Abscisic Acid-Responsive Sequences from the Em Gene of Wheat

Abstract

We demonstrate that a chimeric gene containing the beta-glucuronidase (GUS) reporter gene linked to a 646-base pair 5' fragment (-554 to +92) from the abscisic acid (ABA)-regulated Em gene from wheat is correctly expressed in transgenic tobacco. We observe high activity only in embryos of mature seeds, and immature seeds cultured on ABA show enhanced expression. Using a rice transient assay, we identify a 260-base pair fragment (-168 to +92) that accounts for the ABA-specific 15-fold to 20-fold increase in GUS expression. A 50-base pair sequence (-152 to -103) fused 5' in either orientation to a truncated cauliflower mosaic virus promoter (35S) increases GUS activity threefold in the presence of ABA. Insertion of the Em 5'-untranslated region (+6 to +86) between the 35S promoter and the ATG of GUS results in a 10-fold increase in GUS activity in the absence of ABA. These results suggest the following two functional fragments of the Em 5' region: an ABA response element from -152 to -103 and an element between +6 and +86 that quantitatively increases the ABA response.

Characterisation of LTR sequences involved in the protoplast specific expression of the tobacco Tnt1 retrotransposon

“…The sequence found (GGCATGTGC) is also very similar to a sequence in the Bzl promoter from maize (GGCAGGTGC) that is essential for Bzl expression in the presence of the maize regulatory genes Cl and R (22). The core sequence also resembles the G-box related sequences found in plant genes regulated by many different stimuli such as light or ABA (23,24) A 3 1-bp sequence (BII, Fig 4A) that does not show any clear similarity with any described transcription factor recognition boxes, is found repeated once in the distal and twice in the proximal region (Fig 4A). Interestingly, the major variation found in the U3 region between different transcriptionally active Tntl elements in tobacco is the presence, in most of them, of an extra BII sequence in this region (Casacuberta, unpublished).…”

Significant improvement of stress tolerance in tobacco plants by overexpressing a stress-responsive aldehyde dehydrogenase gene from maize (Zea mays)

“…Consistently, the analysis of the available promoter sequences (accession no. NC_008400.1 and NC_003074.4) upstream the coding regions of Arabidopsis and rice orthologs of ALDH22A1, respectively, predicted that both the putative cis-elements comprise multiple ABA-responsive elements (Marcotte et al 1989;Choi et al 2000;Simpson et al 2003;Kaplan et al 2006), by using PLACE software(http://www.dna.affrc.go.jp/ PLACE/) (Higo et al 1999). This implies that the promoter of ZmALDH22A1 probably contains ABAresponsive elements that are able to sense the signaling molecules induced by the application of exogenous ABA.…”

JIPs and RIPs: the regulation of plant gene expression by jasmonates in response to environmental cues and pathogens.

“…Williamson and Quatrano (1988) proposed that the Em mRNA might be preferentially stabilized by endogenous ABA in wheat embryos as compared to other ABA-regulated transcripts. Inclusion of the 5' untranslated region of Em led to a 10-fold increase in (5-glucuronidase activity in the absence of ABA and to a 20-fold increase in the presence of ABA, suggesting that the 5' region of Em may stabilize the reporter transcript (or lead to its preferential translation) in rice protoplasts (Marcotte et al, 1989;Hetherington and Quatrano, 1991 Polysomes were isolated by Mg 2+ precipitation from an equal number of barley leaf segments that had been either exposed to water or MeJA for 8 hr or left untreated. Ribonucleoprotein material not recovered by this procedure (i.e., containing nonpolysomal RNA) was ethanol precipitated from leaf homogenates.…”