Plant molecular strategies in response to soil contaminants

过去和目前的工业活动，如采矿和石油化工提炼，对环境产生了重大的有害影响，在加拿大各地留下了大片退化和污染的土地。大多数受污染的场地都受到有机和无机化合物的影响。主要的有机污染物包括石油副产品、挥发性有机化合物、芳香烃和杀虫剂。常见的无机污染物是金属和类金属，称为微量元素。植物修复是一种环境技术，旨在利用植物的这些自然机制及其相关的土壤污染物积累或降解特性。对于生长在这种污染土壤中的植物来说，潜在的有毒污染物引起了具有非生物胁迫特征的生理和分子变化。虽然它们的共同出现是众所周知的，其各自的作用和顺序（前因，机制和输出）仍然很少描述。 我的研究计划的长期目标是了解植物如何在受污染的土壤上生长。该计划的一般假设是，植物诱导代谢途径，改变生理过程，使它们能够耐受，提取或降解污染物，以应对土壤污染物引起的非生物胁迫，这些途径可以是特定的或物种之间共享。 利用下一代测序的最新进展，我将使用基于田间实验和受控环境的策略来探索在污染土壤中生长的植物的转录组和生理学。该项目的具体目标是：1）描述在污染土壤环境中建立快速生长的先锋植物物种的转录组学效应，2）评估根系基因表达的变化是否反映在改变的生理机制中，如渗透调节，次生代谢产物和根际生物学。这种结合的方法应允许分离的环境变量固有的田间条件，利用在受控温室实验中获得的结果。该计划的每个目标将在我的监督下分配给一名学员。 这项研究计划将有助于我们了解植物对非生物胁迫，特别是土壤污染的反应。这项研究计划的潜在应用是开发分子生物标志物，可用作土壤污染的指标，以及提供植物选择的基础，知识，可以推进植物修复的发展，以使其成为一个合适的有吸引力的选择生态系统恢复。

Past and current industrial activities, such as mining and petrochemical refinement, have had major deleterious effects on the environment, leaving large areas of degraded and contaminated lands throughout Canada. The majority of contaminated sites is affected by both organic and inorganic compounds. The predominant organic contaminants include petroleum by-products, volatile organic compounds, aromatic hydrocarbons and pesticides. Common inorganic contaminants are metals and metalloids, referred to as trace elements. Phytoremediation is the environmental technique that aims to take advantage of these natural mechanisms in plants and of their associated properties of accumulation or degradation of soil contaminants. For plants growing in such polluted soils the potentially toxic contaminants induce physiological and molecular changes that are characteristic of abiotic stress. Although their co-occurrence is well known, their respective role and sequence (antecedent, mechanism and output) remain poorly described. The long-term goal of my research program is to understand how plants grow on contaminated soils. The general hypothesis of this program is that plants induce metabolic pathways that alter physiological processes allowing them to tolerate, extract or degrade contaminants in response to the abiotic stress induced by soil pollutants, and that these pathways can be specific or shared between species. Taking advantage of recent advances in next generation sequencing, I will use a strategy based on both field experiments and controlled environments to explore the transcriptomes and physiology of plants growing in contaminated soils. The specific objectives of this project are to: 1) Describe the transcriptomic effects of establishing fast-growing pioneer plant species in contaminated soil environments and, 2) evaluate if the changes in root gene expression are reflected in altered physiological mechanisms such as osmotic regulation, secondary metabolites and rhizosphere biology. This combined approach should allow the separation the environmental variables inherent to field conditions by taking advantage of the results obtained in controlled greenhouse experiments. Each of the objectives of the program will be assigned to a trainee under my supervision. This research program will contribute to our understanding of the plant responses to abiotic stresses and to soil contamination in particular. The potential applications of this research program are to develop molecular biomarkers that can be used as indicators of soil contamination as well as provide a basis for plant selection, knowledge which can advance the development of phytoremediation in order to make it a suitable attractive option for ecosystem rehabilitation.