Assessment of soil microbial communities involved in cellulose utilization at two contrasting Alpine forest sites. (February 2019) - Siles, José A.
Abstract: Soil microbial communities involved in 13 C-labeled cellulose utilization from two contrasting (in terms of vegetation and climatic conditions) forest sites at different elevations were studied by using a laboratory microcosm experiment and a PLFA (phospholipid fatty acid)-SIP (stable isotope probing) approach considering the effects of incubation temperature (0, 10 and 20 °C) and time (1–4 weeks). The amounts of cellulose- 13 C assimilated by soil microorganisms and the composition of microbial communities utilizing cellulose were site-dependent. Total, bacterial and actinobacterial biomass incorporated higher amounts of 13 C in soil from the deciduous forest site (at the lower elevation), while fungal biomass contained increased amounts of 13 C in soil from the coniferous forest site (at the higher elevation). Increasing temperatures resulted in increased amounts of 13 C assimilated by the different PLFA-based microbial groups, except fungi, and in significant changes in the community structure of cellulose utilizers. Fungi were better adapted to cold conditions than bacteria. Longer incubation times determined an increase in the amount of 13 C incorporated into total and bacterial PLFAs but had no effect on the composition of labeled microbial communities. Highlights: Soil microbial communities involved in cellulose utilization were investigated. Two forest sites varying in vegetation and environmental conditions were compared. Soil microbial communities utilizing 13 C-cellulose differed between forest sites. Increasing temperatures effected a higher cellulose- 13 C assimilation at both sites. Composition of cellulose utilizers did not change with longer incubation times.