Functional characterization of P1B-type heavy-metal ATPase transporters in grasses

提高粮食作物的营养质量被认为是减少人类营养不良的关键步骤。微量营养素(如铁和锌)营养不良现在被认为是一个全球性问题，影响着30多亿人。作物的生物强化(丰富营养成分)是解决微量营养素营养不良的一种可持续和具有成本效益的解决办法。非必需微量元素如镉的食物链污染也对人类健康构成威胁。设计富含微量营养素的谷类作物，同时降低有毒元素的水平，将需要彻底了解调节这些元素在整个植株中积累和分配的转运体。这项拟议研究的目标是确定与谷类中微量元素的吸收、转运和谷物装载有关的转运蛋白，特别是铜、锌和镉。拟南芥重金属ATPase(HMAS)有助于亚细胞离子的动态平衡、有毒金属的解毒和离子向长途运输系统的输送。草的HMAS将被克隆，并使用酵母和模式草Brachypodium disachyon进行功能鉴定。采用Brachypodium作为模式物种将使知识能够更快地转移到作为生物强化目标的小麦类作物(例如小麦)。查明控制微量元素向谷物转移的机制将有助于发展谷类作物，从而改善人类健康。

Improving the nutritional quality of food crops is recognized as a critical step to reducing human malnourishment. Micronutrient (e.g. iron and zinc) malnutrition is now recognized as a global problem, affecting more than 3 billion people. Biofortification (enriching nutritional content) of crops is a sustainable and cost-effective solution to micronutrient malnourishment. Food-chain contamination by non-essential trace elements, such as cadmium, also poses a risk to human health. Engineering micronutrient-rich cereal crops that also have reduced levels of toxic elements will require a thorough understanding of the transporters mediating accumulation and allocation of these elements throughout the plant. The goal of the proposed research is to identify the transporter proteins involved in uptake, translocation, and grain loading of trace elements, especially copper, zinc and cadmium, in cereals. Arabidopsis heavy-metal ATPases (HMAs) contribute to subcellular ion homeostasis, detoxification of toxic metals, and delivery of ions to long distance transport systems. Grass HMAs will be cloned and functionally characterized using yeast and the model grass, Brachypodium distachyon. Adopting Brachypodium as a model species will enable knowledge to be transferred more quickly to Triticeae crops (e.g. wheat) that are targets for biofortification. Identifying the mechanisms that control translocation of trace elements to grain will aid the development of cereals crops that can improve human health.