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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.


Relative abundance of bacterial phyla detected in rizosheath based on 454 pyrosequencing of 16S rRNA gene.All phyla contributing to less than 1% of the total bacteria were grouped as ‘Other’. 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.g007: Relative abundance of bacterial phyla detected in rizosheath based on 454 pyrosequencing of 16S rRNA gene.All phyla contributing to less than 1% of the total bacteria were grouped as ‘Other’. 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: Rhizosheath bacterial communities in both crop rotations exhibited similar overall patterns of relative abundance of the major groups at the phylum level (Fig 7). In both rotations, Proteobacteria were the most predominant phylum, being 25.1% and 35.7% of the total detected sequeces in wheat-cotton and wheat-rice rotation, respectively (Fig 7). Comparison of the relative abundance of different bacterial phyla in both rotation systems showed that Proteobacteria, Bacteriodetes and Verrucomicrobia were present at higher relative abundance in wheat-rice rotation, where as Actinobacteria, Firmicutes, Chloroflexi, Acidobacteria, Planctomycetes and Cyanobacteria were more abundant in wheat-cotton rotation (Fig 7).


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)

Relative abundance of bacterial phyla detected in rizosheath based on 454 pyrosequencing of 16S rRNA gene.All phyla contributing to less than 1% of the total bacteria were grouped as ‘Other’. 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

License
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getmorefigures.php?uid=PMC4487687&req=5

pone.0130030.g007: Relative abundance of bacterial phyla detected in rizosheath based on 454 pyrosequencing of 16S rRNA gene.All phyla contributing to less than 1% of the total bacteria were grouped as ‘Other’. 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: Rhizosheath bacterial communities in both crop rotations exhibited similar overall patterns of relative abundance of the major groups at the phylum level (Fig 7). In both rotations, Proteobacteria were the most predominant phylum, being 25.1% and 35.7% of the total detected sequeces in wheat-cotton and wheat-rice rotation, respectively (Fig 7). Comparison of the relative abundance of different bacterial phyla in both rotation systems showed that Proteobacteria, Bacteriodetes and Verrucomicrobia were present at higher relative abundance in wheat-rice rotation, where as Actinobacteria, Firmicutes, Chloroflexi, Acidobacteria, Planctomycetes and Cyanobacteria were more abundant in wheat-cotton rotation (Fig 7).

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.