Articles
ESTABLISHMENT OF A MANNOSE-BASED SELECTION SYSTEM FOR THE TRANSFORMATION OF TORENIA HYBRIDS
Article number
743_19
Pages
139 – 142
Language
English
Abstract
Traditional selection markers for the production of transgenic plants such as genes for antibiotic resistance and herbicide tolerance are not accepted by the public opinion.
A promising alternative system consists in the use of mannose as selective agent.
Mannose can not be metabolized by many plant species and accumulates as mannose-6-phosphate resulting in growth inhibition.
By the use of a gene encoding phosphomannose isomerase (PMI) as a selection marker, transgenic cells are enabled to use mannose-6-phophate as carbon source, since PMI catalyses its conversion to fructose-6-phosphate.
A mannose-based selection system has already been successfully established for the production of transgenic crops such as sugar beet, rice, maize or potato.
In this paper we used this positive selection system for the transformation of Torenia hybrids.
The integration and expression of pmi gene was confirmed by PCR analysis.
Furthermore, a spectrophotometrical enzyme assay led to a clear detection of PMI activity in enzyme extracts of the transgenic material.
In contrast, despite the high mannose-tolerance of Torenia, no endogenous PMI activity was found in non-transgenic Torenia tissues.
Taken together, the mannose-based selection system can be successfully applied for the generation of transgenic Torenia plants.
Compared to selection by kanamycin, the mannose-based selection decreases regeneration time up to 25%, the transgenic shoots show favourable rooting even on mannose-media and the transformation efficiency is generally higher.
A promising alternative system consists in the use of mannose as selective agent.
Mannose can not be metabolized by many plant species and accumulates as mannose-6-phosphate resulting in growth inhibition.
By the use of a gene encoding phosphomannose isomerase (PMI) as a selection marker, transgenic cells are enabled to use mannose-6-phophate as carbon source, since PMI catalyses its conversion to fructose-6-phosphate.
A mannose-based selection system has already been successfully established for the production of transgenic crops such as sugar beet, rice, maize or potato.
In this paper we used this positive selection system for the transformation of Torenia hybrids.
The integration and expression of pmi gene was confirmed by PCR analysis.
Furthermore, a spectrophotometrical enzyme assay led to a clear detection of PMI activity in enzyme extracts of the transgenic material.
In contrast, despite the high mannose-tolerance of Torenia, no endogenous PMI activity was found in non-transgenic Torenia tissues.
Taken together, the mannose-based selection system can be successfully applied for the generation of transgenic Torenia plants.
Compared to selection by kanamycin, the mannose-based selection decreases regeneration time up to 25%, the transgenic shoots show favourable rooting even on mannose-media and the transformation efficiency is generally higher.
Publication
Authors
C. Seitz, S. Bruna, H. Li, B. Hauser, G. Forkmann
Keywords
selection markers, PMI, genetic transformation, mannose metabolism
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