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Last Document: 2.1  Regulations

Table of Contents  Foods derived from genetically modified organisms and detection methods

Next Document: 2.3.1  Differences in national approvals of the 'same' products

2.2 Commercialisation of genetically modified products

The first approval of a genetically engineered plant for human consumption was given in the United States. The Flavr Savr tomato from Calgene received approval from USDA/APHIS and FDA in 1992 and 1994, respectively. Since then, 25 additional transgenic plants have been approved by US authorities. Several of these products have also been approved in other countries, and two further ones in the European Community. These and others are summarised in tables in the following sections.

The new traits introduced into currently approved genetically engineered plants can be categorised as follows (see also  Field trials Table 2 [end of page]):

1. Improved product quality (durability, firmness, fruit ripening delayed, processing value)
2. Pest resistance (insects, nematodes, viruses)
3. Agronomic benefits (herbicide tolerance, hybrid system)

The Flavr Savr tomato belongs to the first category. Constitutive expression of the Flavr Savr gene (antisense-construct derived from the polygalacturonase [PG] gene from tomato) results in a dramatically decreased PG-activity in the transgenic tomatoes. The enzyme PG degrades pectin, a major constituent of the cell wall of the fruit. Thus the Flavr Savr tomatoes can ripen on the vine longer and be harvested long after they turned red, without the risk of excessive softening after harvest. In contrast, more than 80 % of the conventional tomatoes sold in the US are picked while green and exposed to external sources of ethylene in industrial pants to develop red colour.

The majority of the approved genetically modified plants can be categorised under groups II and III. Several of the pest-resistant transgenic crops carry genes also conferring herbicide resistance for selection purposes ( List of Tables: Tables 3-10). The most frequently used selection marker is the nptII gene also termed kanr or neor, coding for the enzyme aminoglycoside 3'-phosphotransferase II (APH(3')II). Expression of this enzyme allows for selection on media containing kanamycin (kan), and neomycin (neo, G418) (see also section 4).