Crop management strategies for low asparagine grains to limit acrylamide-forming potential

丙烯酰胺是一种2A类致癌化学物质，在油炸、烘焙、烘烤和烘烤谷物、块茎、豆类和其他农作物产品时，由游离天冬酰胺和还原糖形成。游离天冬酰胺浓度决定了谷物产品中形成的丙烯酰胺的量。游离天冬酰胺浓度在小麦品种之间不同，但也高度响应于环境和作物管理因素，包括向作物提供的施肥水平。学生将研究氮肥和硫肥的作用，并确定其他矿物质，灌溉和疾病的影响。他/她将研究小麦中天冬酰胺合成和分解的昼夜调节，研究天冬酰胺合成酶（天冬酰胺的形成）和天冬酰胺酶（天冬酰胺分解）。将分析软质小麦作图群体以鉴定游离天冬酰胺浓度的QTL，并且将筛选染色体3B上天冬酰胺合成酶-2基因的存在/不存在的品种：该基因已显示在一些品种中缺失，并且将研究该基因的缺失对谷粒中游离天冬酰胺浓度的影响。学生还将比较饼干生产线中低天冬酰胺和高天冬酰胺谷物的性能。低、中、高天冬酰胺软质小麦品种将在法国的Rothamsted Woburn农场和Mondelez农场进行田间试验。试验将研究不同氮硫比对游离天冬酰胺浓度的影响，其他矿物质的影响以及灌溉和疾病控制的重要性。试验将持续三年，由Mondelez提供资金。学生将监督试验，包括与统计学家一起设计试验和分析数据。学生还将参观位于阅读RSSL的Mondelez实验室，分析试验中谷物样品中的游离天冬酰胺。不仅游离天冬酰胺浓度本身存在品种差异，而且游离天冬酰胺对硫的反应也存在差异，一些低天冬酰胺品种在缺硫条件下表现出最大的增加。学生将研究这些反应的分子基础。天冬酰胺合成和分解在拟南芥中被证明是昼夜调节的，不同的天冬酰胺合成酶在白天和晚上都有活性。学生将研究这种现象在不同的小麦组织，包括粮食：哪些酶/基因是日常监管，在哪些组织;天冬酰胺合成和分解日常监管的粮食和多长时间在发展过程中？天冬酰胺酶小麦籽粒天然含有天冬酰胺酶。学生将研究为什么这些酶不能阻止游离天冬酰胺的积累，以及通过应用植物生长调节剂激活它们的潜力。绘制人口分布图。我们与John Innes小麦遗传学小组合作，制作了一个软质小麦（Claire x Robigus）作图群体。JIC每年都在增加这一人口，并将免费提供谷物进行分析。测量群体中品系的谷粒中的游离天冬酰胺可以使学生能够鉴定控制这一重要性状的QTL。B基因组TaASN 2基因缺失。学生将在位于巴黎附近萨克雷的Mondelez研发中心的小规模饼干生产中比较低，中，高天冬酰胺谷物，评估原料中游离天冬酰胺浓度相对于工艺其他方面的重要性，不同谷物的相对功能，以及在典型的生产过程中使用了多少游离天冬酰胺。饼干中形成的丙烯酰胺将在RU RSSL的Mondelez实验室进行测量。

Acrylamide is a Group 2A carcinogenic chemical that forms from free asparagine and reducing sugars during the frying, baking, roasting and toasting of foods derived from grains, tubers, beans and other crop products. Free asparagine concentration determines the amount of acrylamide that forms in cereal products. Free asparagine concentration differs between wheat varieties but is also highly responsive to environmental and crop management factors, including the level of fertilization provided to the crop. The student will look at the role of nitrogen and sulphur fertilization, and determine the effects of other minerals, irrigation and disease. He/she will investigate diurnal regulation of asparagine synthesis and breakdown in wheat, looking at both asparagine synthetases (formation of asparagine) and asparaginases (asparagine breakdown). A soft wheat mapping population will be analysed to identify QTL for free asparagine concentration, and varieties will be screened for the presence/absence of an asparagine synthetase-2 gene on Chromosome 3B: this gene has been shown to be missing in some varieties, and the effect of the loss of this gene on free asparagine concentration in the grain will be investigated. The student will also compare the performance of low and high asparagine grains in biscuit production lines. Low, medium and high asparagine soft wheat varieties will be grown in field trials at the Rothamsted Woburn farm site and at Mondelez sites in France. The trials will investigate the effects of different nitrogen: sulphur ratios on free asparagine concentration, the effects of other minerals, and the importance of irrigation and disease control. The trials will run for three years, with funding provided by Mondelez. The student will oversee the trials, including working with a statistician on designing the trials and analysing the data. The student will also visit the Mondelez laboratory in Reading RSSL to analyse free asparagine in grain samples from the trials.Differential sulphur responses between varieties. There are not only varietal differences in free asparagine concentration per se but also in the response of free asparagine to sulphur, with some low asparagine varieties showing the largest increases under sulphur deficiency. The student will investigate the molecular basis of these responses. Diurnal regulation Asparagine synthesis and breakdown has been shown to be diurnally regulated in Arabidopsis, with different asparagine synthetases active during the day and night. The student will investigate this phenomenon in different wheat tissues, including grain: which enzymes/genes are diurnally regulated, in which tissues; is asparagine synthesis and breakdown diurnally regulated in the grain and for how long during development?AsparaginasesWheat grain naturally contains asparaginase enzymes. The student will investigate why these enzymes fail to prevent the accumulation of free asparagine, and the potential for activating them by application of a plant growth regulator. Mapping population. We have produced a soft wheat (Claire x Robigus) mapping population in collaboration with the John Innes Wheat Genetics Group. This population is being grown annually at JIC and grain will be made available free of charge for analysis. Measurement of free asparagine in the grain of the lines in the population could enable the student to identify QTL controlling this important trait. Deletion of B genome TaASN2 gene. The student will compare low, medium and high asparagine grains in the manufacture of small-scale biscuits at the Mondelez R&D Centre in Saclay, near Paris, assessing the importance of free asparagine concentration in the raw material relative to other aspects of the process, the relative functionality of different grains, and how much free asparagine is used up in a typical manufacturing process. Acrylamide formed in the biscuits will be measured at the Mondelez laboratory in RU RSSL.