A modern plant breeding technique may provide new crop traits while avoiding some of the pitfalls presented by other new breeding technologies.
The rapid trait development system, or RTDS, is a targeted form of mutagenesis and is new to agricultural breeding. It avoids the market stumbling issue of transgenics, which inserts a foreign gene into a plant, yet still creates new plant traits.
In addition to traditional cross breeding methods, plant breeders of the past few decades have used mutagenesis and transgenic breeding systems to develop new traits in plants.
Read Also
Going beyond “Resistant” on crop seed labels
Variety resistance is getting more specific on crop disease pathogens, but that information must be conveyed in a way that actually helps producers make rotation decisions.
Now, a new gene conversion technology developed by Cibus in the United States allows researchers and breeders to select a plant gene sequence they wish to alter, create what appears to the plant to be a genetic mismatch in its DNA, and coax the plant to make the change on its own.
The technology can create only genetic changes that could be done through traditional plant breeding techniques including mutagenesis, but is much faster.
“We can’t add genes from other species, but we can make changes to traits that might otherwise have been too time consuming or costly to do any other way,” said Keith Walker of Cibus.
Minor-use crops haven’t seen the benefit of the most modern breeding techniques available to them, partly because of development costs associated with mutagenesis and transgenics and partly because of poor market acceptance of transgenic processes.
Transgenics involves the insertion of genes that contain a desired trait into a host plant. For example, a bacterial trait inserted into corn DNA provides the ability for Bt corn to create its own insecticide, which makes it resistant to key pests. As well, glyphosate resistant genes inserted into certain plants such as canola, make herbicide tolerant crops.
Host DNA may not fully accept the new genes or it may not accept them at the locations in the DNA where they are placed. They may not express themselves in the plant as predicted and over generations the new transgenic plants may prove unstable and lose the ability to express the new, desired trait.
Mutagenesis involves creating desired traits by altering a DNA sequence within a gene or chromosome. It is usually achieved by using chemicals or radiation. The process tends to produce many unwanted results because it is difficult to target a single region of the DNA and can be expensive due to a large number of variations that can occur.
Walker said in RTDS, a gene repair oligonucleotide, or GRON, is paired with a plant DNA sequence at a specific point within a gene. The GRON contains the mutation change that breeders have tested in the lab. The plant acts to repair itself, but actually creates a new genetic trait as it copies the GRON into its own DNA.
RTDS may be suited to fill the needs recently outlined by canola growers. At recent Canadian Canola Growers Association meetings, producers endorsed a new program that will focus their research check-off dollars on traits that should benefit producers, such as expanded disease resistance, oil content and shatter proofing seedpods.
As well, Walker said RTDS may be able to serve many crops that have failed to benefit from the rush for new traits enjoyed by soybeans, corn and canola. As well, he said, some crops haven’t taken advantage of all the techniques because of the market rejection of transgenics.
David Voss of Cibus said flax is one of those crops.
“We are talking to (Canadian flax producers’ associations) about opportunities in that crop. It is one that could have traits like improved fibre (while maintaining or increasing) oil content. But large agricultural corporations don’t see a big payback on those traits, so they don’t happen,” he said.
Walker said flax is a good example of a crop that could have new traits developed to serve specific industrial and food markets and create fibre markets, if traditional costs of breeding weren’t so high.
Jerome Konecsni of Genome Prairie in Saskatoon said any new breeding technique, such as RTDS, that produces novel traits, must be evaluated for its long-term stability.
“There are some new (plant breeding) technologies that might make significant changes to prairie agriculture. This may be one of them. But (genetic) stability is one of the crucial points that will need to be proven.”
Voss said the RTDS system does provide stability for subsequent generations. Cibus is setting out to prove it in a recently announced project by the American National Grain Sorghum Producers Foundation.
Walker said the project with the NGSPF and agricultural chemical company Valent is a good example of the role he hopes Cibus will play.
“We are working to develop a non-GMO herbicide tolerant sorghum. The bigger players overlooked sorghum because there weren’t enough acres. The producers who grow the crop have decided they don’t want to be left behind,” he said.
The trait will make the new variety of sorghum resistant to Valent’s Select Max and grass herbicide, solving a problem for growers of that crop.
Voss said the breeding program and the eventual revenue from the seed and its new traits will be shared by the NGSPF. In turn the producers plan to reinvest in more research and the creation of new varieties.
