Chapter 3 - Host–virus interactions in banana-infecting viruses

Abstract

Four viral diseases infecting banana and plantains, viz., banana bunchy top disease (BBTD) caused by Banana bunchy top virus (BBTV), bract mosaic disease (BBrMD) caused by Banana bract mosaic virus (BBrMV), banana streak disease (BSD) caused by different species of Banana streak virus (BSV), and banana mosaic or infectious chlorosis caused by Cucumber mosaic virus (CMV), occur in most of the banana-growing regions around the world. These viruses belong to different families and sometimes all four viruses can infect simultaneously, causing severe infection leading to 100% yield loss. Banana bunchy top disease is a century-old disease but its infectivity has not yet been proven through infectious clones. Bract mosaic virus belongs to the potyviridae family; it is restricted to a few countries such as India, Sri Lanka and the Philippines, whereas streak virus disease is omnipresent and its peculiar characteristic is that the viral genome is integrated into the host chromosome and it infects spontaneously from the host. This virus is a pararetrovirus as the replication of the viral genome does not require integration. The vector for bunchy top virus is Pentalonia nigronervosa which transmits in a persistent manner, whereas BBrMV and CMV are transmitted by different aphids in a non-persistent manner. However, the vector’s role in BBTV and its spread has been documented at length. For BBTV, the transgenic approach has been attempted and has achieved virus-resistant plants through a pathogen-mediated RNAi-based approach. In this chapter the host–virus and vector interactions at plant and molecular level have been reviewed.