Research and analysis

Precision bred organism marketing notice (reference: PBM/26/TRAE/001)

Published 3 July 2026

Applies to England

Information provided to the Secretary of State alongside a notice of intention to market a precision bred plant under schedule 2 of the Genetic Technology (Precision Breeding) Regulations 2025.

1. Name and address of the person with overall responsibility for marketing the precision bred plant

Rothamsted Research, West Common, Harpenden, Herts, AL5 2JQ

2. General description of the precision bred plant

a) Genus and species

Triticum aestivum (common or bread wheat)

b) Intended alterations to characteristics of the plant

Reduced free asparagine concentration in the grain.

c) Types of genetic changes introduced to cause these alterations

Small insertion-deletion mutations (indels) and substitutions in the asparagine synthetase-2 (TaASN2) genes in all three genomes (TaASN-A2; TaASN-B2 and TaASN-D2). 

The Ensembl Plants Triticum aestivum cv. Cadenza database reference numbers for these genes are:

TaASN-A2: TraesCS3A02G077100

TaASN-B2: TraesCAD_scaffold_017129_01G000200.1

TaASN-D2: TraesCS3D02G077300

d) Techniques of modern biotechnology used to make these genetic changes

Wheat (Triticum aestivum) cv. Cadenza plants were produced in which one of the genes encoding asparagine synthetase, TaASN2, had been edited using the clustered, regularly interspaced, short palindromic repeats (CRISPR) system with the Cas9 nuclease (Raffan, S. and others, 2021, Plant Biotechnology Journal 19, 1602–1613. DOI: 10.1111/pbi.13573). The production of the edited plants initially required the introduction by genetic modification of a gene to express guide RNAs (gRNAs) that would interact with the Cas9 nuclease and target it to the TaASN2 gene, as well as a gene to express the Cas9 nuclease itself, and a bar marker gene. These genes were carried on three separate plasmid vectors that were co-transformed into wheat cv. Cadenza by microprojectile bombardment. T0 plants were self-pollinated to generate T1 seed and this and subsequent generations were cultivated under glass and in the field (Raffan and others, 2023, Plant Biotechnology Journal 21, 1097-1099, DOI: 10.1111/pbi.14026.202; GM field trial Consent 21/R08/01).  

Individual plants from total TaASN2 knockout Line 23 (Raffan, S. and others, 2021, Plant Biotechnology Journal 19, 1602–1613. DOI: 10.1111/pbi.13573) were analysed by PCR to identify individuals in which the transgenes had segregated away. These lines were propagated under glass and one was selected for further analysis by whole genome sequencing to confirm that it contained no DNA from the plasmids used in the process. This line was designated ACRYLOW Cadenza 23.  

3. Intended use of the precision bred plant

The low asparagine edited wheat line will be cultivated in farm-scale trials in England for processing at pilot scale into real-world food products. Its performance in the field and in processing will be assessed and compared with its non-PBO control. Free asparagine is converted to the toxic, carcinogenic contaminant, acrylamide, during high-temperature cooking and processing, and flour made with grain from the precision bred plants has less potential for acrylamide formation.  

4. Intended genetic changes made

(a) the details of genetic changes made;

The genetic changes are:

A two base pair deletion and two single base pair insertions in exon 1 of the TaASN-A2 gene. The frameshift brought about by the first insertion results in a stop codon being brought into frame and a highly truncated protein being encoded. 

A 173-base pair deletion in exon 1 of the TaASN-B2 gene.

A single base pair insertion and a single base pair substitution in exon 1 of the TaASN-D2 gene. As with the TaASN-A2 gene, the frameshift brought about by the first edit results in a stop codon being brought into frame and a highly truncated protein being encoded.

(b) the location of genetic changes;

TaASN-A2 gene. A single base pair insertion in exon 1 at position 176 relative to the ATG start codon of the wild-type sequence, such that the sequence CCGGCG becomes CCGCGCG. A second single base pair insertion at position 285 of the wild-type sequence, followed by a two base pair deletion at position 291, such that CGACCGGCAGTGACT becomes CGACTCGGCAG–ACT.  

 TaASN-B2 gene. A 173-base pair deletion in exon 1, removing base pairs 112 to 284 relative to the ATG start codon.  

TaASN-D2 gene. A single base pair insertion in exon 1 at position 176 relative to the ATG start codon of the wild-type sequence, such that the sequence CCGGCG becomes CCGAGCG. A single base pair substitution at position 271, such that GGCCACA becomes GGCAACA.  

(c) the stability of genetic changes;

Genotyping of T1 and T2 plants by next generation sequencing showed all three edited alleles to be stably inherited (Raffan, S. and others, 2021, Plant Biotechnology Journal 19, 1602–1613. DOI: 10.1111/pbi.13573). While we have not repeated the genotyping for subsequent generations, the reduction in free asparagine concentration relative to the control has been very consistent (Raffan and others, 2023, Plant Biotechnology Journal 21, 1097-1099). 

(d) when a genetic change involves the insertion of any genetic material, a description of all the genetic elements inserted and the organism from which they originated;

Not applicable.

(e) the purpose of the genetic changes described above in sub-paragraphs (a) to (d), including how they alter the characteristics of the precision bred plant

The purpose of the genetic changes is to reduce the accumulation of free (soluble, non-protein) asparagine in the grain. This is important because free asparagine is the precursor for acrylamide (CH2=CHC(O)NH2) formation during cooking and processing. Acrylamide is classed as a Group 2a carcinogen by the International Agency for Research on Cancer (IARC) and both the United Nations’ Food and Agriculture Organisation & World Health Organisation Joint Expert Committee on Food Additives, and the European Food Safety Authority Panel on Contaminants in the Food Chain (CONTAM) have advised that exposure of consumers to acrylamide through their diet should be reduced. The current European Union (EU) regulation on acrylamide, European Commission (EC) Regulation (EU) 2017/2158, states that ‘acrylamide in food potentially increases the risk of developing cancer for consumers in all age groups and sets Benchmark Levels for acrylamide in different food types. This regulation rolled over into UK law when the UK left the EU. The European Commission is expected to set Maximum Levels above which it would be illegal to sell a food product for acrylamide in some foods, including all the major cereal products, in 2026, with serious implications for food businesses in the EU and its trading partners, including the UK.  

5. Unintended genetic changes made

(a) the details of genetic changes made;

Not present – no unintended genetic changes present.

(b) the location of genetic changes;

Not applicable – no unintended genetic changes present.

(c) the stability of genetic changes;

Not applicable – no unintended genetic changes present.

6. How the intended genetic changes were introduced

(a) which techniques of modern biotechnology were used;

Genome editing of wheat (Triticum aestivum) cv. Cadenza plants was performed using the clustered, regularly interspaced, short palindromic repeats (CRISPR) system with the Cas9 nuclease (Raffan, S. and others, 2021, Plant Biotechnology Journal 19, 1602–1613. DOI: 10.1111/pbi.13573). A gene encoding the four gRNAs, as well as a gene to express the Cas9 nuclease itself, and a bar marker gene were co-transformed into wheat cv. Cadenza by microprojectile bombardment of embryos (Raffan and others, 2023, Plant Biotechnology Journal 21, 1097-1099, DOI: 10.1111/pbi.14026.202). 

(b) information about any transgenic intermediates used;

Initially, the plants were stably transformed with plasmids carrying the three transgenes. The three plasmids used were: 

pRRes209.481.ASN2. This plasmid contained the four gRNA-encoding DNAs incorporated into a single, polycistronic gene, separated by tRNA sequences, downstream of a rice small nucleolar RNA U3 (U3sno) gene promoter.  

pRRes.486. This plasmid carried a Cas9 gene that has been codon-optimised for wheat, driven by a maize Ubi1 promoter plus first intron. 

pRRes1.111. This plasmid carried the selectable marker gene (bar) encoding phosphinothrycin acetyl transferase (PAT), also under the control of a maize Ubi1 gene promoter and first intron.  

These foreign genetic elements were removed from edited plants by segregation to produce ACRYLOW Cadenza 23.  

7. Analysis and procedures used

(a) description of the analysis and procedures used to confirm the plant only contains genetic sequences that could arise by traditional processes.

The absence of the foreign DNA elements (plasmid sequences) was confirmed initially by polymerase chain reaction analysis using primer pairs specific to the gRNA, Cas9 and bar gene sequences, and then by whole genome sequencing. For the latter, fresh leaf material was collected and DNA extracted for library preparation and nucleotide sequencing, with 11.64-fold genome coverage. Read alignment and kmer analyses of the nucleotide sequence data detected no DNA originating from the plasmids used in the transformation process.  

8. Other precision bred plants covered by this marketing notice

(a) Total number of precision bred plants being notified 

Not applicable

(b) Confirmation of precision breeding criteria

Not applicable

(c) Variations in intended genetic changes introduced

Not applicable

(d) Variations in unintended genetic changes introduced

Not applicable