Temporal dynamics of microbial communities in the rhizosphere of two genetically modified (GM) maize hybrids in tropical agrosystems

Abstract Familiarity based approval of the newly developed GM cereal events is based upon the stable and safe consumption of conventional grains. The level of concentrations of mycotoxins and biomolecules establishes the criteria for premarket evaluation of genetically modified cereals e.g. MON 810 maize. The objective of the present study was to comparatively evaluate food biosafety of the conventional and GM maize. Grain samples from the harvest lot of 10 maize hybrids in the year 2011 were collected arbitrarily. Well ground and homogenized samples were analysed for the deoxynivalenol (DON) and ochratoxin A (OTA) mycotoxins. Contamination rates and levels of DON and OTA were low and did not exceed the maximum levels, indicating their possible safe use as food and feed under the EC regulation 1881/2006.The samples were further analysed for the possible effect of mycotoxin concentration upon that of starch and proteins. The study reveals the absence of any negative impact of the presence of mycotoxins upon these biomolecules as their concentrations lie within the normal range. A comparative review of data for the mycotoxins in conventional maize grains invalidate the argument from the producers of GM maize hybrids that conventional hybrids are inferior for food biosafety with respect to mycotoxins.

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Effect of Feeding Cows Genetically Modified Maize on the Bacterial Community in the Bovine Rumen

Applied and Environmental Microbiology ◽

10.1128/aem.01060-06 ◽

2007 ◽

Vol 73 (24) ◽

pp. 8012-8017 ◽

Cited By ~ 13

Author(s):

S. Wiedemann ◽

P. Gürtler ◽

C. Albrecht

Keyword(s):

Bacterial Community ◽

Real Time ◽

Real Time Pcr ◽

Genetically Modified ◽

Genetically Modified Maize ◽

Bacterial Strains ◽

Maize Silage ◽

Bovine Rumen ◽

Gm Maize ◽

Effect Of Feeding

ABSTRACT Rumen-cannulated cows (n = 4) were fed successively silage made from either conventional or genetically modified (GM) maize. Results revealed no effects of GM maize on the dynamics of six ruminal bacterial strains (investigated by real-time PCR) compared to the conventional maize silage.

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Life on leaves : uncovering temporal dynamics in Arabidopsis' leaf microbiota

10.1101/2021.07.06.450897 ◽

2021 ◽

Author(s):

Juliana Almario ◽

Maryam Mahmoudi ◽

Samuel Kroll ◽

Matthew Agler ◽

Aleksandra Placzek ◽

...

Keyword(s):

Microbial Communities ◽

Photosynthetic Activity ◽

Temporal Dynamics ◽

Growing Season ◽

High Turnover ◽

Microbial Network ◽

Stabilization Phase ◽

Time Patterns ◽

Microbe Interactions ◽

Compositional Changes

Leaves are primarily responsible for the plant′s photosynthetic activity. Thus, changes in the phyllosphere microbiota, which includes deleterious and beneficial microbes, can have far reaching effects on plant fitness and productivity. In this context, identifying the processes and microorganisms that drive the changes in the leaf microbiota over a plant′s lifetime is crucial. In this study we analyzed the temporal dynamics in the leaf microbiota of Arabidopsis thaliana, integrating both compositional changes and changes in microbe-microbe interactions via the study of microbial networks. Field-grown Arabidopsis were used to follow leaf bacterial, fungal and oomycete communities, throughout the plant′s growing season (extending from November to March), over three consecutive years. Our results revealed the existence of conserved time patterns, with microbial communities and networks going through a stabilization phase (decreasing diversity and variability) at the beginning of the plant′s growing season. Despite a high turnover in these communities, we identified 19 "core" taxa persisting in Arabidopsis leaves across time and plant generations. With the hypothesis these microbes could be playing key roles in the structuring of leaf microbial communities, we conducted a time-informed microbial network analysis which showed core taxa are not necessarily highly connected network "hubs" and "hubs" alternate with time. Our study shows that leaf microbial communities exhibit reproducible dynamics and patterns, suggesting it could be possible to predict and drive these microbial communities to desired states.

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Temporal and spatial dynamics of peat microbiomes in drained and rewetted soils of three temperate peatlands

10.1101/2020.02.16.951285 ◽

2020 ◽

Author(s):

Haitao Wang ◽

Micha Weil ◽

Dominik Zak ◽

Diana Münch ◽

Anke Günther ◽

...

Keyword(s):

Microbial Communities ◽

Greenhouse Gas Emissions ◽

Greenhouse Gas ◽

Community Composition ◽

Structural Equation ◽

Structural Equation Models ◽

Temporal Dynamics ◽

Salt Water ◽

Microbial Community Composition ◽

Gas Emissions

AbstractBackgroundDrainage of high-organic peatlands for agricultural purposes has led to increased greenhouse gas emissions and loss of biodiversity. In the last decades, rewetting of peatlands is on the rise worldwide, to mitigate these negative impacts. However, it remains still questionable how rewetting would influence peat microbiota as important drivers of nutrient cycles and ecosystem restoration. Here, we investigate the spatial and temporal dynamics of the diversity, community composition and network interactions of prokaryotes and eukaryotes, and the influence of rewetting on these microbial features in formerly long-term drained and agriculturally used fens. Peat-soils were sampled seasonally from three drained and three rewetted sites representing the dominating fen peatland types of glacial landscapes in Northern Germany, namely alder forest, costal fen and percolation fen.ResultsCostal fens as salt-water impacted systems showed a lower microbial diversity and their microbial community composition showed the strongest distinction from the other two peatland types. Prokaryotic and eukaryotic community compositions showed a congruent pattern which was mostly driven by peatland type and rewetting. Rewetting decreased the abundances of fungi and prokaryotic decomposers, while the abundance of potential methanogens was significantly higher in the rewetted sites. Rewetting also influenced the abundance of ecological clusters in the microbial communities identified from the co-occurrence network. The microbial communities changed only slightly with depth and over time. According to structural equation models rewetted conditions affected the microbial communities through different mechanisms across the three studied peatland types.ConclusionsOur results suggest that rewetting strongly impacts the structure of microbial communities and, thus, important biogeochemical processes, which may explain the high variation in greenhouse gas emissions upon rewetting of peatlands. The improved understanding of functional mechanisms of rewetting in different peatland types lays the foundation for securing best practices to fulfil multiple restoration goals including those targeting on climate, water, and species protection.

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Meeting the Tolerance: How Successful is Coexistence in Commodity Corn Handling Systems?

Applied Engineering in Agriculture ◽

10.13031/aea.14042 ◽

2020 ◽

Vol 36 (5) ◽

pp. 777-784

Author(s):

Chad J. Dolphin ◽

Gretchen A. Mosher ◽

R.P. Kingsly Ambrose ◽

Saxon J. Ryan

Keyword(s):

Monte Carlo Simulation ◽

Monte Carlo ◽

Genetically Modified ◽

List Type ◽

Genetic Traits ◽

Tolerance Level ◽

Gm Maize ◽

Isolation Distance ◽

Adventitious Presence ◽

Handling Practices

HighlightsMeeting the 0.9% tolerance level was challenging under most conditions.Non-GM loads in the simulation were able to meet a 1.5% or 3% tolerance level under specific conditions.Field isolation distance plays a large role in a non-GM load meeting the posted tolerance levelAbstract. The open-air growth environment used in maize production makes it nearly impossible to ensure 100% purity of specified genetic traits. One measure of successful coexistence is a low level of unintended material in seed, grain, and feed or food products, termed “adventitious presence” (AP). To allow the coexistence of genetically modified (GM) and non-genetically modified (non-GM) maize, tolerance levels regulate how much AP of genetically modified corn is allowed in each unit of maize. This research sought to model four factors contributing to levels of adventitious presence: seed purity, field isolation distance, combine cleanout, and grain elevator receipt and handling practices. Monte Carlo simulation was used to test nine scenarios to determine the feasibility of successfully meeting three tolerance levels for adventitious presence (0.9%, 1.5%, and 3.0%). After 50,000 iterations for each model, sensitivity analysis was performed to identify factors that play an important role in whether the load meets the posted tolerance level or not. Results suggest that non-GM maize loads would not meet a tolerance level of 0.9% in most cases. Non-GM maize loads were found to meet tolerance levels of 1.5% and 3.0% in certain cases. The most significant factors affecting the probability of the unit of maize meeting the posted tolerance level were field isolation distance, elevator handling practices, and seed purity. Keywords: Adventitious presence, Coexistence, Identity preservation, Monte Carlo simulation, Transgenic grain.

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Do genetically modified plants affect adversely on soil microbial communities?

Agriculture Ecosystems & Environment ◽

10.1016/j.agee.2016.10.026 ◽

2016 ◽

Vol 235 ◽

pp. 289-305 ◽

Cited By ~ 17

Author(s):

Zheng-jun Guan ◽

Shun-bao Lu ◽

Yan-lin Huo ◽

Zheng-Ping Guan ◽

Biao Liu ◽

...

Keyword(s):

Microbial Communities ◽

Genetically Modified ◽

Soil Microbial Communities ◽

Genetically Modified Plants ◽

Soil Microbial

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Effects of Spatial Variability and Relic DNA Removal on the Detection of Temporal Dynamics in Soil Microbial Communities

mBio ◽

10.1128/mbio.02776-19 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 4

Author(s):

Paul Carini ◽

Manuel Delgado-Baquerizo ◽

Eve-Lyn S. Hinckley ◽

Hannah Holland‐Moritz ◽

Tess E. Brewer ◽

...

Keyword(s):

Microbial Community ◽

Spatial Variability ◽

Spatial Heterogeneity ◽

Microbial Communities ◽

Temporal Variability ◽

Temporal Dynamics ◽

Microbial Community Composition ◽

Soil Microbial Communities ◽

Environmental Preferences ◽

Soil Microbial

ABSTRACT Few studies have comprehensively investigated the temporal variability in soil microbial communities despite widespread recognition that the belowground environment is dynamic. In part, this stems from the challenges associated with the high degree of spatial heterogeneity in soil microbial communities and because the presence of relic DNA (DNA from dead cells or secreted extracellular DNA) may dampen temporal signals. Here, we disentangle the relationships among spatial, temporal, and relic DNA effects on prokaryotic and fungal communities in soils collected from contrasting hillslopes in Colorado, USA. We intensively sampled plots on each hillslope over 6 months to discriminate between temporal variability, intraplot spatial heterogeneity, and relic DNA effects on the soil prokaryotic and fungal communities. We show that the intraplot spatial variability in microbial community composition was strong and independent of relic DNA effects and that these spatial patterns persisted throughout the study. When controlling for intraplot spatial variability, we identified significant temporal variability in both plots over the 6-month study. These microbial communities were more dissimilar over time after relic DNA was removed, suggesting that relic DNA hinders the detection of important temporal dynamics in belowground microbial communities. We identified microbial taxa that exhibited shared temporal responses and show that these responses were often predictable from temporal changes in soil conditions. Our findings highlight approaches that can be used to better characterize temporal shifts in soil microbial communities, information that is critical for predicting the environmental preferences of individual soil microbial taxa and identifying linkages between soil microbial community composition and belowground processes. IMPORTANCE Nearly all microbial communities are dynamic in time. Understanding how temporal dynamics in microbial community structure affect soil biogeochemistry and fertility are key to being able to predict the responses of the soil microbiome to environmental perturbations. Here, we explain the effects of soil spatial structure and relic DNA on the determination of microbial community fluctuations over time. We found that intensive spatial sampling was required to identify temporal effects in microbial communities because of the high degree of spatial heterogeneity in soil and that DNA from nonliving sources masks important temporal patterns. We identified groups of microbes with shared temporal responses and show that these patterns were predictable from changes in soil characteristics. These results provide insight into the environmental preferences and temporal relationships between individual microbial taxa and highlight the importance of considering relic DNA when trying to detect temporal dynamics in belowground communities.

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Interlaboratory Study of Qualitative PCR Methods for Genetically Modified Maize Events MON810, Bt11, GA21, and CaMV P35S

Journal of AOAC International ◽

10.5740/jaoacint.12-141 ◽

2013 ◽

Vol 96 (2) ◽

pp. 346-352 ◽

Cited By ~ 3

Author(s):

Reona Takabatake ◽

Kaori Takashima ◽

Takeyo Kurashima ◽

Junichi Mano ◽

Satoshi Furui ◽

...

Keyword(s):

Quantitative Methods ◽

Genetically Modified ◽

False Negative ◽

Cauliflower Mosaic Virus ◽

Interlaboratory Study ◽

35S Promoter ◽

Gm Maize ◽

Detection And Identification ◽

Pcr Products ◽

Qualitative Pcr

Abstract Qualitative PCR methods for the genetically modified (GM) maize events MON810, Bt11, and GA21, and the 35S promoter (P35S) region of the cauliflower mosaic virus (CaMV) were evaluated in an interlaboratory study. Real-time PCR-based quantitative methods for these GM events using the same primer pairs had already been validated in previous studies. Fifteen laboratories in Japan participated in this interlaboratory study. Each participant extracted DNA from blind samples, performed qualitative PCR assays, and then detected the PCR products with agarose gel electrophoresis. The specificity, sensitivity, and false-negative and false-positive rates of these methods were determined with different concentrations of GM mixing samples. LODs of these methods for MON810, Bt11, GA21, and the P35S segment calculated as the amount of MON810 were 0.2, 0.2, 0.1, and 0.2% or less, respectively, indicating that the LODs of MON810, Bt11, and P35S were lower than 10 copies, and the LOD of GA21 was lower than 25 copies of maize haploid genome. The current study demonstrated that the qualitative methods would be fit for the detection and identification of these GM maize events and the P35S segment.

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