Integrating functional genomics and genetic mapping to clone genes responsible for low grain cadmium concentration in durum wheat

整合功能基因组学和遗传图谱来克隆导致硬粒小麦籽粒镉浓度低的基因

• 批准号: 336119-2006
• 负责人: Taylor, Gregory
• 金额: $ 9.81万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Strategic Projects - Group
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=398999
• 关键词: Integrating; functional; genomics; genetic; mapping

The dominant source of human exposure to environmental cadmium (Cd) in Canada is through Cd-contaminated food. Accumulation of Cd in Canadian durum wheat, which is worth in excess of $1 billion a year, may pose an unacceptable risk in terms of Cd exposure and may threaten exports of durum wheat. Several pairs of durum wheat lines have been established that differ in grain Cd concentration (high vs. low), but that are otherwise genetically similar. We have previously shown that differences in Cd translocation from the roots to the shoot may explain the differing grain-Cd levels for one of these pairs. The mechanism that limits Cd translocation to the shoot has yet to be identified. We propose to combine the power of transcriptome profiling (to identify genes of interest by comparing gene expression levels) with genetic mapping (to determine which genes of interest are genetically linked to this trait) to identify candidate genes that are potentially involved in regulating Cd accumulation in grain. We will use yeast-based assays as well as a plant-based system (virus-induced gene silencing) to complete a functional analysis of the candidate genes in an attempt to identify the mechanism(s) underlying low grain-Cd. We believe that this approach will expedite the identification of a zero-distance marker for low grain-Cd, thus providing a rapid and accurate method to identify low Cd breeding lines. This will enable continued development of durum wheat varieties with Cd concentrations that meet international regulatory standards. Additionally, such a marker could be used to authenticate and trace Canada's durum wheat exports. Identification of the mechanism underlying low grain-Cd in durum wheat could accelerate similar discoveries in other crops. The techniques and expertise developed in this project could also be extended to other important agronomic traits.

在加拿大，人类接触环境镉(Cd)的主要来源是受Cd污染的食物。加拿大硬质小麦中Cd的积累每年价值超过10亿美元，就Cd暴露而言，这可能构成不可接受的风险，并可能威胁到硬质小麦的出口。已经建立了几对硬粒小麦品系，它们的籽粒镉浓度不同(高与低)，但在其他方面遗传相似。我们以前已经证明，Cd从根到地上转移的差异可能解释了这些配对中的一个的不同籽粒-Cd水平。限制Cd转运到新梢的机制尚未确定。我们建议结合转录组图谱(通过比较基因表达水平来识别感兴趣的基因)和遗传图谱(确定哪些感兴趣的基因与这一性状有遗传联系)来识别潜在参与调控谷物镉积累的候选基因。我们将使用基于酵母的分析以及基于植物的系统(病毒诱导的基因沉默)来完成候选基因的功能分析，试图确定导致低粒镉的机制(S)。我们相信，这一方法将加快低粒镉零距离标记的鉴定，从而为低镉育种系的鉴定提供一种快速、准确的方法。这将使硬质小麦品种的Cd浓度继续达到国际监管标准。此外，这种标记还可以用来鉴定和追踪加拿大的硬质小麦出口。识别硬粒小麦籽粒低Cd的机制可以加速在其他作物中的类似发现。该项目开发的技术和专门知识还可以推广到其他重要的农艺性状。