Soil chemical properties affect the reaction of forest soil bacteria to drought and rewetting stress

Abstract

Reaction of soil bacteria to drought and rewetting stress may depend on soil chemical properties. The objectives of this study were to test the reaction of different bacterial phyla to drought and rewetting stress and to assess the influence of different soil chemical properties on the reaction of soil bacteria to this kind of stress. The soil samples were taken at ten forest sites and measured for pH and the contents of organic C (Corg) and total N (Nt), Zn, Cu, and Pb. The samples were kept without water addition at 20 – 30 °C for 8 weeks and subsequently rewetted to achieve moisture equal to 50 – 60 % of their maximum water-holding capacity. Prior to the drought period and 24 h after the rewetting, the structure of soil bacterial communities was determined using pyrosequencing of 16S rRNA genes. The drought and rewetting stress altered bacterial community structure. Gram-positive bacterial phyla, Actinobacteria and Firmicutes, increased in relative proportion after the stress, whereas the Gram-negative bacteria in most cases decreased. The largest decrease in relative abundance was for Gammaproteobacteria and Bacteroidetes. For several phyla the reaction to drought and rewetting stress depended on the chemical properties of soils. Soil pH was the most important soil property influencing the reaction of a number of soil bacterial groups (including all classes of Proteobacteria, Bacteroidetes, Acidobacteria, and others) to drought and rewetting stress. For several bacterial phyla the reaction to the stress depended also on the contents of Nt and Corg in soil. The effect of heavy metal pollution was also noticeable, although weaker compared to other chemical soil properties. We conclude that soil chemical properties should be considered when assessing the effect of stressing factors on soil bacterial communities.Electronic supplementary materialThe online version of this article (doi:10.1007/s13213-014-1002-0) contains supplementary material, which is available to authorized users.

How environment selects: Resilience and survival of microbial mat community within intermittent karst spring Krčić (Croatia)

“…Drought phenomenon is also known to lead to alternations in environmental factors including pronounced oligotrophy, increased solute concentration and oxygen content, reduced substrate diffusion, and osmolyte production (Naylor & Coleman‐Derr, ). In this type of stress, an increase in the ratio of Gram‐positive phyla Firmicutes and Actinobacteria was observed (Chodak, Gołębiewski, Morawska‐Płoskonka, Kuduk, & Niklińska, ; Naylor & Coleman‐Derr, ), concurring with our results. Many Gram‐positive bacteria, characterized metabolically as “oligotrophs,” can survive better in these conditions by adaptations including thicker cell walls, sporulation, and production of osmolytes (Naylor, DeGraaf, Purdom, & Coleman‐Derr, ).…”

A decade of irrigation transforms the soil microbiome of a semi‐arid pine forest

“…; Chodak et al . ). However, this phylum did not respond to irrigation when all soil horizons were included in the analysis (Fig.…”

“…; Chodak et al . ), whereas others have suggested a more oligotrophic life strategy of Verrucomicrobia in respect to water availability (Bachar et al . ; von Rein et al .…”

“…; Chodak et al . ), and to consistently decrease during long‐term water limitation in a Mediterranean forest (Curiel Yuste et al . ), ultimately supporting what has been observed in the present study.…”

Bacterial-mediated drought tolerance: Current and future prospects

“…Drought stress affects soil bacteria through osmotic stress and resource competition (Schimel et al, 2007;Chodak et al, 2015) and can result in nucleic acids damages (Dose et al, 1991) that may occur via chemical modifications (alkylation or oxidation), cross-linking, or base removal (Potts, 1999). Drought stress results in an accumulation of free radicals due to conformational protein changes, restricted enzyme efficiency, and changes in electron transport chains (Vriezen et al, 2007;Bérard et al, 2015).…”