The Nucleic Acids of Multipartite, Defective, and Satellite Plant Viruses

2018 ◽  
pp. 65-110
Author(s):  
L. C. Lane
Keyword(s):  
2015 ◽  
Vol 105 (6) ◽  
pp. 716-727 ◽  
Author(s):  
Marilyn J. Roossinck ◽  
Darren P. Martin ◽  
Philippe Roumagnac

In recent years plant viruses have been detected from many environments, including domestic and wild plants and interfaces between these systems—aquatic sources, feces of various animals, and insects. A variety of methods have been employed to study plant virus biodiversity, including enrichment for virus-like particles or virus-specific RNA or DNA, or the extraction of total nucleic acids, followed by next-generation deep sequencing and bioinformatic analyses. All of the methods have some shortcomings, but taken together these studies reveal our surprising lack of knowledge about plant viruses and point to the need for more comprehensive studies. In addition, many new viruses have been discovered, with most virus infections in wild plants appearing asymptomatic, suggesting that virus disease may be a byproduct of domestication. For plant pathologists these studies are providing useful tools to detect viruses, and perhaps to predict future problems that could threaten cultivated plants.


2009 ◽  
Vol 83 (9) ◽  
pp. 4642-4651 ◽  
Author(s):  
Joseph G. Victoria ◽  
Amit Kapoor ◽  
Linlin Li ◽  
Olga Blinkova ◽  
Beth Slikas ◽  
...  

ABSTRACT We analyzed viral nucleic acids in stool samples collected from 35 South Asian children with nonpolio acute flaccid paralysis (AFP). Sequence-independent reverse transcription and PCR amplification of capsid-protected, nuclease-resistant viral nucleic acids were followed by DNA sequencing and sequence similarity searches. Limited Sanger sequencing (35 to 240 subclones per sample) identified an average of 1.4 distinct eukaryotic viruses per sample, while pyrosequencing yielded 2.6 viruses per sample. In addition to bacteriophage and plant viruses, we detected known enteric viruses, including rotavirus, adenovirus, picobirnavirus, and human enterovirus species A (HEV-A) to HEV-C, as well as numerous other members of the Picornaviridae family, including parechovirus, Aichi virus, rhinovirus, and human cardiovirus. The viruses with the most divergent sequences relative to those of previously reported viruses included members of a novel Picornaviridae genus and four new viral species (members of the Dicistroviridae, Nodaviridae, and Circoviridae families and the Bocavirus genus). Samples from six healthy contacts of AFP patients were similarly analyzed and also contained numerous viruses, particularly HEV-C, including a potentially novel Enterovirus genotype. Determining the prevalences and pathogenicities of the novel genotypes, species, genera, and potential new viral families identified in this study in different demographic groups will require further studies with different demographic and patient groups, now facilitated by knowledge of these viral genomes.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2683
Author(s):  
Tatsuji Hataya

Gene amplification techniques such as polymerase chain reaction (PCR) are widely used for the diagnosis of plant diseases caused by viruses and viroids. It is preferable that sample preparation methods for PCR or reverse transcription (RT) PCR are rapid, straightforward, and inexpensive. We previously reported a method for the extraction of nucleic acids without mechanical tissue grinding using a buffer containing potassium ethyl xanthogenate (PEX) to detect viroid RNAs. In the present report, the previous PEX method was improved and simplified. In the simplified PEX (SPEX) method, the process of PEX buffer treatment for plant cell wall disruption is improved to one step of incubation at 80 °C for 10 min, instead of three steps that took more than 26 min at 65 °C in the previous method. Total nucleic acids could be extracted from fresh, frozen, or dried leaves of a cultivar or wild species of tobacco, tomato, citron, hop plants, and pericarps of persimmon fruits by the SPEX method. Several RNA viruses and viroids were successfully detected from the extracted nucleic acids together with an internal mRNA by RT-PCR. The SPEX method may be useful for detecting not only viruses and viroids, but also other plant pathogens.


Author(s):  
Evan E. Ellison ◽  
◽  
James C. Chamness ◽  
Daniel F. Voytas ◽  
◽  
...  

A significant challenge for plant gene editing is the delivery of editing reagents to germline or regenerable cells to recover heritable genetic modifications. Reagent delivery using biolistics or Agrobacterium is only possible with a limited range of species and genotypes, and inefficient editing or lengthy tissue culture steps further limit throughput. Viruses are natural vectors for nucleic acids, and both DNA and RNA plant viruses have been engineered to extend or replace conventional vectors for delivery of gene editing reagents. Here, we review aspects of viral biology essential for engineering vectors, highlight landmark studies using viruses to overcome traditional limitations in gene editing, and outline important considerations for the use of viral vectors in new systems or for new targets. Motivated by fundamental differences in both their infection modes and utility as vectors, DNA and RNA viruses are treated separately.


Author(s):  
N.C. Lyon ◽  
W. C. Mueller

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.


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