Department of Soil Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440, Bayreuth, Germany.
Proc Biol Sci. 2022 May 11;289(1974):20220130. doi: 10.1098/rspb.2022.0130.
Microbial community members are the primary microbial colonizers and active decomposers of deadwood. This study placed sterilized standardized beech and spruce sapwood specimens on the forest ground of 8 beech- and 8 spruce-dominated forest sites. After 370 days, specimens were assessed for mass loss, nitrogen (N) content and N isotopic signature, hydrolytic and lignin-modifying enzyme activities. Each specimen was incubated with bromodeoxyuridine (BrdU) to label metabolically active fungal and bacterial community members, which were assessed using amplicon sequencing. Fungal saprotrophs colonized the deadwood accompanied by a distinct bacterial community that was capable of cellulose degradation, aromatic depolymerization, and N fixation. The latter were governed by the genus , which was co-present with the majority of saprotrophic fungi regardless of whether beech or spruce specimens were decayed. Moreover, the richness of the diazotrophic group was significantly correlated with mass loss, N content and N isotopic signature. By contrast, presence of obligate predator spp. shifted bacterial community composition and were linked to decreased beech deadwood decay rates. Our study provides the first account of the composition and function of metabolically active wood-colonizing bacterial and fungal communities, highlighting cross-kingdom interactions during the early and intermediate stages of wood decay.
微生物群落成员是枯木的主要微生物定殖者和活性分解者。本研究将经过灭菌的标准化山毛榉和云杉边材标本放置在 8 个山毛榉和 8 个云杉主导的森林地表面。370 天后，评估标本的质量损失、氮 (N) 含量和 N 同位素特征、水解和木质素修饰酶活性。每个标本都用溴脱氧尿苷 (BrdU) 孵育，以标记代谢活跃的真菌和细菌群落成员，然后使用扩增子测序进行评估。真菌腐生物伴随着能够进行纤维素降解、芳香族解聚和 N 固定的独特细菌群落定殖到枯木中。后者由 属控制，无论腐烂的是山毛榉还是云杉标本，该属都与大多数腐生真菌共存。此外，固氮 属的丰富度与质量损失、N 含量和 N 同位素特征呈显著正相关。相比之下，专性捕食者 种的存在改变了细菌群落组成，并与山毛榉枯木腐烂率的降低有关。本研究首次描述了代谢活跃的木材定殖细菌和真菌群落的组成和功能，强调了在木材腐烂的早期和中期阶段跨领域的相互作用。
