EIN2, a bifunctional transducer of ethylene and stress responses in Arabidopsis

Ethylene regulates plant growth, development, and responsiveness to a varie ty of stresses. Cloning of the Arabidopsis EIN2 gene identifies a central c omponent: of the ethylene signaling pathway. The amino-terminal integral me mbrane domain of EIN2 shows similarity to the disease-related Nramp family of metal-ion transporters. Expression of the EIN2 CEND is sufficient to con stitutively activate ethylene responses and restores responsiveness to jasm onic acid and paraquat-induced oxygen radicals to mutant plants. EIN2 is th us recognized as a molecular link between previously distinct hormone respo nse pathways. plants may use a combinatorial mechanism for assessing variou s stresses by enlisting a common set of signaling molecules.