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Different pioneer plant species select specific rhizosphere bacterial communities in a high mountain environment.

Ciccazzo S, Esposito A, Rolli E, Zerbe S, Daffonchio D, Brusetti L - Springerplus (2014)

Bottom Line: The rhizobacterial communities of 29 pioneer plants belonging to 12 species were investigated in an alpine ecosystem to assess if plants from different species could select for specific rhizobacterial communities.Rhizospheres and unvegetated soils were collected from a floristic pioneer stage plot at 2,400 m a.s.l. in the forefield of Weisskugel Glacier (Matsch Valley, South Tyrol, Italy), after 160 years of glacier retreat.ARISA fingerprinting showed that rhizobacterial genetic structure was extremely different from bare soil bacterial communities while rhizobacterial communities clustered strictly together according to the plant species.

View Article: PubMed Central - PubMed

Affiliation: DeFENS, Department of Food, Environmental and Nutritional Sciences, University of Milan, via Celoria 2, 20133 Milan, Italy.

ABSTRACT
The rhizobacterial communities of 29 pioneer plants belonging to 12 species were investigated in an alpine ecosystem to assess if plants from different species could select for specific rhizobacterial communities. Rhizospheres and unvegetated soils were collected from a floristic pioneer stage plot at 2,400 m a.s.l. in the forefield of Weisskugel Glacier (Matsch Valley, South Tyrol, Italy), after 160 years of glacier retreat. To allow for a culture-independent perspective, total environmental DNA was extracted from both rhizosphere and bare soil samples and analyzed by Automated Ribosomal Intergenic Spacer Analysis (ARISA) and Denaturing Gradient Gel Electrophoresis (DGGE). ARISA fingerprinting showed that rhizobacterial genetic structure was extremely different from bare soil bacterial communities while rhizobacterial communities clustered strictly together according to the plant species. Sequencing of DGGE bands showed that rhizobacterial communities were mainly composed of Acidobacteria and Proteobacteria whereas bare soil was colonized by Acidobacteria and Clostridia. UniFrac significance calculated on DGGE results confirmed the rhizosphere effect exerted by the 12 species and showed different bacterial communities (P < 0.05) associated with all the plant species. These results pointed out that specific rhizobacterial communities were selected by pioneer plants of different species in a high mountain ecosystem characterized by oligotrophic and harsh environmental conditions, during an early primary succession.

No MeSH data available.


Related in: MedlinePlus

Taxa identification by 16S rRNA gene DGGE-PCR. Stacked barcharts representing the relative abundance of each bacterial taxon in bare soil and in the rhizosphere of the 12 pioneer plants. Plant names are as listed in Figure 1.
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Fig3: Taxa identification by 16S rRNA gene DGGE-PCR. Stacked barcharts representing the relative abundance of each bacterial taxon in bare soil and in the rhizosphere of the 12 pioneer plants. Plant names are as listed in Figure 1.

Mentions: DGGE was performed to investigate the different microenvironments in terms of their dominant bacterial population. A total of 250 sequences of more than 300 bp were obtained, and RDP facilitated the determination of putative taxonomic affiliation of the recovered sequences. Major bacterial taxa included Acidobacteria Gp3 and Gp1, α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Sphingobacteria, Actinobacteria, and Firmicutes (Figure 3). Members of Acidobacteria were present in all the rhizosphere and bare soil samples except in S. bryoides and S. procumbens rhizospheres. They were the most abundant taxa up to 74% of the 23 obtained sequences in G. supinum. We also found Proteobacteria in almost all the samples, except within Ln. alpina, Lc. alpina and S. acaulis, which was less abundant than Acidobacteria, except for V. bellidioides. However, Proteobacteria represented 74% of the 21 obtained sequences of the rhizosphere bacterial communities in S. procumbens. Sphingobacteria were 75% of the 19 obtained sequences of the bacterial communities associated to S. bryoides but they were recovered in a few of the samples with lower percentages. Members of Firmicutes and Actinobacteria taxa were even less abundant, being present in four and three plant species, respectively. We did not find Proteobacteria, Sphingobacteria and Actinobacteria associated to bare soil samples. Despite bias associated with sampling, DNA extraction, PCR amplification, and DGGE run, the pattern of differences in bacterial communities between bare soils and plant rhizosphere found by ARISA analysis were supported by the DGGE results.Figure 3


Different pioneer plant species select specific rhizosphere bacterial communities in a high mountain environment.

Ciccazzo S, Esposito A, Rolli E, Zerbe S, Daffonchio D, Brusetti L - Springerplus (2014)

Taxa identification by 16S rRNA gene DGGE-PCR. Stacked barcharts representing the relative abundance of each bacterial taxon in bare soil and in the rhizosphere of the 12 pioneer plants. Plant names are as listed in Figure 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4125605&req=5

Fig3: Taxa identification by 16S rRNA gene DGGE-PCR. Stacked barcharts representing the relative abundance of each bacterial taxon in bare soil and in the rhizosphere of the 12 pioneer plants. Plant names are as listed in Figure 1.
Mentions: DGGE was performed to investigate the different microenvironments in terms of their dominant bacterial population. A total of 250 sequences of more than 300 bp were obtained, and RDP facilitated the determination of putative taxonomic affiliation of the recovered sequences. Major bacterial taxa included Acidobacteria Gp3 and Gp1, α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Sphingobacteria, Actinobacteria, and Firmicutes (Figure 3). Members of Acidobacteria were present in all the rhizosphere and bare soil samples except in S. bryoides and S. procumbens rhizospheres. They were the most abundant taxa up to 74% of the 23 obtained sequences in G. supinum. We also found Proteobacteria in almost all the samples, except within Ln. alpina, Lc. alpina and S. acaulis, which was less abundant than Acidobacteria, except for V. bellidioides. However, Proteobacteria represented 74% of the 21 obtained sequences of the rhizosphere bacterial communities in S. procumbens. Sphingobacteria were 75% of the 19 obtained sequences of the bacterial communities associated to S. bryoides but they were recovered in a few of the samples with lower percentages. Members of Firmicutes and Actinobacteria taxa were even less abundant, being present in four and three plant species, respectively. We did not find Proteobacteria, Sphingobacteria and Actinobacteria associated to bare soil samples. Despite bias associated with sampling, DNA extraction, PCR amplification, and DGGE run, the pattern of differences in bacterial communities between bare soils and plant rhizosphere found by ARISA analysis were supported by the DGGE results.Figure 3

Bottom Line: The rhizobacterial communities of 29 pioneer plants belonging to 12 species were investigated in an alpine ecosystem to assess if plants from different species could select for specific rhizobacterial communities.Rhizospheres and unvegetated soils were collected from a floristic pioneer stage plot at 2,400 m a.s.l. in the forefield of Weisskugel Glacier (Matsch Valley, South Tyrol, Italy), after 160 years of glacier retreat.ARISA fingerprinting showed that rhizobacterial genetic structure was extremely different from bare soil bacterial communities while rhizobacterial communities clustered strictly together according to the plant species.

View Article: PubMed Central - PubMed

Affiliation: DeFENS, Department of Food, Environmental and Nutritional Sciences, University of Milan, via Celoria 2, 20133 Milan, Italy.

ABSTRACT
The rhizobacterial communities of 29 pioneer plants belonging to 12 species were investigated in an alpine ecosystem to assess if plants from different species could select for specific rhizobacterial communities. Rhizospheres and unvegetated soils were collected from a floristic pioneer stage plot at 2,400 m a.s.l. in the forefield of Weisskugel Glacier (Matsch Valley, South Tyrol, Italy), after 160 years of glacier retreat. To allow for a culture-independent perspective, total environmental DNA was extracted from both rhizosphere and bare soil samples and analyzed by Automated Ribosomal Intergenic Spacer Analysis (ARISA) and Denaturing Gradient Gel Electrophoresis (DGGE). ARISA fingerprinting showed that rhizobacterial genetic structure was extremely different from bare soil bacterial communities while rhizobacterial communities clustered strictly together according to the plant species. Sequencing of DGGE bands showed that rhizobacterial communities were mainly composed of Acidobacteria and Proteobacteria whereas bare soil was colonized by Acidobacteria and Clostridia. UniFrac significance calculated on DGGE results confirmed the rhizosphere effect exerted by the 12 species and showed different bacterial communities (P < 0.05) associated with all the plant species. These results pointed out that specific rhizobacterial communities were selected by pioneer plants of different species in a high mountain ecosystem characterized by oligotrophic and harsh environmental conditions, during an early primary succession.

No MeSH data available.


Related in: MedlinePlus