Expression pattern and activity of six glutelin gene promoters in transgenic rice

Abstract

The shortage of strong endosperm-specific expression promoters for driving the expression of recombinant protein genes in cereal endosperm is a major limitation in obtaining the required level and pattern of expression. Six promoters of seed storage glutelin genes (GluA-1, GluA-2, GluA-3, GluB-3, GluB-5, and GluC) were isolated from rice (Oryza sativa L.) genomic DNA by PCR. Their spatial and temporal expression patterns and expression potential in stable transgenic rice plants were examined with β-glucuronidase (GUS) used as a reporter gene. All the promoters showed the expected spatial expression within the endosperm. The GluA-1, GluA-2, and GluA-3 promoters directed GUS expression mainly in the outer portion (peripheral region) of the endosperm. The GluB-5 and GluC promoters directed GUS expression in the whole endosperm, with the latter expressed almost evenly throughout the whole endosperm, a feature different from that of other rice glutelin gene promoters. The GluB-3 promoter directed GUS expression solely in aleurone and subaleurone layers. Promoter activities examined during seed maturation showed that the GluC promoter had much higher activity than the other promoters. These promoters are ideal candidates for achieving gene expression for multiple purposes in monocot endosperm but avoid promoter homology-based gene silencing. The GluC promoter did not contain the endosperm specificity-determining motifs GCN4, AACA, and the prolamin-box, which suggests the existence of additional regulatory mechanism in determining endosperm specificity.

Gradually Decreasing Starch Branching Enzyme Expression Is Responsible for the Formation of Heterogeneous Starch Granules

“…At first thought, the glutelin GT1 (GluA-2) promoter utilized in TRS transgenic plants might be responsible for the regional distribution of the three SBEs, as the activity of this promoter is stronger in the outer portion but much weaker in the inner part of the endosperm (Qu et al, 2008). This resulted in the three SBE isoforms being more severely inhibited in the outer portion of the endosperm but less inhibited in the inner region.…”

Reporter Gene Expression Patterns Regulated by an Ara h 2 Promoter Differ in Homologous Versus Heterologous Systems1

“…These included the 2300 element (also present in the Ara h 2.02 promoter) that moreover quantitatively regulates prolamin expression, an endosperm protein in cereals (Colot et al, 1987). Qu et al (2008) found prolamin and endospermspecific motifs in all but one rice glutelin gene promoter which controlled seed specific expression. Our results for reporter gene expression in peanut under the control of the Ara h 2 promoter largely conform with the results obtained by Kang et al (2007b) who showed that Ara h 2 polypeptides were abundant in mature seeds and diminished after germination during seedling growth.…”

Comparative sequence and expression analysis of tapetum specific male sterility related genes in Medicago truncatula

“…Nine genes (MtTsms5,14,27,32,33,34,43,49, and 51) were found to be expressed at low levels across all tissues. The expression profiles of these genes diverged, implying that they contribute to functional maintenance through regulatory subfunctionalization or neofunctionalization (Qu et al, 2008). MtTsms11 and MtTsms25 were highly expressed in root tissue, while MtTsms19 and MtTsms56 were highly expressed in stem tissue.…”

“…It therefore serves as a central model system for translational genomics based studies in plants (Town et al, 2006). Although many studies have specifically studied MS in A. thaliana, Brassica oleracea, and Oryza sativa (Honys and Twell, 2003;Qu et al, 2008;Ji et al, 2011;Zhang and Zhang, 2014), few studies have assessed MS in forage plants. In this study, we attempted to identify tapetum specific male sterility (TSMS) related genes in M. truncatula, via comparisons with A. thaliana, as a source of genomic information.…”