DISSERTATION RESEARCH: The evolution of selenium hyperaccumulation in Stanleya (Brassicaceae)

硒在原子上与硫相似，由于这种关系，它可以取代蛋白质中的硫。意外摄入硒会导致人类、牲畜和野生动物患病甚至死亡。然而，硒也是许多动物、原核生物和藻类必需的微量营养素，尽管硒在陆地植物中的功能尚不清楚。有四个植物属的物种被认为是硒超积累者（积累0.1%的干重硒），包括美国西部的斯坦利（王子羽；芸苔科）。stanley包括7种，其中一种（Stanleya pinnata）是已知的硒超富集植物。本项目的目的是在种内关系的背景下，推断stanley中硒的积累、耐受性、定位和化学形态的多样化过程，以更好地了解哪些DNA变化引起了这些生理变化。通过了解哪些DNA变化导致了硒的积累和耐受性，我们可以改善作物的植物修复（利用植物清理环境）和生物强化。据估计，硒缺乏每年给牲畜生产者造成5.45亿美元的损失。旗袍草将硒代谢成一种健康的抗癌形式，了解这一生理途径可能有助于人类和牲畜改良作物。

Selenium is atomically similar to sulfur and because of this relationship it can replace sulfur in proteins. Accidental incorporation of selenium can cause disease and even death in humans, livestock and wildlife. Yet selenium is also an essential micronutrient for many animals, prokaryotes and algae, though there is no known function of selenium in land plants. There are four plant genera with species recognized as selenium hyperaccumulators (accumulating 0.1% dry weight selenium), including Stanleya (prince's plume; Brassicaceae) in the western United States. Stanleya includes seven species, one of which (Stanleya pinnata) is a known selenium hyperaccumulator. The goal of this project is to infer the process of diversification of selenium accumulation, tolerance, localization and chemical form in the context of intraspecific relationships within Stanleya to better understand which DNA changes caused these physiological changes. By understanding which DNA changes gave rise to selenium accumulation and tolerance we can improve crops for both phytoremediation (environmental clean-up using plants) and biofortification. Selenium deficiency is estimated to cause $545 million in losses to livestock producers every year. Stanleya pinnata metabolizes selenium into a healthy anti-carcinogenic form, and understanding this physiological pathway may lead to improved crops for both humans and livestock.