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Chen H.,Ludwig Maximilians University of Munich | Chen H.,Leibniz Institute DSMZ Deutsche Sammlung von Mikroorganismen und Zellkulturen Braunschweig GmbH | Jogler M.,Ludwig Maximilians University of Munich | Jogler M.,Leibniz Institute DSMZ Deutsche Sammlung von Mikroorganismen und Zellkulturen Braunschweig GmbH | And 7 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2012

'Caulobacter leidyi' DSM 4733T has been shown to be affiliated with the family Sphingomonadaceae instead of the Caulobacteraceae, and due to its poor characterization has been omitted from the current edition of Bergey's Manual of Systematic Bacteriology and removed to limbo. We isolated a novel sphingoglycolipid-containing dimorphic prosthecate bacterium, designated strain 247, from a pre-alpine freshwater lake. Strain 247 and 'Caulobacter leidyi' DSM 4733T were characterized in detail. The rod-shaped cells were Gram-stain-negative, aerobic, catalase- and oxidase-positive, and formed a stalk or polar flagellum. Both strains grew optimally at 28-30 °C, and pH 6.0-8.0. The major fatty acids were C18: 1ω7c, C16: 0 and 11-methyl C18: 1ω7c. C14: 0 2-OH represents the major 2-hydroxy fatty acid. Q-10 was the major respiratory quinone and the major polar lipids were diphosphatidylglycerol, phosphatidyldimethylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylcholine, three glycolipids, two phosphoaminolipids and two unidentified sphingoglycolipids. The major polyamine was sym-homospermidine. The G+C content of genomic DNA of strains 247 and DSM 4733T was 67.6 mol% and 67.0 mol%, respectively. According to 16S rRNA gene sequence analysis and DNA-DNA hybridization, strains DSM 4733T and 247 were phylogenetically closely related (99.6 % 16S rRNA gene sequence similarity, 82.9 % DNA-DNA hybridization value) and affiliated to the genus Sphingomonas. The closest recognized species was Sphingomonas aquatilis DSM 15581T (98.1 % sequence similarity). In addition, the presence of cystine arylamidase, absence of β-galactosidase, and the inability to utilize l-arabinose, galactose and sucrose distinguished strains DSM 4733T and 247 from most other members of the family Sphingomonadaceae. So far, the dimorphic life cycle that involves a prosthecate and a flagellated stage is unique for strains DSM 4733T and 247 among all members of the family Sphingomonadaceae. Therefore, Caulobacter leidyi is reclassified as Sphingomonas leidyi, with the type strain DSM 4733T (= ATCC 15260T = CIP 106443T = VKM B-1368T) and strain 247 (DSM 25078 = LMG 26658) as an additional strain of this species. © 2012 IUMS.

PubMed | University of California at Los Angeles, Montpellier University and Leibniz Institute DSMZ Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH Braunschweig
Type: | Journal: Frontiers in plant science | Year: 2015

In previous work, we showed that coinoculating Rhizobium leguminosarum bv. viciae 128C53 and Bacillus simplex 30N-5 onto Pisum sativum L. roots resulted in better nodulation and increased plant growth. We now expand this research to include another alpha-rhizobial species as well as a beta-rhizobium, Burkholderia tuberum STM678. We first determined whether the rhizobia were compatible with B. simplex 30N-5 by cross-streaking experiments, and then Medicago truncatula and Melilotus alba were coinoculated with B. simplex 30N-5 and Sinorhizobium (Ensifer) meliloti to determine the effects on plant growth. Similarly, B. simplex 30N-5 and Bu. tuberum STM678 were coinoculated onto Macroptilium atropurpureum. The exact mechanisms whereby coinoculation results in increased plant growth are incompletely understood, but the synthesis of phytohormones and siderophores, the improved solubilization of inorganic nutrients, and the production of antimicrobial compounds are likely possibilities. Because B. simplex 30N-5 is not widely recognized as a Plant Growth Promoting Bacterial (PGPB) species, after sequencing its genome, we searched for genes proposed to promote plant growth, and then compared these sequences with those from several well studied PGPB species. In addition to genes involved in phytohormone synthesis, we detected genes important for the production of volatiles, polyamines, and antimicrobial peptides as well as genes for such plant growth-promoting traits as phosphate solubilization and siderophore production. Experimental evidence is presented to show that some of these traits, such as polyamine synthesis, are functional in B. simplex 30N-5, whereas others, e.g., auxin production, are not.

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