Genome editing for low acrylamide wheat

Acrylamide (C3H5NO) is a food processing contaminant that has been classed as a probable (Group 2a) human carcinogen. Acrylamide forms from the reaction of free (non-protein) asparagine with reducing sugars during food processing. All major cereal products are affected and wheat products represent one of the main sources of dietary acrylamide intake in Europe. Asparagine concentration is the determining factor for acrylamide formation in cereal products. Asparagine biosynthesis is catalysed by a family of enzymes called asparagine synthetases (ASNs). The ASN genes were investigated and five ASN genes (TaASN1-4, with a double copy of TaASN3) identified in wheat (Triticum aestivum), with TaASN2 showing grain-specific expression. CRISPR/Cas9 was used to knock out the TaASN2 gene of wheat cv. Cadenza. A polycistronic gene containing four gRNAs, interspaced with tRNAs, was designed and introduced into wheat embryos by particle bombardment. The subsequent edits were characterised in the T1 and T2 generations using Next Generation Sequencing nucleotide sequence analysis. Triple (A, B, and D genome) nulls were identified, alongside an AD and an A genome null. Amino acid concentrations were measured in the T2 and T3 seed, with one triple null line showing a substantial reduction in the free asparagine concentration in the grain (90 % in the T2 seed and 50 % in the T3 seed compared with wildtype). The free asparagine also reduced as a proportion of the total free amino acid pool. Significant effects were also seen in glutamate and aspartate concentrations. Free asparagine and total free amino acid concentrations were higher in the T3 than T2 seeds, probably due to heat stress, but the concentrations in the edited plants remained substantially lower than in wildtype. Some of the edited lines showed poor germination, but this could be overcome by application of exogenous asparagine and no other phenotype was noted

Genome Editing for Low-Acrylamide Wheat

Acrylamide (C3H5NO) is a food processing contaminant that has been classed as a probable (Group 2a) human carcinogen. Acrylamide forms from the reaction of free (non-protein) asparagine with reducing sugars during food processing. All major cereal products are affected and wheat products represent one of the main sources of dietary acrylamide intake in Europe. Asparagine concentration is the determining factor for acrylamide formation in cereal products. Asparagine biosynthesis is catalysed by a family of enzymes called asparagine synthetases (ASNs). The ASN genes were investigated and five ASN genes (TaASN1-4, with a double copy of TaASN3) identified in wheat (Triticum aestivum), with TaASN2 showing grain-specific expression. CRISPR/Cas9 was used to knock out the TaASN2 gene of wheat cv. Cadenza. A polycistronic gene containing four gRNAs, interspaced with tRNAs, was designed and introduced into wheat embryos by particle bombardment. The subsequent edits were characterised in the T1 and T2 generations using Next Generation Sequencing nucleotide sequence analysis. Triple (A, B, and D genome) nulls were identified, alongside an AD and an A genome null. Amino acid concentrations were measured in the T2 and T3 seed, with one triple null line showing a substantial reduction in the free asparagine concentration in the grain (90 % in the T2 seed and 50 % in the T3 seed compared with wildtype). The free asparagine also reduced as a proportion of the total free amino acid pool. Significant effects were also seen in glutamate and aspartate concentrations. Free asparagine and total free amino acid concentrations were higher in the T3 than T2 seeds, probably due to heat stress, but the concentrations in the edited plants remained substantially lower than in wildtype. Some of the edited lines showed poor germination, but this could be overcome by application of exogenous asparagine and no other phenotype was noted

Injury patterns of South African international cricket players over a two-season period

Objective. The aim of the study was to determine the incidence and nature of injury patterns of South African international cricket players. Methods. A questionnaire was completed for each cricketer who presented with an injury during the 2004 - 2005 (S1) and 2005 - 2006 (S2) cricket seasons to determine the anatomical site, month, diagnosis and mechanism of injury. Results. The results showed that 113 injuries were sustained, with a match exposure time of 1 906 hours for one-day internationals (ODIs) and 5 070 hours for test matches. The injury prevalence was 4% per match, while the incidence of injury was 90 injuries per 10 000 hours of matches. Injuries occurred mostly to the lower limbs, back and trunk, upper limbs and head and neck. The injuries occurred primarily during test matches (43%), practices (20%) and practices and matches (19%). Acute injuries comprised 87% of the injuries. The major injuries during S1 were haematomas (20 %), muscle strains (14%) and other trauma (20%), while during S2 the injuries were primarily muscle strains (16%), other trauma (32%), tendinopathy (10%) and acute sprains (12%). The primary mechanisms of injury occurred when bowling (67%), on impact by the ball (batting – 65%, fielding – 26%) and when sliding for the ball (19%). Conclusion. The study provided prospective injury incidence and prevalence data for South African cricketers playing at international level over a two-season period, high-lighting the increased injury prevalence for away matches and an increased match injury incidence for test and ODI matches possibly as a result of increased match exposure time

Progress towards the production of potatoes and cereals with low acrylamide-forming potential

The presence of acrylamide in foods derived from grains, tubers, storage roots, beans and other crop products has become a difficult problem for the food industry. Here we review how acrylamide is formed predominantly from free asparagine and reducing sugars, the relationship between precursor concentration and acrylamide formation, and the challenge of complying with increasingly stringent regulations. Progress made in reducing acrylamide levels in foods is assessed, along with the difficulty of dealing with a raw material that may be highly variable due to plant responses to nutrition, disease and cold storage. The potential for plant breeding and biotechnology to deliver low acrylamide varieties is assessed, in the context of a regulatory landscape covering acrylamide, crop biotechnology and crop protection