Page 214 - Microbial methane cycling in a warming world From biosphere to atmosphere Michiel H in t Zandt

Chapter 9. Long-term warming effects on permafrost soil microbial communities
Dissimilatory sulfate reduction genes (dissimilatory sulfite reductase dsrAB) decreased in AL and PF, but increased in TL. Genes were affiliated with Proteobacteria (24-40%), Firmicutes (13-38%) and Acidobacteria (18-32%). Assimilatory sulfate reduction (phosphoadenosine phosphosulfate reductase cysH) showed minor decreases in AL and PF and the most pronounced decrease in TL.
Figure 7. Fold changes in relative abundance (TPM) of the carbohydrate-active enzyme classes involved in the degradation of cellulose and hemicellulose in dead plant residuals detected in the active layer (AL), transition layer (TL), and permafrost (PF). Orange dots indicate an increase after incubation; blue dots indicate a decrease after incubation. Non-filled orange circles indicate a clade which was below the detection limit in initial samples but present in incubated samples; blue circles indicate the lineage was present in the initial but below the detection limit in incubated samples. Bubble sizes represent the fold changes after long-term incubation. Bubble sizes of non-filled circles do not represent fold-changes. GH: Glycoside Hydrolases, GT: Glycosyltransferases, PL: Polysaccharide Lyases, CE: Carbohydrate Esterases, CBM: Carbohydrate-Binding Modules, AA: Auxiliary Activities.
Regarding carbohydrate metabolism, we focused on the protein groups related to cellulose and hemicellulose which are import for the decomposition of dead plant biomass (Fig. 7, Fig. S6). A general increase in abundance of cellulases (mainly GH5, GH9, GH3, and GH51) and hemicellulases (mainly GH31, GH43, and GH26) was observed after incubation. Moreover, a slight increase also occurred in carbohydrate binding modules (CBM, mainly CBM6 and
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