Seasonal and altitudinal changes of culturable bacterial and yeast diversity in Alpine forest soils.
The effect of altitude and season on abundance and diversity of the culturable heterotrophic bacterial and yeast community was examined at four forest sites in the Italian Alps along an altitude gradient (545-2000 m). Independently of altitude, bacteria isolated at 0 °C (psychrophiles) were less numerous than those recovered at 20 °C. In autumn, psychrophilic bacterial population increased with altitude. The 1194 bacterial strains were primarily affiliated with the classes Alpha-, Beta-, Gammaproteobacteria, Spingobacteriia and Flavobacteriia. Fifty-seven of 112 operational taxonomic units represented potential novel species. Strains isolated at 20 °C had a higher diversity and showed similarities in taxa composition and abundance, regardless of altitude or season, while strains isolated at 0 °C showed differences in community composition at lower and higher altitudes. In contrast to bacteria, yeast diversity was season-dependent: site- and altitude-specific effects on yeast diversity were only detected in spring. Isolation temperature affected the relative proportions of yeast genera. Isolations recovered 719 strains, belonging to the classes Dothideomycetes, Saccharomycetes, Tremellomycetes and Mycrobotryomycetes. The presence of few dominant bacterial OTUs and yeast species indicated a resilient microbial population that is not affected by season or altitude. Soil nutrient contents influenced significantly abundance and diversity of culturable bacteria, but not of culturable yeasts.
Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria.
Luís
L
França
Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
Ciro
C
Sannino
Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
Benedetta
B
Turchetti
Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
Pietro
P
Buzzini
Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria. rosa.margesin@uibk.ac.at.
Rosa
R
Margesin
D000531:Altitude; D001419:Bacteria / Q000235:genetics / Q000302:isolation & purification*; D065928:Forests; D005658:Fungi / Q000235:genetics / Q000302:isolation & purification*; D064307:Microbiota; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012621:Seasons; D012988:Soil Microbiology
D012336:RNA, Ribosomal, 16S
16S rRNA gene; 26S rRNA gene; Alpine soils; Bacterial OTUs; Culturable bacteria and yeasts; ITS1&2; Psychrophiles; Yeast species