Phenotypic Analysis of Arabidopsis Mutants: Ethylene Hormone Response

Abstract

Ethylene is one of the five classic plant hormones, having profound effects at all stages of plant growth and development from seed germination to tissue senescence. Tremendous strides have been made in our understanding of the molecular components of the ethylene signal transduction pathway through the identification of mutants having altered responses to ethylene. These mutants were isolated by screening for seedlings with an altered triple-response phenotype, which is manifested upon exposure to high levels of ethylene in the dark. The triple response consists of the formation of a pronounced apical hook, along with a shortening and thickening of both the hypocotyl and root and a proliferation of root hairs. This is unlike an untreated seedling, which normally has a long etiolated hypocotyl, normal root, and no apical hook formation. To carry out an ethylene gas treatment, seedlings must be grown in an enclosed system to maintain the levels of ethylene desired. This protocol describes ethylene treatment of seedlings in wide-mouth Mason jars sealed with canning jar lids.