Plant and microbial community composition in connection with soil chemistry determines soil nutrient cycling. The study aimed at demonstrating links between plant and microbial communities and soil chemistry occurring among and within four sites: two pine forests with contrasting soil pH and two grasslands of dissimilar soil chemistry and vegetation. Soil was characterized by C and N content, particle size, and profiles of low-molecular-weight compounds determined by high-performance liquid chromatography (HPLC) of soil extracts. Bacterial and actinobacterial community composition was assessed by terminal restriction fragment length polymorphism (T-RFLP) and cloning followed by sequencing. Abundances of bacteria, fungi, and actinobacteria were determined by quantitative PCR. In addition, a pool of secondary metabolites was estimated by erm resistance genes coding for rRNA methyltransferases. The sites were characterized by a stable proportion of C/N within each site, while on a larger scale, the grasslands had a significantly lower C/N ratio than the forests. A Spearman's test showed that soil pH was correlated with bacterial community composition not only among sites but also within each site. Bacterial, actinobacterial, and fungal abundances were related to carbon sources while T-RFLP-assessed microbial community composition was correlated with the chemical environment represented by HPLC profiles. Actinobacteria community composition was the only studied microbial characteristic correlated to all measured factors. It was concluded that the microbial communities of our sites were influenced primarily not only by soil abiotic characteristics but also by dominant litter quality, particularly, by percentage of recalcitrant compounds.

• MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• bakteriální nálož MeSH
• biodiverzita MeSH
• DNA bakterií chemie   genetika   MeSH
• dusík analýza   MeSH
• fylogeneze MeSH
• houby klasifikace   genetika   izolace a purifikace   MeSH
• koncentrace vodíkových iontů MeSH
• methyltransferasy genetika   MeSH
• molekulární sekvence - údaje MeSH
• organické látky analýza   MeSH
• počet mikrobiálních kolonií MeSH
• polymorfismus délky restrikčních fragmentů MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• rostliny mikrobiologie   MeSH
• sekvenční analýza DNA MeSH
• shluková analýza MeSH
• uhlík analýza   MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Members of the Actinobacteria are among the most important litter decomposers in soil. The site of a waterlogged deciduous forest with acidic soil was explored for actinobacteria because seasonality of litter inputs, temperature, and precipitation provided contrasting environmental conditions, particularly variation of organic matter quantity and quality. We hypothesized that these factors, which are known to influence decomposition, were also likely to affect actinobacterial community composition. The relationship between the actinobacterial community, soil moisture and organic matter content was assessed in two soil horizons in the summer and winter seasons using a 16S rRNA taxonomic microarray and cloning-sequencing of 16S rRNA genes. Both approaches showed that the community differed significantly between horizons and seasons, paralleling the changes in soil moisture and organic matter content. The microarray analysis further indicated that the actinobacterial community of the upper horizon was characterized by high incidence of the genus Mycobacterium. In both horizons and seasons, the actinobacterial clone libraries were dominated (by 80%) by sequences of a separate clade sharing an ancestral node with Streptosporangineae. This relatedness is supported also by some common adaptations, for example, to soil acidity and periodic oxygen deprivation or dryness.

• MeSH
• Actinobacteria klasifikace   genetika   růst a vývoj   MeSH
• koncentrace vodíkových iontů MeSH
• molekulární sekvence - údaje MeSH
• podnebí MeSH
• půda chemie   MeSH
• půdní mikrobiologie MeSH
• roční období MeSH
• sekvence nukleotidů MeSH
• stromy mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH