Table 1.

Relative abundance of clones from triplicate unimproved and improved grassland soil samples and belonging to a number of bacterial phylogenetic groups

Phylogenetic groupaRelative clone abundance (%)
Library from unimproved grasslandLibrary from improved grasslandGrassland mean valuePooled data set (improved and unimproved grasslands)
SAF1SAF2SAF3SL1SL2SL3UnimprovedSL improved
Proteobacteria
 α-Proteobacteria52.124.453.322.243.537.043.3 (±18.5)b 34.2 (±12.3)39.6
 β-Proteobacteria8.311.12.22.22.26.57.2 (±5.1)3.6 (±2.8)5.6
 γ-Proteobacteria2.104.46.72.26.52.2 (±2.5)5.1 (±2.9)3.7
 β-/γ-Proteobacteria4.211.14.40.02.206.6 (±4.4)0.7 (±1.4)3.7
Flavobacteria02.2017.804.30.7 (±1.5)7.4 (±10.5)4.1
Green sulfur bacteria002.20000.7 (±1.5)0 (ND)c 0.4
Actinomycetes2.117.84.413.319.622.28.1 (±9.6)18.2 (±4.9)13.3
Low-G+C-content bacteria002.2002.20.7 (±1.5)0.7 (±1.4)0.7
Deinococcus-Thermusgroup002.20000.7 (±1.5)0 (ND)0.4
Acidimicrobium-Microthrixgroup2.115.66.76.78.708.1 (±7.8)5.1 (±5.1)6.7
Rubrobacter 6.34.4011.14.32.23.6 (±3.6)5.9 (±5.3)4.8
Holophaga 4.28.904.44.304.4 (±5.0)2.9 (±2.9)3.7
Acidobacterium 4.2006.74.32.21.4 (±2.7)4.4 (±2.5)3.0
Verrucomicrobium 02.26.74.40.04.33.0 (±3.8)2.9 (±2.9)3.0
Unclassified groupsd
 Sourhope group 14.22.22.2002.22.9 (±1.3)0.7 (±1.4)1.9
 Sourhope group 22.10002.200.7 (±1.4)0.7 (±1.4)0.7
 Sourhope group 34.200002.21.4 (±2.7)0.7 (±1.4)1.1
 Sourhope group 4000002.20 (ND)0.7 (±1.4)0.4
 Sourhope group 54.2002.22.201.4 (±2.7)1.5 (±1.4)1.5
 Sourhope group 6004.40001.5 (±2.9)0 (ND)0.7
 Sourhope group 7004.42.24.34.31.5 (±2.9)3.6 (±1.4)2.6
 Sourhope group 8000002.20 (ND)0.7 (±1.4)0.4
  • a The numbers of clones in the libraries and data set were as follows: SAF1, 48; SAF2, 45; SAF3, 45; SL1, 45; SL2, 46; SL3, 46; and pooled data set, 275.

  • b The values in parentheses are 95% confidence limits.

  • c ND, not determined.

  • d Unclassified Sourhope groups 1 through 8 are defined in the phylogenetic tree in Fig. 4.