Ethylene: A gaseous signal molecule in plants

Citation
Ab. Bleecker et H. Kende, Ethylene: A gaseous signal molecule in plants, ANN R C DEV, 16, 2000, pp. 1
Citations number
68
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Cell & Developmental Biology
Journal title
ANNUAL REVIEW OF CELL AND DEVELOPMENTAL BIOLOGY
ISSN journal
1081-0706 → ACNP
Volume
16
Year of publication
2000
Database
ISI
SICI code
1081-0706(2000)16:<1:EAGSMI>2.0.ZU;2-B
Abstract
Ethylene regulates a multitude of plant processes, ranging from seed germin ation to organ senescence. Of particular economic importance is the role of ethylene as an inducer of fruit ripening. Ethylene is synthesized from S-a denosyl-L-methionine via 1-aminocyclopropane-1-carboxylic acid (ACC). The e nzymes catalyzing the two reactions in this pathway are ACC synthase and AC C oxidase. Environmental and endogenous signals regulate ethylene biosynthe sis primarily through differential expression of ACC synthase genes. Compon ents of the ethylene signal transduction pathway have been identified by ch aracterization of ethylene-response mutants in Arabidopsis thaliana. One cl ass of mutations, exemplified by etr1, led to the identification of the eth ylene receptors, which turned out to be related to bacterial two-component signaling systems. Mutations that eliminate ethylene binding to the recepto r yield a dominant, ethylene-insensitive phenotype. CTR1 encodes a Raf-like Ser/Thr protein kinase that acts downstream from the ethylene receptor and may be part of a MAP kinase cascade. Mutants in CTR1 exhibit a constitutiv e ethylene-response phenotype. Both the ethylene receptors and CTR1 are neg ative regulators of ethylene responses. EIN2 and EIN3 are epistatic to CTR1 , and mutations in either gene lead to ethylene insensitivity. Whereas the function of EIN2 in ethylene transduction is not known, EIN3 is a putative transcription factor involved in regulating expression of ethylene-responsi ve genes. Biotechnological modifications of ethylene synthesis and of sensi tivity to ethylene are promising methods to prevent spoilage of agricultura l products such as fruits, whose ripening is induced by ethylene.