ACS-BNØØ3-6 - InVigor™ canola | BCH-LMO-SCBD-14755 | Living Modified Organism | Biosafety Clearing-House


Living Modified Organism (LMO)

Decisions on the LMO Risk Assessments  
published: 05 Jun 2006 last updated: 30 Jan 2023
Living Modified Organism identity
The image below identifies the LMO through its unique identifier, trade name and a link to this page of the BCH. Click on it to download a larger image on your computer. For help on how to use it go to the LMO quick-links page.
InVigor™ canola
The canola (Brassica napus) was modified to contain a fertility restoration system and display glufosinate herbicide tolerance. To restore male fertility, the canola expresses Bacillus amyloliquefaciens barstar, which is an inhibitor of the ribonuclease barnase. This allows the modified canola to be used in conjunction with a male-sterile canola (expressing barnase) for controlling pollination and the production of hybrid seeds. In addition to fertility restoration, the canola expresses Streptomyces hygroscopicus phosphinothricin N-acetyltransferase to confer tolerance to the herbicide phosphinothricin (glufosinate ammonium). The enzyme inactivates the herbicide through acetylation. Further, the expression of phosphinothricin N-acetyltransferase also allowed for selection of modified plants during transformation. 
The term “Recipient organism” refers to an organism (either already modified or non-modified) that was subjected to genetic modification, whereas “Parental organisms” refers to those that were involved in cross breeding or cell fusion.
  • ACS-BNØØ5-8 - InVigor™ canola
    | Bayer CropScience | Changes in physiology and/or production (Reproduction, Male sterility), Resistance to antibiotics (Kanamycin), Resistance to herbicides (Glufosinate)
Characteristics of the modification process
  • Agrobacterium-mediated DNA transfer
Some of these genetic elements may be present as fragments or truncated forms. Please see notes below, where applicable.
  • BCH-GENE-SCBD-14974-7 Barstar | Bacillus amyloliquefaciens (BACAM)
    Protein coding sequence | Changes in physiology and/or production (Fertility restoration)
  • BCH-GENE-SCBD-14972-12 Phosphinothricin N-acetyltransferase gene | Streptomyces hygroscopicus (STRHY)
    Protein coding sequence | Resistance to herbicides (Glufosinate)
  • BCH-GENE-SCBD-101407-6 pTA29 pollen specific promoter | Nicotiana tabacum (Tobacco, TOBAC )
  • BCH-GENE-SCBD-101409-2 Barstar gene terminator | Bacillus amyloliquefaciens (BACAM)
  • BCH-GENE-SCBD-100269-8 Nopaline Synthase Gene Terminator | Agrobacterium tumefaciens (Agrobacterium)
  • BCH-GENE-SCBD-103851-5 rbcS Promoter | Arabidopsis thaliana (Thale cress, Mouse-ear cress, Arabidopsis, ARATH)
  • BCH-GENE-SCBD-103067-9 Transcript 7 gene 3' untranslated region | Agrobacterium tumefaciens (Agrobacterium)
The modified canola contains two gene cassettes: Bacillus amyloliquefaciens barstar and Streptomyces hygroscopicus phosphinothricin N-acetyltransferase (bar).

The bar coding sequence is under control of Arabidopsis thaliana ribulose-1,5-bisphosphate carboxylase small subunit (rbcS) protomer and A. tumefaciens transcript 7 gene 3' untranslated region.

The barstar coding sequence is under control of the Nicotiana tabacum TA29 promoter and Agrobacterium tumefaciens nopaline synthase (nos) terminator. Despite the presence of the barstar 3' untranslated region, transcription is expected to be terminated by the nos terminator. Due to the pollen-specific nature of the promoter, expression of barstar is only expect in pollen.

A second barstar cassette is present with the same genetic elements as above. The TA29 promoter present in this second is truncated, but functional. The cassette terminated by a nos terminator. A partial rbcS promoter is also present, but not functional.

  • On the N-terminal, two codons of the wild-type bar coding region have been substituted for the codons ATG and GAC.
  • Southern blot and PCR analysis indicated that the LMO contains one complete copy of the transformation cassette with a second partial cassette, arranged in an inverted repeat orientation centered around the left border. The partial repeat contains the functional genetic elements for the barstar cassette, but the rbcS promoter is non-functional.
  • The exact genetic element sizes for the truncated promoters in the second partial repeat are not available and thus have not been indicated.
LMO characteristics
  • Feed
  • Food
  • Other (Hybrid seed production)
Detection method(s)
Additional Information
The transgenic line RF3 was engineered to restore fertility in the hybrid lines. Transgenic RF3 plants contain the barstar gene, isolated from Bacillus amyloliquefaciens. The barstar gene codes for a ribonuclease inhibitor (barstar enzyme), which is a specific inhibitor of barnase, an RNAse expressed by male-sterile lines. In the absence of barstar, expression of barnase in the tapetum cells, completely degrades RNA in maturing pollen, arresting pollen development and resulting in male-specific sterility overall. When both barstar and barnase are expressed, barstar associates with barnase to form a stable complex,inactivating the RNase activity of barnase. As a result, when pollen from the restorer line RF3 is crossed to a male-sterile line expressing barnase, the resultant progeny express the RNAse inhibitor in the tapetum cells of the anthers, allowing hybrid plants to have normal pollen development. Thus, fertility is restored in the hybrid progeny.

RF3 was also engineered to express tolerance to glufosinate ammonium, the active ingredient in phosphinothricin herbicides (Basta®, Rely®, Finale®, and Liberty®). Glufosinate chemically resembles the amino acid glutamate and acts to inhibit an enzyme, called glutamine synthetase, which is involved in the synthesis of glutamine. Essentially, glufosinate acts enough like glutamate, the molecule used by glutamine synthetase to make glutamine, that it blocks the enzyme's usual activity. Glutamine synthetase is also involved in ammonia detoxification. The action of glufosinate results in reduced glutamine levels and a corresponding increase in concentrations of ammonia in plant tissues, leading to cell membrane disruption and cessation of photosynthesis resulting in plant withering and death. 

Glufosinate tolerance in this line was the result of introducing a gene encoding the enzyme phosphinothricin-N-acetyltransferase isolated from the common aerobic soil actinomycete, Streptomyces hygroscopicus. The enzyme catalyzes the acetylation of phosphinothricin, which inactivates the herbicidal compound.