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Effects of Spartina alterniflora invasion on the communities of methanogens and sulfate-reducing bacteria in estuarine marsh sediments.

Zeleke J, Sheng Q, Wang JG, Huang MY, Xia F, Wu JH, Quan ZX - Front Microbiol (2013)

Bottom Line: Similar trends were observed for SRB, and they were up to two orders of magnitude higher than the methanogens.Diversity indices indicated a lower diversity of methanogens in the S. alterniflora stands than the P. australis stands.The results showed that in the sediments of tidal salt marsh where S. alterniflora displaced P. australis, the abundances of methanogens and SRB increased, but the community composition of methanogens appeared to be influenced more than did the SRB.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University Shanghai, China.

ABSTRACT
The effect of plant invasion on the microorganisms of soil sediments is very important for estuary ecology. The community structures of methanogens and sulfate-reducing bacteria (SRB) as a function of Spartina alterniflora invasion in Phragmites australis-vegetated sediments of the Dongtan wetland in the Yangtze River estuary, China, were investigated using 454 pyrosequencing and quantitative real-time PCR (qPCR) of the methyl coenzyme M reductase A (mcrA) and dissimilatory sulfite-reductase (dsrB) genes. Sediment samples were collected from two replicate locations, and each location included three sampling stands each covered by monocultures of P. australis, S. alterniflora and both plants (transition stands), respectively. qPCR analysis revealed higher copy numbers of mcrA genes in sediments from S. alterniflora stands than P. australis stands (5- and 7.5-fold more in the spring and summer, respectively), which is consistent with the higher methane flux rates measured in the S. alterniflora stands (up to 8.01 ± 5.61 mg m(-2) h(-1)). Similar trends were observed for SRB, and they were up to two orders of magnitude higher than the methanogens. Diversity indices indicated a lower diversity of methanogens in the S. alterniflora stands than the P. australis stands. In contrast, insignificant variations were observed in the diversity of SRB with the invasion. Although Methanomicrobiales and Methanococcales, the hydrogenotrophic methanogens, dominated in the salt marsh, Methanomicrobiales displayed a slight increase with the invasion and growth of S. alterniflora, whereas the later responded differently. Methanosarcina, the metabolically diverse methanogens, did not vary with the invasion of, but Methanosaeta, the exclusive acetate utilizers, appeared to increase with S. alterniflora invasion. In SRB, sequences closely related to the families Desulfobacteraceae and Desulfobulbaceae dominated in the salt marsh, although they displayed minimal changes with the S. alterniflora invasion. Approximately 11.3 ± 5.1% of the dsrB gene sequences formed a novel cluster that was reduced upon the invasion. The results showed that in the sediments of tidal salt marsh where S. alterniflora displaced P. australis, the abundances of methanogens and SRB increased, but the community composition of methanogens appeared to be influenced more than did the SRB.

No MeSH data available.


Related in: MedlinePlus

Proportions of the major mcrA phylotypes detected in sediments from P. australis (P), S. alterniflora (S) and transition (T) stands. The sample names are as described in Figure 1.
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Figure 4: Proportions of the major mcrA phylotypes detected in sediments from P. australis (P), S. alterniflora (S) and transition (T) stands. The sample names are as described in Figure 1.

Mentions: Both invasion- and growth-associated variations in the relative proportions of mcrA and dsrB phylotypes were analyzed. For methanogens, the orders Methanomicrobiales, Methanococcales and Methanosarcinales together represented 85–90% of the total mcrA sequences (Figure 4). However, their proportion responded differently to the invasion of S. alterniflora. For instance, the mean proportions of Methanomicrobiales, the most dominant methanogens detected in the salt marsh (representing approximately 33.1 and 44% of the sequences in the spring and summer, respectively), were greater in the S. alterniflora stands than in the P. australis stands by approximately 58 and 28% in the spring and summer samples, respectively (Figure 4). This might demonstrate the effect of S. alterniflora invasion in promoting the proliferation of Methanomicrobiales. Almost a reverse phenomenon was observed for the order Methanococcales (Figure 4). In the spring, Methanococcales represented approximately 38% of the total mcrA sequences, but its mean proportions indicated approximately 10% reductions from P. australis to S. alterniflora stands. In the summer, not only were the mcrA sequences related to Methanococcales reduced (approximately 20% of the total mcrA gene sequences), but higher reductions (approximately 37%) were observed from P. australis to S. alterniflora stands. Hence, S. alterniflora growth appeared to favor Methanomicrobiales over Methanococcales. However, the two main genera of the order Methanosarcinales (Methanosarcina and Methanosaeta) represented approximately 20 and 24% of the mcrA sequences, respectively, although they did not display similar trends with S. alterniflora invasion. The mean proportions of Methanosaeta increased with S. alterniflora invasion. In contrast, the mean proportions of the genus Methanosarcina did not display significant variations with either the invasion or growth of S. alterniflora (Figure 4). With the exception of ANME-3, most of the rare mcrA phylotypes, such as Methanobacteriales, Methanocellales and ZC-I, detected in this study dominated the P. australis stands. This is consistent with the diversity index results (Table 3) that indicated lower diversity of methanogens in the S. alterniflora stands compared with the transition or P. australis stands.


Effects of Spartina alterniflora invasion on the communities of methanogens and sulfate-reducing bacteria in estuarine marsh sediments.

Zeleke J, Sheng Q, Wang JG, Huang MY, Xia F, Wu JH, Quan ZX - Front Microbiol (2013)

Proportions of the major mcrA phylotypes detected in sediments from P. australis (P), S. alterniflora (S) and transition (T) stands. The sample names are as described in Figure 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750361&req=5

Figure 4: Proportions of the major mcrA phylotypes detected in sediments from P. australis (P), S. alterniflora (S) and transition (T) stands. The sample names are as described in Figure 1.
Mentions: Both invasion- and growth-associated variations in the relative proportions of mcrA and dsrB phylotypes were analyzed. For methanogens, the orders Methanomicrobiales, Methanococcales and Methanosarcinales together represented 85–90% of the total mcrA sequences (Figure 4). However, their proportion responded differently to the invasion of S. alterniflora. For instance, the mean proportions of Methanomicrobiales, the most dominant methanogens detected in the salt marsh (representing approximately 33.1 and 44% of the sequences in the spring and summer, respectively), were greater in the S. alterniflora stands than in the P. australis stands by approximately 58 and 28% in the spring and summer samples, respectively (Figure 4). This might demonstrate the effect of S. alterniflora invasion in promoting the proliferation of Methanomicrobiales. Almost a reverse phenomenon was observed for the order Methanococcales (Figure 4). In the spring, Methanococcales represented approximately 38% of the total mcrA sequences, but its mean proportions indicated approximately 10% reductions from P. australis to S. alterniflora stands. In the summer, not only were the mcrA sequences related to Methanococcales reduced (approximately 20% of the total mcrA gene sequences), but higher reductions (approximately 37%) were observed from P. australis to S. alterniflora stands. Hence, S. alterniflora growth appeared to favor Methanomicrobiales over Methanococcales. However, the two main genera of the order Methanosarcinales (Methanosarcina and Methanosaeta) represented approximately 20 and 24% of the mcrA sequences, respectively, although they did not display similar trends with S. alterniflora invasion. The mean proportions of Methanosaeta increased with S. alterniflora invasion. In contrast, the mean proportions of the genus Methanosarcina did not display significant variations with either the invasion or growth of S. alterniflora (Figure 4). With the exception of ANME-3, most of the rare mcrA phylotypes, such as Methanobacteriales, Methanocellales and ZC-I, detected in this study dominated the P. australis stands. This is consistent with the diversity index results (Table 3) that indicated lower diversity of methanogens in the S. alterniflora stands compared with the transition or P. australis stands.

Bottom Line: Similar trends were observed for SRB, and they were up to two orders of magnitude higher than the methanogens.Diversity indices indicated a lower diversity of methanogens in the S. alterniflora stands than the P. australis stands.The results showed that in the sediments of tidal salt marsh where S. alterniflora displaced P. australis, the abundances of methanogens and SRB increased, but the community composition of methanogens appeared to be influenced more than did the SRB.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University Shanghai, China.

ABSTRACT
The effect of plant invasion on the microorganisms of soil sediments is very important for estuary ecology. The community structures of methanogens and sulfate-reducing bacteria (SRB) as a function of Spartina alterniflora invasion in Phragmites australis-vegetated sediments of the Dongtan wetland in the Yangtze River estuary, China, were investigated using 454 pyrosequencing and quantitative real-time PCR (qPCR) of the methyl coenzyme M reductase A (mcrA) and dissimilatory sulfite-reductase (dsrB) genes. Sediment samples were collected from two replicate locations, and each location included three sampling stands each covered by monocultures of P. australis, S. alterniflora and both plants (transition stands), respectively. qPCR analysis revealed higher copy numbers of mcrA genes in sediments from S. alterniflora stands than P. australis stands (5- and 7.5-fold more in the spring and summer, respectively), which is consistent with the higher methane flux rates measured in the S. alterniflora stands (up to 8.01 ± 5.61 mg m(-2) h(-1)). Similar trends were observed for SRB, and they were up to two orders of magnitude higher than the methanogens. Diversity indices indicated a lower diversity of methanogens in the S. alterniflora stands than the P. australis stands. In contrast, insignificant variations were observed in the diversity of SRB with the invasion. Although Methanomicrobiales and Methanococcales, the hydrogenotrophic methanogens, dominated in the salt marsh, Methanomicrobiales displayed a slight increase with the invasion and growth of S. alterniflora, whereas the later responded differently. Methanosarcina, the metabolically diverse methanogens, did not vary with the invasion of, but Methanosaeta, the exclusive acetate utilizers, appeared to increase with S. alterniflora invasion. In SRB, sequences closely related to the families Desulfobacteraceae and Desulfobulbaceae dominated in the salt marsh, although they displayed minimal changes with the S. alterniflora invasion. Approximately 11.3 ± 5.1% of the dsrB gene sequences formed a novel cluster that was reduced upon the invasion. The results showed that in the sediments of tidal salt marsh where S. alterniflora displaced P. australis, the abundances of methanogens and SRB increased, but the community composition of methanogens appeared to be influenced more than did the SRB.

No MeSH data available.


Related in: MedlinePlus