Elevated CO2 and Warming Altered Grassland Microbial Communities in Soil Top-Layers.

As two central issues of global climate change, the continuous increase of both atmospheric CO2 concentrations and global temperature has profound effects on various terrestrial ecosystems. Microbial communities play pivotal roles in these ecosystems by responding to environmental changes through regulation of soil biogeochemical processes. However, little is known about the effect of elevated CO2 (eCO2) and global warming on soil microbial communities, especially in semiarid zones. We used a functional gene array (GeoChip 3.0) to measure the functional gene composition, structure, and metabolic potential of soil microbial communities under warming, eCO2, and eCO2 + warming conditions in a semiarid grassland. The results showed that the composition and structure of microbial communities was dramatically altered by multiple climate factors, including elevated CO2 and increased temperature. Key functional genes, those involved in carbon (C) degradation and fixation, methane metabolism, nitrogen (N) fixation, denitrification and N mineralization, were all stimulated under eCO2, while those genes involved in denitrification and ammonification were inhibited under warming alone. The interaction effects of eCO2 and warming on soil functional processes were similar to eCO2 alone, whereas some genes involved in recalcitrant C degradation showed no significant changes. In addition, canonical correspondence analysis and Mantel test results suggested that NO3-N and moisture significantly correlated with variations in microbial functional genes. Overall, this study revealed the possible feedback of soil microbial communities to multiple climate change factors by the suppression of N cycling under warming, and enhancement of C and N cycling processes under either eCO2 alone or in interaction with warming. These findings may enhance our understanding of semiarid grassland ecosystem responses to integrated factors of global climate change

Exploration of phyllosphere microbiomes in wheat varieties with differing aphid resistance

Background: Leaf-associated microbes play an important role in plant development and response to exogenous stress. Insect herbivores are known to alter the phyllosphere microbiome. However, whether the host plant’s defense against insects is related to the phyllosphere microbiome remains mostly elusive. Here, we investigated bacterial communities in the phyllosphere and endosphere of eight wheat cultivars with differing aphid resistance, grown in the same farmland. Results: The bacterial community in both the phyllosphere and endosphere showed significant differences among most wheat cultivars. The phyllosphere was connected to more complex and stable microbial networks than the endosphere in most wheat cultivars. Moreover, the genera Pantoea, Massilia, and Pseudomonas were found to play a major role in shaping the microbial community in the wheat phyllosphere. Additionally, wheat plants showed phenotype-specific associations with the genera Massilia and Pseudomonas. The abundance of the genus Exiguobacterium in the phyllosphere exhibited a significant negative correlation with the aphid hazard grade in the wheat plants. Conclusion: Communities of leaf-associated microbes in wheat plants were mainly driven by the host genotype. Members of the genus Exiguobacterium may have adverse effects on wheat aphids. Our findings provide new clues supporting the development of aphid control strategies based on phyllosphere microbiome engineering

A Synthetic Algorithm for Tracking a Moving Object in a Multiple-Dynamic Obstacles Environment Based on Kinematically Planar Redundant Manipulators

This paper presents a synthetic algorithm for tracking a moving object in a multiple-dynamic obstacles environment based on kinematically planar manipulators. By observing the motions of the object and obstacles, Spline filter associated with polynomial fitting is utilized to predict their moving paths for a period of time in the future. Several feasible paths for the manipulator in Cartesian space can be planned according to the predicted moving paths and the defined feasibility criterion. The shortest one among these feasible paths is selected as the optimized path. Then the real-time path along the optimized path is planned for the manipulator to track the moving object in real-time. To improve the convergence rate of tracking, a virtual controller based on PD controller is designed to adaptively adjust the real-time path. In the process of tracking, the null space of inverse kinematic and the local rotation coordinate method (LRCM) are utilized for the arms and the end-effector to avoid obstacles, respectively. Finally, the moving object in a multiple-dynamic obstacles environment is thus tracked via real-time updating the joint angles of manipulator according to the iterative method. Simulation results show that the proposed algorithm is feasible to track a moving object in a multiple-dynamic obstacles environment

Optimized gene editing technology for Drosophila melanogaster using germ line-specific Cas9

The ability to engineer genomes in a specific, systematic, and cost-effective way is critical for functional genomic studies. Recent advances using the CRISPR-associated single-guide RNA system (Cas9/sgRNA) illustrate the potential of this simple system for genome engineering in a number of organisms. Here we report an effective and inexpensive method for genome DNA editing in Drosophila melanogaster whereby plasmid DNAs encoding short sgRNAs under the control of the U6b promoter are injected into transgenic flies in which Cas9 is specifically expressed in the germ line via the nanos promoter. We evaluate the off-targets associated with the method and establish a Web-based resource, along with a searchable, genome-wide database of predicted sgRNAs appropriate for genome engineering in flies. Finally, we discuss the advantages of our method in comparison with other recently published approaches.Multidisciplinary SciencesSCI(E)46ARTICLE4719012-1901711

Native fungal community remains resilient during bioremediation of DBP pollution by exogenous Gordonia phthalatica QH-11T

Microbial bioremediation is a highly effective method to degrade phthalates in the environment. However, the response of native microbial communities to the exogenously introduced microorganism remains unknown. In this study, the native fungal community was monitored by amplicon sequencing of the fungal ITS region during the restoration process of the di-n-butyl phthalate (DBP)-contaminated soils with Gordonia phthalatica QH-11T. Our results showed that the diversity, composition, and structure of the fungal community in the bioremediation treatment did not differ from the control, and no significant correlations were found between number of Gordonia and variation of fungal community. It was also observed that DBP pollution initially increased the relative abundance of plant pathogens and soil saprotrophs first, but their proportions returned to the initial level. Molecular ecological network analysis showed that DBP pollution increased the network complexity, while the network was not significantly altered by bioremediation. Overall, the introduction of Gordonia was shown to not have a long-term impact on the native soil fungal community. Therefore, this restoration method can be considered safe in terms of soil ecosystem stability. The present study provides a deeper insight into the effect of bioremediation on fungal communities and provides an extended basis to further explore the ecological risks of introducing exogenous microorganisms

Biodegradation of Di-n-Butyl Phthalate by a Newly Isolated Halotolerant Sphingobium sp.

A Gram-negative strain (TJ) capable of growing aerobically on mixed phthalate esters (PAEs) as the sole carbon and energy source was isolated from the Haihe estuary, Tianjin, China. It was identified as belonging to the Sphingobium genus on the basis of morphological and physiological characteristics and 16S rRNA and gyrb gene sequencing. The batch tests for biodegradation of di-n-butyl phthalate (DBP) by the Sphingobium sp. TJ showed that the optimum conditions were 30 °C, pH 7.0, and the absence of NaCl. Stain TJ could tolerate up to 4% NaCl in minimal salt medium supplemented with DBP, although the DBP degradation rates slowed as NaCl concentration increased. In addition, substrate tests showed that strain TJ could utilize shorter side-chained PAEs, such as dimethyl phthalate and diethyl phthalate, but could not metabolize long-chained PAEs, such as di-n-octyl phthalate, diisooctyl phthalate, and di-(2-ethyl-hexyl) phthalate. To our knowledge, this is the first report on the biodegradation characteristics of DBP by a member of the Sphingobium genus

The sensitivity and stability of bacterioplankton community structure to wind-wave turbulence in a large, shallow, eutrophic lake

Abstract Lakes are strongly influenced by wind-driven wave turbulence. The direct physical effects of turbulence on bacterioplankton community structure however, have not yet been addressed and remains poorly understood. To examine the stability of bacterioplankton communities under turbulent conditions, we simulated conditions in the field to evaluate the responses of the bacterioplankton community to physical forcing in Lake Taihu, using high-throughput sequencing and flow cytometry. A total of 4,520,231 high quality sequence reads and 74,842 OTUs were obtained in all samples with α-proteobacteria, γ-proteobacteria and Actinobacteria being the most dominant taxa. The diversity and structure of bacterioplankton communities varied during the experiment, but were highly similar based on the same time of sampling, suggesting that bacterioplankton communities are insensitive to wind wave turbulence in the lake. This stability could be associated with the traits associated with bacteria. In particular, turbulence favored the growth of bacterioplankton, which enhanced biogeochemical cycling of nutrients in the lake. This study provides a better understanding of bacterioplankton communities in lake ecosystems exposed to natural mixing/disturbances

The color of biodegradable mulch films is associated with differences in peanut yield and bacterial communities

Biodegradable mulch films (BDMs) are increasingly used in agricultural production as desirable alternatives to the current widespread use of polyethylene (PE) mulch films in China. However, potential effects of different colors of BDMs on field crop production and microbiomes remain unexplored. Here, the differences in bacterial communities of peanut rhizosphere soil (RS) and bulk soil (BS) under non-mulching (CK), PE, and three different colors of BDMs were studied. The results indicated that all treatments could increase the soil temperature, which positively affected the growth of the peanut plants. Moreover, mulching affected the bacterial community structure in RS and BS compared to CK. Furthermore, certain BDM treatments significantly enriched N-fixing bacteria (Bradyrhizobium and Mesorhizobium) and functional groups, increased the closeness of bacterial networks, and harbored more beneficial bacteria as keystone taxa in the RS. This in turn facilitated the growth and development of the peanut plants under field conditions. Our study provides new insights into the micro-ecological effects of mulch films, which can be affected by both the mulch type and color. The observed effects are likely caused by temperature and prevalence of specific microbial functions under the employed films and could guide the development of optimized mulching materials