Photorhabdus temperata subsp. cinerea subsp. nov., isolated from Heterorhabditis nematodes

Abstract

Research and Extension Centre for Fruit Growing, Vadastag 2, H-4244 Ú jfehé rtó , HungaryDuring the characterization of symbiotic bacteria of Hungarian entomopathogenic nematode isolates, a number of bacteria (including strain 3107 T ) isolated from Heterorhabditis downesi and Heterorhabditis megidis showed only moderate 16S rRNA gene sequence similarity to the type strains of all described Photorhabdus species and subspecies. On the basis of the 16S rRNA gene sequence, the phylogenetic relationships of these isolates were uncertain, because of the low bootstrap values. Using gyrB sequences for phylogenetic analysis, these isolates were shown to be part of the species Photorhabdus temperata, with clear separation from both Palaearctic and American strains (phylogenetic distances are 6.9 and 7.9 %, respectively). Physiological properties and carbon-source utilization profiles supported the phylogenetic position of these strains; therefore, a novel subspecies, Photorhabdus temperata subsp. cinerea subsp. nov. is proposed, with the type strain 3107 T (5DSM 19724 T 5NCAIM B 02271 T ).

Phylogenetic and cophylogenetic relationships of entomopathogenic nematodes (Heterorhabditis: Rhabditida) and their symbiotic bacteria (Photorhabdus: Enterobacteriaceae)

“…Previous studies have suggested that the ITS sequences provide detailed information about variation within and among species of Heterorhabditis (Malan et al, 2008;Nguyen et al, 2008), and gyrB gene sequences are more useful in investigating intrageneric phylogenies of Photorhabdus in contrast to the normally used 16S ribosomal DNA sequences (Akhurst et al, 2004;Tóth and Lakatos, 2008). For phylogenetic analyses in this study, ITS region and gyrB gene were amplified from the genomic DNA of the nematodes and the bacteria, respectively.…”

“…After removing low quality and vector sequences, the resulting high quality sequences were used to produce alignments of ITS or gyrB with other known nematodes or bacteria (Appendix A) for comparative purposes using ClustalW algorithm (Thompson et al, 1994). For phylogenetic analysis, the unaligned sequence ends were deleted, gaps in the aligned domains were treated as either missing data or a fifth base, and Caenorhabditis elegans and Xenorhabdus nematophila were used as outgroup taxa and to root the trees for Heterorhabditis and Photorhabdus, respectively according to previous studies (Malan et al, 2008;Tóth and Lakatos, 2008). Initially, all our 67 strains were included in phylogenetic analyses using both maximum parsimony (MP) and maximum likelihood (ML) methods.…”

“…Although mutualistic association between Heterorhabditis and Photorhabdus species was originally thought to be strictly one-to-one in terms of cospeciation, with the increased number of nematode and bacterial isolates, it has been observed that some bacterial species colonize more than one recognized nematode species. For example, while all the bacterial partners of H. megidis are identified to be P. temperata (Kuwata et al, 2007), this bacterial species has been found associated with H. bacteriophora, H. zealandica, and H. downesi (Adams et al, 2006;An andGrewal, 2010b, 2011;Boemare, 2002;Tóth and Lakatos, 2008). While this calls into question the strict specificity of Heterorhabditis-Photorhabdus species associations, it has been assumed that the apparent exceptions do not fundamentally modify the oneto-one concept just because they are essentially the result of taxonomic classification based on phenotypic and genotypic discriminations (Boemare and Akhurst, 2006).…”

Diversity, Biology and Evolutionary Relationships

“…Furthermore, chemotaxis studies have shown that, when given a choice, different hosts of X. bovienii prefer either their cognate strain or a strain that comes from a host that is phylogenetically closer to their cognate host The association between Heterorhabditis and Photorhabdus was originally thought to be strictly one-to-one in terms of cospeciation. However, with the increasing number of nematode and bacterial isolates, it has come to light that some Photorhabdus species such as P. temperata (Kuwata, Yoshiga, Yoshida, & Kondo, 2007) (Adams et al, 2006;An & Grewal, 2010;Boemare, 2002;Tóth & Lakatos, 2008). Recently, Maneesakorn et al (2011) investigated coevolutionary relationships between Photorhabdus and Heterorhabditis considering a single gene approach.…”

Structure of a zwitterionic O-polysaccharide from Photorhabdus temperata subsp. cinerea 3240

“…cinerea 3240 isolated from larvae of the entomopathogenic nematode Heterorhabditis downesi in Hungary. 5 The polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide isolated from bacterial cells by the phenol-water procedure. The 1 H NMR and 13 C NMR ( Fig.…”