Soil nickel contamination levels entail changes in the bacterial communities associated to the rhizosphere and endosphere of Odontarrhena chalcidica


Durand A., Goux X., Lopez S., Leglize P., Benizri E.


Plant and Soil, vol. 493, n° 1-2, pp. 17-43, 2023


Aims: Phytomining relies on the use of metal hyperaccumulating plants growing on ultramafic soils. Such soils, naturally enriched with nickel, have drawn the attention of the scientific community for several decades, yet little is known about the effect of this metal on the structure and composition of the rhizosphere and endospheric bacterial communities of hyperaccumulators. This work aimed to investigate the impact of a Ni concentration gradient on soil's physicochemical properties and on the composition of the rhizosphere and endophytic bacterial communities of Odontarrhena chalcidica. Methods: We characterized the bacterial communities associated with O. chalcidica growing in controlled conditions on an ultramafic soil with various levels of nickel contamination obtained by spiking the soil with nickel sulfate. Results: An increase in the available nickel in soil induced changes in the dominant bacterial genera in the communities of the rhizosphere soil and in the root and shoot endosphere. This increase in available nickel also entailed changes in the relative abundance of the predicted functions, for the rhizosphere and root endospheric bacterial communities. In addition, topological features of the bacterial networks seemed to indicate that at an intermediate level of nickel contamination, two coexisting bacterial sub-communities were in competition, one adapted to “low” soil nickel content and the other to higher nickel content, while the bacterial communities were more stable at the lowest and the highest nickel soil contamination levels. Our results revealed shifts in the microbial community's structure and functions, depending of the gradient of soil nickel availability in the soil.



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