Source: CropBiotech Update

Biotech crops that produce non-GM pollen

The lateral gene transfer or “escape” of transgenes into the environment is a major biosafety concern. Pollen from biotech crops could fertilize conventional varieties or wild species, thereby releasing the transgene with potential adverse effects on biodiversity.

The use of Genetic Use Restriction Technologies (GURTs), which can be used both to develop sterile plants and to regulate the expression of the transgene by the application of chemicals or by a specific set of environmental conditions, have been proposed as a tool to prevent lateral gene transfer. These technologies have however met with considerable opposition.

The possibility of producing essential vaccines and medicines in biotech plants makes the need to prevent lateral gene transfer essential, especially when food crops are used for biopharming. Biopharming can potentially benefit developing countries most, where the lack of infrastructure, road access and refrigeration are often major constrains to delivering required pharmaceuticals to where there are most needed. Edible medicines would be cheaper to produce, purer, easier to transport, and would require no refrigeration.

Can we develop biotech crops that produce GM-free pollen and are also fertile? A team of researchers, lead by Jan-Peter Nap of the Wageningen University in the Netherlands, show us we can. The group generated transgenic tobacco plants that carry, in addition to the transgene of interest, a second gene that will excise the first transgene. The team ensured the second gene is only active during reproduction by using a pollen specific promoter. Transgene removal becomes therefore an integral part of the biology of pollen maturation, and does not require any external stimulus or chemical application. Highly efficient excision of transgenes from tobacco pollen was achieved with a potential failure rate of at most two out of 16 800 seeds (0.024%).

To read the abstract of the article “Directed microspore-specific recombination of transgenic alleles to prevent pollen-mediated transmission of transgenes”, published in the Plant Biotechnology Journal, visit:
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1467-7652.2006.00194.