Phenolic acid-degrading Paraburkholderia prime decomposition in forest soil

AbstractPlant-derived phenolic acids are catabolized by soil microorganisms whose activity may enhance the decomposition of soil organic carbon (SOC). We characterized whether phenolic acid-degrading bacteria enhance SOC mineralization in forest soils when primed with 13C-labeled p-hydroxybenzoic acid (pHB). We further tested whether pHB-induced priming could explain differences in SOC content among mono-specific tree plantations in a 70-year-old common garden experiment. pHB addition primed significant losses of SOC (3–13 µmols C g−1 dry wt soil over 7 days) compared to glucose, which reduced mineralization (-3 to -8 µmols C g−1 dry wt soil over 7 days). The principal degraders of pHB were Paraburkholderia and Caballeronia in all plantations regardless of tree species or soil type, with one predominant phylotype (RP11ASV) enriched 23-fold following peak pHB respiration. We isolated and confirmed the phenolic degrading activity of a strain matching this phylotype (RP11T), which encoded numerous oxidative enzymes, including secretion signal-bearing laccase, Dyp-type peroxidase and aryl-alcohol oxidase. Increased relative abundance of RP11ASV corresponded with higher pHB respiration and expression of pHB monooxygenase (pobA), which was inversely proportional to SOC content among plantations. pobA expression proved a responsive measure of priming activity. We found that stimulating phenolic-acid degrading bacteria can prime decomposition and that this activity, corresponding with differences in tree species, is a potential mechanism in SOC cycling in forests. Overall, this study highlights the ecology and function of Paraburkholderia whose associations with plant roots and capacity to degrade phenolics suggest a role for specialized bacteria in the priming effect.

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Phenolic acid-degrading Paraburkholderia prime decomposition in forest soil

10.1101/2020.09.28.317347 ◽

2020 ◽

Cited By ~ 1

Author(s):

Roland C. Wilhelm ◽

Christopher M. DeRito ◽

James P. Shapleigh ◽

Eugene L. Madsen ◽

Daniel H. Buckley

Keyword(s):

Forest Soils ◽

Phenolic Acid ◽

Alcohol Oxidase ◽

Common Garden ◽

Significant Loss ◽

Oxidative Enzymes ◽

Specific Response ◽

Secretion Signal ◽

Degrading Bacteria ◽

Soc Mineralization

AbstractPlant-derived phenolic acids are metabolized by soil microorganisms whose activity may enhance the decomposition of soil organic carbon (SOC). We characterized whether phenolic acid-degrading bacteria would enhance SOC mineralization in forest soils when primed with 13C-labeled p-hydroxybenzoic acid (PHB). We further investigated whether PHB-induced priming could explain differences in SOC content among mono-specific tree plantations in a 70-year-old common garden experiment. The activity of Paraburkholderia and Caballeronia dominated PHB degradation in all soils regardless of tree species or soil type. We isolated the principal PHB-degrading phylotype (Paraburkholderia madseniana RP11T), which encoded numerous oxidative enzymes, including secretion signal-bearing laccase, aryl-alcohol oxidase and DyP-type peroxidase, and confirmed its ability to degrade phenolics. The addition of PHB to soil led to significant enrichment (23-fold) of the RP11T phylotype (RP11ASV), as well as enrichment of other phylotypes of Paraburkholderia and Caballeronia. Metabolism of PHB primed significant loss of SOC (3 to 13 µmols C g-1 dry wt soil over 7 days). In contrast, glucose addition reduced SOC mineralization (−3 to -8 µmols C g-1 dry wt soil over 7 days). RP11ASV abundance and the expression of PHB monooxygenase (pobA) correlated with PHB respiration and were inversely proportional to SOC content in the field. We propose that plant-derived phenolics stimulate the activity of phenolic acid-degrading bacteria thereby causing soil priming and SOC loss. We show that Burkholderiaceae dominate soil priming in diverse forest soils and this observation counters the prevailing view that priming phenomena are a generalized non-specific response of community metabolism.

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Light and propagule pressure affect invasion intensity of Prunus serotina in a 14-tree species forest common garden experiment

NeoBiota ◽

10.3897/neobiota.46.30413 ◽

2019 ◽

Vol 46 ◽

pp. 1-21 ◽

Cited By ~ 6

Author(s):

Andrzej M. Jagodziński ◽

Marcin K. Dyderski ◽

Paweł Horodecki ◽

Kathleen S. Knight ◽

Katarzyna Rawlik ◽

...

Keyword(s):

Aboveground Biomass ◽

Tree Species ◽

Propagule Pressure ◽

Light Availability ◽

Common Garden ◽

Additive Models ◽

Common Garden Experiment ◽

Tree Stand ◽

Biomass Increment ◽

The Impact

Experiments testing multiple factors that affect the rate of invasions in forests are scarce. We aimed to assess how the biomass of invasive Prunusserotina changed over eight years and how this change was affected by light availability, tree stand growth, and propagule pressure. The study was conducted in Siemianice Experimental Forest (W Poland), a common garden forest experiment with 14 tree species. We investigated aboveground biomass and density of P.serotina within 53 experimental plots with initial measurements in 2005 and repeated in 2013. We also measured light availability and distance from seed sources. We used generalized additive models to assess the impact of particular predictors on P.serotina biomass in 2013 and its relative change over eight years. The relative biomass increments of P.serotina ranged from 0 to 22,000-fold. The success of P.serotina, expressed as aboveground biomass and biomass increment, varied among different tree species stands, but was greater under conifers. Total biomass of P.serotina depended on light and propagule availability while biomass increment depended on the change in tree stand biomass, a metric corresponding to tree stand maturation. Our study quantified the range of invasion intensity, expressed as biomass increment, in a forest common garden experiment with 14 tree species. Canopy cover was the most important variable to reduce susceptibility to invasion by P.serotina. Even a modest decrease of overstory biomass, e.g. caused by dieback of coniferous species, may be risky in areas with high propagule pressure from invasive tree species. Thus, P.serotina control may include maintaining high canopy closure and supporting natural regeneration of tree species with high leaf area index, which shade the understory.

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Effects of litter traits, soil biota, and soil chemistry on soil carbon stocks at a common garden with 14 tree species

Biogeochemistry ◽

10.1007/s10533-015-0083-6 ◽

2015 ◽

Vol 123 (3) ◽

pp. 313-327 ◽

Cited By ~ 49

Author(s):

Kevin E. Mueller ◽

Sarah E. Hobbie ◽

Jon Chorover ◽

Peter B. Reich ◽

Nico Eisenhauer ◽

...

Keyword(s):

Soil Carbon ◽

Tree Species ◽

Soil Chemistry ◽

Common Garden ◽

Carbon Stocks ◽

Soil Biota ◽

Litter Traits ◽

Soil Carbon Stocks

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High-level expression of aryl-alcohol oxidase 2 from Pleurotus eryngii in Pichia pastoris for production of fragrances and bioactive precursors

Applied Microbiology and Biotechnology ◽

10.1007/s00253-020-10878-4 ◽

2020 ◽

Vol 104 (21) ◽

pp. 9205-9218

Author(s):

Nina Jankowski ◽

Katja Koschorreck ◽

Vlada B. Urlacher

Keyword(s):

Pichia Pastoris ◽

Alcohol Oxidase ◽

Building Blocks ◽

Pleurotus Eryngii ◽

Oxidation Products ◽

Oxidative Enzymes ◽

Biotechnological Applications ◽

Positive Health ◽

Neuroprotective Effects ◽

Flavor Compound

Abstract The fungal secretome comprises various oxidative enzymes participating in the degradation of lignocellulosic biomass as a central step in carbon recycling. Among the secreted enzymes, aryl-alcohol oxidases (AAOs) are of interest for biotechnological applications including production of bio-based precursors for plastics, bioactive compounds, and flavors and fragrances. Aryl-alcohol oxidase 2 (PeAAO2) from the fungus Pleurotus eryngii was heterologously expressed and secreted at one of the highest yields reported so far of 315 mg/l using the methylotrophic yeast Pichia pastoris (recently reclassified as Komagataella phaffii). The glycosylated PeAAO2 exhibited a high stability in a broad pH range between pH 3.0 and 9.0 and high thermal stability up to 55 °C. Substrate screening with 41 compounds revealed that PeAAO2 oxidized typical AAO substrates like p-anisyl alcohol, veratryl alcohol, and trans,trans-2,4-hexadienol with up to 8-fold higher activity than benzyl alcohol. Several compounds not yet reported as substrates for AAOs were oxidized by PeAAO2 as well. Among them, cumic alcohol and piperonyl alcohol were oxidized to cuminaldehyde and piperonal with high catalytic efficiencies of 84.1 and 600.2 mM−1 s−1, respectively. While the fragrance and flavor compound piperonal also serves as starting material for agrochemical and pharmaceutical building blocks, various positive health effects have been attributed to cuminaldehyde including anticancer, antidiabetic, and neuroprotective effects. PeAAO2 is thus a promising biocatalyst for biotechnological applications. Key points • Aryl-alcohol oxidase PeAAO2 from P. eryngii was produced in P. pastoris at 315 mg/l. • Purified enzyme exhibited stability over a broad pH and temperature range. • Oxidation products cuminaldehyde and piperonal are of biotechnological interest. Graphical abstract

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Invasive earthworms unlock arctic plant nitrogen limitation

Nature Communications ◽

10.1038/s41467-020-15568-3 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 1

Author(s):

Gesche Blume-Werry ◽

Eveline J. Krab ◽

Johan Olofsson ◽

Maja K. Sundqvist ◽

Maria Väisänen ◽

...

Keyword(s):

Fine Root ◽

Common Garden ◽

Root Production ◽

Common Garden Experiment ◽

Arctic Ecosystems ◽

Plant Nitrogen ◽

Soil Microbial ◽

Invasive Earthworms ◽

Plant Soil ◽

And Function

AbstractArctic plant growth is predominantly nitrogen (N) limited. This limitation is generally attributed to slow soil microbial processes due to low temperatures. Here, we show that arctic plant-soil N cycling is also substantially constrained by the lack of larger detritivores (earthworms) able to mineralize and physically translocate litter and soil organic matter. These new functions provided by earthworms increased shrub and grass N concentration in our common garden experiment. Earthworm activity also increased either the height or number of floral shoots, while enhancing fine root production and vegetation greenness in heath and meadow communities to a level that exceeded the inherent differences between these two common arctic plant communities. Moreover, these worming effects on plant N and greening exceeded reported effects of warming, herbivory and nutrient addition, suggesting that human spreading of earthworms may lead to substantial changes in the structure and function of arctic ecosystems.

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Selection of tree species for forests under climate change: is PSI functioning a better predictor for net photosynthesis and growth than PSII?

Tree Physiology ◽

10.1093/treephys/tpaa084 ◽

2020 ◽

Vol 40 (11) ◽

pp. 1561-1571 ◽

Cited By ~ 1

Author(s):

Martina Pollastrini ◽

Elisabetta Salvatori ◽

Lina Fusaro ◽

Fausto Manes ◽

Riccardo Marzuoli ◽

...

Keyword(s):

Climate Change ◽

Chlorophyll Fluorescence ◽

Tree Species ◽

Leaf Gas Exchange ◽

Central Italy ◽

Common Garden ◽

Net Photosynthesis ◽

Photosynthetic Performance ◽

Seasonal Temperature

Abstract A chlorophyll fluorescence (ChlF) assessment was carried out on oak seedlings (Quercus ilex L., Quercus pubescens Willd., Quercus frainetto Ten.) of Italian and Greek provenance, during the years 2017 and 2018, in a common garden in central Italy planted in 2017. This trial aimed to test the relative performances of the oak species in the perspective of assisted migration as part of the actions for the adaptation of forests to climate change. The assessment of the photosynthetic performance of the tree species included the analysis of the prompt chlorophyll fluorescence (PF) transient and the modulated reflection (MR) at 820 nm, leaf chlorophyll content, leaf gas exchange (net photosynthesis, stomatal conductance), plant growth (i.e., height) and mortality rate after 2 years from the beginning of the experiment. The assessment of the performance of the three oak species was carried out ‘in vivo’. Plants were generated from seeds and exposed to several environmental factors, including changing seasonal temperature, water availability, and soil biological and physical functionality. The results of PF indicate a stable functionality of the photosynthetic system PSII (expressed as FV/FM) across species and provenances and a decline in photochemistry functionality at the I–P phase (ΔVIP) in Q. frainetto, thus indicating a decline of the content of PSI in this species. This result was confirmed by the findings of MR analysis, with the speed of reduction and subsequent oxidation of PSI (VRED and VOX) strongly correlated to the amplitude of ΔVIP. The photosynthetic rates (net photosynthesis, PN) and growth were correlated with the parameters associated with PSI content and function, rather than those related to PSII. The low performance of Q. frainetto in the common garden seems to be related to early foliar senescence with the depletion of nitrogen, due to suboptimal climatic and edaphic conditions. Chlorophyll fluorescence allowed discrimination of populations of oak species and individuation of the less (or/and best) suitable species for future forest ecology and management purposes.

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The colour of fossil feathers

Biology Letters ◽

10.1098/rsbl.2008.0302 ◽

2008 ◽

Vol 4 (5) ◽

pp. 522-525 ◽

Cited By ~ 123

Author(s):

Jakob Vinther ◽

Derek E.G Briggs ◽

Richard O Prum ◽

Vinodkumar Saranathan

Keyword(s):

Lower Cretaceous ◽

Carbon Residue ◽

Energy Dispersive ◽

Colour Pattern ◽

Rock Matrix ◽

X Ray ◽

Theropod Dinosaurs ◽

Degrading Bacteria ◽

And Function

Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1–2 μm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.

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