scholarly journals Unveiling Endophytic Bacterial Community Structures of Different Rice Cultivars Grown in a Cadmium-Contaminated Paddy Field

2021 ◽  
Vol 12 ◽  
Author(s):  
Chaoqun Chu ◽  
Meiyu Fan ◽  
Chongyang Song ◽  
Ni Li ◽  
Chao Zhang ◽  
...  

Endophytic bacteria play potentially important roles in the processes of plant adaptation to the environment. Understanding the composition and dynamics of endophytic bacterial communities under heavy metal (HM) stress can reveal their impacts on host development and stress tolerance. In this study, we investigated root endophytic bacterial communities of different rice cultivars grown in a cadmium (Cd)-contaminated paddy field. These rice cultivars are classified into low (RBQ, 728B, and NX1B) and high (BB and S95B) levels of Cd-accumulating capacity. Our metagenomic analysis targeting 16S rRNA gene sequence data reveals that Proteobacteria, Firmicutes, Actinobacteria, Acidobacteria, Bacteroidetes, and Spirochaetes are predominant root endophytic bacterial phyla of the five rice cultivars that we studied. Principal coordinate analysis shows that the developmental stage of rice governs a larger source of variation in the bacterial communities compared to that of any specific rice cultivar or of the root Cd content. Endophytic bacterial communities during the reproductive stage of rice form a more highly interconnected network and exhibit higher operational taxonomic unit numbers, diversities, and abundance than those during the vegetative stage. Forty-five genera are significantly correlated with Cd content in rice root, notably including positive-correlating Geobacter and Haliangium; and negative-correlating Pseudomonas and Streptacidiphilus. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States analysis shows that functional pathways, such as biosynthesis of siderophore and type II polyketide products, are significantly enhanced during the reproductive stage compared to those during the vegetative stage under Cd stress. The isolated endophytic bacteria from the Cd-contaminated rice roots display high Cd resistance and multiple traits that may promote plant growth, suggesting their potential application in alleviating HM stress on plants. This study describes in detail for the first time the assemblage of the bacterial endophytomes of rice roots under Cd stress and may provide insights into the interactions among endophytes, plants, and HM contamination.

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Michele Pittol ◽  
Erin Scully ◽  
Daniel Miller ◽  
Lisa Durso ◽  
Lidia Mariana Fiuza ◽  
...  

In agricultural systems, interactions between plants and microorganisms are important to maintaining production and profitability. In this study, bacterial communities in floodwaters of rice fields were monitored during the vegetative and reproductive stages of rice plant development using 16S amplicon sequencing. The study was conducted in the south of Brazil, during the crop years 2011/12 and 2012/13. Comparative analyses showed strong differences between the communities of floodwaters associated with the two developmental stages. During the vegetative stage, 1551 operational taxonomic units (OTUs) were detected, while less than half that number (603) were identified in the reproductive stage. The higher bacterial richness observed in floodwater collected during the vegetative stage may have been favored by the higher concentration of nutrients, such as potassium, due to rhizodeposition and fertilizer application. Eighteen bacterial phyla were identified in both samples. Both communities were dominated by Gammaproteobacteria. In the vegetative stage, Alphaproteobacteria and Betaproteobacteria were more abundant and, in contrast, Bacilli and Clostridia were the more dominant classes in the reproductive stage. The major bacterial taxa identified have been previously identified as important colonizers of rice fields. The richness and composition of bacterial communities over cultivation time may contribute to the sustainability of the crop.


2018 ◽  
Vol 84 (22) ◽  
Author(s):  
Jonah E. Einson ◽  
Asha Rani ◽  
Xiaomeng You ◽  
Allison A. Rodriguez ◽  
Clifton L. Randell ◽  
...  

ABSTRACTFermented vegetables are highly popular internationally in part due to their enhanced nutritional properties, cultural history, and desirable sensorial properties. In some instances, fermented foods provide a rich source of the beneficial microbial communities that could promote gastrointestinal health. The indigenous microbiota that colonize fermentation facilities may impact food quality, food safety, and spoilage risks and maintain the nutritive value of the product. Here, microbiomes within sauerkraut production facilities were profiled to characterize variance across surfaces and to determine the sources of these bacteria. Accordingly, we used high-throughput sequencing of the 16S rRNA gene in combination with whole-genome shotgun analyses to explore biogeographical patterns of microbial diversity and assembly within the production facility. Our results indicate that raw cabbage and vegetable handling surfaces exhibit more similar microbiomes relative to the fermentation room, processing area, and dry storage surfaces. We identified biomarker bacterial phyla and families that are likely to originate from the raw cabbage and vegetable handling surfaces. Raw cabbage was identified as the main source of bacteria to seed the facility, with human handling contributing a minor source of inoculation.LeuconostocandLactobacillaceaedominated all surfaces where spontaneous fermentation occurs, as these taxa are associated with the process. Wall, floor, ceiling, and barrel surfaces host unique microbial signatures. This study demonstrates that diverse bacterial communities are widely distributed within the production facility and that these communities assemble nonrandomly, depending on the surface type.IMPORTANCEFermented vegetables play a major role in global food systems and are widely consumed by various global cultures. In this study, we investigated an industrial facility that produces spontaneous fermented sauerkraut without the aid of starter cultures. This provides a unique system to explore and track the origins of an “in-house” microbiome in an industrial environment. Raw vegetables and the surfaces on which they are handled were identified as the likely source of bacterial communities rather than human contamination. As fermented vegetables increase in popularity on a global scale, understanding their production environment may help maintain quality and safety goals.


2020 ◽  
Vol 7 ◽  
Author(s):  
Bishnu Adhikari ◽  
Guillermo Tellez-Isaias ◽  
Tieshan Jiang ◽  
Brian Wooming ◽  
Young Min Kwon

The importance of microbiota in the health and diseases of farm animals has been well-documented for diverse animal species. However, studies on microbiotas in turkey and turkey farms are relatively limited as compared to other farm animal species. In this study, we performed a comprehensive survey of the litter microbiotas in 5 commercial turkey farms in the Northwest Arkansas (H, M, V, K, and R farms) including one farm with positive incidence of cellulitis (R farm). Altogether 246 boot swabs were used for 16S rRNA gene profiling of bacterial communities. At phylum level, 11 major bacterial phyla (≥0.01%) were recovered. At genus level, 13 major bacterial genera were found whose relative abundance were ≥2%. The microbial composition at both phylum and genus levels as well as their diversities varied across different farms, which were further affected by different flocks within the same farms and the ages of turkeys. Generally, the Firmicutes were higher in the flocks of younger birds, while the Actinobacteria and Bacteroidetes were higher in the flocks of the older birds. The Proteobacteria were highly enriched (47.97%) in K farm housing 56-day-old turkeys (K-56), but Bacteroidetes were found the highest in the flock C of M farm housing 63-day-old turkeys (M-C-63; 22.38%), followed by K-84 group (17.26%). Four core bacterial genera (Staphylococcus, Brevibacterium, Brachybacterium, and Lactobacillus) were identified in all samples except for those from R farm. In contrast, 24 core bacterial genera were found based in all cellulitis-associated samples (R farm), including Corynebacterium, an unknown genus of family Bacillaceae, Clostridium sensu stricto 1 (>97% similarity with C. septicum), and Ignatzschineria among others, suggesting their possible roles in etiopathogenesis of cellulitis in turkeys. Overall results of this study may provide valuable foundation for future studies focusing on the role of microbiota in the health and diseases of turkeys.


2015 ◽  
Vol 12 (13) ◽  
pp. 10233-10269 ◽  
Author(s):  
J. Comte ◽  
C. Lovejoy ◽  
S. Crevecoeur ◽  
W. F. Vincent

Abstract. Permafrost thaw ponds and lakes are widespread across the northern landscape and may play a central role in global biogeochemical cycles, yet knowledge about their microbial ecology is limited. We sampled a set of thaw ponds and lakes as well as shallow rock-basin lakes that are located in distinct valleys along a North–South permafrost degradation gradient. We applied high-throughput sequencing of the 16S rRNA gene to determine co-occurrence patterns among bacterial taxa, and then analyzed these results relative to environmental variables to identify factors controlling bacterial community structure. Network analysis was applied to identify possible ecological linkages among the bacterial taxa and with abiotic and biotic variables. The results showed an overall high level of shared taxa among bacterial communities within each valley, however the bacterial co-occurrence patterns were non-random, with evidence of habitat preferences. There were taxonomic differences in bacterial assemblages among the different valleys that were statistically related to dissolved organic carbon concentration, conductivity and phytoplankton biomass. Co-occurrence networks revealed complex interdependencies within the bacterioplankton communities and showed contrasting linkages to environmental conditions among the main bacterial phyla. The thaw pond networks were composed of a limited number of highly connected taxa. This "small world network" property would render the communities more robust to environmental change but vulnerable to the loss of microbial keystone species.


Insects ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 497
Author(s):  
Phakamas Subta ◽  
Phongsathon Yodsuwan ◽  
Rujipas Yongsawas ◽  
Ammarin In-on ◽  
Natapot Warrit ◽  
...  

This study investigated different bacterial communities in three intestinal parts (foregut, midgut and hindgut) of Xylocopatenuiscapa to understand the roles of gut bacteria. Our phylogenetic analysis revealed that X. tenuiscapa is closely related to Xylocopa latipes. The 16S rRNA gene in the genomic DNA samples from the gut was examined by illumina (Solexa) and a total of 998 operational taxonomic unit (OTUs) clusters were found. Taxonomic classification identified 16 bacterial phyla and unclassified bacteria. The dominant bacteria taxa in the three parts of X. tenuiscapa gut were Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria. In the foregut, Lactobacillales and Enterobacteriaceae were predominantly found. The population in the midgut was similar to that in the foregut, with the addition of Gilliamella, which was also abundant. The most dominant bacteria identified in the hindgut were similar to those in the midgut and Lactobacillales, Enterobacteriaceae, Gilliamella, Bifidobacteriaceae and Flavobacteriaceae appeared in abundance. Moreover, our results suggest that a community structure of bacteria in different parts of X. tenuiscapa’s gut may be an important indicator of carpenter bees’ health. This functional study of bacterial communities revealed significant differences among the three intestinal parts and is the first report of the gut bacteria structure in solitary bees.


2016 ◽  
Vol 13 (1) ◽  
pp. 175-190 ◽  
Author(s):  
J. Comte ◽  
C. Lovejoy ◽  
S. Crevecoeur ◽  
W. F. Vincent

Abstract. Permafrost thaw ponds and lakes are widespread across the northern landscape and may play a central role in global biogeochemical cycles, yet knowledge about their microbial ecology is limited. We sampled a set of thaw ponds and lakes as well as shallow rock-basin lakes that are located in distinct valleys along a north–south permafrost degradation gradient. We applied high-throughput sequencing of the 16S rRNA gene to determine co-occurrence patterns among bacterial taxa (operational taxonomic units, OTUs), and then analyzed these results relative to environmental variables to identify variables controlling bacterial community structure. Network analysis was applied to identify possible ecological linkages among the bacterial taxa and with abiotic and biotic variables. The results showed an overall high level of shared taxa among bacterial communities within each valley; however, the bacterial co-occurrence patterns were non-random, with evidence of habitat preferences. There were taxonomic differences in bacterial assemblages among the different valleys that were statistically related to dissolved organic carbon concentration, conductivity and phytoplankton biomass. Co-occurrence networks revealed complex interdependencies within the bacterioplankton communities and showed contrasting linkages to environmental conditions among the main bacterial phyla. The thaw pond networks were composed of a limited number of highly connected taxa. This “small world network” property would render the communities more robust to environmental change but vulnerable to the loss of microbial “keystone species”. These highly connected nodes (OTUs) in the network were not merely the numerically dominant taxa, and their loss would alter the organization of microbial consortia and ultimately the food web structure and functioning of these aquatic ecosystems.


Author(s):  
Colton Robert Alexander Stephens ◽  
Breanne M McAmmond ◽  
Jonathan Douglas Van Hamme ◽  
Ken A Otter ◽  
Matthew W Reudink ◽  
...  

Host associated microbial communities play important roles in wildlife health, but these dynamics can be influenced by environmental factors. Urbanization has numerous consequences on wildlife; however, the degree to which wildlife associated bacterial communities and potential bacterial pathogens vary across urban to rural/native habitat gradients remains largely unknown. We used 16S rRNA gene amplicon sequencing to examine bacterial communities found on mountain chickadee (Poecile gambeli) feathers and nests in urban and rural habitats. Feathers and nests in urban and rural sites had similar abundances of major bacterial phyla and dominant genera with pathogenic members. However, richness of bacterial communities and potential pathogens on birds were higher in urban habitats, and potential pathogens accounted for some of the differences in bacterial occurrence between urban and rural environments. We predicted habitat using potential pathogen occurrence with a 90% success rate for feather bacteria, and a 72.2% success rate for nest bacteria, suggesting an influence of urban environments on potential pathogen presence. We additionally observed similarities in bacterial communities between nests and their occupants, suggesting bacterial transmission between them. These findings improve our understanding of the bacterial communities associated with urban wildlife and suggest that urbanization may impact wildlife associated bacterial community compositions.


PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0240916
Author(s):  
Luisa M. Arias-Giraldo ◽  
Marina Muñoz ◽  
Carolina Hernández ◽  
Giovanny Herrera ◽  
Natalia Velásquez-Ortiz ◽  
...  

Triatomines (Hemiptera: Reduviidae) are the insect vectors of Trypanosoma cruzi, the causative agent of Chagas disease. The gut bacterial communities affect the development of T. cruzi inside the vector, making the characterization of its composition important in the understanding of infection development. We collected 54 triatomine bugs corresponding to four genera in different departments of Colombia. DNA extraction and PCR were performed to evaluate T. cruzi presence and to determine the discrete typing unit (DTU) of the parasite. PCR products of the bacterial 16S rRNA gene were pooled and sequenced. Resulting reads were denoised and QIIME 2 was used for the identification of amplicon sequence variants (ASVs). Diversity (alpha and beta diversity) and richness analyses, Circos plots, and principal component analysis (PCA) were also performed. The overall T. cruzi infection frequency was 75.9%, with TcI being the predominant DTU. Approximately 500,000 sequences were analyzed and 27 bacterial phyla were identified. The most abundant phyla were Proteobacteria (33.9%), Actinobacteria (32.4%), Firmicutes (19.6%), and Bacteroidetes (7.6%), which together accounted for over 90% of the gut communities identified in this study. Genera were identified for these main bacterial phyla, revealing the presence of important bacteria such as Rhodococcus, Serratia, and Wolbachia. The composition of bacterial phyla in the gut of the insects was significantly different between triatomine species, whereas no significant difference was seen between the state of T. cruzi infection. We suggest further investigation with the evaluation of additional variables and a larger sample size. To our knowledge, this study is the first characterization of the gut bacterial structure of the main triatomine genera in Colombia.


2018 ◽  
Vol 84 (12) ◽  
pp. e02797-17 ◽  
Author(s):  
Dandi Hou ◽  
Zhi Lin ◽  
Runze Wang ◽  
Jun Ge ◽  
Shuai Wei ◽  
...  

ABSTRACTRhizospheric bacteria play important roles in plant tolerance and activation of heavy metals. Understanding the bacterial rhizobiome of hyperaccumulators may contribute to the development of optimized phytoextraction for metal-polluted soils. We used 16S rRNA gene amplicon sequencing to investigate the rhizospheric bacterial communities of the cadmium (Cd) hyperaccumulating ecotype (HE)Sedum alfrediiin comparison to its nonhyperaccumulating ecotype (NHE). Both planting of two ecotypes ofS. alfrediiand elevated Cd levels significantly decreased bacterial alpha-diversity and altered bacterial community structure in soils. The HE rhizosphere harbored a unique bacterial community differing from those in its bulk soil and NHE counterparts. Several key taxa fromActinobacteria,Bacteroidetes, and TM7 were especially abundant in HE rhizospheres under high Cd stress. The actinobacterial genusStreptomyceswas responsible for the majority of the divergence of bacterial community composition between the HE rhizosphere and other soil samples. In the HE rhizosphere, the abundance ofStreptomyceswas 3.31- to 16.45-fold higher than that in other samples under high Cd stress. These results suggested that both the presence of the hyperaccumulatorS. alfrediiand Cd exposure select for a specialized rhizosphere bacterial community during phytoextraction of Cd-contaminated soils and that key taxa, such as the species affiliated with the genusStreptomyces, may play an important role in metal hyperaccumulation.IMPORTANCESedum alfrediiis a well-known Cd hyperaccumulator native to China. Its potential for extracting Cd relies not only on its powerful uptake, translocation, and tolerance for Cd but also on processes underground (especially rhizosphere microbes) that facilitate root uptake and tolerance of the metal. In this study, a high-throughput sequencing approach was applied to gain insight into the soil-plant-microbe interactions that may influence Cd accumulation in the hyperaccumulatorS. alfredii. Here, we report the investigation of rhizosphere bacterial communities ofS. alfrediiin phytoremediation of different levels of Cd contamination in soils. Moreover, some key taxa in its rhizosphere identified in the study, such as the species affiliated with genusStreptomyces, may shed new light on the involvement of bacteria in phytoextraction of contaminated soils and provide new materials for phytoremediation optimization.


Plants ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 42 ◽  
Author(s):  
Clarisse Brígido ◽  
Sakshi Singh ◽  
Esther Menéndez ◽  
Maria Tavares ◽  
Bernard Glick ◽  
...  

The aims of this study were to isolate, identify and characterize culturable endophytic bacteria from chickpea (Cicer arietinum L.) roots grown in different soils. In addition, the effects of rhizobial inoculation, soil and stress on the functionality of those culturable endophytic bacterial communities were also investigated. Phylogenetic analysis based on partial 16S rRNA gene sequences revealed that the endophytic bacteria isolated in this work belong to the phyla Proteobacteria, Firmicutes and Actinobacteria, with Enterobacter and Pseudomonas being the most frequently observed genera. Production of indoleacetic acid and ammonia were the most widespread plant growth-promoting features, while antifungal activity was relatively rare among the isolates. Despite the fact that the majority of bacterial endophytes were salt- and Mn-tolerant, the isolates obtained from soil with Mn toxicity were generally more Mn-tolerant than those obtained from the same soil amended with dolomitic limestone. Several associations between an isolate’s genus and specific plant growth-promoting mechanisms were observed. The data suggest that soil strongly impacts the Mn tolerance of endophytic bacterial communities present in chickpea roots while rhizobial inoculation induces significant changes in terms of isolates’ plant growth-promoting abilities. In addition, this study also revealed chickpea-associated endophytic bacteria that could be exploited as sources with potential application in agriculture.


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