Current Approaches and Prospective Strategies for Plant Virus Management

Plant viruses are one of the most troublesome and challenging pathogens of food and fiber crops worldwide, posing a serious threat to sustainable agriculture. They cause more than US $30 billion in crop losses annually. Several factors, including international trade of biomaterials, insect vectors, climate change, and the ability of viruses to evolve quickly, are responsible for the frequent emergence of viral diseases. The challenge of dealing with these noxious entities has long been open, with very few success stories in the field. Since there is no viricide available for virus control, reliance is placed on the use of resistant plant varieties, vector control, and prophylactic measures to restrain virus spread. Plant disease resistance against viruses has been achieved through plant breeding technologies or advanced biotechnological tools such as RNA interference (RNAi) and clustered regularly interspaced short palindromic repeats (CRISPRs), which are based on a bacterial defense system and form the basis for CRISPR-Cas9 genome editing tools. Marker-assisted selection (MAS) has largely replaced traitoriented conventional breeding as a more efficient and indirect method of selection. Biotechnological methods include genetic engineering and plant transformation protocols, which involve the development of resistance using RNA-based (e.g., RNAi) and protein-based approaches. In addition to these, 122genome editing technologies using CRISPR-Cas9 and nanotechnology are also being employed with greater potential for success. Prophylactic measures include quarantine (border control), the use of certified virus-free germplasm to prevent the entry of new viruses in a geographical area, control of insect vectors by chemical pesticides, and other cultural methods either to prevent the vectors from reaching the crop or to interfere in the transmission of viruses. Here, we have discussed all the strategies and protocols in practice for the better management of plant viruses. The current trends, future prospects, and a comparative analysis of all the approaches are the main focus of this chapter.