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**Conflict of Interest Statement:** Authors AT and JK were employed by the company alchemia-nova GmbH. This company is also doing research in the area of phytomining.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2018 Kidd, Bani, Benizri, Gonnelli, Hazotte, Kisser, Konstantinou, Kuppens, Kyrkas, Laubie, Malina, Morel, Olcay, Pardo, Pons, Prieto-Fernández, Puschenreiter, Quintela-Sabarís, Ridard, Rodríguez-Garrido, Rosenkranz, Rozpądek, Saad, Selvi, Simonnot, Tognacchini, Turnau, Wažny, Witters and Echevarria. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Vigil, M., Marey-Pérez, M. F., Martinez Huerta, G., and Álvarez Cabal V. (2015). Is phytoremediation without biomass valorization sustainable? — Comparative LCA of landfilling vs. anaerobic co-digestion. *Sci. Tot. Environ.* 505, 844–850. doi: 10.1016/j.scitotenv.2014.10.047

Warwick, S. I., Sauder, C. A., and Al-Shehbaz, I. A. (2008). Phylogenetic relationships in the tribe Alyseae (Brassicaceae) based on nuclear ribosomal ITS DNA sequences. *Botany* 86, 315–336. doi: 10.1139/B08-013

Wažny, R., Rozpądek, P., Jedrzejczyk, R., Janicka, M., Lichtsheidl, I., and Turnau, K. (2017). "Endophytic fungal mycobiota in hyperaccumulating Thlaspi," in *Proceedings of the 9th International Conference on Serpentine Ecology* (Tirana), 179.

Wei, Z. B., Guo, X. F., Wu, Q. T., Long, X. X., and Penn, C. J. (2011). Phytoextraction of heavy metals from contaminated soil by co-cropping with chelator application and assessment of associated leaching risk. *Int. J. Phytoremdiat.* 13, 717–729. doi: 10.1080/15226514.2010.525554

Wenzel, W. W., and Jockwer, F. (1999) Accumulation of heavy metals in plants grown on mineralised soils of the Austrian Alps. *Environ. Pollut.* 104, 145–155.

Witters, N., Mendelsohn, R. O., Van Slycken, S., Weyens, N., Schreurs, E., Meers, E., et al. (2012). Phytoremediation, a sustainable remediation technology? Conclusions from a case study. I: energy production and carbon dioxide abatement. *Biomass Bioenergy* 38, 454–469. doi: 10.1016/j.biombioe.2011.08.016

Wu, Q. T., Hei, L., Wong, J. W., Schwartz, C., and Morel, J. L. (2007). Co-cropping for phyto-separation of zinc and potassium from sewage sludge. *Chemosphere* 68, 1954–1960. doi: 10.1016/j.chemosphere.2007.02.047

Yang, J., Kloepper, J. W., and Ryu, C. M. (2009). Rhizosphere bacteria help plants tolerate abiotic stress. *Trends Plant Sci.* 14, 1–4. doi: 10.1016/j.tplants.2008.10.004

Zaidi, A., Oves, M., Ahmad, E., and Khan, M. S. (2011). "Importance of free-living fungi in heavy metal remediation," in *Biomanagement of Metal-Contaminated Soils*, eds M. S. Khan, A. Zaidi, R. Goel, and J. Musarrat (Springer Science Publishers), 479–494.

Zhang, Q., Zhang, J., Yang, L., Zhang, L., Jiang, D., Chen, W., et al. (2014). Diversity and biocontrol potential of endophytic fungi in Brassica napus. *Biol. Control* 72, 98–108.

Zhang, X., Laubie, B., Houzelot, V., Plasari, E., Echevarria, G., and Simonnot, M.-O. (2016). Increasing purity of Ammonium nickel sulfate hexahydrate and production sustainability in nickel phytomining process. *Chem. Eng. Res. Des.* 106, 26–32. doi: 10.1016/j.cherd.2015.12.009

Zhang, Y., Zhang, Y., Liu, M., Shi, X., and Zhao, Z. (2008). Dark septate endophyte (DSE) fungi isolated from metal polluted soils: their taxonomic position, tolerance, and accumulation of heavy metals *in vitro*. *J. Microbiol.* 46, 624–632. doi: 10.1007/s12275-008-0163-6

**Conflict of Interest Statement:** Authors AT and JK were employed by the company alchemia-nova GmbH. This company is also doing research in the area of phytomining.

The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2018 Kidd, Bani, Benizri, Gonnelli, Hazotte, Kisser, Konstantinou, Kuppens, Kyrkas, Laubie, Malina, Morel, Olcay, Pardo, Pons, Prieto-Fernández, Puschenreiter, Quintela-Sabarís, Ridard, Rodríguez-Garrido, Rosenkranz, Rozpądek, Saad, Selvi, Simonnot, Tognacchini, Turnau, Wažny, Witters and Echevarria. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.