The Greening of One Health: Plants, Pathogens, and the Environment.

One Health has an aspirational goal of ensuring the health of humans, animals, plants, and the environment through transdisciplinary, collaborative research. At its essence, One Health addresses the human clash with Nature by formulating strategies to repair and restore a (globally) perturbed ecosystem. A more nuanced evaluation of humankind's impact on the environment (Nature, Earth, Gaia) would fully intercalate plants, plant pathogens, and beneficial plant microbes into One Health.

Plant virology: an RNA treasure trove.

Key principles pertaining to RNA biology not infrequently have their origins in plant virology. Examples have arisen from studies on viral RNA-intrinsic properties and the infection process from gene expression, replication, movement, and defense evasion to biotechnological applications. Since RNA is at the core of the central dogma in molecular biology, how plant virology assisted in the reinforcement or adaptations of this concept, while at other instances shook up elements of the doctrine, is discussed.

The Past Is Present: Coevolution of Viruses and Host Resistance Within Geographic Centers of Plant Diversity.

Understanding the coevolutionary history of plants, pathogens, and disease resistance is vital for plant pathology. Here, I review Francis O. Holmes's work with tobacco mosaic virus (TMV) framed by the foundational work of Nikolai Vavilov on the geographic centers of origin of plants and crop wild relatives (CWRs) and T.

Practicing virology: making and knowing a mid-twentieth century experiment with Tobacco mosaic virus.

Tobacco mosaic virus (TMV) has served as a model organism for pathbreaking work in plant pathology, virology, biochemistry and applied genetics for more than a century. We were intrigued by a photograph published in Phytopathology in 1934 showing that Tabasco pepper plants responded to TMV infection with localized necrotic lesions, followed by abscission of the inoculated leaves. This dramatic outcome of a biological response to infection observed by Francis O.

Brachypodium and plant viruses: entwined tools for discovery.

In just a decade, Brachypodium distachyon (Brachypodium) has fulfilled its initial promise as a key tool for realizing new strategies for understanding host and pathogen biology during virus infections of the Poaceae. For this Tansley Insight, I have identified four areas - from the laboratory to the field - that may be particularly fruitful to explore, with a particular focus on Brachypodium-virus infections. These focus areas include: mechanisms of RNA modification of host plants and viruses; coevolution of virus-host interactions; viruses as tools of discovery; and how to explicate the complex outcomes during multivirus infections.

and Its Satellites Acquire RNA Modifications Associated with Host-Mediated Antiviral Degradation.

Positive-sense RNA viruses in the family have genomes lacking a 5' cap structure and prototypical 3' polyadenylation sequence. Instead, these viruses utilize an extensive network of intramolecular RNA-RNA interactions to direct viral replication and gene expression. Here we demonstrate that the genomic RNAs of (PMV) and its satellites undergo sequence modifications at their 3' ends upon infection of host cells.

: A Monocot Grass Model Genus for Plant Biology.

The genus represents a model system that is advancing our knowledge of the biology of grasses, including small grains, in the postgenomics era. The most widely used species, , is a C plant that is distributed worldwide. has a small genome, short life cycle, and small stature and is amenable to genetic transformation.

De novo generation of helper virus-satellite chimera RNAs results in disease attenuation and satellite sequence acquisition in a host-dependent manner.

Panicum mosaic virus (PMV) is a helper RNA virus for satellite RNAs (satRNAs) and a satellite virus (SPMV). Here, we describe modifications that occur at the 3'-end of a satRNA of PMV, satS. Co-infections of PMV+satS result in attenuation of the disease symptoms induced by PMV alone in Brachypodium distachyon and proso millet.

A Beacon for Applied Plant Pathology: The Origins of Plant Disease.

This year marks a full century since the founding of the journal Plant Disease. The story of how the journal developed, from its origins as a service publication of the USDA in 1917 to the leading applied journal in the field today, reflects on major historical themes in plant pathology. Central to this narrative is the delicate balancing act in plant pathology between fundamental and applied science.

Genomic Approaches to Analyze Alternative Splicing, A Key Regulator of Transcriptome and Proteome Diversity in Brachypodium distachyon.

Alternative splicing (AS) promotes transcriptome and proteome diversity in plants, which influences growth and development, and host responses to stress. Advancements in next-generation sequencing, bioinformatics, and computational biology tools have allowed biologists to investigate AS landscapes on a genome-wide scale in several plant species. Furthermore, the development of Brachypodium distachyon (Brachypodium) as a model system for grasses has facilitated comparative studies of AS within the Poaceae.

Complete nucleotide sequences and virion particle association of two satellite RNAs of panicum mosaic virus.

Over six decades ago, panicum mosaic virus (PMV) was identified as the first viral pathogen of cultivated switchgrass (Panicum virgatum). Subsequently, PMV was demonstrated to support the replication of both a satellite RNA virus (SPMV) and satellite RNA (satRNA) agents during natural infections of host grasses. In this study, we report the isolation and full-length sequences of two PMV satRNAs identified in 1988 from St.

Spicing Up the N Gene: F. O. Holmes and Tobacco mosaic virus Resistance in Capsicum and Nicotiana Plants.

One of the seminal events in plant pathology was the discovery by Francis O. Holmes that necrotic local lesions induced on certain species of Nicotiana following rub-inoculation of Tobacco mosaic virus (TMV) was due to a specific interaction involving a dominant host gene (N). From this, Holmes had an idea that if the N gene from N.

Characterization of SCL33 splicing patterns during diverse virus infections in Brachypodium distachyon.

In eukaryotes alternative splicing (AS) influences transcriptome and proteome diversity. The mechanism and the genetic components mediating AS during plant-virus interactions are not known. Using RNA sequencing approaches, we recently analyzed the global AS changes occurring in Brachypodium distachyon (Brachypodium) during infections of Panicum mosaic virus (PMV) and its satellite virus (SPMV).

Genomic architecture and functional relationships of intronless, constitutively- and alternatively-spliced genes in Brachypodium distachyon.

Splicing and alternative splicing (AS) are widespread co- and post-transcriptional regulatory processes in plants. Recently, we characterized genome-wide AS landscapes and virus-induced AS patterns in Brachypodium distachyon (Brachypodium), a C3 model grass. Brachypodium plants infected with Panicum mosaic virus (PMV) alone or in mixed infections with its satellite virus (SPMV) were used for high-throughput, paired-end RNA sequencing.

Multi-Year Pathogen Survey of Biofuel Switchgrass Breeding Plots Reveals High Prevalence of Infections by Panicum mosaic virus and Its Satellite Virus.

Switchgrass (Panicum virgatum) cultivars are currently under development as lignocellulosic feedstock. Here we present a survey of three established switchgrass experimental nurseries in Nebraska in which we identified Panicum mosaic virus (PMV) as the most prevalent virus. In 2012, 72% of 139 symptomatic plants tested positive for PMV.

Finding our roots and celebrating our shoots: Plant virology in Virology, 1955-1964.

To celebrate the sixtieth anniversary of Virology a survey is made of the plant viruses, virologists and their institutions, and tools and technology described in the first decade of plant virus publications in Virology. This was a period when plant viruses increasingly became tools of discovery as epistemic objects and plant virology became a discipline discrete from plant pathology and other life sciences.

Genome-wide analysis of alternative splicing landscapes modulated during plant-virus interactions in Brachypodium distachyon.

In eukaryotes, alternative splicing (AS) promotes transcriptome and proteome diversity. The extent of genome-wide AS changes occurring during a plant-microbe interaction is largely unknown. Here, using high-throughput, paired-end RNA sequencing, we generated an isoform-level spliceome map of Brachypodium distachyon infected with Panicum mosaic virus and its satellite virus.

Comparative analysis of antiviral responses in Brachypodium distachyon and Setaria viridis reveals conserved and unique outcomes among C3 and C4 plant defenses.

Viral diseases cause significant losses in global agricultural production, yet little is known about grass antiviral defense mechanisms. We previously reported on host immune responses triggered by Panicum mosaic virus (PMV) and its satellite virus (SPMV) in the model C3 grass Brachypodium distachyon. To aid comparative analyses of C3 and C4 grass antiviral defenses, here, we establish B.

Plant immune responses against viruses: how does a virus cause disease?

Plants respond to pathogens using elaborate networks of genetic interactions. Recently, significant progress has been made in understanding RNA silencing and how viruses counter this apparently ubiquitous antiviral defense. In addition, plants also induce hypersensitive and systemic acquired resistance responses, which together limit the virus to infected cells and impart resistance to the noninfected tissues.

Making a Virus Visible: Francis O. Holmes and a biological assay for tobacco mosaic virus.

In the early twentieth century, viruses had yet to be defined in a material way. Instead, they were known better by what they were not - not bacteria, not culturable, and not visible with a light microscope. As with the ill-defined "gene" of genetics, viruses were microbes whose nature had not been revealed.

Characterization of a viral synergism in the monocot Brachypodium distachyon reveals distinctly altered host molecular processes associated with disease.

Panicum mosaic virus (PMV) and its satellite virus (SPMV) together infect several small grain crops, biofuel, and forage and turf grasses. Here, we establish the emerging monocot model Brachypodium (Brachypodium distachyon) as an alternate host to study PMV- and SPMV-host interactions and viral synergism. Infection of Brachypodium with PMV+SPMV induced chlorosis and necrosis of leaves, reduced seed set, caused stunting, and lowered biomass, more than PMV alone.

Host impact on the stability of a plant virus gene vector as measured by a new fluorescent local lesion passaging assay.

Viruses can be used as vectors for transient expression of proteins in plants but frequently foreign gene inserts are not maintained stably over time due to recombination events. In this study the hypothesis was that the choice of plant host affects the foreign gene retention level by a Tomato bushy stunt virus (TBSV) vector expressing green fluorescent protein (GFP). To accomplish this, a novel virus vector integrity bioassay was developed based on an old concept, whereby RNA transcripts of the TBSV-GFP vector were rub-inoculated onto leaves of test plants, and at 3 days post inoculation (dpi), these leaves were used as inoculum for passage to cowpea (Vigna unguiculata), a local lesion host.

Top 10 plant viruses in molecular plant pathology.

Many scientists, if not all, feel that their particular plant virus should appear in any list of the most important plant viruses. However, to our knowledge, no such list exists. The aim of this review was to survey all plant virologists with an association with Molecular Plant Pathology and ask them to nominate which plant viruses they would place in a 'Top 10' based on scientific/economic importance.

Induction and suppression of RNA silencing: insights from plant viral infections--a BARD workshop report.

An international workshop on ''Induction and Suppression of RNA Silencing: Insights from Plant Viral Infections'' was sponsored by the United States-Israel Binational Agricultural Research and Development Fund (BARD) and organized in Eilat, Israel in March 2010. The focus of this workshop was on molecular mechanisms employed by viruses or their hosts, and their interactions, for the regulation of virus-induced silencing and suppression. Several of the talks also served as potent reminders of scientific hubris and the need to be attentive to earlier results, both for analyses and perspective regarding new findings.