Effects of elevated O3 on microbes in the rhizosphere of mycorrhizal snap bean with different O3 sensitivity

2014 ◽  
Vol 60 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Shuguang Wang ◽  
Fei Wang ◽  
Xiaojun Diao ◽  
Liansheng He
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Community Structure ◽  
Relative Proportion ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Mycorrhizal Plant ◽  
Snap Bean ◽  
Elevated Ozone

Elevated ozone (O3) generally affects microbial biomass and community structure in rhizosphere, but these effects are unclear in mycorrhizal plants because arbuscular mycorrhizal (AM) fungi often benefit microbial growth in the rhizosphere. Here, we investigate the effects of elevated O3 on microbial biomass and community structure in the rhizosphere of mycorrhizal snap bean (Phaseolus vulgaris L.) with different O3 sensitivity (R123: O3-tolerant plant; S156: O3-sensitive plant) based on the phospholipid fatty acids (PLFAs) method. Compared with ambient O3, elevated O3 significantly decreased mycorrhizal colonization rates in the 2 genotypes, especially in S156 plants. The wet masses of shoot and root were decreased by elevated O3 in the 2 genotypes independent of AM inoculation, but they were higher in the mycorrhizal plant than in the nonmycorrhizal plant independent of O3 concentration. Elevated O3 significantly decreased the relative proportion of specific fungal PLFAs in the nonmycorrhizal plant, but this effect disappeared in the mycorrhizal plant. The relative proportions of specific PLFAs of other microbial groups (Gram-positive, Gram-negative, and actinomycete) in the rhizosphere and all specific PLFAs in the hyphosphere were not affected by elevated O3 independent of AM inoculation. In the rhizosphere of the 2 genotypes, microbial community structure was changed by AM inoculation and elevated O3 as well as by their interaction; in the hyphosphere, however, microbial community structure was changed by elevated O3 only in R123 plants. It is concluded that AM inoculation can offset negative effect of elevated O3 on fungal biomass but seems to enhance shift of microbial community structure in rhizosphere under elevated O3.

scholarly journals Nitrogen Addition Affects Soil Respiration Primarily through Changes in Microbial Community Structure and Biomass in a Subtropical Natural Forest

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 435 ◽  
Author(s):  
Jiacong Zhou ◽  
Xiaofei Liu ◽  
Jinsheng Xie ◽  
Maokui Lyu ◽  
Yong Zheng ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Soil Respiration ◽  
Forest Soil ◽  
Microbial Community Structure ◽  
N Deposition ◽  
N Addition ◽  
C Cycling ◽  
Total Plfa

Forest soil respiration plays an important role in global carbon (C) cycling. Owing to the high degree of C and nitrogen (N) cycle coupling, N deposition rates may greatly influence forest soil respiration, and possibly even global C cycling. Soil microbes play a crucial role in regulating the biosphere–atmosphere C exchange; however, how microbes respond to N addition remains uncertain. To better understand this process, the experiment was performed in the Castanopsis kawakamii Hayata Nature Reserve, in the subtropical zone of China. Treatments involved applying different levels of N (0, 40, and 80 kg ha−2 year−1) over a three-year period (January 2013–December 2015) to explore how soil physicochemical properties, respiration rate, phospholipid fatty acid (PLFA) concentration, and solid state 13C nuclear magnetic resonance responded to various N addition rate. Results showed that high levels of N addition significantly decreased soil respiration; however, low levels of N addition significantly increased soil respiration. High levels of N reduced soil pH and enhanced P and C co-limitation of microorganisms, leading to significant reductions in total PLFA and changes in the structure of microbial communities. Significant linear relationships were observed between annual cumulative respiration and the concentration of microbial biomass (total PLFA, gram-positive bacteria (G+), gram-negative bacteria (G−), total bacteria, and fungi) and the microbial community structure (G+: G− ratio). Taken together, increasing N deposition changed microbial community structure and suppressed microbial biomass, ultimately leading to recalcitrant C accumulation and soil C emissions decrease in subtropical forest.

scholarly journals Predation by protists influences the temperature response of microbial communities

2021 ◽  
Author(s):  
Jennifer D Rocca ◽  
Andrea Yammine ◽  
Marie Simonin ◽  
Jean Gibert
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Communities ◽  
Microbial Community Structure ◽  
Temperature Response ◽  
Global Carbon Cycle ◽  
Structure And Function ◽  
And Function ◽  
Global Carbon

Temperature strongly influences microbial community structure and function, which in turn contributes to the global carbon cycle that can fuel further warming. Recent studies suggest that biotic interactions amongst microbes may play an important role in determining the temperature responses of these communities. However, how microbial predation regulates these communities under future climates is still poorly understood. Here we assess whether predation by one of the most important bacterial consumers globally, protists, influences the temperature response of a freshwater microbial community structure and function. To do so, we exposed these microbial communities to two cosmopolitan species of protists at two different temperatures, in a month-long microcosm experiment. While microbial biomass and respiration increased with temperature due to shifts in microbial community structure, these responses changed over time and in the presence of protist predators. Protists influenced microbial biomass and function through effects on community structure, and predation actually reduced microbial respiration rate at elevated temperature. Indicator species and threshold indicator taxa analyses showed that these predation effects were mostly determined by phylum-specific bacterial responses to protist density and cell size. Our study supports previous findings that temperature is an important driver of microbial communities, but also demonstrates that predation can mediate these responses to warming, with important consequences for the global carbon cycle and future warming.

Response of soil microbial biomass, activities, and community structure at a pine stand in northeastern Germany 5 years after thinning

2006 ◽  
Vol 36 (6) ◽  
pp. 1427-1434 ◽  
Author(s):  
Sebastian Maassen ◽  
Hannu Fritze ◽  
Stephan Wirth
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Community Structure ◽  
Basal Respiration ◽  
Organic Layer ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Significant Difference ◽  
Northeastern Germany

A thinned and an unthinned treatment were compared in a 62-year-old pine stand located in northeastern Germany (Brandenburg, Ost-Prignitz, Revier Beerenbusch) (year of thinning: 1999, degree of canopy opening: 0.4). Samples of the organic layer (O) and the mineral horizon (Aeh) of an acid brown earth were collected along a transect at each treatment in November 2003 and April 2004. Substrate induced respiration, basal respiration, and a suite of enzymes involved in the degradation of lignocellulose (endocellulase, exocellulase, β-glucosidase, endoxylanase, exoxylanase, phenoloxidase, peroxidase) were assayed. Microbial community structure and relative biomass of bacteria, actinomycetes, and fungi were assayed by phospholipid fatty acid analysis. Five years after thinning, microbial biomass, basal respiration, and enzyme activities in both soil layers did not differ significantly between thinned and unthinned treatments. However, the analysis of soil microbial community structure revealed a significant difference between the thinned and unthinned treatment at both sampling dates. Thus, it was concluded that thinning had not yet resulted in any response in soil microbial activities at the site under study, but since early evidence of change in the microbial community was detected, long-term monitoring and additional studies on mineralization activities are required.

scholarly journals Biome-Level Biogeography of Streambed Microbiota

2008 ◽  
Vol 74 (10) ◽  
pp. 3014-3021 ◽  
Author(s):  
Robert H. Findlay ◽  
Christine Yeates ◽  
Meredith A. J. Hullar ◽  
David A. Stahl ◽  
Louis A. Kaplan
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Bacterial Community ◽  
Microbial Community Structure ◽  
Bacterial Community Structure ◽  
Phospholipid Fatty Acid ◽  
Principal Component ◽  
Community Structures ◽  
Microbial Community Structures

ABSTRACT A field study was conducted to determine the microbial community structures of streambed sediments across diverse geographic and climatic areas. Sediment samples were collected from three adjacent headwater forest streams within three biomes, eastern deciduous (Pennsylvania), southeastern coniferous (New Jersey), and tropical evergreen (Guanacaste, Costa Rica), to assess whether there is biome control of stream microbial community structure. Bacterial abundance, microbial biomass, and bacterial and microbial community structures were determined using classical, biochemical, and molecular methods. Microbial biomass, determined using phospholipid phosphate, was significantly greater in the southeastern coniferous biome, likely due to the smaller grain size, higher organic content, and lower levels of physical disturbance of these sediments. Microbial community structure was determined using phospholipid fatty acid (PLFA) profiles and bacterial community structure from terminal restriction fragment length polymorphism and edited (microeukaryotic PLFAs removed) PLFA profiles. Principal component analysis (PCA) was used to investigate patterns in total microbial community structure. The first principal component separated streams based on the importance of phototrophic microeukaryotes within the community, while the second separated southeastern coniferous streams from all others based on increased abundance of fungal PLFAs. PCA also indicated that within- and among-stream variations were small for tropical evergreen streams and large for southeastern coniferous streams. A similar analysis of bacterial community structure indicated that streams within biomes had similar community structures, while each biome possessed a unique streambed community, indicating strong within-biome control of stream bacterial community structure.

scholarly journals Microbial Response to Phytostabilization in Mining Impacted Soils Using Maize in Conjunction with Biochar and Compost

2021 ◽  
Vol 9 (12) ◽  
pp. 2545
Author(s):  
Thomas F. Ducey ◽  
Gilbert C. Sigua ◽  
Jeffrey M. Novak ◽  
James A. Ippolito ◽  
Kurt A. Spokas ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Plant Growth ◽  
Microbial Community Structure ◽  
Poultry Litter ◽  
Management Tool ◽  
Soil Microbial Community Structure ◽  
Poultry Litter Biochar ◽  
The Impact

Even after remediation, mining impacted soils can leave behind a landscape inhospitable to plant growth and containing residual heavy metals. While phytostabilization can be used to restore such sites by limiting heavy metal spread, it is reliant on soil capable of supporting plant growth. Manure-based biochars, coupled with compost, have demonstrated the ability to improve soil growth conditions in mine impacted soils, however there is a paucity of information regarding their influence on resident microbial populations. The objective of this study was to elucidate the impact of these soil amendments on microbial community structure and function in mine impacted soils placed under phytostabilization management with maize. To this aim, a combination of phospholipid fatty acid (PLFA) and enzymatic analyses were performed. Results indicate that microbial biomass is significantly increased upon addition of biochar and compost, with maximal microbial biomass achieved with 5% poultry litter biochar and compost (62.82 nmol g−1 dry soil). Microbial community structure was impacted by biochar type, rate of application, and compost addition, and influenced by pH (r2 = 0.778), EC (r2 = 0.467), and Mg soil concentrations (r2 = 0.453). In three of the four enzymes analyzed, poultry litter biochar treatments were observed with increased activity rates that were often significantly greater than the unamended control. Overall, enzyme activities rates were influenced by biochar type and rate, and addition of compost. These results suggest that using a combination of biochar and compost can be utilized as a management tool to support phytostabilization strategies in mining impacted soils.

scholarly journals Soil microbial communities following bush removal in a Namibian savanna

2015 ◽  
Vol 2 (2) ◽  
pp. 1393-1418
Author(s):  
J. S. Buyer ◽  
A. Schmidt-Küntzel ◽  
M. Nghikembua ◽  
J. E. Maul ◽  
L. Marker
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Communities ◽  
Microbial Community Structure ◽  
Phospholipid Fatty Acid ◽  
Soil Microbial Communities ◽  
Management Approach ◽  
Polymorphism Analysis ◽  
Soil Microbial

Abstract. Savanna ecosystems are subject to desertification and bush encroachment, which reduce the carrying capacity for wildlife and livestock. Bush thinning is a management approach that can, at least temporarily, restore grasslands and raise the grazing value of the land. In this study we examined the soil microbial communities under bush and grass in Namibia. We analyzed the soil through a chronosequence where bush was thinned at 9, 5, or 3 years before sampling. Soil microbial biomass, the biomass of specific taxonomic groups, and overall microbial community structure was determined by phospholipid fatty acid analysis, while the community structure of Bacteria, Archaea, and fungi was determined by multiplex terminal restriction fragment length polymorphism analysis. Soil under bush had higher pH, C, N, and microbial biomass than under grass, and the microbial community structure was also altered under bush compared to grass. A major disturbance to the ecosystem, bush thinning, resulted in an altered microbial community structure compared to control plots, but the magnitude of this perturbation gradually declined with time. Community structure was primarily driven by pH, C, and N, while vegetation type, bush thinning, and time since bush thinning were of secondary importance.

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