Interactions of plants with the environment: impacts of contaminants on plants and phytoremediation of contaminants

植物暴露于多种环境应激源，包括多环芳烃(PAHs)、石油烃(PHCS)、金属、盐和农药等污染物。这些污染物中的大多数在与环境相关的浓度下对植物都是有毒的，而且许多都是通过活性氧物种(ROS)起作用的。当了解了毒性的机制后，就可以制定缓解压力的策略，提高植物用于土壤修复(植物修复)的机会。在我的研究计划中，有两个正在进行的项目与植物如何与污染物相互作用有关。1)植物毒性机制：我们已经证明多环芳烃、氧基多环芳烃、PHCS、金属和盐具有植物毒性。这些化合物通常通过ROS机制影响光合作用。为了更好地了解植物毒害的机制，我们将研究多环芳烃和金属对油菜、浮萍和拟南芥光合作用的影响。我们还发现，多环芳烃、金属和UVB通过ROS和氧化还原信号通路激活了许多相同的驯化过程。因此，我们将通过积累ROS清除酶和类黄酮，以及ROS和氧化还原诱导的基因表达来检验驯化。2)优化植物修复：要修复工业场地(如棕地和油井)的持久性污染物，开发有效的、对环境负责的修复技术至关重要。虽然植物的根可以去除土壤中的污染物，但这些污染物往往会造成植物压力，阻碍生长。基于我们以上的毒理学工作，我们可以改进现有的植物修复策略，以提高植物对受影响土壤的耐受性。我们正在开发的系统的关键是用植物生长促进根际细菌缓解植物胁迫。为了使这些系统更有效，我们需要更好地了解植物在植物修复过程中的逆境和驯化机制。为此，我们将利用光合作用、类黄酮组成、ROS清除能力和基因表达作为驯化和胁迫的指标，研究禾本科植物和谷物在PHC和盐分植物修复过程中的表现。

Plants are exposed to numerous environmental stressors including contaminants such as polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), metals, salt and pesticides. Most of these contaminants are toxic to plants at environmentally relevant concentrations, and many act through reactive oxygen species (ROS). When the mechanisms of toxicity are understood, a strategy to alleviate stress can be established, improving the chances that plants can be used for soil remediation (phytoremediation). Two ongoing projects in my research program pertain to how plants interact with contaminants. 1) Mechanisms of Phytotoxicity: We have shown that PAHs, oxyPAHs, PHCs, metals and salt are phytotoxic. These compounds impact on photosynthesis, often via ROS mechanisms. To better understand mechanisms of phytotoxicity, we will examine the effects of PAHs and metals on photosynthesis in Brassica, Lemna and Arabidopsis. We also found that PAHs, metals and UVB activate many of the same acclimation processes via ROS and redox signaling pathways. Thus, we will examine acclimation via accumulation of ROS scavenging enzymes and flavonoids, as well as ROS and redox induced gene expression. 2) Optimization of Phytoremediation: To remediate persistent contaminants from industrial sites (e.g., brownfields and oil wells), development of effective and environmentally responsible remediation technologies such as phytoremediation are crucial. Although plant roots can remove contaminants from soil, these contaminants often cause plant stress, impeding growth. Based on our toxicology work above, we can refine existing phytoremediation strategies to improve plant tolerance in impacted soils. The key to the systems we are developing is the alleviation of plant stress with plant growth promoting rhizobacteria. To make these systems more effective we need to better understand the mechanisms of plant stress and acclimation during phytoremediation. To do this we will study the performance of grass species and cereals during phytoremediation of PHC and salt using photosynthesis, flavonoid composition, ROS scavenging capacity and gene expression as measures of acclimation and stress.