A Homolog Of The Arabidopsis EIN3 Gene OsEIL1 Regulates The Ethylene Response As A Positive Component In Rice

The plant hormone ethylene regulates many aspects of growth, development and responses to the environment. ETHYLENE INSENSITIVE3 (EIN3) is a transcription factor involved in the ethylene signal transduction pathway in Arabidopsis. To gain a better understanding of the ethylene signal-transduction pathway in rice, we have isolated a homolog of the Arabidopsis EIN3 gene (OsEILI). In contrast with what has been previously found in EIN3-, TEIL- and VR-EIL-over-expression plants, over-expression of OsEILI in rice exhibited coil root phenotype and increased sensitivity to exogenous ethylene. In addition, OsEBP89 gene encoding an ethylene responsive element binding protein (EREBP) transcription factor and one of ACC oxidase gene OsACOl were constitutively expressed in 35S::OsEILI lines without ethylene. These results indicated that OsEILI was involved in ethylene signal transduction pathway and acted as a positive regulator of ethylene response in rice, thereby effectively activated its upstream and downstream partners and enhanced sensitivity to ethylene and possibly resulted in the coil roots.