Correction: The Rhizosphere Selects for Particular Groups of Acidobacteria and Verrucomicrobia
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SUBMITTER: The Staff
PROVIDER: S-EPMC3972092 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:There is a lack in our current understanding on the putative interactions of species of the phyla of Acidobacteria and Verrucomicrobia with plants. Moreover, progress in this area is seriously hampered by the recalcitrance of members of these phyla to grow as pure cultures. The purpose of this study was to investigate whether particular members of Acidobacteria and Verrucomicrobia are avid colonizers of the rhizosphere. Based on previous work, rhizosphere competence was demonstrated for the Verrucomicrobia subdivision 1 groups of Luteolibacter and Candidatus genus Rhizospheria and it was hypothesized that the rhizosphere is a common habitat for Acidobacteria subdivision 8 (class Holophagae). We assessed the population densities of Bacteria, Verrucomicrobia subdivision 1 groups Luteolibacter and Candidatus genus Rhizospheria and Acidobacteria subdivisions 1, 3, 4, 6 and Holophagae in bulk soil and in the rhizospheres of grass, potato and leek in the same field at different points in time using real-time quantitative PCR. Primers of all seven verrucomicrobial, acidobacterial and holophagal PCR systems were based on 16S rRNA gene sequences of cultivable representatives of the different groups. Luteolibacter, Candidatus genus Rhizospheria, subdivision 6 acidobacteria and Holophaga showed preferences for one or more rhizospheres. In particular, the Holophaga 16S rRNA gene number were more abundant in the leek rhizosphere than in bulk soil and the rhizospheres of grass and potato. Attraction to, and colonization of, leek roots by Holophagae strain CHC25 was further shown in an experimental microcosm set-up. In the light of this remarkable capacity, we propose to coin strain CHC25 Candidatus Porrumbacterium oxyphilus (class Holophagae, Phylum Acidobacteria), the first cultured representative with rhizosphere competence.
| S-EPMC3862674 | biostudies-literature
Project description:The culturability of bacteria in the bulk soil of an Australian pasture was investigated by using nutrient broth at 1/100 of its normal concentration (dilute nutrient broth [DNB]) as the growth medium. Three-tube most-probable-number serial dilution culture resulted in a mean viable count that was only 1.4% of the mean microscopically determined total cell count. Plate counts with DNB solidified with agar and with gellan gum resulted in viable counts that were 5.2 and 7.5% of the mean microscopically determined total cell count, respectively. Prior homogenization of the soil sample with an ultrasonic probe increased the viable count obtained by using DNB solidified with gellan gum to 14.1% of the mean microscopically determined cell count. A microscopic examination of the cell aggregates that remained after sonication revealed that the potential CFU count was only 70.4% of the total cell count, due to cells occurring as pairs or in clumps of three or more cells. Staining with SYTO 9 plus propidium iodide indicated that 91.3% of the cells in sonicated soil samples were potentially viable. Together, these findings suggest that the maximum achievable CFU count may be as low as 64.3% of the total cell count. Thirty isolates obtained from plate counting experiments performed with DNB as the growth medium were identified by comparative analysis of partial 16S rRNA gene sequences. A large proportion of these isolates represent the first known isolates of globally distributed groups of soil bacteria belonging to novel lineages within the divisions Actinobacteria, Acidobacteria, Proteobacteria, and Verrucomicrobia.
| S-EPMC127570 | biostudies-literature
Project description:A number of novel bacteria including members of rarely cultivated phyla, Acidobacteria and Verrucomicrobia, were successfully isolated from the roots of two emergent plants, Iris pseudacorus and Scirpus juncoides, by a simple culturing method. A total of 47.1% (66 strains) for I. pseudacorus and 42.1% (59 strains) for S. juncoides of all isolates (140 strains from each sample) were phylogenetically novel. Furthermore, Acidobacteria and Verrucomicrobia occupied 10.7% (15 strains) and 2.9% (4 strains) of I. pseudacorus isolates, and 2.1% (3 strains) and 3.6% (5 strains) of S. juncoides isolates, respectively, indicating that plant roots are attractive sources for isolating rarely cultivated microbes.
| S-EPMC5606700 | biostudies-literature
Project description:Halophytes classified under the common name of salicornia colonize salty and coastal environments across tidal inundation gradients. To unravel the role of tide-related regimes on the structure and functionality of root associated bacteria, the rhizospheric soil of Salicornia strobilacea (synonym of Halocnemum strobilaceum) plants was studied in a tidal zone of the coastline of Southern Tunisia. Although total counts of cultivable bacteria did not change in the rhizosphere of plants grown along a tidal gradient, significant differences were observed in the diversity of both the cultivable and uncultivable bacterial communities. This observation indicates that the tidal regime is contributing to the bacterial species selection in the rhizosphere. Despite the observed diversity in the bacterial community structure, the plant growth promoting (PGP) potential of cultivable rhizospheric bacteria, assessed through in vitro and in vivo tests, was equally distributed along the tidal gradient. Root colonization tests with selected strains proved that halophyte rhizospheric bacteria (i) stably colonize S. strobilacea rhizoplane and the plant shoot suggesting that they move from the root to the shoot and (ii) are capable of improving plant growth. The versatility in the root colonization, the overall PGP traits and the in vivo plant growth promotion under saline condition suggest that such beneficial activities likely take place naturally under a range of tidal regimes.
| S-EPMC4992691 | biostudies-literature
Project description: Not available
| S-EPMC8285782 | biostudies-literature
Project description:[This corrects the article DOI: 10.1371/journal.pone.0158144.].
| S-EPMC5068734 | biostudies-literature
Project description:Verrucomicrobia is a bacterial phylum that is commonly detected in soil, but little is known about the distribution and diversity of this phylum in the marine environment. To address this, we analyzed the marine microbial community composition in 506 samples from the International Census of Marine Microbes as well as 11 coastal samples taken from the California Current. These samples from both the water column and sediments covered a wide range of environmental conditions. Verrucomicrobia were present in 98% of the analyzed samples, and thus appeared nearly ubiquitous in the ocean. Based on the occurrence of amplified 16S ribosomal RNA sequences, Verrucomicrobia constituted on average 2% of the water column and 1.4% of the sediment bacterial communities. The diversity of Verrucomicrobia displayed a biogeography at multiple taxonomic levels and thus, specific lineages appeared to have clear habitat preference. We found that subdivision 1 and 4 generally dominated marine bacterial communities, whereas subdivision 2 was more frequent in low salinity waters. Within the subdivisions, Verrucomicrobia community composition were significantly different in the water column compared with sediment as well as within the water column along gradients of salinity, temperature, nitrate, depth and overall water column depth. Although we still know little about the ecophysiology of Verrucomicrobia lineages, the ubiquity of this phylum suggests that it may be important for the biogeochemical cycle of carbon in the ocean.
| S-EPMC3400412 | biostudies-other
Project description:Only one isolate each of the class "Spartobacteria" (subdivision 2 of the phylum Verrucomicrobia) and of subdivision 3 of Verrucomicrobia have previously been reported to grow in laboratory culture. Using media that had been used successfully in other studies to isolate members of diverse groups of soil bacteria, we generated a collection of over 1,200 isolates from soil from a pasture. An oligonucleotide probe that targets the 16S rRNA genes of verrucomicrobia was used to screen this collection, and 14 new verrucomicrobia were identified. Nine of these belonged to the class "Spartobacteria" and were related to "Chthoniobacter flavus." Five further isolates were members of subdivision 3 and were related to the only known isolate of this subdivision. The differences in the 16S rRNA gene sequences of the new isolates and previously described isolates, of up to 10%, indicated that the new isolates represent new species and genera. All but two of the verrucomicrobial isolates were from colonies that first became visible one or more months after inoculation of plates with soil, but subcultures grew more rapidly. Analysis of PCR-amplified 16S rRNA genes in the pasture soil showed that members of the class "Spartobacteria" were more numerous than members of subdivision 3. Isolates of subdivision 3 were only found on plates receiving an inoculum that yielded a mean of 29 colonies per plate, while members of the class "Spartobacteria" were only found on plates receiving a more dilute inoculum that resulted in a mean of five colonies per plate. This suggested that colony development by members of the class "Spartobacteria" was inhibited by other culturable bacteria.
| S-EPMC1317444 | biostudies-literature
Project description:Sulfur-cycling microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However, their identities and physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite (dsrAB, dsrC, dsrD, dsrN, dsrT, dsrMKJOP) or sulfate respiration (sat, aprBA, qmoABC plus dsr genes). Surprisingly, the genomes also encoded DsrL, which so far was only found in sulfur-oxidizing microorganisms. Metatranscriptome analysis demonstrated expression of acidobacterial sulfur-metabolism genes in native peat soil and their upregulation in diverse anoxic microcosms. This indicated an active sulfate respiration pathway, which, however, might also operate in reverse for dissimilatory sulfur oxidation or disproportionation as proposed for the sulfur-oxidizing Desulfurivibrio alkaliphilus. Acidobacteria that only harbored genes for sulfite reduction additionally encoded enzymes that liberate sulfite from organosulfonates, which suggested organic sulfur compounds as complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis and sugar utilization, aerobic respiration, several fermentative capabilities, and hydrogen oxidation. Our findings extend both, the known physiological and genetic properties of Acidobacteria and the known taxonomic diversity of microorganisms with a DsrAB-based sulfur metabolism, and highlight new fundamental niches for facultative anaerobic Acidobacteria in wetlands based on exploitation of inorganic and organic sulfur molecules for energy conservation.
| S-EPMC6018796 | biostudies-literature
