scholarly journals Evaluation of a Herbicide-resistant Trait Conferred by the Bar Gene Driven by Four Distinct Promoters in Transgenic Blueberry Plants

2008 ◽  
Vol 133 (4) ◽  
pp. 605-611 ◽  
Author(s):  
Guo-Qing Song ◽  
Kenneth C. Sink ◽  
Peter W. Callow ◽  
Rebecca Baughan ◽  
James F. Hancock
Keyword(s):  
Transgenic Plants ◽  
Herbicide Resistance ◽  
Single Copy ◽  
Vaccinium Corymbosum ◽  
Cauliflower Mosaic Virus ◽  
Leaf Damage ◽  
Marker Genes ◽  
Promoter Strength ◽  
Herbicide Resistant ◽  
Selectable Marker Genes

Four chimeric bialaphos resistance (bar) genes driven by different promoters were evaluated for production of herbicide-resistant ‘Legacy’ blueberry plants (73.4% Vaccinium corymbosum L. and 25% Vaccinium darrowi Camp) through Agrobacterium tumefaciens (Smith & Towns.) Conn.-mediated transformation. When the bars were used as selectable marker genes, different promoters yielded different transformation frequencies. Three chimeric bar genes with the promoter nopaline synthase (nos), cauliflower mosaic virus (CaMV) 35S, or CaMV 34S yielded transgenic plants, whereas a synthetic (Aocs)3AmasPmas promoter did not lead to successful regeneration of transgenic plants. In addition, herbicide resistance in bar-expressing plants was influenced by the promoter strength. Under controlled environmental conditions, 3-month-old plants from six single-copy transgenic events with 35S∷bar or nos∷bar, as well as those nontransgenic plants, were sprayed with herbicide glufosinate ammonium (GS) at five levels (0, 750, 1500, 3000, and 6000 mg·L−1). Evaluations on leaf damage 2 weeks after spraying indicated that all transgenic plants exhibited much higher herbicide resistance than nontransgenic plants. Additionally, the transgenic plants with the 35S∷bar showed a higher herbicide resistance than those with the nos∷bar. After application of 6000 mg·L−1 GS, over 90% of the leaves from plants with the 35S∷bar and 19.5% to 51.5% of the leaves from plants with the nos∷bar showed no symptom of herbicide damage, whereas only 5% of leaves from the nontransgenic had no damage. One-year-old, field-grown plants from four transgenic events with the nos∷bar were evaluated for herbicide resistance after spraying with 750 mg·L−1 GS. Transgenic plants survived with variations in the level of foliar damage; in contrast, all nontransgenic plants died. This study is the first investigation of different promoters for engineering transgenic blueberry plants.

scholarly journals ptxD/Phi as alternative selectable marker system for genetic transformation for bio-safety concerns: a review

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11809
Author(s):  
Richard Dormatey ◽  
Chao Sun ◽  
Kazim Ali ◽  
Sajid Fiaz ◽  
Derong Xu ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Genetic Transformation ◽  
Herbicide Resistance ◽  
Selectable Marker ◽  
Selection Marker ◽  
Marker Genes ◽  
Selection System ◽  
Efficient System ◽  
Marker System ◽  
Selectable Marker Genes

Antibiotic and herbicide resistance genes are the most common marker genes for plant transformation to improve crop yield and food quality. However, there is public concern about the use of resistance marker genes in food crops due to the risk of potential gene flow from transgenic plants to compatible weedy relatives, leading to the possible development of “superweeds” and antibiotic resistance. Several selectable marker genes such as aph, nptII, aaC3, aadA, pat, bar, epsp and gat, which have been synthesized to generate transgenic plants by genetic transformation, have shown some limitations. These marker genes, which confer antibiotic or herbicide resistance and are introduced into crops along with economically valuable genes, have three main problems: selective agents have negative effects on plant cell proliferation and differentiation, uncertainty about the environmental effects of many selectable marker genes, and difficulty in performing recurrent transformations with the same selectable marker to pyramid desired genes. Recently, a simple, novel, and affordable method was presented for plant cells to convert non-metabolizable phosphite (Phi) to an important phosphate (Pi) for developing cells by gene expression encoding a phosphite oxidoreductase (PTXD) enzyme. The ptxD gene, in combination with a selection medium containing Phi as the sole phosphorus (P) source, can serve as an effective and efficient system for selecting transformed cells. The selection system adds nutrients to transgenic plants without potential risks to the environment. The ptxD/Phi system has been shown to be a promising transgenic selection system with several advantages in cost and safety compared to other antibiotic-based selection systems. In this review, we have summarized the development of selection markers for genetic transformation and the potential use of the ptxD/Phi scheme as an alternative selection marker system to minimize the future use of antibiotic and herbicide marker genes.

Excision of selectable marker genes from transgenic plants

2002 ◽  
Vol 20 (6) ◽  
pp. 575-580 ◽  
Author(s):  
Peter D. Hare ◽  
Nam-Hai Chua
Keyword(s):  
Transgenic Plants ◽  
Selectable Marker ◽  
Marker Genes ◽  
Selectable Marker Genes

scholarly journals Identification of genes differentially regulated by glucocorticoids and progestins using a Cre/loxP-mediated retroviral promoter-trapping strategy

2002 ◽  
Vol 28 (3) ◽  
pp. 177-192 ◽  
Author(s):  
Y Wan ◽  
SK Nordeen
Keyword(s):  
Target Genes ◽  
Selectable Marker ◽  
Biological Effects ◽  
Fibroblast Cell ◽  
Single Copy ◽  
Mouse Fibroblast ◽  
Marker Genes ◽  
Flanking Sequence ◽  
Selectable Marker Genes ◽  
Promoter Trap

Glucocorticoids and progestins are two classes of steroid hormone with very distinct biological functions. However, the glucocorticoid receptor (GR) and the progesterone receptor (PR) share many structural and functional similarities. One way that glucocorticoids and progestins can exert different biological effects is through their different abilities to regulate the expression of certain target genes. A strategy employing a retroviral promoter-trap and Cre/loxP-mediated site-specific recombination has been developed to identify genes that are differentially regulated by glucocorticoids and progestins. A mouse fibroblast cell line (4F) stably expressing both GR and PR and containing a single copy of a multifunctional selection plasmid is generated. This line is transduced with a self-inactivating retroviral promoter-trap vector carrying coding sequences for Cre-recombinase (Cre) in the U3 region. Integration of the provirus places Cre expression under the control of a genomic flanking sequence. Activation of Cre expression from integration into active genes results in a permanent switch between the selectable marker genes that converts the cells from neomycin-resistant to hygromycin-resistant. Selection for hygromycin resistance after hormone treatment yields recombinants in which Cre sequences in the U3 region are expressed from hormone-inducible upstream cellular promoters. Because Cre-mediated recombination is a permanent event, the expression of the selectable marker genes is independent of ongoing Cre expression. Thus this system permits the identification of genes that are transiently or weakly induced by hormone.

scholarly journals Utility of I-SceI and CCR5-ZFN nucleases in excising selectable marker genes from transgenic plants

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Bhuvan P. Pathak ◽  
Eliott Pruett ◽  
Huazhong Guan ◽  
Vibha Srivastava
Keyword(s):  
Transgenic Plants ◽  
Selectable Marker ◽  
Marker Genes ◽  
Selectable Marker Genes

scholarly journals Constitutive Expression of Pea Defense Gene DRR206 Confers Resistance to Blackleg (Leptosphaeria maculans) Disease in Transgenic Canola (Brassica napus)

1999 ◽  
Vol 12 (5) ◽  
pp. 410-418 ◽  
Author(s):  
Yaping Wang ◽  
Goska Nowak ◽  
David Culley ◽  
Lee A. Hadwiger ◽  
Brian Fristensky
Keyword(s):  
Brassica Napus ◽  
Transgenic Plants ◽  
Leptosphaeria Maculans ◽  
Constitutive Expression ◽  
Single Copy ◽  
Cauliflower Mosaic Virus ◽  
Adult Plant ◽  
35S Promoter ◽  
Transgenic Lines

To identify genes effective against the blackleg fungus Leptosphaeria maculans (Phoma lingam), we have transformed canola (Brassica napus) with four pea (Pisum sativum) genes under constitutive control by the cauliflower mosaic virus 35S promoter: PR10.1, chitinase, DRR206, and defensin. Transgenic lines containing single-copy T-DNA insertions for each gene were screened for both seedling (cotyledonary) and adult plant resistance. Lines for which pea DRR206 mRNA was expressed showed decreased disease scores, compared with non-expressing transgenic lines. Transgenic plants expressing pea defensin showed a slight enhancement of resistance, while for PR10 and chitinase transgenics there was little or no enhancement of resistance. Resistance to L. maculans cosegregated with DRR206 transgenes. Extracts from DRR206 and defensin transgenic plants inhibited fungal germination in vitro. DRR206 transgenic plants also demonstrated decreased hyphal growth at inoculation sites. While the precise function of DRR206 remains to be determined, these results suggest that it does play an important role in defense against fungi.

Comparison of three selectable marker genes for transformation of wheat by microprojectile bombardment

1998 ◽  
Vol 25 (1) ◽  
pp. 39 ◽  
Author(s):  
Barbara Witrzens ◽  
Richard I.S. Brettell ◽  
Fiona R. Murray ◽  
David McElroy ◽  
Zhongyi Li ◽  
...  
Keyword(s):  
Selectable Marker ◽  
Microprojectile Bombardment ◽  
Single Copy ◽  
Transgenic Wheat ◽  
Immature Embryos ◽  
Marker Genes ◽  
Hygromycin B ◽  
Neomycin Phosphotransferase ◽  
Multiple Copy ◽  
Selectable Marker Genes

Three selectable marker genes were compared for their efficacy in the production of transgenic wheat plants following microprojectile bombardment of cultured immature embryos. While transformed plants were recovered using the bar (phosphinothricin acetyltransferase) gene in combination with bialaphos, and the aphA (neomycin phosphotransferase) gene in combination with geneticin or paromomycin, no transgenic material was obtained with the hpt (hygromycin phosphotransferase) gene and hygromycin B. Southern analysis revealed single copy as well as multiple copy insertions of the bar and aphA transgenes. Inheritance of these selectable marker genes was demonstrated in the T1 generation progenies.

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