A promoter derived from taro bacilliform badnavirus drives strong expression in transgenic banana and tobacco plants

Abstract

Taro bacilliform virus (TaBV) is a pararetrovirus of the genus Badnavirus which infects the monocotyledonous plant, taro ( Colocasia esculenta). A region of the TaBV genome spanning nucleotides 6,281 to 12 (T1200), including the 3' end of open reading frame 3 (ORF 3) and the intergenic region to the end of the tRNA(met)-binding site, was tested for promoter activity along with four different 5' deletion fragments (T600, T500, T250 and T100). In transient assays, only the T1200, T600, T500 fragments were shown to have promoter activity in taro leaf, banana suspension cells and tobacco callus. When these three promoters were evaluated in stably transformed, in vitro-grown transgenic banana and tobacco plants, all were found to drive near-constitutive expression of either the green fluorescent protein or beta-glucuronidase (GUS) reporter gene in the stem (or pseudostem), leaves and roots, with strongest expression observed in the vascular tissue. In transgenic banana leaves, the T600 promoter directed four-fold greater GUS activity than that of the T1200, T500 and the maize polyubiquitin-1 promoters. In transgenic tobacco leaves, the levels of GUS expression directed by the three promoters was between four- and ten-fold lower than that of the double Cauliflower mosaic virus 35S promoter. These results indicate that the TaBV-derived promoters may be useful for the high-level constitutive expression of transgenes in either monocotyledonous or dicotyledonous species.

Characterization of a Strong, Constitutive Mung Bean (Vigna radiata L.) Promoter with a Complex Mode of Regulation in planta

“…Constitutive promoters identified from plant viruses, such as the Cauliflower Mosaic Virus (Odell et al, 1985;Kay et al, 1987;Benfey & Chua, 1990;Holtorf et al, 1995;Wilmink et al, 1995), Cassava Vein Mosaic Virus (Verdaguer et al, 1998), Figwort Mosaic Virus (Sanger et al, 1990;Maiti et al, 1997;Bhattacharyya et al, 2002), Peanut Chlorotic Streak Virus (Maiti & Shepherd, 1998;Bhattacharyya et al, 2003), Taro Bacilliform Virus (Yang et al, 2003), Cestrum Yellow Leaf Curling Virus (Stavolone et al, 2003), Mirabilis Mosaic Virus (Dey & Maiti, 1999), Sugarcane Bacilliform Badnavirus (Tzafrir et al, 1998;Schenk et al, 1999Schenk et al, , 2001 and Subterranean Clover Stunt Virus (Schunmann et al, 2003) are widely used in biotechnology. This is in part due to a scarcity of well characterized strong constitutive plant promoters.…”

A novel Sugarcane bacilliform virus promoter confers gene expression preferentially in the vascular bundle and storage parenchyma of the sugarcane culm

“…These include the various enhanced 35S promoters from the dicot-infecting DNA Cauliflower mosaic virus (CaMV) [13] or the promoters of monocot-infecting DNA viruses like Rice tungro bacilliform virus (RTBV) [14, 15], Commelina yellow mottle virus [16], Taro bacilliform virus [17], Banana streak virus (BSV) [18], and Sugarcane bacilliform virus (SCBV) [19, 20]. Viral promoters derived from monocot-infecting DNA viruses are of particular interest because they tend to confer a tissue-specific gene expression, specifically in the vascular system [14, 16–20].…”

Improved tolerance toward fungal diseases in transgenic Cavendish banana (Musa spp. AAA group) cv. Grand Nain

“…Genetic engineering of banana plants has recently proven to be a useful alternative method for the introduction of new desirable traits. Although still labor-and time-consuming, several studies have reported the development of transgenic bananas with enhanced disease tolerance against weevil (Kiggundu et al 2003) and nematodes (Atkinson et al 2004), but to a higher extent it transgenic bananas have been recently used as a model system to study the expression of both plant and viral regulatory sequences (Dugdale et al , 2001Hermann et al 2001;Schenk et al 1999;Yang et al 2003). Previous papers and reviews have discussed the advantages of using chitinases for plant protection because these enzymes are fungicidal, part of the plant defense system, and non-toxic to plants, animals, and higher vertebrates.…”