The Bacillus subtilis group comprises eight closely related species that are indistinguishable from one another by 16S rRNA gene sequence analysis. Therefore, the gyrB gene, which encodes the subunit B protein of DNA gyrase, was selected as an alternative phylogenetic marker. To determine whether gyrB gene sequence analysis could be used for phylogenetic analysis and species identification of members of the B. subtilis group, the congruence of gyrB grouping with both 16S rRNA gene sequencing and DNA-DNA hybridization data was evaluated. Ranges of gyrB nucleotide and translated amino acid sequence similarities among the eight type strains were 75.4-95.0 % and 88.5-99.2 %, respectively, whereas 16S rRNA gene sequence similarities were 98.1-99.8 %. Results showed that gyrB gene sequences provide higher resolution than 16S rRNA gene sequences. The classification achieved by gyrB sequence analysis was in agreement with results obtained with DNA-DNA hybridization. It is concluded that the gyrB gene may be an efficient alternative target for identification and taxonomic analysis of members of the B. subtilis group.Bacillus subtilis is a Gram-positive, spore-forming, fermentative, aerobic, rod-shaped bacterium. The Bacillus subtilis group contains the closely related taxa Bacillus subtilis subsp. subtilis (Smith et al., 1964;Nakamura et al., 1999), Bacillus licheniformis (Skerman et al., 1980), Bacillus amyloliquefaciens (Priest et al., 1987), Bacillus atrophaeus (Nakamura, 1989), Bacillus mojavensis (Roberts et al., 1994), Bacillus vallismortis (Roberts et al., 1996), Bacillus subtilis subsp. spizizenii (Nakamura et al., 1999) and Bacillus sonorensis (Palmisano et al., 2001). These taxa can be differentiated from one another by fatty acid composition analysis, restriction digest analysis and DNA-DNA hybridization analysis, but are quite difficult to differentiate by phenotypic characteristics (Roberts et al., 1994;Nakamura et al., 1999).16S rRNA gene sequence analysis is the most commonly used method for identifying bacteria or for constructing bacterial phylogenetic relationships (Woese, 1987;Vandamme et al., 1996;Joung & Cote, 2002); however, its usefulness is limited because of the high percentage of sequence similarity between closely related species (Ash et al., 1991;Martínez-Murcia et al., 1992;Christensen et al., 1998). The use of protein-encoding genes as phylogenetic markers is now a common approach (Yamamoto & Harayama, 1998;Ko et al., 2004;Chelo et al., 2007). Detailed investigations have demonstrated that sequences from protein-encoding genes can accurately predict genome relatedness and may replace DNA-DNA hybridization for species identification and delineation in the future (Stackebrandt et al., 2002;Zeigler, 2003).The gyrB gene encodes the subunit B protein of DNA gyrase, a type II DNA topoisomerase, which plays an essential role in DNA replication and is distributed universally among bacterial species (Watt & Hickson, 1994;Huang, 1996). The rate of molecular evolution inferred from gyrB gene sequences ...

Bacillus velezensis, isolated from the mouth of the river Vélez in Málaga (southern Spain), has been described recently by Ruiz-García et al. (2005). The type strain BCRC 17467 T (CR-502 T 5LMG 22478 T ) and strain CR-14b had identical 16S rRNA gene sequences and the topology of the phylogenetic tree confirmed that they were members of the Bacillus subtilis group. The 16S rRNA gene sequences of these strains shared 99 % similarity with Bacillus subtilis subsp. subtilis (Nakamura et al., 1999), Bacillus amyloliquefaciens (Priest et al., 1987) and Bacillus vallismortis (Roberts et al., 1996), and 98 % similarity with Bacillus mojavensis (Roberts et al., 1994) and Bacillus atrophaeus (Nakamura, 1989). DNA-DNA hybridization analysis confirmed that B. velezensis BCRC 17467T and CR-14b show less than 20 % relatedness with the species mentioned above. The two strains were characterized by their capacity to produce acids from glycogen, lactose, methyl a-Dglycoside and raffinose, but not from turanose, and produce b-galactosidase (determined by ONPG reaction), but not arginine dihydrolase. Strain CR-502 T showed a specific fatty acid profile characterized mainly by its high C 16 : 0 content and the presence of C 16 : 1 v11c, iso-C 13 : 0 , C 14 : 0 and iso-C 17 : 1 v10c. Genomic and phenotypic data demonstrated that B. velezensis represents a novel species of Bacillus .

Among a large collection of Taiwanese soil isolates, a novel Gram-negative, rod-shaped, non-spore-forming, yellow-pigmented bacterial strain, Soil-3-27 T , was isolated from farmland soil in Wu-Feng, Taiwan. The isolate was subjected to a polyphasic study including 16S rRNA gene sequencing, DNA-DNA hybridization, fatty acid analysis and comparative phenotypic characterization. The 16S rRNA gene sequence analysis indicated that the organism belongs to the genus Chryseobacterium. The organism contains menaquinone MK-6 as the predominant isoprenoid quinone and 15 : 0 iso (43 %), 17 : 1 isov9c (17?5 %) and 17 : 0 iso 3-OH (16?6 %) as the major fatty acids. Phylogenetically, the closest relatives of strain Soil-3-27 T are Chryseobacterium daecheongense, Chryseobacterium defluvii and Chryseobacterium taichungense with 96?7-97?2 % sequence similarity. DNA-DNA hybridization showed relatedness values of 8?5-24?2 % with these species. The DNA G+C content is 36?8 mol%. Strain Soil-3-27 T is clearly distinguishable from other Chryseobacterium species and represents a novel species, for which the name Chryseobacterium taiwanense sp. nov. is proposed. The type strain is strain

A novel Gram-negative, rod-shaped, motile, non-spore-forming bacterial strain, CMS T , isolated from soil was characterized using phenotypic and molecular taxonomic methods. 16S rRNA gene sequence analysis revealed that the organism belongs phylogenetically to the genus Pseudomonas. Pseudomonas monteilii, P. plecoglossicida and P. mosselii were the most closely related species, with 16S rRNA gene sequence similarities to the respective type strains of 99.79, 99.73 and 99.59 %. Relatively low gyrB gene sequence similarities (,90 %) and DNA-DNA reassociation values (,51 %) were obtained between the strain and its phylogenetically closest neighbours. The G+C content of strain CMS T was 62.7 mol%. The major cellular fatty acids were C 18 : 1 v7c, summed feature 3 (C 16 : 1 v7c and/or iso-C 15 : 0 2-OH), C 16 : 0 and C 10 : 0 3-OH.

Strain FIRDI 006 T , isolated from silage cattle feed, was characterized by using phenotypic and molecular taxonomic methods. The strain was a homofermentative lactic acid bacterium; the cells stained Gram-positive and were catalase-negative, non-motile, facultatively anaerobic rods. 16S rRNA gene sequence analysis revealed that the strain belongs phylogenetically to the genus Lactobacillus and can be placed within the Lactobacillus acidophilus-delbrueckii group. Lactobacillus gasseri and Lactobacillus johnsonii were the most closely related species, with 16S rRNA gene sequence similarities of 99.53 and 99.46 % to the respective type strains. Low gyrB gene sequence similarities (,90 %) and low DNA-DNA reassociation values (,45 %) were obtained between the strain and the phylogenetically closest neighbours. Based on phenotypic and genetic evidence, the strain is considered to represent a novel species, for which the name Lactobacillus taiwanensis sp. nov. is proposed. The type strain is FIRDI 006 T (5BCRC 17755 T 5DSM 21401 T ).