Ethylene receptors and genetic engineering of ethylene sensitivity in plants

Ethylene is a gaseous plant hormone which gives cues to various developmental processes and stress responses in plants. Plants regulate their ethylene sensitivity for programmed development and responses to environmental stresses. After the successful isolation of the Arabidopsis ethylene receptor gene ETR1, ethylene receptor genes have been found in various plant species. Characterization of ethylene receptor genes provides clues to understanding how plants regulate their ethylene sensitivity. This knowledge also gives us potential methods for engineering the ethylene sensitivity of plants. Genetically-engineered plants with reduced ethylene sensitivity will be potential resources for improving crop performance. Moreover, those transgenic plants will provide further information to elucidate the mechanism of how plants regulate their ethylene sensitivity. The recent progress in genetic and protein analyses of ethylene receptors is summarized in this review. The possible strategies for altering the ethylene sensitivity of plants using the ethylene receptor genes are also discussed.