FIG. 1.

Schematic presentation of phylogenetic groups of clostridia isolated from various plant sources, based on 16S rRNA gene sequences. The phylogenetic tree was reconstructed from the results of a previous study (16). Groups denoted by black triangles are phylogenetic groups of clostridia isolated from gramineous plants. The phylogenetic positions of type strains of Clostridium species in and around the groups are indicated by the accession numbers of 16S rRNA gene sequences given in parentheses. Gray regions indicate clostridial clusters as defined by Collins et al. (4). Groups marked with asterisks contain the clostridia isolated from M. sinensis (groups I, II, IV, and V), as shown in Table 3. Group III contains two isolates, B905-1 and B904-4, derived from seeds of wild rice, Oryza officinalis (16). Bar = 0.01 base substitutions per nucleotide.