Phytoremediation of Alberta oil sand tailings using native plants and a fungal endophyte species

Abstract

The Athabasca Oil Sands produce a high volume byproduct called tailing sands (TS). Typically, TS are remediated by planting young trees in large quantities of mulch (from elsewhere) plus mineral fertilizer. This is costly and labour intensive. Fungal endophytes colonize host plants without causing disease. Some endophytes confer plant tolerance to harsh environments. Trichoderma harzianum strain TSTh20-1 was isolated from a plant growing on Athabasca oil tailings sand (TS). TS are a high volume waste product from oil sand extraction that the industry is required to remediate. TS are low in organic carbon and mineral nutrients, and are hydrophobic due to residual hydrocarbons. In greenhouse trials, TSTh20-1 supports growth of tomato seedlings on TS without fertilizer. TSTh20-1 is a promising candidate for economical TS remediation. We tested 23 plant species for seed germination and growth on TS in the presence of TSTh20-1. The four best candidates are currently being used in microcosm-scale growth trials, and for outdoor mesocosm trials this summer. Potential mechanisms that contribute to endophyte-induced plant growth promotion are also being assessed. TSTh20-1 is nutritionally frugal, which may be characteristic of other plant fungal endophytes. We are also tagging TSTh20-1 with GFP to follow it in the plant and in the environment.