Data from: Bacterial and fungal growth on fungal necromass and its diverse components: shared profiles and divergent constraints revealed by high-throughput phenotyping

While fungal necromass is increasingly recognized as a major source of
persistent carbon (C) in soils, the relative functional roles of bacteria
and fungi in decomposing necromass are not fully resolved, and the
processes that select for necromass decomposer communities from the
broader soil microbial community are an emerging area of interest. In this
study, we characterized the growth of 52 bacterial and 83 fungal strains
isolated from necromass and soil on 22 C substrates, including different
necromass phenotypes, fungal cell wall polymers, dimers, and monomers. We
found that isolation habitat of the strains used in this experiment
(necromass vs. soil) had no effect on the substrates they were able to
use. Isolates from both microbial domains were able to grow on different
labile carbon substrates, polymers, and necromass phenotypes. However,
fungal growth was limited by necromass melanin content while bacterial
growth was more limited by the abundance of cell wall polysaccharides.
Additionally, overall differences in substrate use between bacteria and
fungi were most pronounced on polymer substrates. Collectively, our
results suggest that there is substantial functional overlap in necromass
substrate use across microbial domains, but some notable differences in
bacterial and fungal utilization of cell wall polymers, which can function
as a direct energy source or a means of accessing other compounds within
necromass. Future studies assessing bacteria and fungi decomposing
necromass together rather than in isolation will help to uncover potential
physical and chemical interactions within and between these two domains
during the decay of this important source of persistent soil C.

尽管真菌残体（fungal necromass）作为土壤中持久性碳（carbon, C）的重要来源日益受到学界认可，但细菌与真菌在分解真菌残体过程中的相对功能角色仍未完全阐明，且从广谱土壤微生物群落中筛选残体分解者群落的相关机制，亦是当前新兴的研究热点。本研究针对22种碳底物（C substrates）——包括不同真菌残体表型、真菌细胞壁聚合物、二聚体与单体——开展实验，对分离自真菌残体与土壤的52株细菌与83株真菌菌株的生长情况进行了表征。研究发现，本实验所用菌株的分离生境（真菌残体 vs 土壤），对其可利用的碳底物并无显著影响；两个微生物类群的分离株均可在不同易变性碳底物、聚合物以及真菌残体表型上生长。然而，真菌的生长会受到真菌残体黑色素含量的限制，而细菌的生长则更多受细胞壁多糖丰度的制约。此外，细菌与真菌在底物利用上的整体差异，在聚合物底物上表现最为显著。综合来看，本研究结果表明，不同微生物类群在真菌残体底物利用上存在广泛的功能重叠，但二者在细胞壁聚合物的利用上存在显著差异——这类聚合物既可作为直接能源，亦能作为获取真菌残体内部其他化合物的媒介。未来若能开展细菌与真菌共同分解真菌残体的相关研究（而非单独培养），将有助于揭示这两类微生物类群在降解这一重要持久性土壤碳源过程中，内部及相互间存在的潜在物理与化学相互作用。