Ethylene-sensitive Dominant Mutation In The Gene Ers2-1 Gene Mechanism Of Action Study

It has been for more than a century since the identification of ethylene as a gaseous plant hormone, and studies on the effects of ethylene to plants have enabled broad applications in agriculture. Dissecting of the signaling pathway has led to the establishment of a genetic model of ethylene signal transduction pathway. However, this model cannot tell how the dominant mutations of the receptor genes, such as ers2-1, confer ethylene-insensitivity. In order to further investigate the mechanism of ethylene-insensitivity conferred by a dominant mutation, we compared the phenotypes of ers2-1 in mutants defective in multiple receptor genes.Under ethylene treatment, the ers2-1 mutant displayed an ethylene-insensitive phenotype. When ers2-1 was introduced to etr1-7; etr2-3; ein4-4 triple mutant, ethylene insensitivity was reduced slightly to the rosettes, but not to the seedling. However, in the etr1-7; etr2-3; ein4-4; ers2-3 quadruple mutant background, in which the wild-type ERS2 gene was lost, the function of ers2-1 reduced to an extent by which the trasngene was unable to display a promising ethylene insensitivity.Accordingly, ers2-1 is still able to confer ethylene insensitivity via a single receptor gene ERS1 in the quadruple mutant, but at a highly reduced level compared to its function in the triple mutants. The major difference between the quadruple and triple mutants is the absence of a wild-type ERS2 gene in the quadruple mutant, and we propose that the dominance conferred by ers2-1 can be mediated and amplified via the wild-type ERS2 to the subfamily I receptor ERS1.