Plant selectable markers and reporter genes
ABSTRACT In recent years, considerable progress has been made in genetic engineering of various plant species, both agronomically important
crops as well as model plants. The bases of this progress were, in addition to efficient transformation methods, the design
of appropriate signals regulating transgene expression and the use of selection marker or reporter genes. In most cases, a
gene of interest is introduced into plants in association with a selectable marker gene (nptII, hpt, acc3, aadA, bar, pat). Recovery of a transgenic plant is, therefore, facilitated by selection of putative transformants on a medium containing
a selection agent, such as antibiotic (nptII, hpt, acc3, aadA), antimetabolite (dhfr), herbicide (bar, pat), etc. On the other hand, use of reporter genes (cat, lacZ, uidA, luc, gfp) allows not only to distinguish transformed and non-transformed plants, but first of all to study regulation of different
cellular processes. In particular, by employing vital markers (Luc, GFP) gene expression, protein localization and intracellular
protein traffic can be now observed in situ, without the need of destroying plant.
Chapter: Concepts of Marker Genes for Plants[Show abstract] [Hide abstract]
ABSTRACT: Marker genes, more exactly named selectable marker genes, are absolutely essential for the production of transgenic plants. They are required to identify, to “mark” the introduced genes and finally to enable the selective growth of transformed cells. These marker genes are co-transformed with the gene of interest (GOI); they are linked to the GOI and therefore remain in the transformed cell. However, once transgenic cells have been identified und regenerated to whole plants, the marker genes are no longer needed. For this reason new concepts of marker genes are discussed with regard to the safety of genetically modified plants to both the environment and the consumer. This chapter reviews the most important marker genes available for gene transfer to plants, focusing particularly on recent advances, and discusses new systems for marker gene-free transformation techniques, as well as marker gene deletion.12/2009: pages 39-60;
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ABSTRACT: Production of vaccines in plant cells provides an alternative system that has several advantages when compared to current vaccine production methods. Establishment of stable seed stocks for a continuous supply of a vaccine is a critical part of production systems. Therefore, a vitrification method for cryopreservation was applied to non-transgenic and three different antigen-expressing transgenic Nicotiana tabacum (NT-1) lines. Preculture of the suspension cultures 1d prior to vitrification was sufficient for cell survival through the cryopreservation process. Inclusion of 0.3M mannitol in the preculture medium was necessary for maintenance of cell viability. Cultures were also treated with and without heat shock prior to vitrification, and it was found that heat shock was unnecessary for growth recovery post cryopreservation. All cultures survived storage in liquid nitrogen at intervals ranging from 1h to 1yr. Antigen expression was measured by enzyme-linked immunosorbent assay for cultures that grew post cryopreservation and those that had never been cryopreserved. Expression levels in cultures derived from cryopreserved material were comparable to cultures that had not been cryopreserved. Transmission electron microscopy showed that the integrity of the cell structure was maintained post cryopreservation.In Vitro Cellular & Developmental Biology - Plant 01/2009; 45(6):750-757. · 1.14 Impact Factor
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ABSTRACT: There has been much interest in the development of embryogenic systems in woody plants, aimed at optimizing efficient genetic transformation methods to incorporate useful genes. Among the different regeneration systems, embryogenic cultures have been the most responsive tissues with competence for in vitro regeneration and genetic transformation. We present an overview of woody plant biotechnology and cover culture systems, methods of transformation, selectable marker genes and some selected case studies representing forest and fruit crops: sandalwood, conifers, acacia, grape, mango, avocado, rubber and walnut. The development of transgenic systems in these plant species is expected to contribute to their overall improvement in wood quality, resistance to diseases and pests and tolerance to environmental stress.Journal of New Seeds 01/2005; 7(2):17-35.