Low biomass production of metal hyperaccumulating plants is a factor limiting the efficiency of Ni agrominning. In recent years, plant associated-bacteria and arbuscular mycorrhizal fungi (AMF) were tested for their ability to improve biomass production and Ni accumulation in plants. Another group of plant symbiotic microorganisms are endophytic fungi. Their biggest advantage over AMF is their ability to grow on artificial media, which facilitates the manufacture of pure inoculum under sterile conditions and eliminates the difficulty of their propagation. This fact is particularly important in relation to large-scale production of inoculum.

In our studies we investigated the potential role of endophytic fungi in improving Ni accumulation of Noccaea caerulescens. We isolated over 200 stains of fungal endophytes from hyperaccumulators inhabiting ultramafic soils in Europe and tested their ability to stimulate plant growth and Ni accumulation. We also investigated the mechanism of endophyte induced alterations in Ni accumulation. Comparing gene expression profiles (Next Generation Sequencing) of plants that developed the Ni accumulation phenotype with plants that were not affected by inoculation with the fungus allowed us to select genes potentially responsible for the development of the beneficial phenotype. The role of the products of these genes and the mechanism of gene expression activation in symbiotic plants is under investigation.

This work was supported by the Polish National Centre for Research and Development (FACCE SURPLUS/I/AGRONICKEL/02/2016)