Early rhizosphere microbiome composition is related to the growth and Zn uptake of willows introduced to a former landfill

Abstract

Although plants introduced for site restoration are pre-selected for specific traits (e.g. trace element bioaccumulation, rapid growth in poor soils), the in situ success of these plants likely depends on the recruitment of appropriate rhizosphere microorganisms from their new environment. We introduced three willow (Salix spp.) cultivars to a contaminated landfill, and performed soil chemical analyses, plant measurements, and Ion Torrent sequencing of rhizospheric fungal and bacterial communities at 4 and 16 months post-planting. The abundance of certain dominant fungi was linked to willow accumulation of Zn, the most abundant trace element at the site. Interestingly, total Zn accumulation was better explained by fungal community structure 4 months post-planting than 16 months post-planting, suggesting that initial microbial recruitment may be critical. In addition, when the putative ectomycorrhizal fungi Sphaerosporella brunnea and Inocybe sp. dominated the rhizosphere 4 months post-planting, Zn accumulation efficiency was negatively correlated with fungal diversity. Although field studies such as this rely on correlation, these results suggest that the soil microbiome may have the greatest impact on plant function during the early stages of growth, and that plant-fungus specificity may be essential.

Plant Community and Nitrogen Deposition as Drivers of Alpha and Beta Diversities of Prokaryotes in Reconstructed Oil Sand Soils and Natural Boreal Forest Soils

“…Diverse root-exudate production in the rhizosphere could also result in the increased ␣-diversity of bacteria in the soils revegetated with S. bebbiana and V. myrtilloides. Both plants can develop symbiotic relationships with fungi: ectomycorrhizae with S. bebbiana and ericoid mycorrhizae with V. myrtilloides (61)(62)(63). Willows associate with specific ectomycorrhizal fungi, which, once established, increase bacterial diversity in the soil (62).…”

“…Both plants can develop symbiotic relationships with fungi: ectomycorrhizae with S. bebbiana and ericoid mycorrhizae with V. myrtilloides (61)(62)(63). Willows associate with specific ectomycorrhizal fungi, which, once established, increase bacterial diversity in the soil (62). Willows also produce a small, but highly labile pool of organic carbon that can support abundant copiotrophic proteobacteria (64).…”

Effect of mycorrhizal inoculation on metal accumulation by poplar leaves at phytomanaged sites

“…Indeed, when associated with endomycorrhizal fungi, poplars exhibit enhanced tolerance to biotic and abiotic stress, with better growth and higher biomass production (Cicatelli et al, 2014). When plants are introduced for site restoration, the in-situ success of these plants will likely be depending on the recruitment of appropriate rhizosphere microorganisms from their new environment (Bell et al, 2015). In a recent study, we demonstrated that the occurrence and persistence of ectomycorrhizal symbionts were greatly driven by site characteristics (Foulon et al, 2016).…”

Comparative Transcriptomic Approaches Exploring Contamination Stress Tolerance in Salix sp. Reveal the Importance for a Metaorganismal de Novo Assembly Approach for Nonmodel Plants

“…Recent work into the human microbiome is proving an essential element in health research (Gill et al, 2006;Turnbaugh et al, 2007;Nelson et al, 2010;Davids et al, 2016), particularly concerning bacterial diversity within gastrointestinal studies. Such diversity in the microbiome is now well established as an essential factor in root-soil interactions, often termed the rhizosphere (Luo et al, 2009;He et al, 2013;Sullivan et al, 2013;Yergeau et al, 2014;Bell et al, 2015;de Vrieze, 2015). Less work has extended the metaorganism beyond bacteria, or singular target pathogens, herbivores, or symbiotes.…”