Field assessment of ultra-low asparagine, low acrylamide, gene edited wheat

超低天冬酰胺、低丙烯酰胺、基因编辑小麦的田间评估

基本信息

批准号：
BB/T017007/1
负责人：
Nigel Halford
金额：
$ 42万
依托单位：
Rothamsted Research
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2021
资助国家：
英国
起止时间：
2021 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FT017007%2F1
关键词：
Field assessment ultra low asparagine

项目摘要

The presence of acrylamide in popular foods has become one of the most difficult problems facing the food industry and its supply chain. Acrylamide is a contaminant that forms from an amino acid called asparagine in its free (non-protein) form and sugars such as glucose, fructose and maltose. The reaction occurs during frying, baking, roasting, toasting and high-temperature processing. Acrylamide is classified as probably cancer-causing in humans and affects development and fertility at high doses. Products made from wheat and other cereals are major sources of dietary acrylamide.Acrylamide in food is covered by regulation (EU) 2017/2158 (2018), which set Benchmark Levels for the presence of acrylamide in food, described compulsory mitigation measures and required all food businesses to monitor the levels of acrylamide in their products. Methods developed to limit acrylamide formation during processing do not work for all products, may adversely affect product quality and are expensive to implement. Our approach has been to lower the acrylamide-forming potential of crop products: for wheat and other cereals that means reducing the concentration of free asparagine in the grain. The project arises from previous BBSRC-funded work in which we have demonstrated large varietal differences in free asparagine concentration in wheat grain and shown it to be highly responsive to sulphur deficiency and other nutritional and environmental stress factors, as well as disease. Asparagine is made by an enzyme called asparagine synthetase and wheat has five genes that encode this enzyme. One of these genes, TaASN2, has emerged as a genetic target because it is highly active specifically in the grain. In our current work, involving teams at Rothamsted Research, Univ. of Bristol and partners AHDB, KWS, Limagrain, RAGT, Saaten Union and Syngenta, we have used the genome editing technique, CRISPR-Cas9, to knock out TaASN2 genes. In addition, we have screened a wheat population in which mutations have been introduced by chemical mutagenesis (a much older technique that has been used in plant breeding since the 1950s) and identified lines with mutations in each of the six versions of TaASN2 in the wheat genome. The TaASN2 mutations in these lines are being 'stacked' by one of our partners and partial knockouts will be available by Year 2 of the project. The concentration of free asparagine in one of the CRISPR lines is reduced by approximately 90%. The aim of this project, which will continue the partnership with Univ. of Bristol, AHDB, Limagrain, RAGT, Saaten Union and Syngenta, is to undertake field trials of these ultra-low asparagine wheat lines with a view to the development of low acrylamide wheat varieties for the UK market. In year 1 we will bulk up seed for the trial. We will also investigate the germination rate of the CRISPR lines: they have shown poor germination so far but this can be reversed by treatment with low concentrations of asparagine. We will check the efficacy and practicality of the asparagine and other potential treatments. We will also develop genetic markers/tools to enable breeders to integrate the ultra-low asparagine trait into breeding lines. Lastly, we will prepare a risk assessment and submit an application for permission to hold the field trial. In year 2 we will conduct the field trial, analysing the low asparagine lines for emergence, physical characteristics, developmental differences, composition, yield and other agronomic characteristics. We will also conduct glasshouse experiments to ascertain whether the low asparagine lines respond to sulphur deficiency in the same way as normal wheat. The project would represent a landmark for crop gene editing, with the field trial, to our knowledge, being the first for gene edited wheat in the UK and Europe, while the involvement of AHDB and wheat breeders will provide a direct pathway to commercialisation if the plants perform well in the field trial.

流行食品中丙烯酰胺的存在已成为食品行业及其供应链面临的最困难的问题之一。丙烯酰胺是一种污染物，由游离（非蛋白质）形式的天冬酰胺氨基酸和葡萄糖、果糖和麦芽糖等糖形成。该反应发生在煎炸、烘烤、烘烤、烘烤和高温加工过程中。丙烯酰胺被归类为可能致癌的物质，高剂量会影响发育和生育能力。由小麦和其他谷物制成的产品是膳食丙烯酰胺的主要来源。食品中的丙烯酰胺受到法规 (EU) 2017/2158 (2018) 的管辖，该法规为食品中丙烯酰胺的存在设定了基准水平，描述了强制性缓解措施，并要求所有食品企业监测其产品中的丙烯酰胺含量。为限制加工过程中丙烯酰胺形成而开发的方法并不适用于所有产品，可能会对产品质量产生不利影响，并且实施成本昂贵。我们的方法是降低农作物产品形成丙烯酰胺的可能性：对于小麦和其他谷物来说，这意味着降低谷物中游离天冬酰胺的浓度。该项目源自 BBSRC 之前资助的工作，在该工作中，我们证明了小麦籽粒中游离天冬酰胺浓度的巨大品种差异，并表明小麦对硫缺乏和其他营养和环境应激因素以及疾病具有高度反应。天冬酰胺是由一种叫做天冬酰胺合成酶的酶产生的，小麦有五个编码这种酶的基因。其中一个基因 TaASN2 已成为遗传靶标，因为它在谷物中特别活跃。在我们目前的工作中，涉及洛桑研究中心的团队。 Bristol 及其合作伙伴 AHDB、KWS、Limagrain、RAGT、Saaten Union 和先正达，我们使用基因组编辑技术 CRISPR-Cas9 来敲除 TaASN2 基因。此外，我们还筛选了通过化学诱变（一种自 20 世纪 50 年代以来一直在植物育种中使用的更古老的技术）引入突变的小麦群体，并鉴定了小麦中 TaASN2 的六个版本中的每一个都具有突变的品系基因组。这些品系中的 TaASN2 突变正由我们的合作伙伴之一“堆叠”，部分敲除将在项目的第二年提供。其中一种 CRISPR 系中游离天冬酰胺的浓度降低了约 90%。该项目的目标是继续与大学的合作。布里斯托尔、AHDB、利马格兰、RAGT、Saaten Union 和先正达的合作伙伴将对这些超低天冬酰胺小麦品系进行田间试验，以期为英国市场开发低丙烯酰胺小麦品种。在第一年，我们将为试验增加种子。我们还将研究 CRISPR 系的发芽率：到目前为止，它们的发芽率较差，但可以通过低浓度天冬酰胺处理来逆转这一情况。我们将检查天冬酰胺和其他潜在治疗方法的功效和实用性。我们还将开发遗传标记/工具，使育种者能够将超低天冬酰胺性状整合到育种系中。最后，我们将准备风险评估并提交进行现场试验的许可申请。第二年，我们将进行田间试验，分析低天冬酰胺品系的出苗率、物理特性、发育差异、成分、产量和其他农艺特性。我们还将进行温室实验，以确定低天冬酰胺品系是否以与普通小麦相同的方式对硫缺乏做出反应。据我们所知，该项目将代表作物基因编辑的一个里程碑，这是英国和欧洲第一个基因编辑小麦的田间试验，而 AHDB 和小麦育种者的参与将为商业化提供直接途径，如果植物在田间试验中表现良好。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Reducing Dietary Acrylamide Exposure from Wheat Products through Crop Management and Imaging.

DOI：
10.1021/acs.jafc.2c07208
发表时间：
2023-02-06
期刊：
Journal of agricultural and food chemistry
影响因子：
6.1
作者：
Oddy J;Addy J;Mead A;Hall C;Mackay C;Ashfield T;McDiarmid F;Curtis TY;Raffan S;Wilkinson M;Elmore JS;Cryer N;de Almeida IM;Halford NG
通讯作者：
Halford NG

Epigenetic switch reveals CRISPR/Cas9 response to cytosine methylation in plants.