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| Titel |
Ice nucleation activity in the widespread soil fungus Mortierella alpina |
| VerfasserIn |
J. Fröhlich-Nowoisky, T. C. J. Hill, B. G. Pummer, P. Yordanova, G. D. Franc, U. Pöschl |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 4 ; Nr. 12, no. 4 (2015-02-19), S.1057-1071 |
| Datensatznummer |
250117823
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| Publikation (Nr.) |
 copernicus.org/bg-12-1057-2015.pdf |
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| Zusammenfassung |
| Biological residues in soil dust are a potentially strong source of
atmospheric ice nuclei (IN). So far, however, the abundance, diversity,
sources, seasonality, and role of biological – in particular, fungal – IN in
soil dust have not been characterized. By analysis of the culturable fungi
in topsoils, from a range of different land use and ecosystem types in
southeast Wyoming, we found ice-nucleation-active (INA) fungi to be both
widespread and abundant, particularly in soils with recent inputs of
decomposable organic matter. Across all investigated soils, 8% of fungal
isolates were INA. All INA isolates initiated freezing at −5 to
−6 °C, and belonged to a single zygomycotic species, Mortierella alpina
(Mortierellales, Mortierellomycotina). To our knowledge this is the first report of ice nucleation activity in
a zygomycotic fungi because the few known INA fungi all belong to the phyla
Ascomycota and Basidiomycota. M. alpina is known to be saprobic and widespread in
soil, and Mortierella spores are present in air and rain. Sequencing of the ITS region and
the gene for γ-linolenic elongase revealed four distinct clades,
affiliated to different soil types. The IN produced by M. alpina seem to be
proteinaceous, < 300 kDa in size, and can be easily washed off the
mycelium. Ice nucleating fungal mycelium will ramify topsoils and probably
also release cell-free IN into it. If these IN survive decomposition or are
adsorbed onto mineral surfaces, their contribution might accumulate over
time, perhaps to be transported with soil dust and influencing its ice
nucleating properties. |
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