Ecological Aspects of Plant Selenium Hyperaccumulation: Below and Beyond

IOS-0817748 PI：Elizabeth Pilon-Smits植物硒过度积累的生态方面-以下和第二元素硒(Se)对许多生物体来说是必不可少的。饮食中的硒可以增强免疫系统，预防癌症以及包括艾滋病毒在内的细菌和病毒感染。另一方面，硒在较高水平下具有毒性，是一种严重的世界性环境污染物。一些原产于美国西部的植物，通常被称为疯草，会过度积累高达其干重1%的硒。研究人员提出，这些植物超积累Se是一种防御草食和微生物感染的化合物，并对积累的Se对超积累植物的生态相互作用的影响感兴趣。在过去的三年里，他们发现，由于威慑和毒性，硒的积累可以保护植物免受各种食草动物的伤害。与此同时，几种耐硒的专业食草动物被发现以超积累植物为食，并积累了相当高的硒水平。继续的研究将调查超积累植物中的Se如何影响当地生态系统中的生态相互作用，“超越”迄今已发现的东西。更具体地说，将研究累积的根硒对超积累植物与邻近植物、与根相关的无脊椎动物和与根相关的微生物之间根区相互作用的影响。除了植物-食草动物或植物-微生物的直接相互作用外，研究人员还将调查专业草食动物或微生物积累Se对这些专家的生态相互作用的影响，这可能会进一步将Se动员到食物链中。这个项目的发现应该会有广泛的影响，并在医学和农业中应用。Se的过度积累对食草动物和其他生态伙伴的影响可能与其他有毒金属和类金属类似。了解食物链中超积累元素的运动对于植物修复(使用植物进行环境清理)和培育具有有益健康特性的元素强化食品的做法至关重要。此外，了解植物Se积累如何影响病原体或食草动物的生长和生存，以及鉴定专门的耐Se病原体或草食动物，都可以用来控制植物害虫和富含Se的有害杂草。

IOS-0817748 PI: Elizabeth Pilon-SmitsEcological aspects of plant selenium hyperaccumulation - below and beyondThe element selenium (Se) is essential for many organisms. Dietary Se can boost the immune system and prevent cancer and bacterial and viral infections including HIV. On the other hand, Se is toxic at higher levels and Se is a serious environmental pollutant worldwide. Some plants native to the Western U.S., commonly called ?locoweeds?, hyperaccumulate Se up to 1 percent of their dry weight. The investigators propose that these plants hyperaccumulate Se as a defense compound against herbivory and microbial infection, and are interested in the effects of the accumulated Se on the ecological interactions of hyperaccumulators. Over the past three years they have discovered that Se accumulation protects plants from a variety of herbivores, due to both deterrence and toxicity. At the same time, several Se-tolerant specialist herbivores were found to feed on hyperaccumulators, and to accumulate fairly high Se levels. Continued studies will investigate how the Se in hyperaccumulators affects ecological interactions in their local ecosystem, going "below and beyond" what has been discovered so far. More specifically, effects of accumulated root Se on root-zone interactions of hyperaccumulator plants with neighboring plants, root-associated invertebrates, and root-associated microbes will be examined. Beyond the direct plant-herbivore or plant-microbe interactions, the researchers will investigate the effects of Se accumulation by specialist herbivores or microbes on the ecological interactions of these specialists that may further mobilize Se into the food chain. The findings from this project should have broad implications, and applications in medicine and agriculture. The effects of hyperaccumulation of Se on herbivores and other ecological partners are probably similar for other toxic metals and metalloids. Understanding the movements of hyperaccumulated elements in the food chain will be critical to the practices of phytoremediation (environmental cleanup using plants) and of cultivating element-fortified foods with health-benefiting properties. In addition, knowledge of how plant Se accumulation affects growth and survival of pathogens or herbivores, and identification of specialist Se-tolerant pathogens or herbivores may be used to both control plant pests and Se-hyperaccumulating noxious weeds.