Fungi in the future: interannual variation and effects of atmospheric change on arbuscular mycorrhizal fungal communities.

T E Anne Cotton,R Michael Miller,Thorunn Helgason,Alex J Dumbrell,Alastair H Fitter

doi:10.1111/nph.13224

Abstract

Understanding the natural dynamics of arbuscular mycorrhizal (AM) fungi and their response to global environmental change is essential for the prediction of future plant growth and ecosystem functions. We investigated the long-term temporal dynamics and effect of elevated atmospheric carbon dioxide (CO2) and ozone (O3) concentrations on AM fungal communities.Molecular methods were used to characterize the AM fungal communities of soybean (Glycine max) grown under elevated and ambient atmospheric concentrations of both CO2 and O3 within a free air concentration enrichment experiment in three growing seasons over 5 yr.Elevated CO2 altered the community composition of AM fungi, increasing the ratio of Glomeraceae to Gigasporaceae. By contrast, no effect of elevated O3 on AM fungal communities was detected. However, the greatest compositional differences detected were between years, suggesting that, at least in the short term, large-scale interannual temporal dynamics are stronger mediators than atmospheric CO2 concentrations of AM fungal communities.We conclude that, although atmospheric change may significantly alter AM fungal communities, this effect may be masked by the influences of natural changes and successional patterns through time. We suggest that changes in carbon availability are important determinants of the community dynamics of AM fungi.

Highlights

Since the industrial revolution, anthropogenic activities have caused an increase in carbon dioxide (CO2) levels from 280 to c. 400 ppm, and tropospheric ozone (O3) levels have more than doubled (Vingarzan, 2004; IPCC, 2007; Royal Society, 2008)
We identified 18 molecular operational taxonomic units (MOTUs) from three families (Gigasporaceae, Glomeraceae and Acaulosporaceae) from the roots obtained from Soybean Free Air Concentration Enrichment (SoyFACE) (Fig. S1)
Of the 18 fungal taxa present, clone analysis showed that the relative abundance of MOTU3 was consistently lower under elevated CO2 (eCO2) than under ambient CO2 (aCO2)

Summary

Introduction

Anthropogenic activities have caused an increase in carbon dioxide (CO2) levels from 280 to c. 400 ppm, and tropospheric ozone (O3) levels have more than doubled (Vingarzan, 2004; IPCC, 2007; Royal Society, 2008). It is important to better understand how global change will affect functionally significant components of soil biodiversity, for example, the arbuscular mycorrhizal (AM) belowground plant–microbe symbioses formed by fungi in the Phylum Glomeromycota (Johnson et al, 2013). These functionally important fungi are widely distributed, colonizing approximately two-thirds of plant species (Fitter & Moyersoen, 1996), and play central roles in many ecosystem processes. Functional differentiation among AM fungal taxa (Munkvold et al, 2004; Jansa et al, 2008) means that the composition and diversity of communities of these fungi can affect plant nutrient status (Jansa et al, 2008), community diversity (Blankinship et al, 2011) and plant productivity (Wagg et al, 2011)

Methods

Results

Discussion

Conclusion