|Tuesday, 27 February 2007|
UNIVERSITY of Connecticut plant biologists have developed a tool – called a "genetically modified gene-deletor" – that they claim could prevent genetically modified gene flow into non-biotech crops or weeds. The team believes the invention could help alleviate public concerns surrounding genetically modified plants.
The technology could be developed to confine genetically modified genes used in vegetatively propagated, undomesticated bioenergy crops, like poplar, willow and switchgrass.
To date, controlling the flow of transgenic genes into the wild via pollen and seeds has been a huge concern to the public and a major challenge for scientists specialising in agricultural biotechnology.
Developed in the laboratory of UConn Associate Professor of Plant Science Yi Li, and published in the March issue of Plant Biotechnology Journal, this technology provides a means of eliminating all of the transgenic genes from pollen and seeds if needed.
The GM-gene-deletor technology also could allow farmers to produce non-genetically modified consumer products, such as seeds, fruits and flowers, from transgenic plants.
"For example, herbicide-resistant genetically modified traits are primarily needed to protect crops during growth prior to seed or fruit development," Li explained.
"The GM-gene-deletor could initiate the gene deletion process immediately prior to seed or fruit development, so farmers would get the benefit of the added crop protection during a critical growth stage without the unintended consequence of the uncontrolled spread of a herbicide-resistant gene, which could create 'super weeds', as some believe."
The GM-gene-deletor also could be used in crops that are genetically modified for the production of pharmaceuticals to block the accidental transmission of these traits into food crops through seed or pollen.
The new UConn technology also holds the potential to end a longstanding debate on so-called "terminator" gene or seed technology that has pitted major agricultural biotechnology companies against poor farmers in developing countries.
The terminator technology inserts terminator or suicidal genes into genetically modified seeds to ensure that no genes from genetically modified crops contaminate non-GM crops.
This process protects the companies' patents and could alleviate some of the same consumer concerns Li's technology addresses, but at the expense of poor farmers in developing countries, who would have to buy fresh seeds every year, because the terminator gene system renders the genetically modified plants sterile.
The terminator technology has yet to be commercialised because of the problems it poses for farmers in developing countries.
"With our technology, the seeds the farmers save will not have genetically modified traits," said Hui Duan, one of Li's former doctoral students and a co-author of the published research.
"The farmers would need to buy new seeds each year if they want the crops to have genetically modified traits such as insect resistance or herbicide resistance. But if they did not want to do so or could not afford to do so, they would still be left with viable seeds to replant."
Li's group at UConn started this project in 2000 with funding from Connecticut Innovation Inc (CII), the Consortium for Plant Biotechnology Research (CPBR), US Department of Energy and UConn.
The team and their collaborators in China and at the University of Tennessee reported a novel use of two site-specific DNA recombination systems to assemble a highly efficient gene eliminator that specifically targets the foreign genes.
By incorporating these systems into the genome of the genetically modified plants, the scientists found the undesirable genes were removed from the pollen and seeds of the plant with as much as 100% efficiency.
Because of the exceptionally high deletion efficiency observed in their experimental plants, Li and his collaborators expect an enormous potential for the technology to be used in large-scale plantings of agricultural crops as well as genetically improved trees and bioenergy/biofuel and pulp generating plant species.
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