Abstract
BackgroundCotton (Gossypium spp.) is an important crop worldwide that provides raw material to 40% of the textile fiber industry. Important traits have been studied aiming the development of genetically modified crops including resistance to insect and diseases, and tolerance to drought, cold and herbicide. Therefore, the characterization of promoters and regulatory regions is also important to achieve high gene expression and/or a specific expression pattern. Commonly, genes involved in ubiquitination pathways are highly and differentially expressed. In this study, we analyzed the expression of a cotton ubiquitin-conjugating enzyme (E2) family member with no previous characterization.ResultsNucleotide analysis revealed high identity with cotton E2 homologues. Multiple alignment showed a premature stop codon, which prevents the encoding of the conserved cysteine residue at the E2 active site, and an intron that is spliced in E2 homologues, but not in GhGDRP85. The GhGDRP85 gene is highly expressed in different organs of cotton plants, and has high transcript levels in roots. Its promoter (uceApro2) and the 5'UTR compose a regulatory region named uceA1.7, and were isolated from cotton and studied in Arabidopsis thaliana. uceA1.7 shows strong expression levels, equaling or surpassing the expression levels of CaMV35S. The uceA1.7 regulatory sequence drives GUS expression 7-fold higher in flowers, 2-fold in roots and at similar levels in leaves and stems. GUS expression levels are decreased 7- to 15-fold when its 5'UTR is absent in uceApro2.ConclusionsuceA1.7 is a strong constitutive regulatory sequence composed of a promoter (uceApro2) and its 5'UTR that will be useful in genetic transformation of dicots, having high potential to drive high levels of transgene expression in crops, particularly for traits desirable in flower and root tissues.
Highlights
Cotton (Gossypium spp.) is an important crop worldwide that provides raw material to 40% of the textile fiber industry
We report the identification of the gland development related protein 85 [GenBank:EU373075] GhGDRP85 gene, a member of the E2 family that presents a high level of transcript accumulation in several cotton tissues
The data generated in this study indicate that uceA1.7 has potential to be a reliable alternative to the CaMV35S promoter and its variations to be applied in genetically modified (GM) crop generation programs
Summary
Cotton (Gossypium spp.) is an important crop worldwide that provides raw material to 40% of the textile fiber industry. Important traits have been studied aiming the development of genetically modified crops including resistance to insect and diseases, and tolerance to drought, cold and herbicide. The characterization of promoters and regulatory regions is important to achieve high gene expression and/or a specific expression pattern. Cotton plants (Gossypium spp.) produce the most widely used textile fiber in the world. The stability and expression patterns of foreign genes driven by the CaMV35S promoter, including genes expressed in cotton [8,9], have been widely debated [9,10,11]. The discovery and characterization of additional plant promoters is essential to a better understanding of transgene expression in GM plant development with predictable high level, temporal and tissuespecific expression patterns [13]
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