Biofortifying Brassica with calcium (Ca) and magnesium (Mg) for human health

超过10%的英国人摄入的钙(钙)或镁(镁)不足，才能获得足够的健康。在19岁至34岁的英国女性中，有40%的人镁摄入量特别低。通过作物的遗传(育种)和农艺(化肥)生物强化，可以增加生物可利用钙和镁的膳食供应。成功的生物强化需要增加可食用作物部分的钙和镁浓度，同时最大限度地减少草酸盐和植酸盐等抗营养素的含量。抗营养素抑制人体肠道对钙和镁的吸收。蔬菜作物是很好的目标，因为它们含有高容量的钙和镁，低草酸和植酸含量，以及其他健康益处。蔬菜甘蓝的定向遗传改良可以对英国和全球饮食中的钙和镁的输送产生重大影响。在以前的进化研究的基础上，我们最近首次表明，控制叶片钙和镁浓度的遗传位点相对较少(叶钙和镁；Broadley MR等人)。2008年；植物生理学。146、1707-20)。我们还表明，甘蓝型油菜存在足够的自然遗传变异和遗传力，可以尝试进行遗传生物强化。根据英国饮食调查，食用单一部分的甘蓝叶或小花(例如西兰花、卷心菜、羽衣甘蓝、白菜)--种植以获得实际可获得的钙和镁含量--可能会使英国的摄入量增加到超过300万(钙)和500万(毫克)成年人的LRNIS(下限参考营养素摄入量)的水平。然而，目前控制叶片钙、镁的遗传位点和单个基因还不能很好地用于育种，也不能揭示控制叶片钙、镁的基因的调控。我们已经组建了一个专家财团，以应对这一及时的机会。首先，我们将从基因水平上解析与叶钙和镁相关的候选基因座。我们将利用我们最近发布的数据集和新的Brassica技术，包括用于关联分析(遗传基因组学，或eQTL)的基因表达阵列。这项工作现在才成为可能，因为出现了作物Brassica基因组序列和新的Brassica遗传/基因组资源。我们将利用新的油菜突变体群体来确定候选基因在植物中的功能，同时还将对已知对拟南芥叶片钙和镁有复杂影响的钙转运蛋白基因进行功能研究。财团内的公益预育管道将用于传播信息。其次，我们将开发一个模型框架，定义控制油菜叶片钙和镁的调控基因网络。我们将使用最先进的基于系统的专业知识和资源来整合矿物输入和输出数据、基因活性和等位基因变异。我们将在工业硝酸钙(Ca(NO3)2)肥料使用量增加的背景下定义基因、等位基因及其调控网络结构。硝酸钙是一种理想的氮肥，因为它提高了油菜作物的质量，减少了温室气体排放，并提高了化肥运输和储存的安全性，因为它不能用于炸药。

Over 10% of the UK population consumes insufficient calcium (Ca) or magnesium (Mg) for adequate health. Magnesium intakes are especially low for >40% of UK women aged 19-34. Dietary delivery of bioavailable Ca and Mg can be increased through genetic (breeding) and agronomic (fertiliser) biofortification of crops. Successful biofortification requires increasing the Ca and Mg concentration of edible crop portions whilst minimising the content of antinutrients such as oxalate and phytate. Antinutrients inhibit Ca and Mg uptake in the human gut. Vegetable Brassica crops are good targets as they have a high capacity for Ca and Mg, and low oxalate and phytate contents, along with other health benefits. Targeted genetic improvement of vegetable Brassica can have significant effects on Ca and Mg delivery to UK and global diets. Building on previous evolutionary studies, we showed recently for the first time that relatively few genetic loci control leaf Ca and Mg concentration (leaf-Ca and Mg; Broadley MR et al. 2008; Plant Physiol. 146, 1707-20). We also showed that sufficient natural genetic variation and heritability exists to attempt genetic biofortification in Brassica. Based on UK dietary surveys, consumption of a single portion of Brassica leaf or floret (e.g. broccoli, cabbage, kale, pak choi) - bred for realistically-achievable Ca and Mg contents - could increase UK intakes to levels greater than the LRNIs (Lower Reference Nutrient Intake) for three (Ca) and five (Mg) million adults. However, at present, genetic loci and individual genes controlling leaf-Ca and Mg are insufficiently resolved to be useful in breeding or to reveal the regulation of genes controlling leaf-Ca and Mg. We have assembled an expert consortium to address this timely opportunity. First, we will resolve candidate loci associated with leaf-Ca and Mg to the gene level. We will exploit our recently-published datasets and new Brassica technologies including gene expression arrays for association analysis (genetical genomics, or eQTL). This work is only now becoming possible because of the emerging crop Brassica genome sequence and new Brassica genetic/genomic resources. We will determine the function of candidate genes in planta using new populations of B. rapa mutants, alongside functional studies of Ca-transporter genes known to have complex effects on leaf-Ca and Mg in Arabidopsis. Public-good pre-breeding pipelines within the consortium will be used to disseminate information. Second, we will develop a modelling framework that defines regulatory gene networks controlling leaf-Ca and Mg in Brassica. We will integrate mineral input and output data, gene activity and allelic variation using state-of-the-art systems-based expertise and resources. We will define genes, alleles, and their regulatory network architecture in the context of increasing industry-use of calcium nitrate (Ca(NO3)2) fertiliser. Ca(NO3)2 is a desirable N fertiliser since it improves Brassica crop quality, reduces greenhouse gas emissions, and improves the security of fertiliser transport and storage, since it cannot be used in explosives.