Terminator Seeds

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"Terminator Seeds" is a name used to refer to genetically engineered seeds that produce sterile offspring. A farmer who buys a terminator seed can plant and produce a crop, but he or she cannot save and plant the resulting seeds because they will be sterile. Only two companies - Bayer CropScience and Pioneer Hi-Bred (DuPont) - have "terminator seeds" that can be legally grown in the U.S., and the terminator seeds are for only two crops - corn and canola.

Once developed, terminator seeds produced such an outcry that they were never sold commercially. More recently, Pioneer Hi-Bred (DuPont) created its own male sterile line of corn that it plans to use solely in the production of non-genetically engineered hybrid corn seed.

History

1990s:

2000s:

2010s:

  • June 28, 2011: U.S. deregulates Pioneer Hi-Bred's Male Sterile/Female Inbred Corn, DP-32138-1[1]

Varieties

Plant Genetic Systems Male Sterile Corn MS3

"Event MS3 has been genetically engineered with a gene from Bacillus amyloliquefaciens encoding a ribonuclease called barnase, which inhibits pollen formation and results in male sterility of the transformed plants. The subject corn line also contains the bar gene isolated from the bacterium Streptomyces hygroscopicus that encodes a phosphinothricin acetyltransferase (PAT) enzyme, which, when introduced into a plant cell, inactivates glufosinate. Linkage of the barnase gene, which induces male sterility, with the bar gene, a glufosinate tolerance gene used as a marker, enables identification of the male sterile line before the plant begins to flower. Event MS3 was transformed via immature embryo electroporation in yellow dent corn material. Expression of the introduced genes is controlled in part by the P35S promoter derived from the plant pathogen cauliflower mosaic virus and the 3' nos sequence from the plant pathogen Agrobacterium tumefaciens."[2]

(Plant Genetic Systems was acquired by AgrEvo, which was ultimately acquired by Bayer CropScience.)

Pioneer Hi-Bred's Male sterile & Glufosinate Tolerant Corn, 676, 678, 680

"Corn lines 676, 678, and 680 have been genetically engineered to contain a dam gene derived from Escherichia coli. The dam gene expresses a DNA adenine methylase enzyme in specific plant tissue, which results in the inability of the transformed plants to produce anthers or pollen. The subject corn lines also contain the pat selectable marker gene isolated from the bacterium Streptomyces viridochromogenes. The pat gene encodes a phosphinothricin acetyltransferase (PAT) enzyme, which, when introduced into a plant cell, inactivates glufosinate. Linkage of the dam gene, which induces male sterility, with the pat gene, a glufosinate tolerance gene used as a marker, enables identification of the male sterile line for the production of hybrid seed. The subject corn lines were transformed by the particle gun process, and expression of the introduced genes is controlled in part by gene sequences derived from the plant pathogen cauliflower mosaic virus."[3]

AgrEvo's Glufosinate Tolerant, Male sterile Corn, MS6

"Male sterile corn transformation event MS6 is similar to the antecedent organism described in the AgrEvo petition 95-228-01p except that it was developed by a new transformation event using the same biolistic particle bombardment techqnique. MS6 expresses the barnase (ribonuclease) from B. amyloliquefaciens whose transcription is directed by the corn PCA55 pollen-specific promoter and whose termination is signal is from nopaline synthase gene from Agrobacterium tumefaciens and a selectable marker gene phosphinothricin acetyltransferase (bar) from Streptomyces hygroscopicus whose transcription is directed 35S cauliflower mosaic caulomovirus (CaMV) promoter and whose termination signal is from nopaline synthase. The nopaline synthase terminator gene for barnase was truncated. Even MS3 had different pollen specific promoter than MS6. MS6 does not contain the complete beta-lactamose gene (bla) or the bacterial origin of replication (ori)."[4]

AgrEvo's Male Sterile Canola, MS8, and Restored Fertility Canola, RF3

"The subject transformation events have been genetically engineered to contain a barnase gene (MS8) for male sterility or a barstar gene (RF3) for fertility restoration. The barnase gene expresses a ribonuclease that blocks pollen development and results in a male sterile plant, and the barstar gene encodes a specific inhibitor of this ribonuclease and restores fertility. The barnase and barstar genes were derived from Bacillus amyloliquefaciens, and are linked in the subject transformation events to the bar' gene derived from Streptomyces hygroscopicus. The bar gene encodes the enzyme phosphinothricin-N-acetyletransferase (PAT), which confers tolerance to the herbicide glufosinate. The herbicide tolerance trait allows for selection of plants carrying the linked genes for pollination control during breeding and for tolerance to the herbicide during commercial cultivation. Expression of the added genes is controlled in part by gene sequences derived from Arabidopsis thaliana, Nicotiana tabacum, and the plant pathogen Agrobacterium tumefaciens. The A. tumefaciens method was used to transfer the added genes into the parental canola variety, Drakkar."[5]

Aventis CropScience's Male Sterile Canola MS1, and Fertility Restored Canola, RF1 and RF2

"Like the antecedent organisms [MS8 and RF3], canola events MS1 and RF1 and RF2 have been genetically engineered to contain a barnase gene (MS1) for male sterility or a barstar gene (RF1 and RF2) for fertility restoration. The barnase gene expresses a ribonuclease that blocks pollen development and results in a male-sterile plant, and the barstar gene encodes a specific inhibitor of this ribonuclease and restores fertility. The barnase and barstar genes were derived from Bacillus amyloliquefaciens, and are linked in the subject canola events to the bar gene derived from Streptomyces hygroscopicus. The bar gene encodes the enzyme phosphinothricin-N-acetyletransferase (PAT), which confers tolerance to the herbicide glufosinate. The subject canola events and the antecedent organisms were developed through use of the Agrobacterium tumefaciens method, and expression of the added genes in MS1 and RF1 and RF2 and the antecedent organisms is controlled in part by gene sequences derived from the plant pathogen A. tumefaciens. In summary, the Aventis extension request states that canola events MS1 and RF1 and RF2 and the antecedent organisms contain the same genetic elements with the exception of the antibiotic resistance marker gene nptII in MS1 and RF1 and RF2, which was used as a transformant selection tool during the developmental process. The parental variety Drakkar was used to develop both the antecedentorganisms and MS1 and RF1 and RF2."[6]

Pioneer Hi-Bred's Male Sterile, Female Inbred, Visual Marker Corn, DP-32138-1

"According to Pioneer, DP-32128-1 is engineered to produce male steril female inbred plants for the generation of hybrid corn seed that is non-transgenic (Pioneer 2009). As detailed in the petition, the carefully controlled expression of a seed color marker and pollen fertility and sterility genes allows for the generation of red transgenic seed for seed increase of male sterile and female inbred lines. The multistep process yields a non-transgenic male-sterile female parent. This non-transgenic material can then be used for hybrid see production (Pioneer 2009)...
"As detailed in the petition, the carefully controlled expression of a seed color marker gene and pollen fertility and sterility gene allows for the generation of red transgenic seed for seed increase of male sterile female inbed lines that are used for non-transgenic hybrid commercial seed production. Typically, detasseling is needed in corn seed production, and confers substantial expense, lower seed yield and lower genetic purity. Use of DP-32138-1 would eliminate detasseling and lead to increased seed yield and higher genetic purity during seed increase operations. As detailed in the petition, the process predictably and reliably results in a commercial product which does not contain the DP-32138-1 transgenes."[7]

Articles and resources

Related SourceWatch articles

References

  1. Federal Register, Vol. 76, No. 124, June 28, 2011.
  2. Federal Register, Vol. 61, No. 46, March 7, 1996.
  3. Federal Register, Vol. 63, No. 103, May 29, 1998.
  4. Rebecca A. Bech, Approval of AgrEvo Request (98-349-01p) Seeking Extension of Determination of Non-regulated Status for Male Sterile Corn Event MS6, Environmental Assessment and Finding of No Significant Impact, March 16, 1999.
  5. Federal Register, Vol. 64, No. 61, March 31, 1999.
  6. Federal Register, Vol. 67, No. 226, November 22, 2002.
  7. Cindy Eck, Final Environmental Assessment, USDA, May 2011.

External resources

External articles