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Cultivation-Based and Molecular Assessment of Bacterial Diversity in the Rhizosheath of Wheat under Different Crop Rotations.

Tahir M, Mirza MS, Hameed S, Dimitrov MR, Smidt H - PLoS ONE (2015)

Bottom Line: Diversity of rhizosheath-associated bacteria was evaluated by cultivation, as well as by 454-pyrosequencing of PCR-tagged 16S rRNA gene amplicons.From a total of 46,971 sequences, 10.9% showed ≥97% similarity with 16S rRNA genes of 32 genera previously shown to include isolates with plant growth promoting activity (nitrogen fixation, phosphate-solubilization, IAA production).Among these, the most predominant genera were Arthrobacter, Azoarcus, Azospirillum, Bacillus, Cyanobacterium, Paenibacillus, Pseudomonas and Rhizobium.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road Faisalabad, Punjab, Pakistan.

ABSTRACT
A field study was conducted to compare the formationand bacterial communities of rhizosheaths of wheat grown under wheat-cotton and wheat-rice rotation and to study the effects of bacterial inoculation on plant growth. Inoculation of Azospirillum sp. WS-1 and Bacillus sp. T-34 to wheat plants increased root length, root and shoot dry weight and dry weight of rhizosheathsoil when compared to non-inoculated control plants, and under both crop rotations. Comparing both crop rotations, root length, root and shoot dry weight and dry weight of soil attached with roots were higher under wheat-cotton rotation. Organic acids (citric acid, malic acid, acetic acid and oxalic acid) were detected in rhizosheaths from both rotations, with malic acid being most abundant with 24.8±2 and 21.3±1.5 μg g(-1) dry soil in wheat-cotton and wheat-rice rotation, respectively. Two sugars (sucrose, glucose) were detected in wheat rhizosheath under both rotations, with highest concentrations of sucrose (4.08±0.5 μg g(-1) and 7.36±1.0 μg g(-1)) and glucose (3.12±0.5 μg g(-1) and 3.01± μg g(-1)) being detected in rhizosheaths of non-inoculated control plants under both rotations. Diversity of rhizosheath-associated bacteria was evaluated by cultivation, as well as by 454-pyrosequencing of PCR-tagged 16S rRNA gene amplicons. A total of 14 and 12 bacterial isolates predominantly belonging to the genera Arthrobacter, Azospirillum, Bacillus, Enterobacter and Pseudomonaswere obtained from the rhizosheath of wheat grown under wheat-cotton and wheat-rice rotation, respectively. Analysis of pyrosequencing data revealed Proteobacteria, Bacteriodetes and Verrucomicrobia as the most abundant phyla in wheat-rice rotation, whereas Actinobacteria, Firmicutes, Chloroflexi, Acidobacteria, Planctomycetes and Cyanobacteria were predominant in wheat-cotton rotation. From a total of 46,971 sequences, 10.9% showed ≥97% similarity with 16S rRNA genes of 32 genera previously shown to include isolates with plant growth promoting activity (nitrogen fixation, phosphate-solubilization, IAA production). Among these, the most predominant genera were Arthrobacter, Azoarcus, Azospirillum, Bacillus, Cyanobacterium, Paenibacillus, Pseudomonas and Rhizobium.

No MeSH data available.


PCoA plot of weighted UniFrac distances of rhizosheath soils samples from wheat under wheat-cotton and wheat-rice rotation.Wheat-cotton rotation: rhizosheath soil samples inoculated with Bacillus sp. T-34 (A1 and A3); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (B1 and B3) and rhizosheath soil samples of non-inoculated plants (E1 and E3). Wheat-rice rotation:: rhizosheath soil samples inoculated with Bacillus sp. T-34 (1.1 and 1.2); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (2.1 and 2.2) and rhizosheath soil samples of non-inoculated plants (5.1 and 5.2).
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pone.0130030.g006: PCoA plot of weighted UniFrac distances of rhizosheath soils samples from wheat under wheat-cotton and wheat-rice rotation.Wheat-cotton rotation: rhizosheath soil samples inoculated with Bacillus sp. T-34 (A1 and A3); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (B1 and B3) and rhizosheath soil samples of non-inoculated plants (E1 and E3). Wheat-rice rotation:: rhizosheath soil samples inoculated with Bacillus sp. T-34 (1.1 and 1.2); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (2.1 and 2.2) and rhizosheath soil samples of non-inoculated plants (5.1 and 5.2).

Mentions: Principal Coordinate Analysis (PCoA) of pyrosequencing data was performed to assess potential differences in the composition of the different bacterial communities (Fig 6). Overall, the first two principal coordinates explained 60.49% and 7.79% of the variation in the compositional data, and revealed clear differences between bacterial communities in both crop rotations as well as inoculated and non-inoculated rhizosheath. Rhizosheath soil B1 (Azospirillum sp. WS-1 inoculation under wheat-cotton rotation), rhizosheath soil A1 (inoculated with Bacillus sp. T-34 under wheat-cotton rotation) and rhizosheath soil E1 (non-inoculated under wheat-cotton rotation) were found separated from the rest of the samples, including corresponding duplicates, along the first principal coordinate axis (Fig 6). For other samples, duplicates were found separated mostly along the second principal coordinate, with samples 5.1 and 5.2 (non-inoculated, wheat-rice rotation) being most closely related.


Cultivation-Based and Molecular Assessment of Bacterial Diversity in the Rhizosheath of Wheat under Different Crop Rotations.

Tahir M, Mirza MS, Hameed S, Dimitrov MR, Smidt H - PLoS ONE (2015)

PCoA plot of weighted UniFrac distances of rhizosheath soils samples from wheat under wheat-cotton and wheat-rice rotation.Wheat-cotton rotation: rhizosheath soil samples inoculated with Bacillus sp. T-34 (A1 and A3); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (B1 and B3) and rhizosheath soil samples of non-inoculated plants (E1 and E3). Wheat-rice rotation:: rhizosheath soil samples inoculated with Bacillus sp. T-34 (1.1 and 1.2); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (2.1 and 2.2) and rhizosheath soil samples of non-inoculated plants (5.1 and 5.2).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4487687&req=5

pone.0130030.g006: PCoA plot of weighted UniFrac distances of rhizosheath soils samples from wheat under wheat-cotton and wheat-rice rotation.Wheat-cotton rotation: rhizosheath soil samples inoculated with Bacillus sp. T-34 (A1 and A3); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (B1 and B3) and rhizosheath soil samples of non-inoculated plants (E1 and E3). Wheat-rice rotation:: rhizosheath soil samples inoculated with Bacillus sp. T-34 (1.1 and 1.2); Rhizosheath soil samples inoculated with Azospirillum sp. WS-1 (2.1 and 2.2) and rhizosheath soil samples of non-inoculated plants (5.1 and 5.2).
Mentions: Principal Coordinate Analysis (PCoA) of pyrosequencing data was performed to assess potential differences in the composition of the different bacterial communities (Fig 6). Overall, the first two principal coordinates explained 60.49% and 7.79% of the variation in the compositional data, and revealed clear differences between bacterial communities in both crop rotations as well as inoculated and non-inoculated rhizosheath. Rhizosheath soil B1 (Azospirillum sp. WS-1 inoculation under wheat-cotton rotation), rhizosheath soil A1 (inoculated with Bacillus sp. T-34 under wheat-cotton rotation) and rhizosheath soil E1 (non-inoculated under wheat-cotton rotation) were found separated from the rest of the samples, including corresponding duplicates, along the first principal coordinate axis (Fig 6). For other samples, duplicates were found separated mostly along the second principal coordinate, with samples 5.1 and 5.2 (non-inoculated, wheat-rice rotation) being most closely related.

Bottom Line: Diversity of rhizosheath-associated bacteria was evaluated by cultivation, as well as by 454-pyrosequencing of PCR-tagged 16S rRNA gene amplicons.From a total of 46,971 sequences, 10.9% showed ≥97% similarity with 16S rRNA genes of 32 genera previously shown to include isolates with plant growth promoting activity (nitrogen fixation, phosphate-solubilization, IAA production).Among these, the most predominant genera were Arthrobacter, Azoarcus, Azospirillum, Bacillus, Cyanobacterium, Paenibacillus, Pseudomonas and Rhizobium.

View Article: PubMed Central - PubMed

Affiliation: National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road Faisalabad, Punjab, Pakistan.

ABSTRACT
A field study was conducted to compare the formationand bacterial communities of rhizosheaths of wheat grown under wheat-cotton and wheat-rice rotation and to study the effects of bacterial inoculation on plant growth. Inoculation of Azospirillum sp. WS-1 and Bacillus sp. T-34 to wheat plants increased root length, root and shoot dry weight and dry weight of rhizosheathsoil when compared to non-inoculated control plants, and under both crop rotations. Comparing both crop rotations, root length, root and shoot dry weight and dry weight of soil attached with roots were higher under wheat-cotton rotation. Organic acids (citric acid, malic acid, acetic acid and oxalic acid) were detected in rhizosheaths from both rotations, with malic acid being most abundant with 24.8±2 and 21.3±1.5 μg g(-1) dry soil in wheat-cotton and wheat-rice rotation, respectively. Two sugars (sucrose, glucose) were detected in wheat rhizosheath under both rotations, with highest concentrations of sucrose (4.08±0.5 μg g(-1) and 7.36±1.0 μg g(-1)) and glucose (3.12±0.5 μg g(-1) and 3.01± μg g(-1)) being detected in rhizosheaths of non-inoculated control plants under both rotations. Diversity of rhizosheath-associated bacteria was evaluated by cultivation, as well as by 454-pyrosequencing of PCR-tagged 16S rRNA gene amplicons. A total of 14 and 12 bacterial isolates predominantly belonging to the genera Arthrobacter, Azospirillum, Bacillus, Enterobacter and Pseudomonaswere obtained from the rhizosheath of wheat grown under wheat-cotton and wheat-rice rotation, respectively. Analysis of pyrosequencing data revealed Proteobacteria, Bacteriodetes and Verrucomicrobia as the most abundant phyla in wheat-rice rotation, whereas Actinobacteria, Firmicutes, Chloroflexi, Acidobacteria, Planctomycetes and Cyanobacteria were predominant in wheat-cotton rotation. From a total of 46,971 sequences, 10.9% showed ≥97% similarity with 16S rRNA genes of 32 genera previously shown to include isolates with plant growth promoting activity (nitrogen fixation, phosphate-solubilization, IAA production). Among these, the most predominant genera were Arthrobacter, Azoarcus, Azospirillum, Bacillus, Cyanobacterium, Paenibacillus, Pseudomonas and Rhizobium.

No MeSH data available.