Appendix 2: sample evaluations of the potential for new plant products to be regulated under Part V of the Seeds Regulations

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Appendix 2F : Elevated rutin levels in asparagus

PNT Determination Work Sheet
A companion document to Regulatory Directive 2009-09:
Plants with Novel Traits Regulated under Part V of the Seeds Regulations

Note: This plant is a hypothetical case study, and not currently under development

Species: Asparagus (Asparagus officinalis L.)
Trait: Elevated levels of rutin (an antioxidant compound with potential human health benefits)

Plant with novel traits Determination Work Sheet - Elevated rutin levels in asparagus

1. Was the trait bred into the plant from, or present in, germplasm (of the same species) cultivatedFootnote 1 in Canada prior to 1996, or previously authorized by the PBO for use in a plant of the same species?

Unknown – Rutin is a compound that is native to asparagus, with considerable variation apparent even between the same cultivars being grown in different environments (Guillén et al. 2008, Motoki et al. 2008).

However, there are currently no data showing the total variation of rutin levels in asparagus cultivars. Thus, it is difficult to determine if making a change to this trait would be considered "new" to the Canadian environment. In such cases, the Plant Biosafety Office has recommended that question 2 (below) be answered.

References:

Guillén, R., Rodríguez, R., Jaramillo, S., Rodríguez, G., Espejo, J.A., Fernández-Bolaños, J., Heredia, A., and Jiménez, A. Antioxidants from asparagus spears: Phenolics. Acta Hort. 776: 247–254.

Motoki, S., Matsunaga, K., Maeda, T., and Kutsuzawa, T. 2008. Selection of asparagus cultivars for cold areas of Japan. Acta Hort. 776: 357–365.

If the answer to question 1 is "yes," then stop. The plant is not a PNT and is not subject to regulation under Part V of the Seeds Regulations. Otherwise, continue:

Plant with novel traits Determination Work Sheet - Elevated rutin levels in asparagus

2. Does the plant have a potential to have a significant negative environmental impact, relative to an appropriate Canadian comparator line (or lines), in terms of:

2a. Weediness potential: Is there an increased potential that the plant will become a weed of agriculture or be invasive in the Canadian environment?

No – Rutin is an antioxidant compound. While antioxidants are involved in plant stress tolerance, there have been no publications that showed a causal link between elevated antioxidant levels and increased plant vigour. Therefore, it is not expected that asparagus with elevated levels of rutin would be any more weedy or invasive than its counterparts.

Other cultivated plants can also have greater concentrations of rutin (or related compounds) than that observed in asparagus (Sakakibara et al. 2003)

References:

Sakakibars, H., Honda, Y., Nakagawa, S., Ashida, H., and Kanazawa, K. 2003. Simultaneous determination of all polyphenols in vegetables fruits and teas. J. Agric. Food Chem. 51: 571-581.

2b. Gene flow: Are there negative consequences to environmental safety resulting from the production of hybrids between the plant and any domestic or wild sexually compatible relatives that are present in Canada?

No – There are no wild relatives of asparagus in the Canadian environment. Moreover, any gene flow from high-rutin asparagus to other asparagus cultivars is not likely to have any negative consequences to environmental safety.

2c. Plant pest potential: Does the plant have increased potential to harbour and/or facilitate the spread of a pest or pathogen of the Canadian environment?

No – There are no studies that show that increased levels of antioxidants increases the potential for asparagus to harbour pests. A study performed in poplar has shown that increased antioxidant levels does not affect the feeding of leaf-chewing insects (Barbehenn et al. 2008).

Disease resistance response in plants is regulated through reactive oxygen species (ROS): increasing antioxidant levels, such as rutin, may reduce the presence of ROS and alter disease response. However, several resistant and susceptible genotypes to various asparagus diseases are already grown in Canada, so it is unlikely that elevated rutin levels will negatively affect disease response in a fashion that is outside the range of that currently seen in the Canadian environment.

References:

Barbehenn, R.V., Jaros, A., Yip, L., Tran, L., Kanellis, A.K., and Constabel, C.P. 2008. Evaluating Ascorbate Oxidase as a Plant Defense Against Leaf-Chewing Insects Using Transgenic Poplar. J. Chem. Ecol. 34: 1331–1340.

2d. Potential negative impacts on non-target organisms: Could the plant have negative impacts on non-target organisms interacting directly or indirectly with it, including humans as workers or bystanders?

No – Given that antioxidants are generally considered desirable and health-improving, it is not likely that the elevated rutin levels in this asparagus would have negative impacts on non-target organisms, including humans.

Liver function did not change in humans taking rutin supplements, suggesting a lack of toxicity of this compound (Boyle et al. 2000)

References:

Boyle, S.P., Dobson, V.L., Duthie, S.J., Hinselwood, D.C., Kyle, J.A.M., and Collins, A.R. 2000. Bioavailability and efficiency of rutin as an antioxidant: a human supplementation study. Eur. J. Clin. Nutr. 54: 774-782.

2e. Other potential negative impacts on biodiversity: Does the plant have any other potential negative impacts on biodiversity, including changes to environmentally sustainable crop management practicesFootnote 2?

No – An increase in rutin levels will not require any changes to current asparagus management practices.

If the answer to any part of question 2 is "yes" or is unclear, then contact the Plant Biosafety Office: the plant may be a PNT and may be regulated under Part V of the Seeds Regulations.

Please note: Depending on the product, data requirements for some criteria may be more extensive than others. Evidence, such as experimental data or peer-reviewed literature, should be available to support the rationale provided in this document.
The PBO reserves the right to request that more extensive data be supplied in support of a determination or to confirm the determination by the proponent.

Conclusion: This plant is not a PNT and is not regulated under Part V of the Seeds Regulations.

The trait of interest in this product does not appear to have the potential for significant negative environmental impact; the PBO does not have to be notified. However, during the course of development of this variety, should any indication of an unexpected change that would impact environmental safety be observed, this conclusion should be revisited.

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