Finding a GMO alternative

Matt Bewley,Nov. 16/2009
http://www.agweek.com/articles/?id=7250&article_id=15553&property_id=41

The Rapid Trait Development System, a genetic plant breeding technology developed by Cibus Genetics L.L.C. of San Diego, holds out hope of being a quicker, less politically charged answer to traditional genetically modified organisms, according to Peter Beetham, the company’s vice president of research.

“I think the time frame for the technology will get faster,” he says. “We’re working on a number of different crops, and if (a new disease) happened to be in that particular crop, we could potentially turn something around in maybe two to four years.”

RTDS also is different from transgenic, or genetically modified, breeding in an important way. In the transgenic approach, a foreign gene is inserted into a plant’s genome to bestow a specific trait, for example, immunity to Roundup. It is this insertion of foreign material into a plant or animal that has caused much of the controversy surrounding GMOs, which are virtually outlawed by the European Union. In the U.S., Roundup Ready varieties of several crop plants also are under fire.

Gene mechanics

RTDS alters a targeted portion of a gene by utilizing the cell’s own gene repair system.

The component that effects this change is called the GRON, short for Gene Repair Oligonucleotide. It is chemically synthesized and may contain DNA, RNA and certain chemical properties. It is designed to fit like a mismatched puzzle piece into an exact location of the gene, for example, where resistance to a certain disease is expressed.

It is intentionally mismatched, carrying the new genetic code for the desired trait. Once in place, this mismatch triggers the cell’s own natural gene repair enzymes, which then modify the gene itself to fit the GRON. After that, the GRON degrades and falls away, leaving the cell to naturally multiply and impart the new genetic trait to the host plant.

This is precise, targeted change in the genetic sequence, in contrast to conventional transgenic GMOs, in which introduction of foreign genetic material is required.

As its moniker implies, RTDS develops traits quickly. In the natural world, this kind of change, called mutagenesis, is a matter of genetic mutation in cells that can take thousands of years to build up into a survivable trait. Modern transgenic development typically takes seven to 10 years to get from genetic modification to the marketplace. The Cibus process takes from three to five years to get from the laboratory to the marketplace.

Interestingly, Beetham calls this time frame a primary limitation to the process.