scholarly journals Cheatgrass Invasion - The Below-Ground Connection

2017 ◽  
Vol 8 (1) ◽  
pp. 27
Author(s):  
Raven Reitstetter ◽  
Rittenhouse Larry R.
Keyword(s):  
Soil Microbial Communities ◽  
Plant Growth Promoting Rhizobacteria ◽  
Invasion Success ◽  
Invasive Grass ◽  
Available Nitrogen ◽  
Soil Microbial ◽  
Plant Soil ◽  
Plant Growth Promoting ◽  
Below Ground

Plant-soil microbial feedback loops play an important role in the establishment and development of plant communities. Microbial soil communities, including pathogens, plant-growth-promoting rhizobacteria and their reciprocal interactions, can influence plant health and nutrient cycling in many ways. We are proposing a model that accounts for cheatgrass (Bromus tectorum) invasion success and long-term persistence in both disturbed and undisturbed sites. In this model cheatgrass alters soil microbial communities that favor nitrifying microorganisms, resulting in elevated NO3- levels. Increased NO3- levels, coupled with B. tectorum life history and climatic and edaphic conditions in the semi-arid western U.S., result in long-term persistence of this invasive annual. In ecosystems that lack major precipitation during the growth season, B. tectorum induced shifts in the nitrifier community result in accumulation of plant available nitrogen during the summer when native perennials are primarily dormant. Increased NO3- levels can be efficiently utilized by cheatgrass ahead of native perennials during fall and winter. Restoration and management efforts must be guided by a thorough understanding of soil microbe-cheatgrass interactions to avoid nutrient flushes resulting from freeze-thaw and wet-dry cycles that benefit this invasive grass.

scholarly journals Rapid transfer of photosynthetic carbon through the plant-soil system in differently managed grasslands

2011 ◽  
Vol 8 (1) ◽  
pp. 921-940 ◽  
Author(s):  
G. B. De Deyn ◽  
H. Quirk ◽  
S. Oakley ◽  
N. Ostle ◽  
R. D. Bardgett
Keyword(s):  
Plant Species ◽  
Plant Diversity ◽  
Soil Microbes ◽  
Soil Microbial Communities ◽  
Short Term ◽  
Soil Microbial ◽  
Plant Soil ◽  
C Cycling ◽  
Rapid Transfer

Abstract. Plant-soil interactions are central to short-term carbon (C) cycling through the rapid transfer of recently assimilated C from plant roots to soil biota. In grassland ecosystems, changes in C cycling are likely to be influenced by land use and management that changes vegetation and the associated soil microbial communities. Here we tested whether changes in grassland vegetation composition resulting from management for plant diversity influences short-term rates of C assimilation, retention and transfer from plants to soil microbes. To do this, we used an in situ 13C-CO2 pulse-labeling approach to measure differential C uptake among different plant species and the transfer of the plant-derived 13C to key groups of soil microbiota across selected treatments of a long-term plant diversity grassland restoration experiment. Results showed that plant taxa differed markedly in the rate of 13C assimilation and retention: uptake was greatest and retention lowest in Ranunculus repens, and assimilation was least and retained longest in mosses. Incorporation of recent plant-derived 13C was maximal in all microbial phosopholipid fatty acid (PLFA) markers at 24 h after labeling. The greatest incorporation of 13C was in the PLFA 16:1ω5, a marker for arbuscular mycorrhizal fungi (AMF), while after one week most 13C was retained in the PLFA 18:2ω6,9 which is indicative of assimilation of plant-derived 13C by saprophytic fungi. Our results of 13C assimilation, transfer and retention within plant species and soil microbes were consistent across management treatments. Overall, our findings suggest that changes in vegetation and soil microbial composition resulting from differences in long-term grassland management will affect short-term cycling of photosynthetic C, but that restoration management does not alter the short-term C uptake and transfer within plant species and within key groups of soil microbes. Moreover, across all treatments we found that plant-derived C is rapidly transferred specifically to AMF and decomposer fungi, indicating their consistent key role in the cycling of recent plant derived C.

scholarly journals Adaptation to chronic drought modifies soil microbial community responses to phytohormones

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Emma J. Sayer ◽  
John A. Crawford ◽  
James Edgerley ◽  
Andrew P. Askew ◽  
Christoph Z. Hahn ◽  
...  
Keyword(s):  
Microbial Community ◽  
Soil Respiration ◽  
Microbial Communities ◽  
Soil Microbial Community ◽  
Plant Stress ◽  
Soil Microbial Communities ◽  
Community Responses ◽  
Soil Microbial ◽  
Plant Soil

AbstractDrought imposes stress on plants and associated soil microbes, inducing coordinated adaptive responses, which can involve plant–soil signalling via phytohormones. However, we know little about how microbial communities respond to phytohormones, or how these responses are shaped by chronic (long-term) drought. Here, we added three phytohormones (abscisic acid, 1-aminocyclopropane-1-carboxylic acid, and jasmonic acid) to soils from long-term (25-year), field-based climate treatments to test the hypothesis that chronic drought alters soil microbial community responses to plant stress signalling. Phytohormone addition increased soil respiration, but this effect was stronger in irrigated than in droughted soils and increased soil respiration at low phytohormone concentrations could not be explained by their use as substrate. Thus, we show that drought adaptation within soil microbial communities modifies their responses to phytohormone inputs. Furthermore, distinct phytohormone-induced shifts in microbial functional groups in droughted vs. irrigated soils might suggest that drought-adapted soil microorganisms perceive phytohormones as stress-signals, allowing them to anticipate impending drought.

scholarly journals Effects of between-site variation in soil microbial communities and plant-soil feedbacks on the productivity and composition of plant communities

2017 ◽  
Vol 54 (4) ◽  
pp. 1028-1039 ◽  
Author(s):  
Jonathan T. Bauer ◽  
Noah Blumenthal ◽  
Anna J. Miller ◽  
Julia K. Ferguson ◽  
Heather L. Reynolds
Keyword(s):  
Microbial Communities ◽  
Plant Communities ◽  
Soil Microbial Communities ◽  
Soil Microbial ◽  
Plant Soil ◽  
Site Variation

scholarly journals A two-phase plant-soil feedback experiment to explore biotic influences on Phragmites australis invasion in North American wetlands

2021 ◽  
Author(s):  
Sean Lee ◽  
Thomas J. Mozdzer ◽  
Samantha K. Chapman ◽  
M. Gonzalez Mateu ◽  
A. H. Baldwin ◽  
...  
Keyword(s):  
North America ◽  
Phragmites Australis ◽  
Biotic Resistance ◽  
Soil Microbial Communities ◽  
Two Phase ◽  
Soil Microbial ◽  
Plant Soil ◽  
Soil Mesocosms ◽  
Soil Feedback ◽  
Resistance To Invasion

Plants can cultivate soil microbial communities that affect subsequent plant growth through a plant-soil feedback (PSF).  Strong evidence indicates that PSFs can mediate the invasive success of exotic upland plants, but many of the most invasive plants occur in wetlands.  In North America, the rapid spread of European Phragmites australis cannot be attributed to innate physiological advantages, thus PSFs may mediate invasion. Here we apply a two-phase fully-factorial plant-soil feedback design in which field-derived soil inocula were conditioned using saltmarsh plants and then were added to sterile soil mesocosms and planted with each plant type.  This design allowed us to assess complete soil biota effects on intraspecific PSFs between native and introduced P. australis as well as heterospecific feedbacks between P. australis and the native wetland grass, Spartina patens. Our results demonstrate that native P. australis experienced negative conspecific feedbacks while introduced P. australis experienced neutral conspecific feedbacks.  Interestingly, S. patens soil inocula inhibited growth in both lineages of P. australis while introduced and native P. australis inocula promoted the growth of S. patens suggestive of biotic resistance against P. australis invasion by S. patens . Our findings suggest that PSFs are not directly promoting the invasion of introduced P. australis in North America. Furthermore, native plants like S. patens seem to exhibit soil microbe mediated biotic resistance to invasion which highlights the importance of disturbance in mediating introduced P. australis invasion.

scholarly journals Increased microbial expression of organic nitrogen cycling genes in long-term warmed grassland soils

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Joana Séneca ◽  
Andrea Söllinger ◽  
Craig W. Herbold ◽  
Petra Pjevac ◽  
Judith Prommer ◽  
...  
Keyword(s):  
Nitrogen Cycling ◽  
Cell Walls ◽  
Organic Nitrogen ◽  
Soil Microbial Communities ◽  
Microbial Cell ◽  
Ambient Conditions ◽  
Soil Microbial ◽  
Soil Temperatures ◽  
Microbial Turnover

AbstractGlobal warming increases soil temperatures and promotes faster growth and turnover of soil microbial communities. As microbial cell walls contain a high proportion of organic nitrogen, a higher turnover rate of microbes should also be reflected in an accelerated organic nitrogen cycling in soil. We used a metatranscriptomics and metagenomics approach to demonstrate that the relative transcription level of genes encoding enzymes involved in the extracellular depolymerization of high-molecular-weight organic nitrogen was higher in medium-term (8 years) and long-term (>50 years) warmed soils than in ambient soils. This was mainly driven by increased levels of transcripts coding for enzymes involved in the degradation of microbial cell walls and proteins. Additionally, higher transcription levels for chitin, nucleic acid, and peptidoglycan degrading enzymes were found in long-term warmed soils. We conclude that an acceleration in microbial turnover under warming is coupled to higher investments in N acquisition enzymes, particularly those involved in the breakdown and recycling of microbial residues, in comparison with ambient conditions.

Soil bacterial communities interact with silicon fraction transformation and promote rice yield after long-term straw return

2021 ◽  
Author(s):  
Alin Song ◽  
Zimin Li ◽  
Fenliang Fan
Keyword(s):  
Microbial Community ◽  
Rice Yield ◽  
Soil Microbial Communities ◽  
Nutrient Sources ◽  
Soil Microbial ◽  
Mn Oxide ◽  
Straw Return ◽  
Soil Bacterial ◽  
Healthy Growth

<p>Returning crop straw into soil is an important practice to balance biogenic and bioavailable silicon (Si) pool in paddy, which is crucial for rice healthy growth. However, it remains elusive how straw return affects Si bioavailability, its uptake, and rice yield, owing to little knowledge about soil microbial communities responsible for straw degradation. Here, we investigated the change of soil Si fractions and microbial community in a 39-year-old paddy field amended by a long-term straw return. Results showed that rice straw-return significantly increased soil bioavailable Si and rice yield to from 29.9% to 61.6% and from 14.5% to 23.6%, respectively, compared to NPK fertilization alone. Straw return significantly altered soil microbial community abundance. Acidobacteria was positively and significantly related to amorphous Si, while Rokubacteria at the phylum level, Deltaproteobacteria and Holophagae at the class level were negatively and significantly related to organic matter adsorbed and Fe/Mn-oxide combined Si in soils. Redundancy analysis of their correlations further demonstrated that Si status significantly explained 12% of soil bacterial community variation. These findings suggest that soil bacteria community and diversity interact with Si mobility via altering its transformation, resulting in the balance of various nutrient sources to drive biological silicon cycle in agroecosystem.</p>

scholarly journals Ozone affects plant, insect, and soil microbial communities: A threat to terrestrial ecosystems and biodiversity

2020 ◽  
Vol 6 (33) ◽  
pp. eabc1176 ◽  
Author(s):  
Evgenios Agathokleous ◽  
Zhaozhong Feng ◽  
Elina Oksanen ◽  
Pierre Sicard ◽  
Qi Wang ◽  
...  
Keyword(s):  
Plant Competition ◽  
Root Exudation ◽  
Soil Microbial Communities ◽  
Alpha Diversity ◽  
Terrestrial Ecosystems ◽  
Insect Communities ◽  
Soil Microbial ◽  
Plant Soil ◽  
Equatorial Africa ◽  
Insect Interactions

Elevated tropospheric ozone concentrations induce adverse effects in plants. We reviewed how ozone affects (i) the composition and diversity of plant communities by affecting key physiological traits; (ii) foliar chemistry and the emission of volatiles, thereby affecting plant-plant competition, plant-insect interactions, and the composition of insect communities; and (iii) plant-soil-microbe interactions and the composition of soil communities by disrupting plant litterfall and altering root exudation, soil enzymatic activities, decomposition, and nutrient cycling. The community composition of soil microbes is consequently changed, and alpha diversity is often reduced. The effects depend on the environment and vary across space and time. We suggest that Atlantic islands in the Northern Hemisphere, the Mediterranean Basin, equatorial Africa, Ethiopia, the Indian coastline, the Himalayan region, southern Asia, and Japan have high endemic richness at high ozone risk by 2100.

scholarly journals Technologies for the Selection, Culture and Metabolic Profiling of Unique Rhizosphere Microorganisms for Natural Product Discovery

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1955 ◽  
Author(s):  
Saliya Gurusinghe ◽  
Tabin L. Brooks ◽  
Russell A. Barrow ◽  
Xiaocheng Zhu ◽  
Agasthya Thotagamuwa ◽  
...  
Keyword(s):  
Microbial Diversity ◽  
Metabolic Profiling ◽  
Plant Growth Promoting Rhizobacteria ◽  
Microbial Culture ◽  
Culture Methods ◽  
Soil Microbial Diversity ◽  
Soil Microbial ◽  
Molecular Features ◽  
Successful Recovery ◽  
Plant Growth Promoting

Small molecule discovery has benefitted from the development of technologies that have aided in the culture and identification of soil microorganisms and the subsequent analysis of their respective metabolomes. We report herein on the use of both culture dependent and independent approaches for evaluation of soil microbial diversity in the rhizosphere of canola, a crop known to support a diverse microbiome, including plant growth promoting rhizobacteria. Initial screening of rhizosphere soils showed that microbial diversity, particularly bacterial, was greatest at crop maturity; therefore organismal recovery was attempted with soil collected at canola harvest. Two standard media (Mueller Hinton and gellan gum) were evaluated following inoculation with soil aqueous suspensions and compared with a novel “rhizochip” prototype buried in a living canola crop rhizosphere for microbial culture in situ. Following successful recovery and identification of 375 rhizosphere microbiota of interest from all culture methods, isolates were identified by Sanger sequencing and/or characterization using morphological and biochemical traits. Three bacterial isolates of interest were randomly selected as case studies for intensive metabolic profiling. After successful culture in liquid media and solvent extraction, individual extracts were subjected to evaluation by UHPLC-DAD-QToF-MS, resulting in the rapid characterization of metabolites of interest from cultures of two isolates. After evaluation of key molecular features, unique or unusual bacterial metabolites were annotated and are reported herein.

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