinases during the elicitor-induced G2 arrest. Possible specific degradation of cell cycle regulators will also be discussed.