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DD2002-42: Determination of the Safety of BASF's Imazethapyr Tolerant PWC16 Rice

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Issued: 2002-12

This Decision Document has been prepared to explain the regulatory decision reached under the guidelines Dir95-03 "Guidelines for the Assessment of Livestock Feed from Plants with Novel Traits " and Dir94-08 "Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits".

The Canadian Food Inspection Agency (CFIA), specifically the Animal Feed Division of the CFIA, with advice from the Plant Biosafety Office of the CFIA has evaluated information submitted by BASF regarding the Imazethapyr tolerant PWC16 rice line. CFIA has determined that feed derived from these plants do not present a concern to environmental or livestock feed safety, when compared to currently commercialized rice varieties in Canada.

Livestock feed use of the rice line PWC16 is therefore authorized as of December 5, 2002. Line PWC16 and any rice lines derived from it may be imported and/or released, provided no inter-specific crosses are performed, provided the intended use is similar and provided it is known following thorough characterization that these plants do not display any additional novel traits and are substantially equivalent to currently commercialized rice, in terms of their potential environmental impact and livestock feed safety.

The rice line PWC16 is subject to the same phytosanitary import requirements as its unmodified counterparts.

Table of Contents

  1. I. Brief Identification of Plant with Novel Traits (PNT)
  2. II. Background Information
  3. III. Description and Assessment of the Novel Trait
    1. Development Method
    2. Imazethapyr Tolerance
    3. Stable Expression
  4. IV. Criteria for the Environmental Assessment
    1. Potential of line PWC16 to Become Weeds of Agriculture or Invasive of Natural Habitats
    2. Potential for Gene Flow from Line PWC16 to Wild Relatives Whose
      Offspring May Become More Weedy or More Invasive
    3. Altered Plant Pest Potential of Line PWC16
    4. Potential Impact on Non-Target Organisms of Line PWC16
    5. Potential Impact on Biodiversity of Line PWC16
  5. V. Criteria for the Livestock Feed Assessment
    1. Potential Impact on Livestock Nutrition
    2. Potential Impact on Livestock and Workers/By-standers
  6. VI. New Information Requirements
  7. VII. Regulatory Decision

I. Brief Identification of Plant with Novel Traits (PNT)

Designation(s) of the PNT: Rice line PWC16

Applicant: BASF

Species: Rice (Oryza sativa)

Novel Traits: Tolerance to imazethapyr, an imidazolinone herbicide

Trait introduction method: Chemically induced seed mutagenesis

Intended use of the PNT: Production of rice for livestock feed, human food and industrial uses. These materials will be grown outside of Canada, in the usual production areas for rice.

II. Background Information

BASF has developed rice line PWC16 tolerant to imazethapyr, an imidazolinone herbicide. This rice line was developed to provide an alternative strategy for weed control.

The development of the PWC16 rice was accomplished using chemically induced seed mutagenesis and whole plant selection procedures. The herbicide tolerance results from a single point mutation in the major acetohydroxyacid synthase (AHAS) gene such that this enzyme, the target of imidazolinone herbicides, is no longer affected by imazethapyr.

PWC16 was field tested in the United States in 2000.

BASF has provided data on the identity of rice line PWC16, a detailed description of the modification method and breeding history, information on the modified gene, the resulting protein and its mode of action and the stability of trait expression.

Agronomic characteristics of rice line PWC16 such as grain yield, days to 50% head, plant height and milling were compared the parental unmodified counterpart.

Nutritional components of PWC16 such as proximates, amino acids and fatty acids were compared with unmodified rice counterparts. Anti-nutritional factors were also determined.

The Animal Feed Division, CFIA, with input from the Plant Biosafety Office, CFIA, has reviewed the above information. The following assessment criteria as described in regulatory directives Dir95-03 and Dir94-08 were used to determine the safety and efficacy as livestock feed and the environmental safety of feed from this plant with novel trait:

III. Description and Assessment of the Novel Traits

1. Development Method

2. Imazethapyr Tolerance

3. Stable Expression

IV. Criteria for the Environmental Assessment

Note: Rice line PWC16 will not be grown in Canada and will only be imported as human food or livestock feed. The majority of rice imported to Canada does not have an intact hull, which results in the seed being incapable of germination and growth. Due to the unfavorable climatic conditions for rice in Canada, it is unlikely that grain from rice line PWC16 would be capable of persisting in the Canadian environment.

1. Potential of Line PWC16 to Become Weeds of Agriculture or Invasive of Natural Habitats

2. Potential for Gene Flow from Line PWC16 to Wild Relatives Whose Offspring May Become More Weedy or More Invasive

The CFIA has therefore determined that gene flow to sexually compatible species in Canada is not possible.

3. Altered Plant Pest Potential of Line PWC16

The CFIA has therefore determined that rice line PWC16 does not present a plant pest concern.

4. Potential Impact on Non-Target Organisms of Line PWC16

Based on the above, the CFIA has determined that rice line PWC16 will not result in altered impacts on non-target organisms, including humans, compared to current rice varieties.

5. Potential Impact on Biodiversity of Line PWC16

The CFIA has therefore concluded that the potential impact on biodiversity of rice line PWC16 does not present any adverse impacts on biodiversity in Canada.

V. Criteria for the Livestock Feed Assessment

1. Potential Impact on Livestock Nutrition

Nutrient and anti-nutrient composition of rice grain from PWC16 was compared with it's control (Cypress), grown in replicated trials in three locations in the southern United States.

Anti-nutritional Factors

Phytic acid and trypsin inhibitor concentrations were determined in rice grain samples from PWC16 and Cypress. There were no differences between the lines in concentration of either phytic acid or trypsin inhibitor.

Nutritional Composition

Nutritional components were measured in grain from rice line PWC16 and Cypress. Components included crude fat, crude protein, crude fibre, amino acids, fatty acids, B vitamins, vitamin E, and the minerals phosphorous, magnesium, iron, zinc. There were no differences between PWC16 and Cypress in nutrient composition, and the composition was typical for rice grain. The CFIA has therefore concluded that rice line PWC16 has nutritional composition equivalent to conventional rice.

2. Potential Impact on Livestock and Workers/By-standers

The AHAS enzyme is found in a wide variety of plants and micro-organisms. AHAS is not a known toxin or allergen and a single base pair change would not be expected to change this. AHAS from PWC16 is feedback inhibited as is unmodified AHAS, it is present in small amounts in the feed, it is heat labile and it is rapidly degraded under conditions in the gastrointestinal tract. Based on the information provided by BASF, the modified AHAS is unlikely to be a novel toxin or allergen.

Based on the detailed characterization provided (nutritional composition, agronomic data and protein profiles of the modified plant compared to the unmodified comparators) it is unlikely that secondary mutations causing unintended effects have occurred in the rice genome.

VI. New Information Requirements

If at any time, BASF becomes aware of any information regarding risk to the environment, including risk to human or animal health that could result from release of these materials in Canada, or elsewhere BASF will immediately provide such information to CFIA. On the basis of such new information, CFIA will re-evaluate the potential impact of the proposed use, and will re-evaluate its decision with respect to the livestock feed use authorization of this rice line.

VII. Regulatory Decision

Based on the review of data and information submitted by BASF, including comparisons of PWC16 with the unmodified parental counterparts, the Animal Feed Division, CFIA, has concluded that the modified gene and its corresponding novel trait will not confer to these plants any characteristic that would raise any concerns regarding the safety or nutritional composition of rice line PWC16. Rice grain, groats, hulls, bran and rice bran oil are currently listed in Schedule IV of the Feeds Regulations and are, therefore approved for use in livestock feeds in Canada. Rice line PWC16 has been assessed and found to be substantially equivalent to the unmodified parental rice variety, with respect to safety and nutritional quality. PWC16 and its products are considered to meet the present ingredient definitions and are approved for use as livestock feed ingredients in Canada. This rice line will not be grown in Canada nor can the seed overwinter, therefore the release of the feed into the environment would result in neither intended nor unintended environmental effects.

Livestock feed use of rice line PWC16 is therefore authorized as of December 5, 2002. PWC16 and any other rice lines derived from it may be imported and/or released, provided no inter-specific crosses are performed, provided the intended use is similar, and provided it is known, following thorough characterization that these plants do not display any additional novel traits and are substantially equivalent to currently grown rice, in terms of their livestock feed safety and environmental impact.

PWC16 is subject to the same phytosanitary import requirements as it's unmodified counterpart.

Please refer to Health Canada's Decisions on Novel Foods for a description of the food safety assessment of PWC16 rice lines.

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