Metal-devouring plant hero

As a vast agricultural nation, our country is confronted with serious soil contamination corroding the fundamental of agriculture. Among these pollutants, the heavy metals, especially those elements that resemble essential minerals, such as mercury (Hg), lead (Pb), and cadmium (Cd), are exerting potential threats on the environment and living beings for the reason of degradation-resistance, long residence and bioaccumulation in food webs.

中国作为一个农业大国，目前正面临着严重的土壤污染。污染类型以重金属为主，比如汞、铅、镉。重金属能引发粮食减产并严重地降低农作物的品质，还可以通过食物链在人类及动物体内进行累积进而危害其健康。

With the food safety issues caused by heavy metals being highly emphasized all over the world. In China, it’s more than 1.5000000 acres arable land, 20000000 ton foods was affected by metal polluted. Economic losses of more than 3 billion USD. Excessive intake of cadmium cause joint deformity, severe pain and other problems, loss of labor.

当前由重金属引起的食品安全问题正引起全世界的关注。在中国，约有1500万公顷的耕地遭受各种重金属的污染，被重金属污染的粮食多达2000万吨，合计经济损失至少300亿元。过量摄入重金属镉会引起骨痛病、关节变形等多种疾病，甚至丧失劳动能力。

A special kind of plants called hyperaccumulating plants not only evolve strategies for extreme tolerance to Cd stress but also hyperaccumulate Cd ions from polluted soils into plant above-ground component (Verbruggen et al., 2009). Hyperaccumulating ecotype of Sedum alfredii Hance is a Cd/Zn/Pb co-hyperaccumulating species of Crassulaceae in China (Yang et al., 2002), and the other ecotype species Sedum alfredii is non-accumulating ecotype, so what differs among these two ecotype Sedum alfredii?

自然界中存在着一类特殊的植物称作超积累植物，它们不仅能够在重金属镉含量较高的土壤中正常地生长，还可以将土壤中的镉离子一定程度地积累于植株的地上部分(Verbruggen et al., 2009)。超积累型东南景天是我国境内东部地区古老的铅锌矿区中发现的，对Cd、Pb、Zn都具有超积累作用的植物（Yang et al., 2002）。同时另一种东南景天为不具有超级累能力的生态型，那到底是什么原因造成了这两种生态型对重金属超级累能力的不同？

On the basis of whole-genome sequencing of S. alfredii, utilizing the comparison of genomics, tolerance and hyperaccumulation, we aim to uncover the homology and divergence between hyperaccumulation ecotype and non-accumulation ecotype S. alfredii. Moreover, we would work on discriminating key genes related with fascinating properties of cadmium tolerance and hyperaccumulation in S. alfredii providing genetic resources for breeding novel hyperaccumulating tree varieties by gene transformation. In summary, our project will provide theoretical guidance and material basis for contaminated soil phytoremediation.

在超积累型东南景天全基因组测序的基础上，以非积累型东南景天为对照，通过基因组测序，开展两种景天属植物比较基因组学以及抗性和超积累能力的进化分析，揭示两个生态型物种基因组间的同源性和差异。进一步筛选东南景天镉耐性和超积累能力形成的关键基因及其作用机制，为利用转基因培育高积累转基因林木提供基因资源，为土壤重金属污染植物修复提供理论指导和物质基础。