Biology subjects

Herr, J. R.

Publications and source records attributed to Herr, J. R..

4 recordsLinked to original sources

bioRxiv2021

The Application of The Skin Virome for Human Identification

The use of skin virome for human identification purposes offers a unique approach to instances where a viable and statistically relevant human DNA profile is unavailable. The human skin virome may act as an alternative DNA profile and/or an additional form of probative genetic material. To date, no study has attempted to investigate the human virome over a time series across various physical locations of the body to identify its potential as a tool for human identification. For this study, we set out to evaluate the stability, diversity, and individualization of the human skin virome. An additional goal was to identify viral signatures that can be used in conjunction with traditional forensic STR loci. In order to accomplish this, human virome metagenomes were collected and sequenced from 42 individuals at three anatomical locations (left hand, right hand, and scalp) across multiple collections periods over a 6-month window of time. Assembly dependent and independent bioinformatic approaches were employed, along with a database-based assessment, which resulted in three sets of stable putative viral markers. In total, with the three sets combined, 59 viral species and uncharacterized viral genome assemblies were identified as being significantly stable (P=5.3x10-15). Viral diversity, based on presence or absence, is significantly different across subjects (P<0.001). Here we demonstrate that not only is the human virome applicable to be used for human identification, but we have identified many viral signatures that can be used for forensic applications, thus providing a foundation to the novel field of forensic virology. HighlightsO_LIHere we provide the largest human skin virome study, to date. Our study revealed novel diversity findings of high abundance for certain viral taxa, for example, the Cress-like DNA phages, that have not previously been characterized in human skin viral ecology studies. C_LIO_LIThere were 59 putative human skin viral biomarkers suitable for human identification from the core stable human skin virome of 42 subjects. C_LIO_LIThe putative markers we identified were significantly stable over a 6-month period of time within individuals and across three autosomal locations of left hand, right hand, and scalp. C_LIO_LIDiversity of profiles, based on the presence and absence of our putative marker data set, were significantly different across test subjects. C_LI

microbiology↗

bioRxiv2021

Global distribution and richness of Armillaria species inferred from public databases and amplicon sequencing datasets

Armillaria is a globally distributed fungal genus most notably recognized as economically important plant pathogens that are found predominantly in forest and agronomic systems. The genus sensu lato has more recently received attention for its role in woody plant decomposition and in mycorrhizal symbiosis with specific plants. Previous phylogenetic analyses suggest that around 50 species are recognized globally. Despite this previous work, no studies have analyzed the global species richness and distribution of the genus using data derived from fungal community sequencing datasets or barcoding initiatives. To assess the global diversity and species richness of Armillaria, we mined publicly available sequencing datasets derived from numerous primer regions for the ribosomal operon, as well ITS sequences deposited on Genbank, and clustered them akin to metabarcoding studies. Our estimates reveal that species richness ranges from 50 to 60 species, depending on whether the ITS1 or ITS2 marker is used. Eastern Asia represents the biogeographic region with the highest species richness. We also assess the overlap of species across geographic regions and propose some hypotheses regarding the drivers of variability in species diversity and richness between different biogeographic regions.

evolutionary biology↗

bioRxiv2021

Transcriptomics reveals the mycoparasitic strategy of the mushroom Entoloma abortivum on species of the mushroom Armillaria

During mycoparasitism, a fungus--the host--is parasitized by another fungus--the mycoparasite. The genetic underpinnings of these relationships have been best characterized in ascomycete fungi. However, within basidiomycete fungi, there are rare instances of mushroom-forming species parasitizing the reproductive structures, or sporocarps, of other mushroom-forming species, which have been rarely investigated on a genetic level. One of the most enigmatic of these occurs between Entoloma abortivum and species of Armillaria, where hyphae of E. abortivum are hypothesized to disrupt the development of Armillaria sporocarps, resulting in the formation of carpophoroids. However, it remains unknown whether carpophoroids are the direct result of a mycoparasitic relationship. To address the nature of this unique interaction, we analyzed gene expression of field-collected Armillaria and E. abortivum sporocarps and carpophoroids. Transcripts in the carpophoroids are primarily from E. abortivum, supporting the hypothesis that this species is parasitizing Armillaria. Most notably, we identified differentially upregulated E. abortivum {beta}-trefoil-type lectins in the carpophoroid, which we hypothesize bind to Armillaria cell wall galactomannoproteins, thereby mediating recognition between the mycoparasite and the host. The most differentially upregulated E. abortivum transcripts in the carpophoroid code for oxalate decarboxylases--enzymes that degrade oxalic acid. Oxalic acid is a virulence factor in many plant pathogens, including Armillaria species, however, E. abortivum has evolved a sophisticated strategy to overcome this defense mechanism. The number of gene models and genes that code for carbohydrate-active enzymes in the E. abortivum transcriptome were reduced compared to other closely related species, perhaps as a result of the specialized nature of this interaction. IMPORTANCEBy studying fungi that parasitize other fungi, we can understand the basic biology of these unique interactions. Studies focused on the genetic mechanisms regulating mycoparasitism between host and parasite have thus far concentrated on a single fungal lineage within the Ascomycota. The work presented here expands our understanding of mycoparasitic relationships to the Basidiomycota and represents the first transcriptomic study to our knowledge that examines fungal-fungal relationships in their natural setting. The results presented here suggest that even distantly related mycoparasites utilize similar mechanisms to parasitize their host. Given that species of the mushroom-forming pathogen Armillaria cause plant root-rot diseases in many agroecosystems, an enhanced understanding of this interaction may contribute to better control of these diseases through biocontrol applications.

ecology↗

bioRxiv2020

Rhizosphere Microbiomes in a Historical Maize/Soybean Rotation System respond to Host Species and Nitrogen Fertilization at Genus and Sub-genus Levels

Root associated microbes are key players in plant health, disease resistance, and nitrogen (N) use efficiency. It remains largely unclear how the interplay of biological and environmental factors affects rhizobiome dynamics in agricultural systems. Here, we quantified the composition of rhizosphere and bulk soil microbial communities associated with maize (Zea mays L.) and soybean (Glycine max L.) in a long-term crop rotation study under conventional fertilization and low N regimes. Over two growing seasons, we evaluated the effects of environmental conditions and several treatment factors on the abundance of rhizosphere and soil colonizing microbial taxa. Time of sampling, host plant species and N fertilization had major effects on microbiomes, while no effect of crop rotation was observed. Using variance partitioning as well as 16S sequence information, we further defined a set of 82 microbial genera and sub-genus groups that show distinct responses to treatment factors. We identified taxa that are highly specific to either maize or soybean rhizospheres, as well as taxa that are sensitive to N fertilization in plant rhizospheres and bulk soil. This study provides insights to harness the full potential of soil microbes in maize and soybean agricultural systems through plant breeding and field management.

plant biology↗