Molecular Community Analysis of Arbuscular Mycorrhizal Fungi in Roots of Geothermal Soils in Yellowstone National Park (USA)

To better understand adaptation of plants and their mycorrhizae to extreme environmental conditions, we analyzed the composition of communities of arbuscular mycorrhizal fungi (AMF) in roots from geothermal sites in Yellowstone National Park (YNP), USA. Arbuscular mycorrhizal fungi were identified using molecular methods including seven specific primer pairs for regions of the ribosomal DNA that amplify different subgroups of AMF. Roots of Dichanthelium lanuginosum, a grass only occurring in geothermal areas, were sampled along with thermal and nonthermal Agrostis scabra and control plants growing outside the thermally influenced sites. In addition, root samples of Agrostis stolonifera from geothermal areas of Iceland were analyzed to identify possible common mycosymbionts between these geographically isolated locations. In YNP, 16 ribosomal DNA phylotypes belonging to the genera Archaeospora, Glomus, Paraglomus, Scutellospora, and Acaulospora were detected. Eight of these phylotypes could be assigned to known morphospecies, two others have been reported previously in molecular studies from different environments, and six were new to science. The most diverse and abundant lineage was Glomus group A, with the most frequent phylotype corresponding to Glomus intraradices. Five of the seven phylotypes detected in a preliminary sampling in a geothermal area in Iceland were also found in YNP. Nonthermal vegetation was dominated by a high diversity of Glomus group A phylotypes while nonthermal plants were not. Using multivariate analyses, a subset of three phylotypes were determined to be associated with geothermal conditions in the field sites analyzed. In conclusion, AMF communities in geothermal soils are distinct in their composition, including both unique phylotypes and generalist fungi that occur across a broad range of environmental condition

CNRM-CM5 median daily SWE forecasts.

<p>Blue lines = Official 30 year SNOTEL daily normals (calculated as 1981–2010 daily medians), obtained from the Natural Resources Conservation Service. Orange Lines = CNRM-CM5 daily medians for 2031–2060. Red Lines = average of CNRM-CM5 SWE daily medians for 2061–2090. The CNRM-CM5 model forecast a greater loss of snow in early winter.</p

Median annual peak SWE for 7 SNOTEL locations under the RCP 4.5 scenario.

<p>Historical (1990–2010) medians are calculated from historical SNOTEL weather station data. Mid- and late- 21^st century values are model forecasts.</p

Map showing Snow-telemetry (SNOTEL) weather stations in and near Yellowstone National Park.

<p>Left: Background shows average number of days per water year (October–September) with SWE greater than 0 cm. Right: Background shows average annual peak (greatest) SWE (cm). Data source = SNODAS [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159218#pone.0159218.ref020" target="_blank">20</a>]. Both panels are averaged over water years ending 2005–2014, which was the length of record available for this data source. Gray areas = Lakes.</p

Mean Absolute Error for modeled data from road points vs. modeled data from the most similar SNOTEL-containing location.

<p>Road points to the right of the dashed red line were excluded from further analysis. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159218#sec002" target="_blank">Methods</a> for details of MAE calculations.</p

Median days per year with SWE greater than zero.

<p>Values from 1990–2010 are calculated from SNOTEL station data, while mid- and late- 21^st century values are model forecasts.</p

The SNOTEL stations considered in this study.

<p>The SNOTEL stations considered in this study.</p

Assessment of the error introduced by matching SNOTEL locations to road points.

<p>Red dots are SNODAS [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159218#pone.0159218.ref020" target="_blank">20</a>] measurements of mean oversnow driveable days (days with SWE > 10 cm) at the SNOTEL locations during 2005–2014. Boxplots show the distribution of SNODAS measurements of mean number of oversnow driveable days from the road points matched to each SNOTEL (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159218#pone.0159218.g006" target="_blank">Fig 6</a>). X-axis positions of the SNOTEL locations (indicated in parentheses in the labels) are the measurements at the SNOTEL locations. The order of station locations on the X-axis is different from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159218#pone.0159218.g015" target="_blank">Fig 15</a> because SNODAS data were available only from water years 2005–2014 and the historical period of the models used in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0159218#pone.0159218.g015" target="_blank">Fig 15</a> is 1990–2006. The blue cross in the White Elephant column indicates the worst road point vs. SNOTEL match.</p