scholarly journals Bacterial Communities in the Rhizosphere and Phyllosphere of Halophytes and Drought-Tolerant Plants in Mediterranean Ecosystems

2020 ◽  
Vol 8 (11) ◽  
pp. 1708
Author(s):  
Savvas Genitsaris ◽  
Natassa Stefanidou ◽  
Kleopatra Leontidou ◽  
Theodora Matsi ◽  
Katerina Karamanoli ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Soil Properties ◽  
Bacterial Communities ◽  
Mediterranean Ecosystems ◽  
Community Diversity ◽  
Sampling Location ◽  
Rrna Gene ◽  
Sodic Soils ◽  
Drought Tolerant ◽  
Tolerant Plants

The aim of the study was to investigate the bacterial community diversity and structure by means of 16S rRNA gene high-throughput amplicon sequencing, in the rhizosphere and phyllosphere of halophytes and drought-tolerant plants in Mediterranean ecosystems with different soil properties. The locations of the sampled plants included alkaline, saline-sodic soils, acidic soils, and the volcanic soils of Santorini Island, differing in soil fertility. Our results showed high bacterial richness overall with Proteobacteria and Actinobacteria dominating in terms of OTUs number and indicated that variable bacterial communities differed depending on the plant’s compartment (rhizosphere and phyllosphere), the soil properties and location of sampling. Furthermore, a shared pool of generalist bacterial taxa was detected independently of sampling location, plant species, or plant compartment. We conclude that the rhizosphere and phyllosphere of native plants in stressed Mediterranean ecosystems consist of common bacterial assemblages contributing to the survival of the plant, while at the same time the discrete soil properties and environmental pressures of each habitat drive the development of a complementary bacterial community with a distinct structure for each plant and location. We suggest that this trade-off between generalist and specialist bacterial community is tailored to benefit the symbiosis with the plant.

scholarly journals Effect of straw biochar amendment on tobacco growth, soil properties, and rhizosphere bacterial communities

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jiayu Zheng ◽  
Jixu Zhang ◽  
Lin Gao ◽  
Rui Wang ◽  
Jiaming Gao ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Soil Properties ◽  
Bacterial Communities ◽  
Agronomic Traits ◽  
Diversity Indices ◽  
Community Diversity ◽  
High Dose ◽  
Rhizosphere Soils ◽  
Tobacco Growth ◽  
Biochar Amendment

AbstractBiochar is an effective soil conditioner. However, we have limited understanding of biochar effects on the tobacco growth and bacterial communities in rhizosphere. The aim of this study was to investigate the effects of different straw biochar amendment (0, 2, 10, and 50 g/kg dry soil) on tobacco growth, soil properties, and bacterial communities in rhizosphere by pot trials. Most of tobacco agronomic traits increased when the application rate varied from 0 to 10 g/kg, but were inhibited by 50 g/kg of biochar application. Soil pH, SOC, available nutrients and soil urease, invertase, and acid phosphatase activities were all increased with the biochar application, whereas catalase activity decreased or remained unchanged. The OTUs and bacterial community diversity indices differed with the biochar application doses in rhizosphere and non-rhizosphere soils. And significant differences in bacterial communities were found between the rhizosphere and non-rhizosphere soils despite the biochar addition. Firmicutes, Proteobacteria, Acidobacteria, Bacteroidetes, and Actinobacteria were the dominant phyla in all soil samples, but they had different abundances in different treatment influenced by the rhizosphere and biochar effect. The high dose of biochar (50 g/kg) decreased the similarity of soil bacterial community structure in rhizosphere compared with those in non-rhizosphere soil. These results provide a better understanding of the microecological benefits of straw biochar in tobacco ecosystem.

scholarly journals Uterine and vaginal bacterial community diversity prior to artificial insemination between pregnant and nonpregnant postpartum cows1

2019 ◽  
Vol 97 (10) ◽  
pp. 4298-4304 ◽  
Author(s):  
Taylor B Ault ◽  
Brooke A Clemmons ◽  
Sydney T Reese ◽  
Felipe G Dantas ◽  
Gessica A Franco ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Artificial Insemination ◽  
Bacterial Communities ◽  
Bacterial Species ◽  
Beef Cows ◽  
Community Diversity ◽  
Rrna Gene ◽  
Bacterial Community Diversity ◽  
Hypervariable Regions ◽  
Time Of Breeding

Abstract The present study evaluated the bovine vaginal and uterine bacterial community diversity and its relationship to fertility. Postpartum beef cows (n = 68) were synchronized beginning on day −21 and ending with timed artificial insemination (TAI) on day 0. Pregnancy was diagnosed 30 d after TAI. Uterine and vaginal flushes were collected on day −21, −9, and −2 for bacterial DNA extraction to sequence the V1 to V3 hypervariable regions of the 16S rRNA gene. Results indicated a decrease in the number of bacterial species over time in the uterus of resulting pregnant and nonpregnant beef cows (P < 0.0001). Principal coordinate analyses (PCoA) depicted clustering of samples, indicating closely related bacterial communities, by day in the uterus and vagina (P < 0.0001). At day −2, uterine samples from nonpregnant and pregnant animals clustered separately (P < 0.0001), with nonpregnant animal samples clustering tightly together. Overall, the current study suggests the shift in the reproductive bacterial communities’ diversity and phylogenetic relationship leading up to the time of breeding may contribute to successful pregnancy establishment.

scholarly journals Bacterial community structure upstream and downstream of cascade dams along the Lancang River in southwestern China

2020 ◽  
Vol 27 (34) ◽  
pp. 42933-42947
Author(s):  
Xia Luo ◽  
Xinyi Xiang ◽  
Guoyi Huang ◽  
Xiaorui Song ◽  
Peijia Wang ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Community Diversity ◽  
Spatial Distance ◽  
Rrna Gene ◽  
Lancang River ◽  
Hydroelectric Dam ◽  
Cascade Dams

Abstract Extensive construction of dams by humans has caused alterations in flow regimes and concomitant alterations in river ecosystems. Even so, bacterioplankton diversity in large rivers influenced by cascade dams has been largely ignored. In this study, bacterial community diversity and profiles of seven cascade dams along the720 km of the Lancang River were studied using Illumina sequencing of the V3-V4 hypervariable region of the 16S rRNA gene. Spatiotemporal variations of bacterial communities in sediment and water of the Gongguoqiao hydroelectric dam and factors affecting these variations were also examined. Microbial diversity and richness in surface water increased slightly from upstream toward downstream along the river. A significant positive correlation between spatial distance and dissimilarities in bacterial community structure was confirmed (Mantel test, r = 0.4826, p = 0.001). At the Gongguoqiao hydroelectric dam, temporal differences in water overwhelmed spatial variability in bacterial communities. Temperature, precipitation, and nutrient levels were major drivers of seasonal microbial changes. Most functional groups associated with carbon cycling in sediment samples decreased from winter to summer. Our findings improve our understanding of associations, compositions, and predicted functional profiles of microbial communities in a large riverine ecosystem influenced by multiple cascade dams.

Effects of fertilisation on microbial communities in short-term coal mine reclamation

Soil Research ◽  
2020 ◽  
Vol 58 (8) ◽  
pp. 779
Author(s):  
Jian Zhang ◽  
Yinghe Xie ◽  
Ying Wei ◽  
Huisheng Meng ◽  
Yanzhuan Cao ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Soil Properties ◽  
Coal Mining ◽  
Coal Mine ◽  
Bacterial Communities ◽  
Community Diversity ◽  
Short Term ◽  
Beneficial Effects

The recovery of the belowground microbial community structure and diversity that occurs in long-term coal mining reclamation is critical to reclamation success. However, long-term coal mining reclamation can take ~10–30 years. Therefore, finding an effective method for promoting coal mine soil restoration in the short-term is necessary to minimise reclamation time. This study investigated the response of soil bacterial communities to fertilisation along a chronosequence of short-term reclamation. Fertilised and unfertilised soils with three short-term reclamation stages were examined to characterise soil properties, as well as bacterial structure and diversity. Fertilisation promoted available nitrogen, phosphate, potassium, and soil organic matter, as well as benefits in bacterial community diversity across the three stages, with the most beneficial effects at 7 years. 16S rRNA sequencing data showed that the predominant phyla across all soils were Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, and Gemmatimonadetes. Abundance of each phylum was altered by reclamation time and fertilisation. Clustering and functional analysis indicated that the bacterial community structure in soils with a longer reclamation time was more similar to that in natural soils, suggesting that longer reclamation resulted in increased soil activity and bacterial community diversity, which is likely also true for fertilisation. Our results demonstrate that reclamation duration is the main driving force to recover soil properties and bacterial communities, and fertilisation could enhance the beneficial effects with longer reclamation duration. Therefore, short-term reclamation, combined with fertiliser, is a potential strategy to improve soil conditions in coal mine areas and shorten the recovery time of reclaimed soils.

scholarly journals Rhizosphere bacteria community and functions under typical natural halophyte communities in North China salinized areas

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259515
Author(s):  
Fating Yin ◽  
Fenghua Zhang ◽  
Haoran Wang
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Acid Metabolism ◽  
Rhizosphere Soil ◽  
Soil Bacterial Community ◽  
Rhizosphere Bacteria ◽  
Community Diversity ◽  
Rrna Gene ◽  
Soil Bacterial ◽  
Suaeda Glauca

Soil salinity is a serious environmental issue in arid China. Halophytes show extreme salt tolerance and are grow in saline-alkaline environments. There rhizosphere have complex bacterial communities, which mediate a variety of interactions between plants and soil. High-throughput sequencing was used to investigated rhizosphere bacterial community changes under the typical halophyte species in arid China. Three typical halophytes were Leymus chinensis (LC), Puccinellia tenuiflora (PT), Suaeda glauca (SG). The dominant phyla were Proteobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes, Acidobacteria and Bacteroidetes, Suaeda glauca rhizosphere has stronger enrichment of Nitrospirae and Cyanobacteria. The Ace, Chao and Shannon indices were significantly higher in soils under LC and SG (P<0.05). Functional predictions, based on 16S rRNA gene by PICRUSt, indicated that Energy metabolism, Amino acid metabolism, Carbohydrate metabolism and Fatty acid metabolism are dominant bacterial functions in three halophytes rhizosphere soil. Carbon metabolism, Oxidative phosphorylation, Methane metabolism, Sulfur metabolism and Nitrogen metabolism in SG were significantly higher than that in LC and PT. Regression analysis revealed that rhizosphere soil bacterial community structure is influenced by soil organic matter (SOM) and soil water content (SWC), while soil bacterial community diversity is affected by soil pH. This study contributes to our understanding of the distribution characteristics and metabolic functions under different halophyte rhizosphere bacterial communities, and will provide references for the use of rhizosphere bacteria to regulate the growth of halophytes and ecological restoration of saline soil.

scholarly journals   Long-term agrichemical use leads to alterations in bacterial community diversity

2012 ◽  
Vol 58 (No. 10) ◽  
pp. 452-458 ◽  
Author(s):  
H. Tan ◽  
M. Barret ◽  
O. Rice ◽  
D.N. Dowling ◽  
J. Burke ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Spring Barley ◽  
Community Diversity ◽  
Rrna Gene ◽  
Soil Bacterial Communities ◽  
Culture Independent ◽  
Concomitant Reduction ◽  
Soil Bacterial

&nbsp; Bacterial communities are key drivers of soil fertility and agriculture productivity. Understanding how soil bacterial communities change in response to different conditions is an important aspect in the development of sustainable agriculture. There is a desire to reduce the current reliance on high inputs of chemicals and fertilisers in agriculture, but limited data are available on how this might impact soil bacterial communities. This study investigated the bacterial communities in a spring barley monoculture site subjected to two different input regimes for over 12 years: a conventional chemical/fertiliser regime, and a reduced input regime. A culture independent approach was performed to compare the bacterial communities through 16S rRNA gene PCR-DGGE. PCO analysis revealed that the rhizosphere has a strong structuring effect on the bacterial community. Moreover, high inputs of agrichemicals lead to an increase of phosphorus level in the soil and a concomitant reduction of the bacterial diversity. These results may help to evaluate the environmental risks associated with agrichemical usage. &nbsp;

scholarly journals Skin bacterial communities of neotropical treefrogs vary with local environmental conditions at the time of sampling

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7044 ◽  
Author(s):  
Angie Estrada ◽  
Myra C. Hughey ◽  
Daniel Medina ◽  
Eria A. Rebollar ◽  
Jenifer B. Walke ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Temporal Variation ◽  
Microbial Communities ◽  
Relative Abundance ◽  
Bacterial Communities ◽  
Community Diversity ◽  
Amphibian Conservation ◽  
Rrna Gene ◽  
Skin Microbiome ◽  
Amphibian Skin

The amphibian skin microbiome has been the focus of recent studies aiming to better understand the role of these microbial symbionts in host defense against disease. However, host-associated microbial communities are complex and dynamic, and changes in their composition and structure can influence their function. Understanding temporal variation of bacterial communities on amphibian skin is critical for establishing baselines from which to improve the development of mitigation techniques based on probiotic therapy and provides long-term host protection in a changing environment. Here, we investigated whether microbial communities on amphibian skin change over time at a single site. To examine this, we collected skin swabs from two pond-breeding species of treefrogs, Agalychnis callidryas and Dendropsophus ebraccatus, over 4 years at a single lowland tropical pond in Panamá. Relative abundance of operational taxonomic units (OTUs) based on 16S rRNA gene amplicon sequencing was used to determine bacterial community diversity on the skin of both treefrog species. We found significant variation in bacterial community structure across long and short-term time scales. Skin bacterial communities differed across years on both species and between seasons and sampling days only in D. ebraccatus. Importantly, bacterial community structures across days were as variable as year level comparisons. The differences in bacterial community were driven primarily by differences in relative abundance of key OTUs and explained by rainfall at the time of sampling. These findings suggest that skin-associated microbiomes are highly variable across time, and that for tropical lowland sites, rainfall is a good predictor of variability. However, more research is necessary to elucidate the significance of temporal variation in bacterial skin communities and their maintenance for amphibian conservation efforts.

scholarly journals The capacity of wastewater treatment plants drives bacterial community structure and its assembly

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Young Kyung Kim ◽  
Keunje Yoo ◽  
Min Sung Kim ◽  
Il Han ◽  
Minjoo Lee ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Community Structure ◽  
Bacterial Community ◽  
Activated Sludge ◽  
Community Assembly ◽  
Bacterial Communities ◽  
Wastewater Treatment Plants ◽  
High Capacity ◽  
Operating Conditions ◽  
Rrna Gene

Abstract Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.

scholarly journals Comparison of Respiratory Microbiome Disruption Indices to Predict VAP and VAE risk at LTACH Admission

2020 ◽  
Vol 41 (S1) ◽  
pp. s179-s180
Author(s):  
Erik Clarke ◽  
Kathleen None Chiotos ◽  
James Harrigan ◽  
Ebbing Lautenbach ◽  
Emily Reesey ◽  
...  
Keyword(s):  
Critical Illness ◽  
Bacterial Community ◽  
16S Rrna ◽  
Respiratory Tract ◽  
Predictive Performance ◽  
Community Diversity ◽  
Rrna Gene ◽  
Sequence Variant ◽  
Antibiotic Exposure ◽  
Shannon Diversity

Background: Healthcare exposure results in significant microbiome disruption, particularly in the setting of critical illness, which may contribute to risk for healthcare-associated infections (HAIs). Patients admitted to long-term acute-care hospitals (LTACHs) have extensive prior healthcare exposure and critical illness; significant microbiome disruption has been previously documented among LTACH patients. We compared the predictive value of 3 respiratory tract microbiome disruption indices—bacterial community diversity, dominance, and absolute abundance—as they relate to risk for ventilator-associated pneumonia (VAP) and adverse ventilator-associated events (VAE), which commonly complicate LTACH care. Methods: We enrolled 83 subjects on admission to an academic LTACH for ventilator weaning and performed longitudinal sampling of endotracheal aspirates, followed by 16S rRNA gene sequencing (Illumina HiSeq), bacterial community profiling (QIIME2) for diversity, and 16S rRNA quantitative PCR (qPCR) for total bacterial abundance. Statistical analyses were performed with R and Stan software. Mixed-effects models were fit to relate the admission MDIs to subsequent clinically diagnosed VAP and VAE. Results: Of the 83 patients, 19 had been diagnosed with pneumonia during the 14 days prior to LTACH admission (ie, “recent past VAP”); 23 additional patients were receiving antibiotics consistent with empiric VAP therapy within 48 hours of admission (ie, “empiric VAP therapy”); and 41 patients had no evidence of VAP at admission (ie, “no suspected VAP”). We detected no statistically significant differences in admission Shannon diversity, maximum amplicon sequence variant (ASV)–level proportional abundance, or 16S qPCR across the variables of interest. In isolation, all 3 admission microbiome disruption indices showed poor predictive performance, though Shannon diversity performed better than maximum ASV abundance. Predictive models that combined (1) bacterial diversity or abundance with (2) recent prior VAP diagnosis and (3) concurrent antibiotic exposure best predicted 14-day VAP (type S error < 0.05) and 30-day VAP (type S error < 0.003). In this cohort, VAE risk was paradoxically associated with higher admission Shannon diversity and lower admission maximum ASV abundance. Conclusions: In isolation, respiratory tract microbiome disruption indices obtained at LTACH admission showed poor predictive performance for subsequent VAP and VAE. But diversity and abundance models incorporating recent VAP history and admission antibiotic exposure performed well predicting 14-day and 30-day VAP.Disclosures: NoneFunding: None

scholarly journals Rhizobacterial communities of five co-occurring desert halophytes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5508 ◽  
Author(s):  
Yan Li ◽  
Yan Kong ◽  
Dexiong Teng ◽  
Xueni Zhang ◽  
Xuemin He ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
Plant Species ◽  
Bacterial Communities ◽  
Bacterial Community Composition ◽  
Community Diversity ◽  
Species Identity ◽  
Halostachys Caspica ◽  
Lycium Ruthenicum ◽  
Limonium Gmelinii

BackgroundRecently, researches have begun to investigate the microbial communities associated with halophytes. Both rhizobacterial community composition and the environmental drivers of community assembly have been addressed. However, few studies have explored the structure of rhizobacterial communities associated with halophytic plants that are co-occurring in arid, salinized areas.MethodsFive halophytes were selected for study: these co-occurred in saline soils in the Ebinur Lake Nature Reserve, located at the western margin of the Gurbantunggut Desert of Northwestern China. Halophyte-associated bacterial communities were sampled, and the bacterial 16S rDNA V3–V4 region amplified and sequenced using the Illumina Miseq platform. The bacterial community diversity and structure were compared between the rhizosphere and bulk soils, as well as among the rhizosphere samples. The effects of plant species identity and soil properties on the bacterial communities were also analyzed.ResultsSignificant differences were observed between the rhizosphere and bulk soil bacterial communities. Diversity was higher in the rhizosphere than in the bulk soils. Abundant taxonomic groups (from phylum to genus) in the rhizosphere were much more diverse than in bulk soils. Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Planctomycetes were the most abundant phyla in the rhizosphere, while Proteobacteria and Firmicutes were common in bulk soils. Overall, the bacterial community composition were not significantly differentiated between the bulk soils of the five plants, but community diversity and structure differed significantly in the rhizosphere. The diversity ofHalostachys caspica,Halocnemum strobilaceumandKalidium foliatumassociated bacterial communities was lower than that ofLimonium gmeliniiandLycium ruthenicumcommunities. Furthermore, the composition of the bacterial communities ofHalostachys caspicaandHalocnemum strobilaceumwas very different from those ofLimonium gmeliniiandLycium ruthenicum. The diversity and community structure were influenced by soil EC, pH and nutrient content (TOC, SOM, TON and AP); of these, the effects of EC on bacterial community composition were less important than those of soil nutrients.DiscussionHalophytic plant species played an important role in shaping associated rhizosphere bacterial communities. When salinity levels were constant, soil nutrients emerged as key factors structuring bacterial communities, while EC played only a minor role. Pairwise differences among the rhizobacterial communities associated with different plant species were not significant, despite some evidence of differentiation. Further studies involving more halophyte species, and individuals per species, are necessary to elucidate plant species identity effects on the rhizosphere for co-occurring halophytes.

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