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Biosafety Considerations for New Plant Breeding Techniques

THIRD WORLD NETWORK BIOSAFETY INFORMATION SERVICE 

Dear Friends and Colleagues 

Biosafety Considerations for New Plant Breeding Techniques  

A study by Environment Agency Austria provides a scientific overview of biotechnology-based approaches in plant breeding other than genetically modification (GM), called “new plant breeding techniques” (NPBTs). This is in response to their increased use by seed companies for commercial purposes; however, some NPBTs may be exempt from current biosafety regulations.

 

Since NPBTs can be used for different purposes such as introducing new traits into crop varieties or modifying existing traits and are often used in combination with other technologies including GM and conventional breeding, the study examined the biosafety aspects of different NPBTs namely, in terms of their potential adverse effects on human health and the environment as well as those associated with practical application.  

The study highlights the potential for adverse unintended effects from using certain NPBT procedures. It recommends that the principles of case-specific risk assessment, including the precautionary principle, be applied to NPBT-crops based on their specific characteristics. It also suggests that four aspects should be specifically considered: modifications introduced into the crop genome;
knowledge and experience with the traits generated by application of NPBTs; presence of non-crop plant sequences
and modification of gene expression. 

The summary and conclusions of the report are reproduced below. The full report is available at http://www.ekah.admin.ch/fileadmin/ekah-dateien/New_Plant_Breeding_Techniques_UBA_Vienna_2014_2.pdf 

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Item 1

NEW PLANT BREEDING TECHNIQUES AND RISKS ASSOCIATED WITH THEIR APPLICATION 

Michael Eckerstorfer, Marianne Miklau and Helmut Gaugitsch
Umweltbundesamt (Environment Agency Austria) 

Summary and Conclusions  

Features of New plant breeding techniques (NPBTs) considered in this study  

Several open questions concerning the application of NPBTs to facilitating crop breeding are currently discussed, primarily the issue whether these NPBTs are subject to present regulation frameworks, e.g. as implemented for GM crops. A different line of discussion is focusing on questions related to the biosafety of NPBT-crops. This study analysed biosafety aspects for a number of different NPBTs, thus addressing an aspect that received considerably less attention in past years than issues concerning the regulatory status of NPBT-crops.   The following conclusions can be drawn from the analysis presented in this report: 

–  The individual NPBTs are indeed very different in approach and characteristics. According to these characteristics some NPBTs are applied to develop a wide range of different products.

–  Some NPBTs are used to modify the genomic DNA of the targeted crop species in a specific way in a stable and heritable form. Other NPBTs are aimed to change gene expression in the target plants – by transient expression of non-integrated genetic elements or modification of epigenetic regulation of gene expression (e.g. agroinfiltration/agroinfection, RdDM). A third group of NPBT-applications (e.g. MAS, TSBs like reverse breeding, accelerated breeding, seed production technology) are applied as tools to facilitate selection or other breeding processes. Genetic modification of a breeding intermediate may be necessary to achieve the breeding objective, e.g. with TSBs – however the final breeding product is not meant to contain these GM modifications.

–  A striking feature is that NPBTs are mostly used in combination. To develop products single NPBTs thus are combined with other NPBTs, with GM technology and conventional breeding approaches.

–  As regards the products developed by NPBTs some are very specific and cannot easily be generated by other approaches (e.g. targeted mutation and targeted integration of recombinant constructs, reverse breeding of parental lines for reconstituting elite hybrids and rapid accelerated breeding in crops like fruit trees).

–  Other products – notably NPBT-crops with traits that render them resistant to certain broadband herbicides – are less specifically linked to NPBTs. Similar crop lines were developed by means of GM techniques and also by conventional breeding in a few crops species. As their phenotype and use is comparable, a similar potential for risks is characteristic for these crops – which should be addressed by a comparable risk assessment approach.

–  For each NPBT the report compiles risk issues corresponding to the characteristics of the type of modifications. The different potential risks can be associated on the one hand with the intended modifications (e.g. introduction of alleles/mutations/regulatory effectors leading to traits which may be also connected to adverse effects). On the other hand potential adverse effects can result from unintended effects resulting of application of NPBT. Some of these unintended effects are due to methods like in vitro cell/tissue cultivation which need to be used in the process of NPBT, but which are not specific to a certain NPBT. Similar effects may also occur upon application of these techniques in conventional breeding.

–  GM techniques are used directly (Cisgenesis/Intragenesis, transcrafting, floral dip) or indirectly (agroinfiltration, TSBs, Nuclease-mediated site-directed mutagenesis by SSNs), as tools in the course of NPBT processes.

–  With indirect applications of GM technology the introduced modifications are intended to be present only in breeding intermediates, and not in the final breeding product. The final product then should be devoid of modifications specific for such a NPBT. This is limiting the possibilities for specific detection of a certain NPBT-crop, an issue which is also relevant for risk assessment and monitoring.  

Comparison of NPBTs with GM-technology and conventional breeding  

When compared with either conventional breeding based on random mutagenesis or GM technology some NPBTs show analogous features of the latter approaches. However, it needs to be noted that these techniques are not strictly “similar” to one another.  

The specifics of NPBTs (e.g. different targeting of insertions or mutation, different frequencies of off-target effects at certain genomic locations, different possibilities to introduce/select certain traits) should be considered in a risk assessment with a view to their specific consequences. A careful assessment of these specifics is a prerequisite for an appropriate design of the risk assessment approach. It can also be used to base the assessment of specific issues of NPBT-crops on existing experience. On this basis appropriate elements from the approaches which are used for conventionally bred crops or GM crops should be selected for NPBT-crops (assessment based on known familiarity, assessment according to incomplete knowledge).  

General framework for risk assessment of NPBT-crops  

Thus far biosafety considerations conducted for NPBT crops have indicated that the general approach developed for the risk assessment of GM crops in principle would also be appropriate to address the currently identified risk issues for NPBT-crops. Also the basic principles implemented in relevant biosafety regulation frameworks – European legislation, Cartagena Protocol, Canadian “Plants with Novel Traits” regulation – are considered to be appropriate for NPBT-crops, taking into account that for some NPBT applications only insufficient knowledge is available as regards their potential for adverse effects.  

Specifically the principles of case-specific risk assessment, requirement of a scientifically based risk assessment according to the risk model and application of the precautionary principle would also be appropriate for NPBT-crops.    

Specific considerations for risk assessment of NPBT-crops  

The case-specific risk assessments should take into account the specific characteristics of the respective NPBT-crop. The report at hands suggests that four aspects should be specifically considered. Some of these aspects are tightly connected to features of the different NPBT-methods used. For other aspects the connection with the used NPBT-methods is less evident, e.g. for traits that may not be exclusively developed by application of NPBTs:

–  the modifications of the genome due to NPBTs,

–  the potential to introduce into the NPBT-genome (recombinant) DNA which is ordinarily not found in this crop species,

–  the traits generated by NPBTs, and

–  modifications to gene expression due to the NPBT or the trait(s) introduced by use of NPBTs.  

As regards the different modifications of the genome introduced by NPBTs the report notes that a general discussion of their safety would not be appropriate. The discussed NPBT-approaches are aimed to achieve a range of different types of modifications, some characterised by a specific level of targeting, e.g. to introduce certain kinds of mutations. NPBT-approaches are also associated with specific potential to induce unintended effects. A characteristic feature of a number of NPBT-applications is that transgenic constructs are only present transiently (e.g. with agroinfiltration), in parts of the breeding product (e.g. transgrafting) or only during intermediary breeding steps. The assessment thus needs to take in account that final breeding products and intermediary breeding lines need to be considered differently.   

Safety considerations should be based on the available evidence for a specific type of modification for the NPBT-approach in question taking into account experience with comparable other breeding methods and the particular differences between the compared situations.  

Different NPBT-approaches are also characterised by a specific potential to introduce certain non-native sequences into the genomes of the resulting NPBT- crops. Again this potential and its significance need to be evaluated on a case- by case basis in comparison with GM and conventional breeding approaches.  

NPBT-applications aim to develop crops with diverse traits – which might or might not be comparable to traits which can be developed with other breeding techniques. Specific assessment requirements should therefore be based on a critical appraisal of the available knowledge on the trait in question and the familiarity with the effects of such traits when used in agriculture and food production. For some traits due to modifications by NPBTs the availability of relevant evidence and thus the level of familiarity which can be deduced from existing experience may be limited. In such situations an appropriate risk assessment would be needed.  

As regards modification of gene expression the report notes that the objective of a range of NPBT applications is to directly influence the expression of target traits. This is done via methods, e.g. RNAi-mediated silencing of gene expression, which may be associated to unintended effects.    

Wider issues concerning the risk assessment of NPBT-crops  

As issues which are crucial for the assessment of NPBT-crops the report specifically highlights the importance which protection goals are considered to design a risk assessment framework for NPBT-crops. Choice of protection goals will influence the definition what is considered a potential adverse effect associated with NPBT-crops (as well as other breeding products) and provide guidance for setting the scope of hazard identification as a first step in risk assessment.  

Another difficult issue is to determine which NPBT-crops need to be subject to risk assessment requirement and what are the triggers for this decision. This is not solely a technical question open to scientific answers, but is also influenced by particularities of the existing regulation frameworks and political decision making. With regard to such questions also the Canadian model of product-based regulation is not free from difficulties and ambiguities.

February 10th, 2015 | Category: Emerging Trends/Techniques
«  
  »

Biosafety Considerations for New Plant Breeding Techniques

Item 1

NEW PLANT BREEDING TECHNIQUES AND RISKS ASSOCIATED WITH THEIR APPLICATION 

Michael Eckerstorfer, Marianne Miklau and Helmut Gaugitsch
Umweltbundesamt (Environment Agency Austria) 

Summary and Conclusions  

Features of New plant breeding techniques (NPBTs) considered in this study  

Several open questions concerning the application of NPBTs to facilitating crop breeding are currently discussed, primarily the issue whether these NPBTs are subject to present regulation frameworks, e.g. as implemented for GM crops. A different line of discussion is focusing on questions related to the biosafety of NPBT-crops. This study analysed biosafety aspects for a number of different NPBTs, thus addressing an aspect that received considerably less attention in past years than issues concerning the regulatory status of NPBT-crops.   The following conclusions can be drawn from the analysis presented in this report: 

–  The individual NPBTs are indeed very different in approach and characteristics. According to these characteristics some NPBTs are applied to develop a wide range of different products.

–  Some NPBTs are used to modify the genomic DNA of the targeted crop species in a specific way in a stable and heritable form. Other NPBTs are aimed to change gene expression in the target plants – by transient expression of non-integrated genetic elements or modification of epigenetic regulation of gene expression (e.g. agroinfiltration/agroinfection, RdDM). A third group of NPBT-applications (e.g. MAS, TSBs like reverse breeding, accelerated breeding, seed production technology) are applied as tools to facilitate selection or other breeding processes. Genetic modification of a breeding intermediate may be necessary to achieve the breeding objective, e.g. with TSBs – however the final breeding product is not meant to contain these GM modifications.

–  A striking feature is that NPBTs are mostly used in combination. To develop products single NPBTs thus are combined with other NPBTs, with GM technology and conventional breeding approaches.

–  As regards the products developed by NPBTs some are very specific and cannot easily be generated by other approaches (e.g. targeted mutation and targeted integration of recombinant constructs, reverse breeding of parental lines for reconstituting elite hybrids and rapid accelerated breeding in crops like fruit trees).

–  Other products – notably NPBT-crops with traits that render them resistant to certain broadband herbicides – are less specifically linked to NPBTs. Similar crop lines were developed by means of GM techniques and also by conventional breeding in a few crops species. As their phenotype and use is comparable, a similar potential for risks is characteristic for these crops – which should be addressed by a comparable risk assessment approach.

–  For each NPBT the report compiles risk issues corresponding to the characteristics of the type of modifications. The different potential risks can be associated on the one hand with the intended modifications (e.g. introduction of alleles/mutations/regulatory effectors leading to traits which may be also connected to adverse effects). On the other hand potential adverse effects can result from unintended effects resulting of application of NPBT. Some of these unintended effects are due to methods like in vitro cell/tissue cultivation which need to be used in the process of NPBT, but which are not specific to a certain NPBT. Similar effects may also occur upon application of these techniques in conventional breeding.

–  GM techniques are used directly (Cisgenesis/Intragenesis, transcrafting, floral dip) or indirectly (agroinfiltration, TSBs, Nuclease-mediated site-directed mutagenesis by SSNs), as tools in the course of NPBT processes.

–  With indirect applications of GM technology the introduced modifications are intended to be present only in breeding intermediates, and not in the final breeding product. The final product then should be devoid of modifications specific for such a NPBT. This is limiting the possibilities for specific detection of a certain NPBT-crop, an issue which is also relevant for risk assessment and monitoring.  

Comparison of NPBTs with GM-technology and conventional breeding  

When compared with either conventional breeding based on random mutagenesis or GM technology some NPBTs show analogous features of the latter approaches. However, it needs to be noted that these techniques are not strictly “similar” to one another.  

The specifics of NPBTs (e.g. different targeting of insertions or mutation, different frequencies of off-target effects at certain genomic locations, different possibilities to introduce/select certain traits) should be considered in a risk assessment with a view to their specific consequences. A careful assessment of these specifics is a prerequisite for an appropriate design of the risk assessment approach. It can also be used to base the assessment of specific issues of NPBT-crops on existing experience. On this basis appropriate elements from the approaches which are used for conventionally bred crops or GM crops should be selected for NPBT-crops (assessment based on known familiarity, assessment according to incomplete knowledge).  

General framework for risk assessment of NPBT-crops  

Thus far biosafety considerations conducted for NPBT crops have indicated that the general approach developed for the risk assessment of GM crops in principle would also be appropriate to address the currently identified risk issues for NPBT-crops. Also the basic principles implemented in relevant biosafety regulation frameworks – European legislation, Cartagena Protocol, Canadian “Plants with Novel Traits” regulation – are considered to be appropriate for NPBT-crops, taking into account that for some NPBT applications only insufficient knowledge is available as regards their potential for adverse effects.  

Specifically the principles of case-specific risk assessment, requirement of a scientifically based risk assessment according to the risk model and application of the precautionary principle would also be appropriate for NPBT-crops.    

Specific considerations for risk assessment of NPBT-crops  

The case-specific risk assessments should take into account the specific characteristics of the respective NPBT-crop. The report at hands suggests that four aspects should be specifically considered. Some of these aspects are tightly connected to features of the different NPBT-methods used. For other aspects the connection with the used NPBT-methods is less evident, e.g. for traits that may not be exclusively developed by application of NPBTs:

–  the modifications of the genome due to NPBTs,

–  the potential to introduce into the NPBT-genome (recombinant) DNA which is ordinarily not found in this crop species,

–  the traits generated by NPBTs, and

–  modifications to gene expression due to the NPBT or the trait(s) introduced by use of NPBTs.  

As regards the different modifications of the genome introduced by NPBTs the report notes that a general discussion of their safety would not be appropriate. The discussed NPBT-approaches are aimed to achieve a range of different types of modifications, some characterised by a specific level of targeting, e.g. to introduce certain kinds of mutations. NPBT-approaches are also associated with specific potential to induce unintended effects. A characteristic feature of a number of NPBT-applications is that transgenic constructs are only present transiently (e.g. with agroinfiltration), in parts of the breeding product (e.g. transgrafting) or only during intermediary breeding steps. The assessment thus needs to take in account that final breeding products and intermediary breeding lines need to be considered differently.   

Safety considerations should be based on the available evidence for a specific type of modification for the NPBT-approach in question taking into account experience with comparable other breeding methods and the particular differences between the compared situations.  

Different NPBT-approaches are also characterised by a specific potential to introduce certain non-native sequences into the genomes of the resulting NPBT- crops. Again this potential and its significance need to be evaluated on a case- by case basis in comparison with GM and conventional breeding approaches.  

NPBT-applications aim to develop crops with diverse traits – which might or might not be comparable to traits which can be developed with other breeding techniques. Specific assessment requirements should therefore be based on a critical appraisal of the available knowledge on the trait in question and the familiarity with the effects of such traits when used in agriculture and food production. For some traits due to modifications by NPBTs the availability of relevant evidence and thus the level of familiarity which can be deduced from existing experience may be limited. In such situations an appropriate risk assessment would be needed.  

As regards modification of gene expression the report notes that the objective of a range of NPBT applications is to directly influence the expression of target traits. This is done via methods, e.g. RNAi-mediated silencing of gene expression, which may be associated to unintended effects.    

Wider issues concerning the risk assessment of NPBT-crops  

As issues which are crucial for the assessment of NPBT-crops the report specifically highlights the importance which protection goals are considered to design a risk assessment framework for NPBT-crops. Choice of protection goals will influence the definition what is considered a potential adverse effect associated with NPBT-crops (as well as other breeding products) and provide guidance for setting the scope of hazard identification as a first step in risk assessment.  

Another difficult issue is to determine which NPBT-crops need to be subject to risk assessment requirement and what are the triggers for this decision. This is not solely a technical question open to scientific answers, but is also influenced by particularities of the existing regulation frameworks and political decision making. With regard to such questions also the Canadian model of product-based regulation is not free from difficulties and ambiguities.

February 10th, 2015 | Category: Biosafety Science
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