Linking phylogeny to abundant ribotypes of community fingerprints: an exercise on the phylotypic responses to plant species, fertilisation and Lolium perenne ingression.

The present study explores the potential of directly linking phylogenetic identities obtained by cloning and sequencing of ITS sequences to dominant ribotypes of molecular community fingerprints to give further insight into dominant members of the communities in three Irish grassland soils. The ten most abundant bacterial ribotypes of untreated bare soils of three grassland microcosms were chosen to represent the "baseline community" of the respective soil. Identities on phylum and order level were assigned to these ribotypes on a weighted basis, by matching sequence homologies of cloned ITS sequences with ribotypes of the same fragment lengths ±5 bp. Results showed that ribotypes were represented by the phyla Acidobacteria, Actinobacteria, Proteobacteria, and Firmicutes and the distribution of the ribotype and phylotype communities was shown to be highly site-specific. Furthermore the response of dominant bacterial phylotypes to plant species composition, fertilisation and Lolium perenne ingression was investigated within a larger microcosm study (Microb Ecol 63:509-521).