AUTHOR=Tláskal Vojtěch , Baldrian Petr 

TITLE=Deadwood-Inhabiting Bacteria Show Adaptations to Changing Carbon and Nitrogen Availability During Decomposition

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.685303

DOI=10.3389/fmicb.2021.685303

ISSN=1664-302X

ABSTRACT=<p>Deadwood decomposition is responsible for a significant amount of carbon (C) turnover in natural forests. While fresh deadwood contains mainly plant compounds and is extremely low in nitrogen (N), fungal biomass and N content increase during decomposition. Here, we examined 18 genome-sequenced bacterial strains representing the dominant deadwood taxa to assess their adaptations to C and N utilization in deadwood. Diverse gene sets for the efficient decomposition of plant and fungal cell wall biopolymers were found in <italic>Acidobacteria, Bacteroidetes</italic>, and <italic>Actinobacteria</italic>. In contrast to these groups, <italic>Alphaproteobacteria</italic> and <italic>Gammaproteobacteria</italic> contained fewer carbohydrate-active enzymes and depended either on low-molecular-mass C sources or on mycophagy. This group, however, showed rich gene complements for N<sub>2</sub> fixation and nitrate/nitrite reduction—key assimilatory and dissimilatory steps in the deadwood N cycle. We show that N<sub>2</sub> fixers can obtain C independently from either plant biopolymers or fungal biomass. The succession of bacteria on decomposing deadwood reflects their ability to cope with the changing quality of C-containing compounds and increasing N content.</p>