Differential induction of three pathogenesis-related genes, PR10, PR1b and PR5 by the ethylene generator ethephon under light and dark in rice (Oryza sativa L.) seedlings

Ethylene has been shown to be involved in triggering pathogenesis-related (PR) gene expression mainly in dicotyledonous species; however, less attention has been devoted identifying and characterizing PR genes in rice (Oryza sativa L.), a monocot and a model of cereal crop genera. Here, we demonstrate that ethylene induces at least three important rice PR genes, the PR10, PR1 basic (PR1b), and PR5 genes in rice (cv. Nipponbare) seedling leaf, upon treatment with the ethylene generator, ethephon (ET), in a light-, time- and dose-dependent manner. Induction of these PR genes was partially blocked by cycloheximide (CHX), a eukaryotic cytoplasmic protein synthesis inhibitor, which indicates an involvement of cytoplasmic de novo protein synthesis in their induction. These results clearly indicate a dynamic role for ethylene in PR genes induction in rice.