Home About us MoEF Contact us Sitemap Tamil Website  
About Envis
Whats New
Microorganisms
Research on Microbes
Database
Bibliography
Publications
Library
E-Resources
Microbiology Experts
Events
Online Submission
Access Statistics

Site Visitors

blog tracking


 
Plant and Soil
Vol. 407 (1), 2016, Pages: 203–215

Nitrogen fertilization affects bacteria utilizing plant-derived carbon in the rhizosphere of beech seedlings

Silvia Gschwendtner, Marion Engel, Tillmann Lueders, Franz Buegger, Michael Schloter

Research Unit Environmental Genomics, German Research Center for Environmental Health (GmbH), Helmholtz Zentrum MünchenNeuherberg, Germany.

Abstract

Background and aims

Forest ecosystems may act as sinks for or source of atmospheric CO2. While inorganic nitrogen (N) fertilization increases aboveground tree biomass, the effects on soil and rhizosphere microorganisms are less clear, indicating potentially unpredictable changes in nutrient cycling processes maintaining ecosystem functioning. Although plant-derived carbon (C) is the main C source in soils during the vegetation period, information on the response of rhizosphere bacteria assimilating rhizodeposits to increased soil N availability mainly for trees is missing.

Methods

We performed a greenhouse experiment with 13C-CO2 labelled young beech seedlings grown under different N fertilization levels. DNA Stable Isotope Probing (DNA-SIP) in combination with TRFLP and pyrosequencing enabled us to identify bacteria assimilating plant-derived C and to assess the main responders phylogenetically.

Results

Although above- and belowground allocation of recently fixed photosynthates remained unchanged, microbial rhizosphere community composition was clearly affected by fertilization. Besides, we found lower 13C incorporation into microbial biomass in fertilized soil. Moreover, it could be shown that only a small subset of the rhizosphere microbiome incorporated recently fixed C into its DNA, dominated by Proteobacteria (Alpha- and Betaproteobacteria) and Actinobacteria (Actinomycetales).

Conclusions

Our results suggest that N fertilization may change both the diversity of bacterial communities using rhizodeposits and assimilation rates of recently fixed photosynthates. Given the close interaction of beneficial and/or deleterious microbes and plants in the rhizosphere, this could potentially have positive or negative implications for plant performance on long-term.

Keywords:Fertilization, Plant-derived carbon, Rhizosphere microbiome, DNA-SIP, Pyrosequencing.

Copyright © 2005 ENVIS Centre ! All rights reserved
This site is optimized for 1024 x 768 screen resolution