A microcosm approach highlights the response of soil mineral weathering bacterial communities to an increase of K and Mg availability

O Nicolitch,M Feucherolles,S Uroz,L Fauchery,J.-L Churin,M.-P Turpault

doi:10.1038/s41598-019-50730-y

O Nicolitch, M Feucherolles + Show 4 more

Open Access

https://doi.org/10.1038/s41598-019-50730-y

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Abstract

The access and recycling of the base cations are essential processes for the long-lasting functioning of forest ecosystems. While the role of soil bacterial communities has been demonstrated in mineral weathering and tree nutrition, our understanding of the link between the availability of base cations and the functioning of these communities remains limited. To fill this gap, we developed a microcosm approach to investigate how an increase in key base cations (potassium or magnesium) impacted the taxonomic and functional structures of the bacterial communities. During a 2-month period after fertilization with available potassium or magnesium, soil properties, global functions (metabolic potentials and respiration) as well as mineral weathering bioassays and 16S rRNA amplicon pyrosequencing were monitored. Our analyses showed no or small variations in the taxonomic structure, total densities and global functions between the treatments. In contrast, a decrease in the frequency and effectiveness of mineral weathering bacteria was observed in the fertilized treatments. Notably, quantitative PCR targeting specific genera known for their mineral weathering ability (i.e., Burkholderia and Collimonas) confirmed this decrease. These new results suggest that K and Mg cation availability drives the distribution of the mineral weathering bacterial communities in forest soil.

Highlights

Understanding how microorganisms adapt to variations in resource availability is a central question in ecology and evolutionary biology
Base cations correspond to inorganic compounds, termed mineral nutrients or inorganic nutrients, such as potassium (K), magnesium (Mg) or calcium (Ca), which act as nutrients, co-factors, or structural components
Through the resource manipulation performed, this work demonstrated for the first time that an increase of base cation (i.e., K and Mg) concentration in the soil more strongly affects the functional structure of the soil bacterial communities than the taxonomic structure

Summary

Introduction

Understanding how microorganisms adapt to variations in resource availability is a central question in ecology and evolutionary biology. PH is known as one of the main soil parameters determining the distribution of the soil bacterial communities[24] and liming is used to rectify the acidity and fertility of the soil[42,43] In this context, our study aimed to understand how the availability of important base cations, such as potassium or magnesium, drives the taxonomic and functional distribution of the soil bacterial communities and especially the mineral weathering bacteria in forest soil. Our study aimed to understand how the availability of important base cations, such as potassium or magnesium, drives the taxonomic and functional distribution of the soil bacterial communities and especially the mineral weathering bacteria in forest soil Such questioning is important in forestry, as liming is considered as an effective management practice to recover soil fertility and its use may be intensified to increase wood productivity. The same soil samples were used for quantitative PCR analyses to quantify the total bacterial abundance as well as specific bacterial genera such as Burkholderia, Collimonas and Pseudomonas

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