Limits...
The diversity and abundance of As(III) oxidizers on root iron plaque is critical for arsenic bioavailability to rice.

Hu M, Li F, Liu C, Wu W - Sci Rep (2015)

Bottom Line: Iron plaque is a strong adsorbent on rice roots, acting as a barrier to prevent metal uptake by rice.The microbial composition and diversity of the root iron plaque were significantly different from those of the bulk and rhizosphere soils.Using the aoxB gene as an identifying marker, we determined that the arsenite-oxidizing microbiota on the iron plaque was dominated by Acidovorax and Hydrogenophaga-affiliated bacteria.

View Article: PubMed Central - PubMed

Affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, PR China.

ABSTRACT
Iron plaque is a strong adsorbent on rice roots, acting as a barrier to prevent metal uptake by rice. However, the role of root iron plaque microbes in governing metal redox cycling and metal bioavailability is unknown. In this study, the microbial community structure on the iron plaque of rice roots from an arsenic-contaminated paddy soil was explored using high-throughput next-generation sequencing. The microbial composition and diversity of the root iron plaque were significantly different from those of the bulk and rhizosphere soils. Using the aoxB gene as an identifying marker, we determined that the arsenite-oxidizing microbiota on the iron plaque was dominated by Acidovorax and Hydrogenophaga-affiliated bacteria. More importantly, the abundance of arsenite-oxidizing bacteria (AsOB) on the root iron plaque was significantly negatively correlated with the arsenic concentration in the rice root, straw and grain, indicating that the microbes on the iron plaque, particularly the AsOB, were actively catalyzing arsenic transformation and greatly influencing metal uptake by rice. This exploratory research represents a preliminary examination of the microbial community structure of the root iron plaque formed under arsenic pollution and emphasizes the importance of the root iron plaque environment in arsenic biogeochemical cycling compared with the soil-rhizosphere biotope.

No MeSH data available.


Related in: MedlinePlus

Principal component analysis (PCoA) derived from pairwise unweighted UniFrac distances of 16S rRNA gene between microbial communities of rhizosphere soil (black triangle), bulk soil (red circles) and iron plaque (green squares).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4555042&req=5

f1: Principal component analysis (PCoA) derived from pairwise unweighted UniFrac distances of 16S rRNA gene between microbial communities of rhizosphere soil (black triangle), bulk soil (red circles) and iron plaque (green squares).

Mentions: To assess the differences in the structures of the microbial communities between samples, phylogenetic tree-based beta diversity metrics (UniFrac) were calculated. A relatively small UniFrac distance implies that the two communities are similar20. Visualization of the unweighted UniFrac distances by PCoA demonstrated that the root iron plaque samples clustered together, whereas the samples from the bulk soil and rhizosphere soil comprised another group (Fig. 1). The unweighted UniFrac distance calculations indicated that the divergence in the microbial community structure of the rhizosphere soil samples was the smallest (with an unweighted UniFrac distance of 0.31 ± 0.06, mean ± SD), whereas these values were 0.45 ± 0.11 for the bulk soil and 0.39 ± 0.11 for the root plaque.


The diversity and abundance of As(III) oxidizers on root iron plaque is critical for arsenic bioavailability to rice.

Hu M, Li F, Liu C, Wu W - Sci Rep (2015)

Principal component analysis (PCoA) derived from pairwise unweighted UniFrac distances of 16S rRNA gene between microbial communities of rhizosphere soil (black triangle), bulk soil (red circles) and iron plaque (green squares).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555042&req=5

f1: Principal component analysis (PCoA) derived from pairwise unweighted UniFrac distances of 16S rRNA gene between microbial communities of rhizosphere soil (black triangle), bulk soil (red circles) and iron plaque (green squares).
Mentions: To assess the differences in the structures of the microbial communities between samples, phylogenetic tree-based beta diversity metrics (UniFrac) were calculated. A relatively small UniFrac distance implies that the two communities are similar20. Visualization of the unweighted UniFrac distances by PCoA demonstrated that the root iron plaque samples clustered together, whereas the samples from the bulk soil and rhizosphere soil comprised another group (Fig. 1). The unweighted UniFrac distance calculations indicated that the divergence in the microbial community structure of the rhizosphere soil samples was the smallest (with an unweighted UniFrac distance of 0.31 ± 0.06, mean ± SD), whereas these values were 0.45 ± 0.11 for the bulk soil and 0.39 ± 0.11 for the root plaque.

Bottom Line: Iron plaque is a strong adsorbent on rice roots, acting as a barrier to prevent metal uptake by rice.The microbial composition and diversity of the root iron plaque were significantly different from those of the bulk and rhizosphere soils.Using the aoxB gene as an identifying marker, we determined that the arsenite-oxidizing microbiota on the iron plaque was dominated by Acidovorax and Hydrogenophaga-affiliated bacteria.

View Article: PubMed Central - PubMed

Affiliation: Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, PR China.

ABSTRACT
Iron plaque is a strong adsorbent on rice roots, acting as a barrier to prevent metal uptake by rice. However, the role of root iron plaque microbes in governing metal redox cycling and metal bioavailability is unknown. In this study, the microbial community structure on the iron plaque of rice roots from an arsenic-contaminated paddy soil was explored using high-throughput next-generation sequencing. The microbial composition and diversity of the root iron plaque were significantly different from those of the bulk and rhizosphere soils. Using the aoxB gene as an identifying marker, we determined that the arsenite-oxidizing microbiota on the iron plaque was dominated by Acidovorax and Hydrogenophaga-affiliated bacteria. More importantly, the abundance of arsenite-oxidizing bacteria (AsOB) on the root iron plaque was significantly negatively correlated with the arsenic concentration in the rice root, straw and grain, indicating that the microbes on the iron plaque, particularly the AsOB, were actively catalyzing arsenic transformation and greatly influencing metal uptake by rice. This exploratory research represents a preliminary examination of the microbial community structure of the root iron plaque formed under arsenic pollution and emphasizes the importance of the root iron plaque environment in arsenic biogeochemical cycling compared with the soil-rhizosphere biotope.

No MeSH data available.


Related in: MedlinePlus