New RTDS Technology
By Dan Davidson
DTN Staff Agronomist
Rapid Trait Development System technology provides an alternative to transgenic traits without introducing foreign genes into a plant.
OMAHA (DTN) -- In the past 10 years, biotechnology has brought farmers new traits, such as Roundup Ready and Bt, and made crop management easier.
These genetically modified traits and others like them were created using transformation, a process that takes a gene for a novel trait such as glyphosate tolerance from one organism and puts it into another -- mostly corn, soybeans and other commercially valuable crops.
But successful gene transformations are expensive to create, expensive to get approved and market acceptance can be hard to come by. That's just in the U.S. Some overseas markets do not accept GM products in their food and even when governments approve the technology, consumers often shun it.
Cibus, a company based in San Diego, Calif., recently announced its own proprietary non-GM gene conversion technology known as the Rapid Trait Development System or RTDS. Cibus will collaborate with the National Grain Sorghum Producers Foundation to develop and commercialize new traits for sorghum.
"For the first time since GMO products hit the market more than a decade ago, there is a viable technology that can replicate the attributes of certain GMO crops without the introduction of foreign genetic material," said Keith Walker, president of Cibus.
Cibus' RTDS technology is a molecular breeding technology that enables seed companies to develop plants with novel and commercially valuable traits. However, unlike direct genetic modification, RTDS introduces genetic traits through site-directed mutagenesis, which uses the natural gene-repair process. Cibus can make small changes in the DNA sequence that codes for the gene and ultimately change its function.
Like traits produced by transformation, the new RTDS traits are patentable, said Walker.
So how does Cibus' technology work? It has three elements.
First, scientists need to know the sequence of the gene; Cibus uses genomics to understand the gene's function.
Second, the scientists need to know what changes they want to introduce in a gene. This is usually a very precise, targeted change.
Third, there has to be a tissue culture system in place to grow a whole plant from a changed cell.
Cibus' technology uses the plant's own internal DNA repair mechanism to cut out one or more nucleotides, or DNA building blocks, at a precise location along the DNA strand and replace them with other nucleotides to effect a change in the gene's function.
By changing nucleotides in the DNA strand, Cibus changes the amino acid sequence that is the template for the final protein. Once the correction process is complete, the newly modified gene is expressed and produces a new protein according to the new DNA plan. This procedure effects a precise change in the genetic sequence while the rest of the gene is left unchanged.
In contrast to transgenic (GM) plants, there is no insertion of foreign DNA in the plant. The changes in the genetic sequence are precise and not randomly inserted. And because the affected gene remains in its native location, no unexpected or negative gene expression can occur.
"Non-GM products are very attractive in certain markets," said Walker. There are high regulatory costs and unexpected consequences with transgenic introductions, he said.
"We do not transfer the entire gene so the original gene remains and will still be expressed as in nature, but have a slightly different property."
RTDS technology is best for targeting single enzymes such as herbicide tolerance, Walker said. "Herbicide tolerance is a huge opportunity for Cibus and our technology is cost effective. Any trait related to a specific enzyme system can be tweaked once we know what the enzyme is."
RTDS has some limitations. It cannot bring in novel traits such as Bt for insect protection. In principle it is limited to single-gene traits because the time and cost to modify several genes in a process might not be economical.
"Right now with RTDS it is difficult to make massive changes to the genome to create new value," Walker said.
Cibus wants to focus on trait development and partner with crop associations, seed or chemical companies, or end-use companies to modify and develop traits. The partnering company would help market the technology to farmers.
David Voss, vice president of commercial development at Cibus, said the company is currently applying the RTDS technology to canola, rice and sorghum.
Cibus is not currently focusing on corn and soybeans, Voss said, because a number of major companies have already invested significant resources in transgenic technology. Cibus plans to focus on crops where transgenic investments are unlikely. Rice is one example because it is a food crop with regulatory hurdles that can be high for GM varieties, and sorghum is another example because the total acreage for sorghum is too small to justify developing a transgenic variety.
