Rhizosphere Microbial Response to Multiple Metal(loid)s in Different Contaminated Arable Soils Indicates Crop-Specific Metal-Microbe Interactions

Abstract

In this study, we sampled rhizosphere soils from seven different agricultural fields adjacent to mining areas and cultivated with different crops (corn, rice, or soybean), to study the interactions among the innate microbiota, soil chemical properties, plants, and metal contamination. The rhizosphere bacterial communities were characterized by Illumina sequencing of the 16S rRNA genes, and their interactions with the local environments, including biotic and abiotic factors, were analyzed. Overall, these soils were heavily contaminated with multiple metal(loid)s, including V, Cr, Cu, Sb, Pb, Cd, and As. The interactions between environmental parameters and microbial communities were identified using multivariate regression tree analysis, canonical correspondence analysis, and network analysis. Notably, metal-microbe interactions were observed to be crop specific. The rhizosphere communities were strongly correlated with V and Cr levels, although these sites were contaminated from Sb and Zn/Pb mining, suggesting that these two less-addressed metals may play important roles in shaping the rhizosphere microbiota. Members ofGaiellaceaecooccurred with other bacterial taxa (biotic interactions) and several metal(loid)s, suggesting potential metal(loid) resistance or cycling involving this less-well-known taxon.IMPORTANCEThe rhizosphere is the “hub” for plant-microbe interactions and an active region for exchange of nutrients and energy between soil and plants. In arable soils contaminated by mining activities, the rhizosphere may be an important barrier resisting metal uptake. Therefore, the responses of the rhizosphere microbiota to metal contamination involve important biogeochemical processes, which can affect metal bioavailability and thus impact food safety. However, understanding these processes remains a challenge. The current study illustrates that metal-microbe interactions may be crop specific and some less-addressed metals, such as V and Cr, may play important roles in shaping bacterial communities. The current study provides new insights into metal-microbe interactions and contributes to future implementation and monitoring efforts in contaminated arable soils.

Comparative Analysis of Rhizosphere Microbiomes of Southern Highbush Blueberry (Vaccinium corymbosum L.), Darrow’s Blueberry (V. darrowii Camp), and Rabbiteye Blueberry (V. virgatum Aiton)

“…Gaiellaceae is a recently discovered family that belongs to a deep lineage of the class Actinobacteria and consists of a single genus with only one cultured species, Gaiella occulta (Albuquerque et al, 2011). These aerobic chemoorganotrophs have been found worldwide in the rhizosphere of corn, rice, soybean, hemp, and sudex (Eo et al, 2015;Sun et al, 2018;Wang et al, 2019). Members of Gaiellaceae, together with Sphingomonadaceae, and Streptomycetaceae were associated with the soil suppressiveness to F. oxysporum f. sp.…”

Bioremediation of Hexavalent Chromium by Chromium Resistant Bacteria Reduces Phytotoxicity

“…Microorganisms provide higher surface area to the volume due to the small size and can assimilate metals from surrounding settings [ 20 ]. Various microorganisms are found in the industrial effluents discharging area and are capable of protecting themselves from the toxicity of existing heavy metals in the effluents [ 21 , 22 , 23 , 24 ]. These microorganisms including bacteria, fungi, algae, and protozoa use diverse systems for survival against heavy metal toxicity, such as uptake of heavy metal, adsorption, oxidation, methylation, and reduction of heavy metals to nontoxic forms [ 21 , 25 ].…”

Community Compositions of Phytoplankton and Eukaryotes during the Mixing Periods of a Drinking Water Reservoir: Dynamics and Interactions

“…In module I, notably, Penicillium was observed to have more significant correlations with other eukaryotic genera, with the highest degree (number of connections) of 19. Among these correlations, 18 were negative and only one was positive (with Bromeliophrya), indicating that Penicillium negatively affected the growth of the majority of other genera, or that there might be an antagonistic and competitive [36], or saprophytic [14], association between Penicillium and these genera. Correlations from modules II and V-VII were all positive, and positive correlations from modules V-VII were especially significant, indicating that the eukaryotic genera from these modules might arise from similar niches or mutualism [60,61,66].…”