Study of the impact of anthropogenic stress on frankia sp., alders, and their symbiosis

弗兰克氏菌属的丝状放线菌普遍存在，并在全球固氮中发挥着重要作用。它们与寄主植物(放线菌植物，其中包括赤杨)建立了类似于带有根瘤菌的豆类植物的根瘤共生关系。在北美，赤杨因其分布、坚固性和对各种恶劣环境条件的适应性而特别令人感兴趣。尽管放线菌赤杨通常用于废弃地(如含金属矿山废料)的植被恢复，但很少有人关注人为污染物(重金属、环烷酸和氯代芳烃)如何影响放线菌共生。考虑到凤尾藻在腐生的生命周期中直接暴露在这些土壤污染物中，这些问题更加重要。

Filamentous actinobacteria of the genus Frankia are ubiquitous and participate significantly in global nitrogen fixation. With their host plants (actinorhizal plants, amongst which alders), they establish a root nodule symbiosis analogous to that of legumes with rhizobia. In North America, alders are of particular interest for their distribution, robustness and adaptation to a wide range of harsh environmental conditions. Although actinorhizal alders are routinely used for the revegetation of derelict lands (e.g. metalliferous mine wastes), little research has focussed on how anthropogenic contaminants (heavy metals, naphtenic acids, and chloroaromatic hydrocarbons) affect the actinorhizal symbiosis. These questions are even more important considering that frankiae, in their saprophytic life cycle, are directly exposed to these soil contaminants.