PROMOTER ELEMENTS INVOLVED IN ABIOTIC STRESS RESPONSE OCCUR UPSTREAM OF AQUAPORIN GENES OF PLANTS

摘要

Many plant genes are induced by abiotic stresses including drought, salt and cold which can allow the plant to tolerate difficult environmental conditions. The expression of genes involved in abiotic stress tolerance is controlled by the presence of stress-inducible ds-acting promoter elements. The abiotic stress-responsive elements of plants include dehydration-(DRE), low temperature- (LTRE), anaerobic- (ARE), abscisic acid- (ABRE) and pro- or hypoosmolarity (PRE) responsive elements. ABA (abscisicacid) is a phytohormone that has important roles in response to drought, salinity and cold (Shinozaki and Yamaguchi-Shinozaki, 1997). ABREs and DREs have now been identified upstream of a variety of genes from A. thaliana, rice, maize, barley (reviewed in Ingram and Bartels, 1996, Yamaguchi-Shinozaki and Shinozaki, 2006). Trans-acting factors are transcription factors that bind to cw-acting elements in the promoter region, for example DRE-binding factors DREB1A and DREB2A identified in A. thaliana, thegenes of which are themselves activated by cold stress and dehydration, respectively (Liu et al, 1998). Multiple signal transduction pathways have been predicted in plant responses to abiotic stresses through gene expression, including both ABA-dependentand -independent pathways, and are thought to explain the observed complex plant responses to these harsh conditions (Shinozaki and Yamaguchi-Shinozaki. 1997). Recently, the aquaporin gene family has been implicated in a range of abiotic stress responses in many plants through observations of regulation of expression, and/or transgenic approaches (reviewed in Forrest and Bhave, 2007).