Modern Seed Development and the Inability of Seeds to Propagate Naturally

Modern Seed Development and the Inability of Seeds to Propagate Naturally

Posted by Auntie Sue on Jul 28th 2020

Hybrid seeds are sterile due to incessant inbreeding. Hybrid plants do not produce a next generation that grows true to form. Hybrid seed’s infertility has caused a need to buy seed from seed companies year after year, creating a profitable dependence on multinational agribusinesses.

There is now movement pushing for the application of terminator seeds as a way to further protect seed companies’ technology. Terminator seed prevent genetically modified (GM) seed DNA from escaping by also making GM seeds sterile.

Development of the terminator seed

The terminator technology was developed by the USDA and Delta & Pine Company, a Mississippi cotton-seed supplier, as a technology protection system (TPS). Terminator technology is a method of protecting genetically engineered traits by making GM plant seeds sterile. Developers created the terminator technology by incorporating 3 genes into seeds, 1) the terminator gene, 2) a recombinase gene, and 3) a repressor gene. Terminator technology has not yet been applied to commercial crops, but the technology has been developed and could potentially enter the market at any time.

How terminator seed works

Before a crop matures, scientists would engineer a toxin to release in the seed embryos, killing the next generation of seeds. The toxic gene that is used ironically is called RIP, or Ribosome Inhibitor Protein, also called Saporin. RIP is taken from the plant Saponaria officinalis (also called soapwort, bouncing bet, and sweet betty), and works to stop plant ribosomes from producing proteins, a process needed in order to live.

RIP would be set to activate only after the seeds have matured on the plant so they can still be used for commercial purposes. Scientists fuse a RIP toxic genetic coding sequence to the promoter gene Late Embryogenesis Abundant (LEA), a seed-specific gene that activates just before the seeds have finished maturing. The promoter LEA gene is fused to both ends of the RIP toxic gene, with an additional piece of blocking DNA attached between the two.

A recombinase gene is attached to the sequence, blocked by a repressor gene. The repressor is preceded by a tetracycline-responsive promoter. Tetracycline is an agricultural antibiotic. If the seeds come into contact with tetracycline, the tetracycline-promoter gene deactivates the repressor and releases the recombinase enzyme. The recombinase enzyme cuts through the blocking DNA and releases the RIP toxin allowing it to act with the seed-specific promoter. When the seeds reach the end of maturity, the promoter gene works as normal, and the unblocked RIP toxin activates along with it and kills the seeds.

In order to activate the RIP gene in seeds, germinating seeds need to be soaked in the antibiotic tetracycline before being sold to farmers.

Problems with terminator technology

Terminator technology may encourage monopolistic control over the seed industry. By causing all seeds to be sterile, farmers and gardeners would be required to purchase seeds from seed companies year after year.

The spread of the RIP toxin to other plants is a high probability. Pollen from plants with an activated RIP toxin can carry the RIP toxin gene and kill the next plant generation. This could make saving seeds absolutely impossible for neighboring farmers without terminator crops.

A loss of genetic resources would result. Terminator seeds short-circuit the process of selecting seeds that do the best in any given climate and soil type, and no evolving of the best gene pool would be allowed to occur. If the terminator gene spread to heirloom varieties a complete loss of genetic heritage could result.

The safety of eating terminator seeds is unknown. While the RIP technology is supposed to only harm plants, there are doubts that this is truly the case. No one knows if the dead seeds will have different nutritional properties than living seeds, and what effects they will have on the body.

Proponents claim that terminator technology would only be used on crops meant for forage and flowers. But as already mentioned, it would be impossible to keep the RIP toxin from spreading to other crops that are edible via pollination. This has the potential to cause unforeseen allergic reactions since farmers would not be able to tell if their non-GM seeds had been polluted by the RIP toxin and would not be able to inform consumers on the labeling. Also, birds, animals, insects, fungus, good bacteria, and soil organisms can also digest the seeds or RIP DNA if the seeds fall to the soil, potentially causing them to become infertile.

The indirect effects of antibiotic use could be detrimental.The use of tetracycline antibiotic treatments to activate the RIP toxin before the seeds are sold increases the already slowly occurring resistance and tolerance to antibiotics. Unsafe handling of the antibiotic soaked seeds would pose risks to seed handles and farmers. In addition, plants need the microorganisms and bacteria that would be killed from the RIP toxin, in order to function properly.

Terminator genes could easily mutate. Any biologist will tell you that organisms are always changing and adapting. The silent toxins in plants could become randomly active even without tetracycline treatments. Genetics have complex ways of mixing and interacting with one another and the environment, and the changes in RIP genetics is unforeseeable. The terminator could be activated at wrong times or placed in different places of the plant.

Terminator technology cannot be guaranteed to work. The one potential benefit of terminator seeds is that they could reduce the spreading of GM genes to heritage crops. This however is unlikely since no genetic engineering can be 100% effective. Some seeds will fail to be soaked enough to activate the toxin, while other genes simply won’t respond to the antibiotics. And the issue of gene silencing, when introduced genetic material simply does not work, can also occur.