Viroid disease control and strategies. In: Adkar-Purushothama, C. R., Sano, T., Perreault, J-P., Yanjarappa, S. M., Di Serio, F., Daros, J.A., editors. Fundamentals of Viroid Biology. London, UK: Academic Press.

Authors: Hammond, Rosemarie

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 7/9/2023
Publication Date: 1/1/2024
Citation: Hammond, R. 2024. Viroid disease control and strategies. In: Adkar-Purushothama, C. R., Sano, T., Perreault, J-P., Yanjarappa, S. M., Di Serio, F., Daros, J.A., editors. Fundamentals of Viroid Biology. London, UK: Academic Press.. Book Chapter. 17:323-335. https://doi.org/10.1016/B978-0-323-99688-4.00020-1.
DOI: https://doi.org/10.1016/B978-0-323-99688-4.00020-1

Interpretive Summary: Viroids, the smallest infectious agents endowed with autonomous replication, are small, 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 worldwide. While control can be achieved for several viroid diseases by planting certified-free seeds or germplasm and quarantine and eradication following sensitive and specific testing protocols, cross-protection and breeding for resistance has shown success in some cases. As viroid RNAs are stable and easily mechanically transmissible, disinfection and decontamination of tools and equipment prevents their spread. 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 chapter. Although the general objective of this book is to act as a handbook for teaching students in plant pathology, the subject matter will be of interest to all scientists who are developing novel plant disease control strategies.

Technical Abstract: While many plant species are non-hosts for viroids, no naturally occurring durable resistance has been observed in most viroid host species. Current effective control methods for viroid diseases include phytosanitary certification programs, exclusion, quarantine, early detection followed by eradication, and implementation of cultural practices, such as decontamination measures to prevent mechanical transmission. In addition, viroid elimination by heat or cold therapy combined with meristem tip culture have been successful in eliminating the viroid in some viroid-host combinations. Introduction of resistance to viroids in viroid host species include strategies such as cross-protection and biotechnological approaches by transgenic engineering of plants developed to mediate degradation of the single and double-stranded viroid RNAs. This chapter summarizes the current perspectives on control of viroid disease and provides an outlook for enhancing resistance using additional approaches.