Tropospheric ozone (O3) threatens agroecosystems, yet its long‐term effects on intricate plant‐microbe‐soil interactions remain overlooked. This study employed two soybean genotypes of contrasting ...O3‐sensitivity grown in field plots exposed elevated O3 (eO3) and evaluated cause‐effect relationships with their associated soil microbiomes and soil quality. Results revealed long‐term eO3 effects on belowground soil microbiomes and soil health surpass damage visible on plants. Elevated O3 significantly disrupted belowground bacteria‐fungi interactions, reduced fungal diversity, and altered fungal community assembly by impacting soybean physiological properties. Particularly, eO3 impacts on plant performance were significantly associated with arbuscular mycorrhizal fungi, undermining their contribution to plants, whereas eO3 increased fungal saprotroph proliferation, accelerating soil organic matter decomposition and soil carbon pool depletion. Free‐living diazotrophs exhibited remarkable acclimation under eO3, improving plant performance by enhancing nitrogen fixation. However, overarching detrimental consequences of eO3 negated this benefit. Overall, this study demonstrated long‐term eO3 profoundly governed negative impacts on plant‐soil‐microbiota interactions, pointing to a potential crisis for agroecosystems. These findings highlight urgent needs to develop adaptive strategies to navigate future eO3 scenarios.
Soybean, a global staple crop, is used in rotation practices worldwide to decrease fertilizer use due to its symbiotic relationship with soil nitrogen fixation microbes. Soybean, however, is vulnerable to ozone pollution, leading to low performance and yield. As ozone pollution is projected to increase, a crucial task is understanding how ozone damages soybean and soil microbes, which could reveal a crisis in underground ecosystems. This study demonstrates how long‐term ozone pollution profoundly degrades plant and soil health by altering plant‐microbe‐soil interactions. The findings highlight the urgency for adaptive strategies against future food and economic losses resulting from ozone damage.
Background. Dingji Fumai decoction (DFD) is used to treat ventricular arrhythmia, and it has provided a very good curative effect. However, its cellular electrophysiological mechanism is unknown. ...Methods. Electrocardiogram was recorded, and oxidative stress response and ion-channel-related molecules were detected in rats with barium chloride- and aconitine-induced ventricular arrhythmia. Moreover, whole-cell patch-clamp assay was used to investigate the inhibitory effect of DFD on Nav1.5 in Chinese hamster ovary cells. Results. DFD prolonged the occurrence time and shortened the duration of ventricular arrhythmia, decreased the malondialdehyde and increased the superoxide dismutase, and alleviated the activation of Na+-K+-ATPase and connexin-43. DFD suppressed Nav1.5dose-dependently with an IC50 of 24.0 ± 2.4 mg/mL. Conclusions. The clinical antiarrhythmic mechanisms of DFD are based on its antioxidant potential, alleviation of Na+-K+-ATPase and connexin-43, and class I antiarrhythmic properties by suppressing Nav1.5dose-dependently with an IC50 of 24.0 ± 2.4 mg/mL.
Summary
Mosses harbor fungi whose interactions within their hosts remain largely unexplored. Trophic ranges of fungal endophytes from the moss Dicranum scoparium were hypothesized to encompass ...saprotrophism. This moss is an ideal host to study fungal trophic lability because of its natural senescence gradient, and because it can be grown axenically.
Dicranum scoparium was co‐cultured with each of eight endophytic fungi isolated from naturally occurring D. scoparium. Moss growth rates, and gene expression levels (RNA sequencing) of fungi and D. scoparium, were compared between axenic and co‐culture treatments. Functional lability of two fungal endophytes was tested by comparing their RNA expression levels when colonizing living vs dead gametophytes.
Growth rates of D. scoparium were unchanged, or increased, when in co‐culture. One fungal isolate (Hyaloscyphaceae sp.) that promoted moss growth was associated with differential expression of auxin‐related genes. When grown with living vs dead gametophytes, Coniochaeta sp. switched from having upregulated carbohydrate transporter activity to upregulated oxidation‐based degradation, suggesting an endophytism to saprotrophism transition. However, no such transition was detected for Hyaloscyphaceae sp.
Individually, fungal endophytes did not negatively impact growth rates of D. scoparium. Our results support the long‐standing hypothesis that some fungal endophytes can switch to saprotrophism.
Summary
Research on mycorrhizal symbiosis has been slowed by a lack of established study systems. To address this challenge, we have been developing Suillus, a widespread ecologically and ...economically relevant fungal genus primarily associated with the plant family Pinaceae, into a model system for studying ectomycorrhizal (ECM) associations. Over the last decade, we have compiled extensive genomic resources, culture libraries, a phenotype database, and protocols for manipulating Suillus fungi with and without their tree partners. Our efforts have already resulted in a large number of publicly available genomes, transcriptomes, and respective annotations, as well as advances in our understanding of mycorrhizal partner specificity and host communication, fungal and plant nutrition, environmental adaptation, soil nutrient cycling, interspecific competition, and biological invasions. Here, we highlight the most significant recent findings enabled by Suillus, present a suite of protocols for working with the genus, and discuss how Suillus is emerging as an important model to elucidate the ecology and evolution of ECM interactions.
Bacteria and fungi are primary components in wetland soil microbial communities and provide essential ecosystem functions and services. Understanding responses of bacterial and fungal communities to ...multiple drivers of environmental change and their interactions is crucial for wetland conservation and management, particularly for those embedded in agricultural landscapes. Yet little is known about effect of agricultural land use and wetland management on soil microbial communities in subtropical seasonal wetlands. Here, we used a long-term whole-ecosystem wetland experiment to examine individual and interactive effects of upland land-use intensification, livestock grazing, and prescribed fire on soil bacteria and fungi. We asked: (1) How do land-use intensification, grazing and fire disturbances interact to alter taxonomic composition and functional potential of wetland soil bacterial and fungal communities? (2) To what extent would these management and disturbance effects on wetland microbial communities manifest through alterations in soil properties? Our results showed that both microbial taxonomic and functional composition are responsive to agricultural land use and wetland management. Upland land-use intensification was the strongest driver (as compared to fire and grazing) in shaping bacterial and fungal community composition. Specifically, land-use intensification increased functional richness of both bacteria and fungi, whereas grazing and fire only interactively affected bacterial functional richness. In addition, responses of bacterial and fungal species diversity to wetland management varied, where grazing and fire reduced fungal species diversity in wetlands embedded in low-intensity managed pastures, but none of these management practices altered bacterial species diversity. Further, we found that pH and secondary nutrients (i.e., Ca and Mg) availability were the most important soil properties that explain how agricultural land use and wetland management drive the composition of bacterial and fungal communities. Our findings suggest that integration of lime application into intensified land uses to neutralize soil pH could facilitate maintenance of microbial diversity and associated functions. Our results highlight the need to comprehensively assess management impacts on soil microorganisms, rather than using a single or few indicators, due to inconsistent responses of bacterial and fungal communities, as well as their varied taxonomic and functional responses.
●Agricultural land use and wetland management have either individual or interactive effects on soil microbial communities.●Upland intensification exerts stronger effects on wetland soil microbial communities than grazing and fire.●Fungal diversity is more responsive to land management than bacterial diversity.●Agricultural management and disturbances can affect potential microbial functions in wetlands.
Summary
Bryophytes harbour microbiomes, including diverse communities of fungi. The molecular mechanisms by which perennial mosses interact with these fungal partners along their senescence gradients ...are unknown, yet this is an ideal system to study variation in gene expression associated with trophic state transitions. We investigated differentially expressed genes of fungal communities and their host Dicranum scoparium across its naturally occurring senescence gradient using a metatranscriptomic approach. Higher activity of fungal nutrient‐related (carbon, nitrogen, phosphorus and sulfur) transporters and Carbohydrate‐Active enZyme (CAZy) genes was detected toward the bottom, partially decomposed, layer of the moss. The most prominent variation in the expression levels of fungal nutrient transporters was from inorganic nitrogen‐related transporters, whereas the breakdown of organonitrogens was detected as the most enriched gene ontology term for the host D. scoparium, for those transcripts having higher expression in the partially decomposed layer. The abundance of bacterial rRNA transcripts suggested that more living members of Cyanobacteria are associated with the photosynthetic layer of D. scoparium, while members of Rhizobiales are detected throughout the gametophytes. Plant genes for specific fungal–plant communication, including defense responses, were differentially expressed, suggesting that different genetic pathways are involved in plant‐microbe crosstalk in photosynthetic tissues compared to partially decomposed tissues.
Lethal toxin (LT) is the critical virulence factor of
, the causative agent of anthrax. One common symptom observed in patients with anthrax is thrombocytopenia, which has also been observed in mice ...injected with LT. Our previous study demonstrated that LT induces thrombocytopenia by suppressing megakaryopoiesis, but the precise molecular mechanisms behind this phenomenon remain unknown. In this study, we utilized 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced megakaryocytic differentiation in human erythroleukemia (HEL) cells to identify genes involved in LT-induced megakaryocytic suppression. Through cDNA microarray analysis, we identified Dachshund homolog 1 (
) as a gene that was upregulated upon TPA treatment but downregulated in the presence of TPA and LT, purified from the culture supernatants of
. To investigate the function of DACH1 in megakaryocytic differentiation, we employed short hairpin RNA technology to knock down DACH1 expression in HEL cells and assessed its effect on differentiation. Our data revealed that the knockdown of DACH1 expression suppressed megakaryocytic differentiation, particularly in polyploidization. We demonstrated that one mechanism by which
LT induces suppression of polyploidization in HEL cells is through the cleavage of MEK1/2. This cleavage results in the downregulation of the ERK signaling pathway, thereby suppressing
gene expression and inhibiting polyploidization. Additionally, we found that known megakaryopoiesis-related genes, such as
,
,
,
,
, and
genes may be positively regulated by
. Furthermore, we observed an upregulation of DACH1 during in vitro differentiation of CD34-megakaryocytes and downregulation of DACH1 in patients with thrombocytopenia. In summary, our findings shed light on one of the molecular mechanisms behind LT-induced thrombocytopenia and unveil a previously unknown role for DACH1 in megakaryopoiesis.
Zinc (Zn) is a plant essential micronutrient involved in a wide range of cellular processes. Ectomycorrhizal fungi (EMF) are known to play a critical role in regulating plant Zn status. However, how ...EMF control uptake and translocation of Zn and other nutrients in plant roots under different Zn conditions is not well known. Using X-ray fluorescence imaging, we found the EMF species Suillus luteus increased pine root Zn acquisition under low Zn concentrations and reduced its accumulation under higher Zn levels. By contrast, non-mycorrhizal pine roots exposed to high Zn indiscriminately take up and translocate Zn to root tissues, leading to Zn stress. Regardless of S. luteus inoculation, the absorption pattern of Ca and Cu was similar to Zn. Compared to Ca and Cu, effects of S. luteus on Fe acquisition were more marked, leading to a negative association between Zn addition and Fe concentration within EMF roots. Besides, higher nutrient accumulation in the fungal sheath, compared to hyphae inhabiting between intercellular space of cortex cells, implies the fungal sheath serves as a barrier to regulate nutrient transportation into fungal Hartig net. Our results demonstrate the crucial roles EMF play in plant nutrient uptake and how fungal partners ameliorate soil chemical conditions either by increasing or decreasing element uptake.
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•S. luteus dually regulated Zn uptake of pine roots depending on external Zn level.•Non-mycorrhizal pine roots exposed to high Zn indiscriminately take up Zn.•The absorption pattern of Ca, Cu, and Zn in pine roots was similar across Zn levels.•Fe uptake was negatively affected by Zn level within ectomycorrhizal pine root.•Higher accumulation of nutrients was found in fungal sheath compared to Hartig net.
As our understanding of soil biology deepens, there is a growing demand for investigations addressing microbial processes in the earth beneath the topsoil layer, called subsoil. High clay content in ...subsoils often hinders the recovery of sufficient quantities of DNA as clay particles bind nucleic acids. Here, an efficient and reproducible DNA extraction method for 200 mg dried soil based on sodium dodecyl sulfate (SDS) lysis in the presence of phosphate buffer has been developed. The extraction protocol was optimized by quantifying bacterial 16S and fungal 18S rRNA genes amplified from extracts obtained by different combinations of lysis methods and phosphate buffer washes. The combination of one minute of bead beating, followed by ten min incubation at 65°C in the presence of 1 M phosphate buffer with 0.5% SDS, was found to produce the best results. The optimized protocol was compared with a commonly used cetyltrimethylammonium bromide (CTAB) method, using Phaeozem soil collected from 60 cm depth at a conventional agricultural field and validated on five subsoils. The reproducibility and robustness of the protocol was corroborated by an interlaboratory comparison. The DNA extraction protocol offers a reproducible and cost-effective tool for DNA-based studies of subsoil biology.
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