Sustainable Management of Economically Important Plant Viral Pathogens by Plant Growth-Promoting Rhizobacteria

Plant viruses are a category of viruses that infect plants, predominantly affecting vascular plants or higher plants. Collectively, these viruses contribute about $600 million in global crop yield losses. Functioning as obligate intracellular parasites, plant viruses lack the necessary molecular machinery for replication independent of a host, and therefore, they are required to highjack host machinery. The major class of these viruses have small single-stranded ssRNA genome, although some exhibit double-stranded RNA followed by ssDNA or double-stranded DNA also. Viruses of plant are less comprehensively understood unlike animal counterparts; the one prominent example is the tobacco mosaic virus (TMV). As of now, plant viruses are categorized into 73 genera and 49 families; however, these classifications pertain mainly to cultivated plants, representing only a fraction of the vast variety of plant species. This chapter focuses and provides insight into the top 10 plant viruses ranked based on their prevalence and the economic damages they inflict on their host plants and their management using growth-promoting rhizobacteria (PGPR). The top 10 (in rank order) list includes (1) Tobacco mosaic virus, (2) Tomato spotted wilt virus, (3) Tomato yellow leaf curl virus, (4) Cucumber mosaic virus, (5) Potato virus Y, (6) Cauliflower mosaic virus, (7) African cassava mosaic virus, (8) Plum pox virus, (9) Brome mosaic virus, and (10) Potato virus X. Unlike to fungi and bacteria pathogens, plant viruses lack chemical control. However, the utilization of PGPR stands out as an environmentally friendly mean for the management of viruses and enhances crop yield. In recent times, there has been a notable shift towards leveraging PGPR-induced systemic resistance (ISR) for viral disease management, although previous research predominantly focused on fungal and bacterial pathogens. This chapter will explore the range of PGPR-induced ISR focused on combating the top 10 plant viruses.