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Plants > Biotechnology / PNTs > Unconfined Release > Decision Documents Decision Document 98-28:
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| Designation(s) of the PNT: | HCR-1 |
| Applicant: | AgrEvo Canada Inc. |
| Plant Species: | Brassica rapa canola |
| Novel Traits: | Novel tolerance to glufosinate ammonium herbicide |
| Trait Introduction Method: | Inter-specific cross with transgenic B. napus |
| Proposed Use of PNT's: | Production of B. rapa for seed oil for human consumption and seed oil and meal for livestock feed. These materials will not be grown outside the normal production area for canola. |
AgrEvo Canada Inc. has developed a Brassica rapa canola hybrid, HCR-1, derived from an inter-specific cross with the B. napus transformation event T45, that expresses a novel tolerance to glufosinate ammonium. This tolerance will allow the use of glufosinate ammonium as a post-emergence herbicide, thus providing an alternative for weed control in canola production, and reducing reliance on soil-incorporated herbicides. B. napus, transformed with the gene conferring glufosinate ammonium tolerance has been approved in May 1996 (see DD96-11.)
A bacterial gene which codes for phosphinothricin acetyltransferase, an enzyme that inactivates glufosinate ammonium through acetylation, was introduced into the HCR-1 line by an interspecific cross with the B. napus transformant T45. The inactivation of glufosinate ammonium by the bacterial enzyme confers the herbicide tolerance onto the novel plant.
Glufosinate ammonium tolerant B. rapa has been field tested in Canada under confined conditions in Saskatchewan and Alberta in 1994, 1995 and 1996.
AgrEvo Canada Inc. has submitted information on the identity of the HCR-1 hybrid line, the description of the development method and provided the expression levels of the novel protein. They have also referred to the information submitted for the environmental release and livestock feed approval of the B. napus line HCN28, a line derived from transformant T45.
Scientific references to support submitted information were cited, when available. In addition, AgrEvo has provided information, data and recorded observations comparing line HCR-1 to unmodified Polish canola counterparts. These comparisons have addressed characteristics that included days to flower, days to maturity, seed production (yield), crop height, lodging, disease tolerance, protein, oil content, fibre and fatty acid composition.
The Plant Biotechnology Office of the Plant Products Division, CFIA, has reviewed the above information, according to the Regulatory Directive Dir94-08, for determining environmental safety of plants with novel traits, which lists the following assessment criteria:
The Feed Section of the Plant Products Division, CFIA, has also reviewed the above information in light of the assessment criteria for determining safety and efficacy of livestock feed, as described in Dir95-03. The following assessment criteria were considered:
The CFIA has evaluated the data and information submitted by AgrEvo Canada Inc., on the reproductive and survival biology of the HCR-1 hybrid. From this, the Agency has found that vegetative vigor, flowering, time to maturity and seed production were within the normal range of expression found in unmodified Polish canola hybrids. HCR-1 has no specific added genes for cold tolerance or winter hibernation. It did not show any stress adaptation other than tolerance to glufosinate ammonium herbicide.
The biology of B. rapa, described in T-1-12-96, shows that this species normally is not invasive of unmanaged habitats in Canada. It occasionally is a weed of cultivated land, especially in the eastern provinces of Canada. According to the information and data provided by AgrEvo Canada Inc., HCR-1 was found to be no different from unmodified canola counterparts in this respect. The CFIA concurs that no competitive advantage was conferred by the insertion of the glufosinate ammonium tolerance gene, other than tolerance to the herbicide. Resistant canola volunteer plants will not be controlled by glufosinate ammonium herbicides, however they can be managed by growers using alternative herbicides with different modes of action.
The above considerations, together with the fact that the novel traits have no intended effect on weediness or invasiveness, has led the CFIA to conclude that HCR-1 has no altered weed or invasiveness potential compared to currently commercialized canola varieties.
Note: A longer term concern, if there is general adoption of several different crop and specific herbicide weed management systems, is the potential development of crop volunteers with a combination of novel resistances to different herbicides. This could result in the loss of the use of these herbicides and any of their potential benefits. Therefore, agricultural extension personnel, in both the private and public sectors, should promote careful management practices for growers who use these herbicide-tolerant crops, to minimize the development of multiple resistance.
Brassica rapa is an obligate outcrosser with other plants of the same species, and potentially with plants of the species B. napus, B. juncea, B. carinata, B. nigra, Diplotaxis muralis, Raphanus raphanistrum, and Erucastrum gallicum (see T-1-12-96). Studies show that potential introgression of the herbicide tolerance is most likely to occur with B. napus, the other major canola species, that is not considered as a weed in Canada.
If glufosinate ammonium tolerant individuals did arise through interspecific or intergeneric hybridization, the tolerance should not confer any competitive advantage to these plants unless challenged by the herbicide. This would only occur in managed ecosystems where glufosinate ammonium is applied for broad spectrum weed control, or in plant varieties developed to exhibit glufosinate ammonium tolerance and in which that herbicide is used to control weeds. As with glufosinate ammonium tolerant B. rapa volunteers, these individuals, should they arise, would be controlled using other available chemical means. Hybrids, if they developed, could potentially result in the loss of glufosinate ammonium as a tool to control these species. This however, can be avoided by the use of sound crop management practices.
The above considerations led the CFIA to conclude that gene flow from the HCR-1 hybrid line to relatives is possible, but should not result in increased weediness or invasiveness of these relatives.
The intended effects of the novel herbicide tolerance trait are unrelated to plant pest potential, and B. rapa is not a plant pest in Canada (see T-1-12-96). In addition, agronomic characteristics, and qualitative and quantitative composition of HCR-1 were shown by AgrEvo to be within the range of values displayed by unmodified canola varieties. The CFIA concurs with the conclusion that plant pest potential has not been inadvertently altered.
The detailed characterization of the novel gene and novel protein, briefly summarized in Part III, suggest that the modified B. rapa should not possess altered toxic or allergenic properties. AgrEvo has presented evidence that shows that the plant expressed PAT is rapidly inactivated in gastric fluids by enzymatic degradation and pH-mediated proteolysis. The PAT enzyme is highly specific and displays enzyme kinetics typical of those found in the plant kingdom. Seed protein profiles and fatty acid composition fall within the range of those of their unmodified counterparts
Based on the above, the CFIA has determined that the unconfined release of the HCR-1 hybrid will not result in altered impacts on interacting organisms, including humans, when compared with current canola varieties.
The introduced genes were determined to be safe to non-target organisms. In addition, the HCR-1 hybrid line has no novel phenotypic characteristics which would extend its use beyond the current geographic range of canola production in Canada. Since outcross species are only found in disturbed habitats, transfer of the novel herbicide tolerance would not affect unmanaged environments.
The CFIA has therefore concluded that the potential impact on biodiversity of the HCR- 1 hybrid line is equivalent to that of currently commercialized canola varieties.
Glucosinolates in the PNT line were determined from composite samples taken from short season zone trials. The glucosinolate levels were not significantly different from the control, unmodified line and well within the established standard of 30 µM/g. dried meal. The relative concentration of erucic acid for the PNT and the control were similar and well within the established limit of 2%.
No statistical differences in nutritional composition, i.e., crude protein, crude fat, crude fibre, ash, gross energy levels, oil content and fatty acid composition were noted between the whole seed from the HCR-1 line and current commercial canola cultivars. These results demonstrate that the introduction of the novel herbicide tolerance into B. rapa, resulting in the HCR-1 hybrid line, did not likely result in any secondary effects on the composition or nutritional quality of the cultivar. Accordingly, the HCR-1 hybrid line was judged to be substantially equivalent to traditional canola varieties in terms of nutritional composition.
This decision takes into consideration the presence of populations of wild bird rape (Brassica rapa) in Quebec, and the Atlantic provinces of Canada, and to a lesser extent in the Southern part of Ontario; and the undesirable movement of glufosinate ammonium herbicide tolerance into these weedy populations where this herbicide is used for weed control. This decision has been reached after consultation with plant breeders, weed scientists, and agronomists in academia and provincial government services.
Based on the review of submitted data, the Feed Section of the Plant Products Division has concluded that the novel gene expressed by the HCR-1 hybrid line does not raise safety or nutritional concerns as livestock feed. As this hybrid line has been assessed and found to be substantially equivalent to traditional B. rapa varieties with respect to feed safety, the HCR- 1 hybrid line and it's byproducts are approved for use as livestock feed ingredients in Canada.
If at any time, AgrEvo becomes aware of any information regarding risk to the environment, or risk to animal or human health, that could result from release of these materials in Canada, or elsewhere, AgrEvo must immediately provide such information to the CFIA. On the basis of such new information, the CFIA may re-evaluate the potential impact of the release and re-evaluate its decision.
Unconfined release into the environment of the B. rapa hybrid line HCR-1 is authorized in British Columbia, Alberta, Saskatchewan and Manitoba. Its use as livestock feed is also authorized. Also, any B. rapa lines derived from HCR-1, resulting from the same transformation event or transformed with the same genetic construct, may be considered substantially equivalent, provided it is known following thorough characterization that: no inter-specific crosses are performed; the intended use is similar; and these plants do not display any additional novel traits.
Please note that, while determining the environmental and livestock feed safety of plants with novel traits is a critical step in the commercialization of these plant types, other requirements may still need to be addressed, such as Variety Registration (CFIA).
This bulletin is published by the Plant Health and Production Division. For further information, please contact the Plant Biosafety Office or the Feed Section at:
| Plant Biosafety Office Plant Health and Production Division Plant Products Directorate 59 Camelot Drive, Nepean Ontario, K1A 0Y9 (613) 225-2342 |
Feed Section Animal Health and Production Division Animal Products Directorate 59 Camelot Drive, Nepean Ontario, K1A 0Y9 (613) 225-2342 |
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