Low concentration of copper inhibits colonization of soil by the arbuscular mycorrhizal fungus Glomus intraradices and changes the microbial community structure

TY - JOUR

T1 - Low concentration of copper inhibits colonization of soil by the arbuscular mycorrhizal fungus Glomus intraradices and changes the microbial community structure

AU - Hagerberg, David

AU - Manique, Nina

AU - Brandt, Kristian Koefoed

AU - Larsen, John

AU - Nybroe, Ole

AU - Olsson, Stefan

PY - 2011/5

Y1 - 2011/5

N2 - Common agricultural practices result in accumulation of copper in agricultural soils worldwide. The effect of bioavailable copper ([Cu]bio) on colonization of soil by the AM fungus Glomus intraradices and other soil microorganisms was investigated in microcosms containing copper-amended soil. To avoid indirect effects through the plant, copper was only added to root-free microcosm compartments. [Cu]bio was measured using a Pseudomonas fluorescens biosensor strain. In the range of 0-1.5 μg g-1 [Cu]bio, a log-log linear relationship between added copper and [Cu]bio was found. Microbial colonization of the root-free compartment was evaluated by whole-cell fatty acid analysis (WCFA) and amplified rDNA restriction analysis (ARDRA). The WCFA analysis showed that the AM fungus soil colonization was severely inhibited by Cu with a 50% reduction of mycorrhizal growth at 0.26 μg g-1 [Cu]bio. The growth of other main microbial groups was not significantly affected by copper. However, ARDRA analysis showed a very strong effect of copper on the bacterial community composition probably caused by an increased proportion of Cu-resistant bacteria. Our results suggest that problems with plant yield may arise when converting slightly copper-contaminated soils to land uses such as low-input and sustainable agriculture that are dependent on AM fungal symbiosis.

AB - Common agricultural practices result in accumulation of copper in agricultural soils worldwide. The effect of bioavailable copper ([Cu]bio) on colonization of soil by the AM fungus Glomus intraradices and other soil microorganisms was investigated in microcosms containing copper-amended soil. To avoid indirect effects through the plant, copper was only added to root-free microcosm compartments. [Cu]bio was measured using a Pseudomonas fluorescens biosensor strain. In the range of 0-1.5 μg g-1 [Cu]bio, a log-log linear relationship between added copper and [Cu]bio was found. Microbial colonization of the root-free compartment was evaluated by whole-cell fatty acid analysis (WCFA) and amplified rDNA restriction analysis (ARDRA). The WCFA analysis showed that the AM fungus soil colonization was severely inhibited by Cu with a 50% reduction of mycorrhizal growth at 0.26 μg g-1 [Cu]bio. The growth of other main microbial groups was not significantly affected by copper. However, ARDRA analysis showed a very strong effect of copper on the bacterial community composition probably caused by an increased proportion of Cu-resistant bacteria. Our results suggest that problems with plant yield may arise when converting slightly copper-contaminated soils to land uses such as low-input and sustainable agriculture that are dependent on AM fungal symbiosis.

U2 - 10.1007/s00248-010-9795-2

DO - 10.1007/s00248-010-9795-2

M3 - Journal article

C2 - 21249353

SN - 0095-3628

VL - 61

SP - 844

EP - 852

JO - Microbial Ecology

JF - Microbial Ecology

IS - 4

ER -