Re-examination of the taxonomic position of Bacillus silvestris Rheims et al. 1999 and proposal to transfer it to Solibacillus gen. nov. as Solibacillus silvestris comb. nov.

Abstract

Re-examination of the taxonomic position of Bacillus silvestris Rheims et al. 1999 Following the transfer of three of the six species enclosed in the original definition of rRNA group 2 of Bacillus to the genus Sporosarcina and two to Lysinibacillus, other species of this group, some of which were added later, still await taxonomic revision. In a recent publication, a set of 'core' characteristics was proposed for species to be included in the genus Bacillus (Kä mpfer et al., 2006). Except for Bacillus silvestris, however, several or none of these properties are available for members of rRNA group 2. According to our analysis of data including the 'core' characteristics, Bacillus silvestris should not be a member of the genus Bacillus. We therefore propose the establishment of a new genus, Solibacillus gen. nov., and transfer Bacillus silvestris to this genus as Solibacillus silvestris comb. nov., with the type strain HR3-23 T (5DSM 12223 T 5ATCC BAA-269 T 5CIP 106059 T ).In a major systematic study based on the 16S rRNA gene sequence analyses of the members of the genus Bacillus, Ash et al. (1991) recognized five distinct groups and proposed that absence of phenotypically definable criteria 'should not preclude the recognition of these groups as distinct genera'. Subsequently, species belonging to rRNA group 3 were placed in a new genus, Paenibacillus (Ash et al., 1993;Shida et al., 1997). Bacillus rRNA group 2 comprises six Bacillus species: Bacillus fusiformis, Bacillus globisporus, Bacillus insolitus, Bacillus pasteurii, Bacillus psychrophilus and Bacillus sphaericus, and also the nonBacillus species Sporosarcina ureae. An increasing number of species descriptions indicated the need to properly define the properties of the genus Bacillus (Farrow et al., 1994;Rheims et al., 1999;Stackebrandt & Swiderski, 2002; Kämpfer et al., 2006;Zhang et al., 2007) and according to Farrow et al. (1994) the 'simplest and most phylogenetically consistent policy would be to exclude the group 2 bacilli from the genus Bacillus'. The same authors also suggested the transfer of B. globisporus, B. pasteurii and B.psychrophilus to the genus Sporosarcina. These three species were subsequently described as members of Sporosarcina by Yoon et al. Supplementary tables showing 16S rRNA gene sequence similarity between Bacillus silvestris and other closely related members of Bacillus rRNA group 2, and comparative fatty acid profiles of B. silvestris, Caryophanon latum and Bacillus subtilis are available with the online version of this paper.

Reclassification of Bacillus isronensis Shivaji et al. 2009 as Solibacillus isronensis comb. nov. and emended description of genus Solibacillus Krishnamurthi et al. 2009

“…Interestingly, the lipid profiles of the two strains overlapped completely, with no spots appearing in one but not the other. These profiles once again match well with the original species description of S. silvestris (Krishnamurthi et al, 2009a). However, there were discrepancies with the lipid data reported by Shivaji et al (2009); they did not find diphosphatidylglycerol in B. isronensis.…”

“…The accession numbers for the ITS region sequences of B. subtilis MTCC 121 the reclassification of B. fusiformis and B. sphaericus to the genus Lysinibacillus and B. insolitus to the genus Psychrobacillus, respectively. It has been recognized that species classified as members of the genus Bacillus within this group should be placed either in a new genus or into already existing genera; examples include the proposal of the genera Viridibacillus (Albert et al, 2007) and Solibacillus (Krishnamurthi et al, 2009a). However, microbiologists have continued to describe novel taxa within this group as members of Bacillus, e.g.…”

Phylogenetic Analyses of the Genus Hymenobacter and Description of Siccationidurans gen. nov., and Parahymenobacter gen. nov

“…Gram-negative and Gram-positive bacteria contain 713/1542 and 568/1542 nucleotides, respectively, in the highly conserved regions [30], and a total of 145/1542 (9.4%) more nucleotides are conserved in Gram-negative bacteria. Under these circumstances, the difference of 88 to 93% among species of Clade1, Clade2 and Clade3, being Gramnegative by virtue, belonging to the genus Hymenobacter, is huge and demands the creation of new genera [30], since earlier the genera were carved with >92% 16S rRNA gene sequence similarity [7,8,[32][33][34]. The main impediment is the lack of diagnostic phenotypic differences.…”

“…In this context, it is worth mentioning that, based on 16S rRNA gene sequence analyses, five distinct phylogenetic groups within the genus Bacillus [3], two novel orders, Solirubrobacterales and Thermoleophilales [4], and a new hierarchic classification structure for the actinomycete line of descent [5] were proposed and the phylogenetic affiliation of the genus pseudomonads was assessed [6]. In congruence with these, to take few examples, several novel genera, such as Solibacillus [7] and Planomicrobium [8], were created on the basis of their 16S rRNA gene sequence. Present work is focused on evaluating the internal features of the 16S rRNA gene sequences of the genus Hymenobacter.…”

Comparison of the Bacterial Microbiota in a Bale of Collected Cardboard Determined by 454 Pyrosequencing and Clone Library

“…Suihko and Stackebrandt [29], Suominen et al [30] and Väisänen et al [31] all found Bacillus and Paenibacillus in final recycled food packaging paper and board. Suihkoand Stackebrandt [29] also found Bacillus silvestris, which has since been renamed Solibacillus silvestris [32], a genus present in our study. Likewise, McCusky Gendron et al [11] and Namjoshi et al [33] found Bacillus and Paenibacillus on unused paper towels and linerboard, respectively.…”