Key messages

• Gene-editing technology provides an exciting new set of tools for crop improvement.
• Knowledge of national and international regulations is needed for Australian growers to exploit the technology.
• The current status of the gene-editing regulatory landscape in countries that import Australian grain is presented, together with future perspectives on consumer acceptance of gene-edited grains.

Aim

The aim of this project is to enable Australian grain growers to gain first-mover advantage in using new breeding technologies, specifically gene-editing, to improve grain crops. This requires an understanding of the underlying science and the policies and regulations related to gene-editing technologies both in Australia and in countries that import Australian grains. It includes participation in helping align the regulations in importing countries with those in Australia and informing the grains industry of the international regulatory landscape.

Introduction

A range of new breeding technologies based on the principles of gene editing (GEd) present new opportunities to generate genetic advances that can be translated rapidly into delivering better grain crops. GEd technology is contributing both to new understanding of gene function and directly to better crops. There is now an air of excitement around potential applications of GEd for crop improvement. However, because most Australian grains are exported, the international policy and regulatory environments must be clarified to avoid non-tariff trade barriers so that the benefits of GEd technologies can be realised by Australian growers.

In a project funded by the Commonwealth Government (DAWE, now DAFF, Program Assisting Small Exporters), we have been addressing this issue. The project entitled ‘Building Capacity for Small Exporters to Exploit New Breeding Technologies’, is supported by DPIRD, Murdoch University, the Australian Seed Federation, CBH Group, COGGO, GreenBlueprint Pty Ltd, CropLife Australia and RAYI Corporation.

Argentina provides an example of the importance of GEd technologies. It deregulated major forms of GEd technology more than six years ago, resulting in a much faster development of GEd crops from bench to market than in the previous 20 years of GMOs (Whelan et al 2020).  Whereas multinational companies had developed 90% of the GMOs previously commercialised, de-regulation of GEd products was game-changing, and commercial GEd products are now developed by local companies, public research organisations (50%) and foreign SMEs (32%), with multinationals at just 9%.

GEd – the science

The science that underlies GEd technologies is presented in more detail in a companion paper by Dr Yong Han. Most agricultural R&D is based on CRISPR technologies, but other forms of GEd have been undertaken in Australia, including the use of Transcription Activator-Like Effector Nucleases (TALENs) and Zinc Finger Nucleases (ZFNs). The CRISPR-associated endonuclease (Cas9, a dsDNAse) enables what is essentially targeted mutagenesis: the site of targeted cleavage of DNA is determined by the associated single guide RNA (sgRNA). CRISPR/Cas9 facilitates targeted modification of genetic information at a specific genomic location, enabling the alteration, deletion or addition of DNA bases at a specific site after DNA repair. The cut ends of the DNA sequence may be repaired, mostly with the loss or addition of a small number of bases (indels) by non-homologous end joining (NHEJ).  Alternatively, with the addition of a donor DNA template, nucleotides can be added at the site of DNA cleavage by a process of homology-dependent repair (HDR).

Definitions of the products of GEd

Gene editing, in which there is a spontaneous repair at a ds-break (dsB) site without introduction of external DNA, is referred to as Site-Directed Nuclease 1 (SDN-1). If a repair oligonucleotide is incorporated at the dsB, it is Site-Directed Nuclease 2 (SDN-2), and if a completely new gene cassette is inserted at the dsB, then it is Site-Directed Nuclease-3 (SDN-3). There is general agreement on the definitions of SDN-1 and SDN-3, but SDN-2 can be interpreted in several ways. SDN-2 is applied to either the insertion of one or a few bases from an HDR oligonucleotide, or the insertion of a complete allele from within the plant’s gene pool, which could have been introduced by conventional breeding. The latter includes allele swopping, which is a standard aim in conventional breeding. To date, an SDN-3 product is regarded as a GMO in most jurisdictions.  It is notable that Ged plants can often be generated more efficiently if a GM selection stage is included, but since the editing occurs at a different location of the genome, null GM edited segregants can be generated and classified as conventionally bred plants.

What can Ged deliver?

A summary of the current data on Ged crops in the ‘EU-SAGE’ database is provided in Figure 1.  We highlight a few examples of the applications of Ged technology to crop improvement, which shows that Ged has been applied to all major crop plants including the cereals wheat, barley, maize, rice, sorghum, and to potato, canola, cotton, and many more. The breeding targets include biotic factors such as resistance to diseases and pests (e.g., resistance to powdery mildew, rice blast, bacterial blight, citrus canker, viruses); quality traits such as the amylose:amylopectin ratio to reduce the Glycemic Index, high oleic acid content, flavour, reduced browning, reduced anti-nutritional factors, improved nutrition such as vitamins A, C, and D; herbicide tolerance; hybrid/breeding systems and maturity dates; grain size, grain number, number of tillers, protein quality, reduced pre-harvest sprouting, reduced allergenicity; improved stress tolerance (e.g., to drought, heat and cold stress), and trait stacking (Jones et al 2022).

Figure 1. A summary of published work on GEd to improve traits of plant/crop species. (A) The number of GEd studies targeting different traits of crop plants. (B) The percentage of GEd studies on different plant species. (C) The frequency of use of five GEd techniques. BE and PE indicate base-editing and prime-editing. (D). Countries where GEd of plants are being studied. (E) The outcome of GEd type in plant research. (EU-SAGE database; https://www.eu-sage.eu, accessed 02/07/2022)

GEd legislation in Australia

Australia has a well-developed system for regulating genetically manipulated (GM) and GEd organisms, based on the Gene Technology (GT) Act 2000 and the Gene Technology Regulations 2001, with corresponding State and Territory laws. The GT Act included establishing the Office of the Gene Technology Regulator (OGTR), which is overseen by the Gene Technology Regulator, who takes advice and consults with a range of bodies and is responsible for ensuring the monitoring and compliance of the gene technology legislation.

Following a national review, in October 2019 the decision was released to deregulate SDN-1 products, but not those which used SDN-2, ODM or SDN-3 technologies, which remain captured as GMOs. Thus, In Australia, only products of SDN-1 technology that do not contain any externally introduced DNA can be grown in the same way as products of conventional breeding activities.

Path to market in Australia

The path-to-market for SDN-1 GEd produce is provided in Figure 2. Similar paths-to-market are provided in detail in Jones et al (2022) for our major grain trading partners, and an international overview of the acceptance of GEd products in the Asia-Pacific is provided in Figure 3.

Figure 2. A summary of the pathways to the deregulation of SDN-1 GEd products in Australia

Although SDN-1 edited grain can be grown in Australia as conventionally bred varieties, Food Standards Australia New Zealand (FSANZ) is responsible for regulating food safety. FSANZ has yet to deliver its view of GEd foods.  Although it will consider applications on a case-by-case basis, at present it is possible that a GEd grain variety could be grown, but be blocked from sale as a food, although this outcome is viewed as unlikely.

Other issues to consider

Other technical considerations regarding GM grains include: the need for a commercial licence (if CRISPR/Cas9 is used), provision of evidence of the absence of external DNA and any new allergenic peptides, possible off-target edits (if present, usually eliminated in subsequent crop breeding), and possible low-level presence of edited seeds in a shipment to a country not yet ready to accept GEd produce. These considerations highlight the need for international harmonisation or alignment of GEd regulations.

Figure 3. The regulatory status of GEd crops in the Asia-Pacific region, based on deregulation of SDN-1 crops (green). Some countries have deregulated SDN-1 and SDN-2 products. Countries with ongoing discussions (yellow) and regulated as GMOs (red). Regulation of GEd crops in China is under discussion but does not use SDN terminology: at present GEd is still under GMO product safety management measures, but with less onerous requirements for commercial approval.

Australian GEd regulations have fallen behind those of some other countries (e.g., Japan, Philippines, Argentina, USA, Canada) which have also deregulated SDN-2 and even some SDN-3 products if introduced sequences are from the same gene pool (Jones et al 2022).

Conclusions

It is clear that regulatory harmonisation, or at least alignment, of GEd crops and produce is crucial, and this is particularly the case for Asia and Australasia. Without the harmonisation/alignment of GEd regulations, crop industries may well face the same trade issues that have limited the wider commercialisation of GM crops. However, it is encouraging that increasingly more of the world’s nations are proceeding to a rational approach of regulating GEd crops, following the principle that like products should be regulated in the same way. With the aid of science diplomacy and meaningful international discussions, the harmonisation or alignment of GEd regulations can be achieved, thus enabling the full benefits of GEd technologies to be realised.

Acknowledgements

Funded by a grant to M.J. and M.A. from the Department of Agriculture, Forestry, and Fisheries (formerly DAWE), Government of Australia, Project Assisting Small Exporters (PASE), Building Capacity for Small Exporters to Exploit ‘new breeding technologies’, Grant number 4-FA4N7WL.

References

Jones, M.G.K., Fosu-Nyarko, J., Iqbal, S., Adeel, M., Romero-Aldemita, R., Arujanan, M., Kasai, M., Wei, X., Prasetya, B., Nugroho, S., Mewett, O., Mansoor, S., Awan, M.J.A., Ordonio, R. L., Rao, S.R., Poddar, A., Hundleby, P., Iamsupasit, N., & Khoo, K. (2022). Enabling Trade in Gene-Edited Produce in Asia and Australasia: The Developing Regulatory Landscape and Future Perspectives. Plants, 11(19), 2538; doi.org/10.3390/plants11192538

Whelan, A.I., Gutti, P., & Lema, M.A. (2020). Gene editing regulation and innovation economics. Frontiers in Bioengineering and Biotechnology, doi: 10.3389/fbioe.2020.00303

Contact details

Professor Michael Jones
Ph: +61 (8) 9360 2424
Email: M.Jones@murdoch.edu.au