Plant viruses, unique and intriguing pathogens, a textbook of plant virology

2001 ◽  
Vol 20 (2) ◽  
pp. 173-174
Author(s):  
J.M Thresh
Keyword(s):  
Author(s):  
András Takács ◽  
József Horváth ◽  
Richard Gáborjányi ◽  
Gabriella Kazinczi ◽  
József Mikulás

2021 ◽  
Vol 11 ◽  
Author(s):  
Muhammad Shafiq Shahid ◽  
Muhammad Naeem Sattar ◽  
Zafar Iqbal ◽  
Amir Raza ◽  
Abdullah M. Al-Sadi

In recent years, next-generation sequencing (NGS) and contemporary Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-CRISPR-associated (Cas) technologies have revolutionized the life sciences and the field of plant virology. Both these technologies offer an unparalleled platform for sequencing and deciphering viral metagenomes promptly. Over the past two decades, NGS technologies have improved enormously and have impacted plant virology. NGS has enabled the detection of plant viruses that were previously undetectable by conventional approaches, such as quarantine and archeological plant samples, and has helped to track the evolutionary footprints of viral pathogens. The CRISPR-Cas-based genome editing (GE) and detection techniques have enabled the development of effective approaches to virus resistance. Different versions of CRISPR-Cas have been employed to successfully confer resistance against diverse plant viruses by directly targeting the virus genome or indirectly editing certain host susceptibility factors. Applications of CRISPR-Cas systems include targeted insertion and/or deletion, site-directed mutagenesis, induction/expression/repression of the gene(s), epigenome re-modeling, and SNPs detection. The CRISPR-Cas toolbox has been equipped with precision GE tools to engineer the target genome with and without double-stranded (ds) breaks or donor templates. This technique has also enabled the generation of transgene-free genetically engineered plants, DNA repair, base substitution, prime editing, detection of small molecules, and biosensing in plant virology. This review discusses the utilities, advantages, applications, bottlenecks of NGS, and CRISPR-Cas in plant virology.


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.


Author(s):  
K. Pegg-Feige ◽  
F. W. Doane

Immunoelectron microscopy (IEM) applied to rapid virus diagnosis offers a more sensitive detection method than direct electron microscopy (DEM), and can also be used to serotype viruses. One of several IEM techniques is that introduced by Derrick in 1972, in which antiviral antibody is attached to the support film of an EM specimen grid. Originally developed for plant viruses, it has recently been applied to several animal viruses, especially rotaviruses. We have investigated the use of this solid phase IEM technique (SPIEM) in detecting and identifying enteroviruses (in the form of crude cell culture isolates), and have compared it with a modified “SPIEM-SPA” method in which grids are coated with protein A from Staphylococcus aureus prior to exposure to antiserum.


Author(s):  
M. F. Miller ◽  
A. R. Rubenstein

Studies of rotavirus particles in humans, monkeys and various non-primates with acute gastroenteritis have involved detection of virus in fecal material by electron microscopy. The EM techniques most commonly employed have been the conventional negative staining (Fig. 1) and immune aggregation (Fig. 2) procedures. Both methods are somewhat insensitive and can most reliably be applied to samples containing large quantities of virus either naturaLly or as a result of concentration by ultracentrifugation. The formation of immune complexes by specific antibody in the immune aggregation procedures confirms the rotavirus diagnosis, but the number of particles per given microscope field is effectively reduced by the aggregation process. In the present communication, we describe use of an on-grid immunoelectron microscopic technique in which rotavirus particles are mounted onto microscope grids that were pre-coated with specific antibody. The technique is a modification of a method originalLy introduced by Derrick (1) for studies of plant viruses.


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