Diverse plant-associated fungi are thought to have symbiotrophic and saprotrophic states because they can be isolated from both dead and living plant tissues. However, such tissues often are ...separated in time and space, and fungal activity at various stages of plant senescence is rarely assessed directly in fungal community studies.
We used fungal ribosomal RNA metatranscriptomics to detect active fungal communities across a natural senescence gradient within wild-collected gametophytes of Dicranum scoparium (Bryophyta) to understand the distribution of active fungal communities in adjacent living, senescing and dead tissues.
Ascomycota were active in all tissues across the senescence gradient. By contrast, Basidiomycota were prevalent and active in senescing and dead tissues. Several fungi were detected as active in living and dead tissues, suggesting their capacity for multi-trophy. Differences in community assembly detected by metatranscriptomics were echoed by amplicon sequencing of cDNA and compared to culture-based inferences and observation of fungal fruit bodies in the field.
The combination of amplicon sequencing of cDNA and metatranscriptomics is promising for studying symbiotic systems with complex microbial diversity, allowing for the simultaneous detection of their presence and activity.
Plant health depends not only on the condition of the plant itself but also on its diverse community of microbes, or microbiota. Just like the better-studied angiosperms, bryophytes (mosses, ...liverworts, and hornworts) harbor diverse communities of bacteria, archaea, fungi, and other microbial eukaryotes. Bryophytes are increasingly recognized as important model systems for understanding plant evolution, development, physiology, and symbiotic interactions. Much of the work on bryophyte microbiota in the past focused on specific symbiont types for each bryophyte group, but more recent studies have started to expand the view. Therefore, this review integrates studies of bryophyte microbes from both scopes to provide a holistic view of the existing research for each bryophyte group and on key themes. The systematic search also reveals the taxonomic and geographic biases in this field, including a severe underrepresentation of the tropics, very few studies on viruses or eukaryotic microbes beyond fungi, and overrepresentation of mycorrhizal fungi studies in liverworts. Such gaps may lead to errors in conclusions about evolutionary patterns in symbiosis. This analysis points to a wealth of future research directions that promise to reveal how the distinct life cycles and physiology of bryophytes interact with their microbiota.
Background In patients with suspected cardiac sarcoidosis, late gadolinium enhancement on cardiovascular magnetic resonance imaging and/or
F-fluorodeoxyglucose uptake on positron emission tomography ...are often used to reach a clinical diagnosis of cardiac sarcoidosis. On the basis of data from the imaging literature of clinical cardiac sarcoidosis, no specific features of myocardial involvement are regarded as pathognomonic for cardiac sarcoidosis. Thus, a diagnosis of cardiac sarcoidosis is challenging to make. There has been no systematic analysis of histologically diagnosed cardiac sarcoidosis for patterns of myocardial involvement. We hypothesized that certain patterns of myocardial involvement are more frequent in histologically diagnosed cardiac sarcoidosis. Methods and Results We performed a systematic review and meta-analysis of gross pathological images from the published literature of patients with histologically diagnosed cardiac sarcoidosis who underwent autopsy or cardiac transplantation. Thirty-three eligible articles provided images of 49 unique hearts. Analysis of these hearts revealed certain features of myocardial involvement in >90% of cases: left ventricular (LV) subepicardial, LV multifocal, septal, and right ventricular free wall involvement. In contrast, other patterns were seen in 0% to 6% of cases: absence of gross LV myocardial involvement, isolated LV midmyocardial involvement, isolated LV subendocardial involvement, isolated LV transmural involvement, absence of septal involvement, or isolated involvement of only one LV level. Conclusions In this systematic review and meta-analysis of histologically diagnosed cardiac sarcoidosis, we identified certain features of myocardial involvement that occurred frequently and others that occurred rarely or never. These patterns could aid the interpretation of cardiovascular magnetic resonance imaging and positron emission tomography imaging and improve the diagnosis and the prognostication of patients with suspected cardiac sarcoidosis.
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
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.
Plant root-associated microbial symbionts comprise the plant rhizobiome. These microbes function in provisioning nutrients and water to their hosts, impacting plant health and disease. The plant ...microbiome is shaped by plant species, plant genotype, soil and environmental conditions, but the contributions of these variables are hard to disentangle from each other in natural systems. We used bioassay common garden experiments to decouple plant genotype and soil property impacts on fungal and bacterial community structure in the
rhizobiome. High throughput amplification and sequencing of 16S, ITS, 28S and 18S rDNA was accomplished through 454 pyrosequencing. Co-association patterns of fungal and bacterial taxa were assessed with 16S and ITS datasets. Community bipartite fungal-bacterial networks and PERMANOVA results attribute significant difference in fungal or bacterial communities to soil origin, soil chemical properties and plant genotype. Indicator species analysis identified a common set of root bacteria as well as endophytic and ectomycorrhizal fungi associated with
in different soils. However, no single taxon, or consortium of microbes, was indicative of a particular
genotype. Fungal-bacterial networks were over-represented in arbuscular mycorrhizal, endophytic, and ectomycorrhizal fungi, as well as bacteria belonging to the orders Rhizobiales, Chitinophagales, Cytophagales, and Burkholderiales. These results demonstrate the importance of soil and plant genotype on fungal-bacterial networks in the belowground plant microbiome.
Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging is more sensitive than echocardiography for the detection of intracardiac thrombus because of its unique ability to ...identify thrombus based on tissue characteristics related to avascularity. The long-term prognostic significance of left ventricular (LV) thrombus detected by LGE CMR is unknown.
We performed a matched cohort study of consecutive adult patients with LV thrombus detected by LGE CMR who were matched on the date of CMR, age, and LV ejection fraction to up to 3 patients without LV thrombus. We investigated the long-term incidence of a composite of embolic events: stroke, transient ischemic attack, or extracranial systemic arterial embolism. We also compared outcomes among patients with LV thrombus detected by LGE CMR stratified by whether the LV thrombus was also detected by echocardiography or not.
Of 157 LV thrombus patients, 155 were matched to 400 non-LV thrombus patients. During a median follow-up of 3.3 years, the cumulative incidence of embolism was significantly higher in LV thrombus patients compared with the matched non-LV thrombus patients (
<0.001), with annualized rates of 3.7% and 0.8% for LV thrombus and matched non-LV thrombus patients, respectively. LV thrombus was the only independent predictor of the composite embolic end point (hazard ratio, 3.99 95% CI, 1.54-10.35;
=0.004). The cumulative incidence of embolism was not different in patients with LV thrombus that was also detected by echocardiography versus patients with LV thrombus not detected by echocardiography (
=0.25).
Despite contemporary antithrombotic treatment, LV thrombus detected by LGE CMR is associated with a 4-fold higher long-term incidence of embolism compared with matched non-LV thrombus patients. LV thrombus detected by LGE CMR but not by echocardiography is associated with a similar risk of embolism as that detected by both LGE CMR and echocardiography.
High-throughput amplicon sequencing that primarily targets the 16S ribosomal DNA (rDNA) (for bacteria and archaea) and the Internal Transcribed Spacer rDNA (for fungi) have facilitated microbial ...community discovery across diverse environments. A three-step PCR that utilizes flexible primer choices to construct the library for Illumina amplicon sequencing has been applied to several studies in forest and agricultural systems. The three-step PCR protocol, while producing high-quality reads, often yields a large number (up to 46%) of reads that are unable to be assigned to a specific sample according to its barcode. Here, we improve this technique through an optimized two-step PCR protocol. We tested and compared the improved two-step PCR meta-barcoding protocol against the three-step PCR protocol using four different primer pairs (fungal ITS: ITS1F-ITS2 and ITS1F-ITS4, and bacterial 16S: 515F-806R and 341F-806R). We demonstrate that the sequence quantity and recovery rate were significantly improved with the two-step PCR approach (fourfold more read counts per sample; determined reads ≈90% per run) while retaining high read quality (Q30 > 80%). Given that synthetic barcodes are incorporated independently from any specific primers, this two-step PCR protocol can be broadly adapted to different genomic regions and organisms of scientific interest.
Implantable cardioverter-defibrillators are used to prevent sudden cardiac death in patients with cardiac sarcoidosis. The most recent recommendations for implantable cardioverter-defibrillator ...implantation in these patients are in the 2017 American Heart Association/American College of Cardiology/Heart Rhythm Society Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. These recommendations, based on observational studies or expert opinion, have not been assessed. We aimed to assess them.
We performed a large retrospective cohort study of patients with biopsy-proven sarcoidosis and known or suspected cardiac sarcoidosis that underwent cardiovascular magnetic resonance imaging. Patients were followed for a composite end point of significant ventricular arrhythmia or sudden cardiac death. The discriminatory performance of the Guideline recommendations was tested using time-dependent receiver operating characteristic analyses. The optimal cutoff for the extent of late gadolinium enhancement predictive of the composite end point was determined using the Youden index.
In 290 patients, the class I and IIa recommendations identified all patients who experienced the composite end point during a median follow-up of 3.0 years. Patients meeting class I recommendations had a significantly higher incidence of the composite end point than those meeting class IIa recommendations. Left ventricular ejection fraction (LVEF) >35% with >5.7% late gadolinium enhancement on cardiovascular magnetic resonance imaging was as sensitive as and significantly more specific than LVEF >35% with any late gadolinium enhancement. Patients meeting 2 class IIa recommendations, LVEF >35% with the need for a permanent pacemaker and LVEF >35% with late gadolinium enhancement >5.7%, had high annualized event rates. Excluding 2 class IIa recommendations, LVEF >35% with syncope and LVEF >35% with inducible ventricular arrhythmia, resulted in improved discrimination for the composite end point.
We assessed the Guideline recommendations for implantable cardioverter-defibrillator implantation in patients with known or suspected cardiac sarcoidosis and identified topics for future research.
Grasses harbor diverse fungi, including some that produce mycotoxins or other secondary metabolites. Recently, Florida cattle farmers reported cattle illness, while the cattle were grazing on ...warm-season grass pastures, that was not attributable to common causes, such as nutritional imbalances or nitrate toxicity. To understand correlations between grass mycobiome and mycotoxin production, we investigated the mycobiomes associated with five prominent, perennial forage and weed grasses Paspalum notatum Flügge, Cynodon dactylon (L.) Pers., Paspalum nicorae Parodi, Sporobolus indicus (L.) R. Br., and Andropogon virginicus (L.) collected from six Florida pastures actively grazed by livestock. Black fungal stromata of
and
were observed on
and
leaves and were investigated. High-throughput amplicon sequencing was applied to delineate leaf mycobiomes. Mycotoxins from
leaves were inspected using liquid chromatography-mass spectrometry (LC-MS/MS). Grass species, cultivars, and geographic localities interactively affected fungal community assemblies of asymptomatic leaves. Among the grass species, the greatest fungal richness was detected in the weed
. The black fungal structures of
leaves were dominated by the genus
, while those of
were codominated by the genus
and a hypermycoparasitic fungus of the genus
. When comparing mycotoxins detected in
leaves with and without
, emodin, an anthraquinone, was the only compound which was significantly different (
< 0.05). Understanding the leaf mycobiome and the mycotoxins it may produce in warm-season grasses has important implications for how these associations lead to secondary metabolite production and their subsequent impact on animal health.
The leaf mycobiome of forage grasses can have a major impact on their mycotoxin contents of forage and subsequently affect livestock health. Despite the importance of the cattle industry in warm-climate regions, such as Florida, studies have been primarily limited to temperate forage systems. Our study provides a holistic view of leaf fungi considering epibiotic, endophytic, and hypermycoparasitic associations with five perennial, warm-season forage and weed grasses. We highlight that plant identity and geographic location interactively affect leaf fungal community composition. Yeasts appeared to be an overlooked fungal group in healthy forage mycobiomes. Furthermore, we detected high emodin quantities in the leaves of a widely planted forage species (
) whenever epibiotic fungi occurred. Our study demonstrated the importance of identifying fungal communities, ecological roles, and secondary metabolites in perennial, warm-season grasses and their potential for interfering with livestock health.
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