Soils of coniferous forest ecosystems are important for the global carbon cycle, and the identification of active microbial decomposers is essential for understanding organic matter transformation in these ecosystems. By the independent analysis of DNA and RNA, whole communities of bacteria and fungi and its active members were compared in topsoil of a Picea abies forest during a period of organic matter decomposition. Fungi quantitatively dominate the microbial community in the litter horizon, while the organic horizon shows comparable amount of fungal and bacterial biomasses. Active microbial populations obtained by RNA analysis exhibit similar diversity as DNA-derived populations, but significantly differ in the composition of microbial taxa. Several highly active taxa, especially fungal ones, show low abundance or even absence in the DNA pool. Bacteria and especially fungi are often distinctly associated with a particular soil horizon. Fungal communities are less even than bacterial ones and show higher relative abundances of dominant species. While dominant bacterial species are distributed across the studied ecosystem, distribution of dominant fungi is often spatially restricted as they are only recovered at some locations. The sequences of cbhI gene encoding for cellobiohydrolase (exocellulase), an essential enzyme for cellulose decomposition, were compared in soil metagenome and metatranscriptome and assigned to their producers. Litter horizon exhibits higher diversity and higher proportion of expressed sequences than organic horizon. Cellulose decomposition is mediated by highly diverse fungal populations largely distinct between soil horizons. The results indicate that low-abundance species make an important contribution to decomposition processes in soils.
- MeSH
- Bacteria klasifikace enzymologie genetika MeSH
- biodiverzita MeSH
- celulosa-1,4-beta-cellobiosidasa genetika MeSH
- celulosa metabolismus MeSH
- ekosystém MeSH
- fylogeneze MeSH
- houby klasifikace enzymologie genetika MeSH
- metagenom MeSH
- půdní mikrobiologie MeSH
- RNA ribozomální 16S genetika MeSH
- smrk fyziologie MeSH
- stromy mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The links among the changes in litter chemistry, the activity of extracellular enzymes and the microbial community composition were observed in Quercus petraea litter. Three phases of decomposition could be distinguished. In the early 4-month stage, with high activities of β-glucosidase, β-xylosidase and cellobiohydrolase, 16.4% of litter was decomposed. Hemicelluloses were rapidly removed while cellulose and lignin degradation was slow. In months 4-12, with high endocellulase and endoxylanase activities, decomposition of cellulose prevailed and 31.8% of litter mass was lost. After the third phase of decomposition until month 24 with high activity of ligninolytic enzymes, the litter mass loss reached 67.9%. After 2 years of decay, cellulose decomposition was almost complete and most of the remaining polysaccharides were in the form of hemicelluloses. Fungi largely dominated over bacteria as leaf endophytes and also in the litter immediately before contact with soil, and this fungal dominance lasted until month 4. Bacterial biomass (measured as phospholipid fatty acid content) in litter increased with time but also changed qualitatively, showing an increasing number of Actinobacteria. This paper shows that the dynamics of decomposition of individual litter components changes with time in accordance with the changes in the microbial community composition and its production of extracellular enzymes.
- MeSH
- Actinobacteria enzymologie metabolismus MeSH
- Bacteria enzymologie metabolismus MeSH
- biodiverzita MeSH
- biomasa MeSH
- dub (rod) MeSH
- glykosidhydrolasy metabolismus MeSH
- houby enzymologie MeSH
- polysacharidy metabolismus MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Changes in the abundance of bacteria and fungi and in the composition of bacterial communities during primary succession were investigated in a brown coal mine deposit area near Sokolov, the Czech Republic, using phospholipid fatty acids analysis, microarray and 16S rRNA gene sequencing. The study considered a chronosequence of sites undergoing spontaneous succession: 6-, 12-, 21- and 45-year-old and a 21-year-old site revegetated with Alnus glutinosa. During succession, organic carbon and the total nitrogen content increased while the pH and the C/N ratio decreased. Microbial biomass and bacterial diversity increased until 21 years and decreased later; bacteria dominated over fungi in the initial and late phases of succession. Bacterial community composition of the 6-year-old site with no vegetation cover largely differed from the older sites, especially by a higher content of Gammaproteobacteria, Cyanobacteria and some Alphaproteobacteria. Bacteria belonging to the genera Acidithiobacillus, Thiobacillus and related taxa, the CO(2) and N(2) fixers, dominated the community at this site. In the later phases, bacterial community development seemed to reflect more the changes in soil nutrient content and pH than vegetation with a decrease of Actinobacteria and an increase of Acidobacteria. The site revegetated with A. glutinosa resembled the 45-year-old primary succession site and exhibited an even lower pH and C/N ratio, indicating that recultivation is able to accelerate soil development.
- MeSH
- Acidobacteria MeSH
- Actinobacteria genetika růst a vývoj MeSH
- Alphaproteobacteria genetika růst a vývoj MeSH
- Bacteria klasifikace genetika růst a vývoj MeSH
- biodiverzita MeSH
- biomasa MeSH
- DNA bakterií analýza MeSH
- dusík analýza metabolismus MeSH
- fylogeneze MeSH
- geny rRNA MeSH
- houby genetika růst a vývoj MeSH
- molekulární sekvence - údaje MeSH
- monitorování životního prostředí MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- RNA ribozomální 16S genetika MeSH
- sekvence nukleotidů MeSH
- sinice genetika růst a vývoj MeSH
- těžba uhlí MeSH
- uhlí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Saprotrophic cord-forming basidiomycetes are important decomposers of lignocellulosic substrates in soil. The production of extracellular hydrolytic enzymes was studied during the growth of two saprotrophic basidiomycetes, Hypholoma fasciculare and Phanerochaete velutina, across the surface of nonsterile soil microcosms, along with the effects of these basidiomycetes on fungi and bacteria within the soil. Higher activities of α-glucosidase, β-glucosidase, cellobiohydrolase, β-xylosidase, phosphomonoesterase and phosphodiesterase, but not of arylsulphatase, were recorded beneath the mycelia. Despite the fact that H. fasciculare, with exploitative hyphal growth, produced much denser hyphal cover on the soil surface than P. velutina, with explorative growth, both fungi produced similar amounts of extracellular enzymes. In the areas where the mycelia of H. fasciculare and P. velutina interacted, the activities of N-acetylglucosaminidase, α-glucosidase and phosphomonoesterase, the enzymes potentially involved in hyphal cell wall damage, and the utilization of compounds released from damaged hyphae of interacting fungi, were particularly increased. No significant differences in fungal biomass were observed between basidiomycete-colonized and noncolonized soil, but bacterial biomass was reduced in soil with H. fasciculare. The increases in the activities of β-xylosidase, β-glucosidase, phosphomonoesterase and cellobiohydrolase with increasing fungal:bacterial biomass ratio indicate the positive effects of fungal enzymes on nutrient release and bacterial abundance, which is reflected in the positive correlation of bacterial and fungal biomass content.
- MeSH
- alfa-glukosidasy analýza metabolismus MeSH
- Bacteria růst a vývoj MeSH
- Basidiomycota růst a vývoj metabolismus fyziologie MeSH
- biomasa MeSH
- celulosa-1,4-beta-cellobiosidasa analýza metabolismus MeSH
- houby růst a vývoj fyziologie MeSH
- hyfy růst a vývoj MeSH
- mycelium fyziologie MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- xylosidasy analýza metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- analýza polymorfismu délky amplifikovaných restrikčních fragmentů metody MeSH
- DNA bakterií genetika chemie MeSH
- DNA fingerprinting metody MeSH
- ekosystém MeSH
- izotopové značení MeSH
- membránové lipidy analýza MeSH
- mikrobiologie životního prostředí MeSH
- pulzní gelová elektroforéza metody MeSH
- sekvenční analýza DNA metody MeSH
The macro- and micro-morphological features, mycelial extension rate, enzymatic activities and possible genetic changes were studied in 30 selected strains of basidiomycetes after 10-year cryopreservation on perlite in liquid nitrogen (LN). Comparisons with the same strains preserved by serial transfers on nutrient media at 4°C were also conducted. Production of ligninolytic enzymes and hydrogen peroxide was studied by quantitative spectrophotometric methods, whereas semiquantitative API ZYM testing was used to compare the levels of a wide range of hydrolytic enzymes. Our results show that cryopreservation in LN did not cause morphological changes in any isolate. The vitality of all fungi was successfully preserved and none of the physiological features were lost, even though the extension rate and enzyme activity were slightly affected. Moreover, sequence analysis of eight strains did not detect any changes in their genetic features after cryopreservation. These findings suggest that the perlite-based freezing protocol is suitable for long-term preservation of large numbers of basidiomycetes.
Liquid cultures with cellulose and solid state fermentation cultures on wheat straw of the white-rot fungi Pleurotus ostreatus and Trametes versicolor and the brown-rot fungus Piptoporus betulinus were assayed for the free and solid fraction-bound activity of lignocellulose-degrading enzymes. The majority of the ligninolytic enzymes laccase and Mn peroxidase was detected in the free fraction of P. ostreatus and T. versicolor. The endocleaving enzymes endo-1,4-beta-glucanase, endo-1,4-beta-mannanase and endo-1,4-beta-xylanase were detected almost exclusively in the free fraction, while significant amounts of 1,4-beta-glucosidase, cellobiohydrolase, 1,4-beta-xylosidase and 1,4-beta-mannosidase were present in the bound fraction depending on the mode of cultivation and the species. The bound enzymes accounted for 66% of the total activity in P. ostreatus straw cultures, 35% in T. versicolor and only 8% in P. betulinus. The enzymes also showed significant differences in freeze-drying stability. Hydrolases in general showed high stability, whereas laccase and Mn peroxidase of P. ostreatus were the least stable.
- MeSH
- celulasy analýza MeSH
- celulosa metabolismus MeSH
- enzymy analýza MeSH
- financování organizované MeSH
- fungální proteiny analýza MeSH
- glykosidhydrolasy analýza MeSH
- kultivační média chemie MeSH
- lakasa analýza MeSH
- lignin metabolismus MeSH
- lyofilizace MeSH
- peroxidasy analýza MeSH
- Pleurotus enzymologie MeSH
- Polyporales enzymologie MeSH
- stabilita enzymů MeSH
