A guide to the contained use of plant virus infectious clones

Abstract

Plant virus infectious clones are important tools with wide‐ranging applications in different areas of biology and medicine. Their uses in plant pathology include the study of plant–virus interactions, and screening of germplasm as part of prebreeding programmes for virus resistance. They can also be modified to induce transient plant gene silencing (Virus Induced Gene Silencing – VIGS) and as expression vectors for plant or exogenous proteins, with applications in both plant pathology and more generally for the study of plant gene function. Plant viruses are also increasingly being investigated as expression vectors for in planta production of pharmaceutical products, known as molecular farming. However, plant virus infectious clones may pose a risk to the environment due to their ability to reconstitute fully functional, transmissible viruses. These risks arise from both their inherent pathogenicity and the effect of any introduced genetic modifications. Effective containment measures are therefore required. There has been no single comprehensive review of the biosafety considerations for the contained use of genetically modified plant viruses, despite their increasing importance across many biological fields. This review therefore explores the biosafety considerations for working with genetically modified plant viruses in contained environments, with focus on plant growth facilities. It includes regulatory frameworks, risk assessment, assignment of biosafety levels, facility features and working practices. The review is based on international guidance together with information provided by plant virus researchers.

Cassava brown streak virus Ham1 protein hydrolyses mutagenic nucleotides and is a necrosis determinant

“…Infected plant material and viral ICs were used under the DEFRA license no. 51045/197610/2 and handled according to Brewer et al (). IC manipulations were performed through homologous yeast recombination according to the protocol outlined in Duff‐Farrier et al (, ).…”

Harnessed viruses in the age of metagenomics and synthetic biology: an update on infectious clone assembly and biotechnologies of plant viruses

“…Containment of plant viruses in laboratories and closed facilities can be achieved by specific regulatory frameworks that include physical and logistical barriers as well as staff training, which have been reviewed recently (Brewer et al, 2018). Notwithstanding, a major goal of synthetic biology is to build engineered organisms with improved or new functions and applications that can solve real-world needs (Liu and Stewart, 2015).…”

Production of Bioactive Recombinant Reteplase by Virus-Based Transient Expression System in Nicotiana benthamiana

“…An outstanding advantage of virus-based expression system is that the target proteins can be produced at very high levels in a matter of days due to viral amplification (Hefferon, 2017). Among various plant viral gene vectors, Tobacco mosaic virus (TMV)-based expression vector has been widely and successfully applied to express biologically active recombinant proteins (Brewer et al, 2018).…”