Engineering resistance against viroid

Authors: FLORES, RICARDO - University Of Valencia; NAVARRO, BEATRIZ - National Research Council - Italy; Kovalskaya, Natalia; Hammond, Rosemarie; DISERIO, FRANCESCO - National Research Council - Italy

Submitted to: Current Opinion in Virology
Publication Type: Review Article
Publication Acceptance Date: 6/28/2017
Publication Date: 7/24/2017
Citation: Flores, R., Navarro, B., Kovalskaya, N.Y., Hammond, R., Diserio, F. 2017. Engineering resistance against viroid. Current Opinion in Virology. 26:1-7. https://doi.org/10.1016/j.coviro.2017.07.003.
DOI: https://doi.org/10.1016/j.coviro.2017.07.003

Interpretive Summary: Viroids are small, noncoding RNAs and are important pathogens of food, industrial and ornamental plants. While control can be achieved for several viroid diseases by eradication and replanting, cross-protection and breeding for resistance have also been attempted with some success. Biotechnological approaches for controlling viroid diseases have been investigated and include the engineering of viroid resistance into host species using basic knowledge of viroid biology. The results of those efforts and the challenges associated with creating viroid resistant plants are summarized in this review. These results will be of interest to scientists who are developing novel plant disease control strategies.

Technical Abstract: Viroids, the smallest infectious agents endowed with autonomous replication, are tiny single-stranded circular RNAs (~250-400 nt) without protein-coding ability that, despite their simplicity, infect and often cause disease in herbaceous and woody plants of economic relevance. To mitigate the resulting losses, several strategies have been developed that include: i) search for naturally resistant cultivars and breeding for resistance, ii) induced resistance by pre-infection with mild strains, iii) ribonucleases targeting double-stranded RNAs and catalytic antibodies endowed with intrinsic ribonuclease activity, iv) antisense, and sense, RNAs, v) catalytic antisense RNAs derived from hammerhead ribozymes, and vi) hairpin RNAs and artificial small RNAs for RNA interference. The mechanisms underpinning these strategies, most of which have been implemented via genetic transformation, together with their present results and future potential, are the subject of this review.