HOW TO CONTROL AND PREVENT THE SPREAD OF BANANA STREAK DISEASE WHEN THE ORIGIN COULD BE VIRAL SEQUENCES INTEGRATED IN THE BANANA GENOME?

Abstract

Banana streak viruses are among the most widely distributed viruses of banana and are responsible for banana streak disease. Natural field spread occurs by either mealybugs or use of infected planting material, such as suckers. Banana streak viruses are pararetroviruses belonging to the genus Badnavirus, in the family Caulimoviridae. Like all members of the Badnavirus genus, they have bacilliform virions, 30 x 150 nm in size and a circular dsDNA genome of 7.4kbp. Fifteen years ago, an increasing number of outbreaks of banana streak disease were reported worldwide. Many occured in banana breeding lines and micropropagated inter-specific banana hybrids. The origin of infections in new hybrids and tissue-cultured plants was linked to the presence of viral DNA sequences integrated into the Musa balbisiana genome. Although integration is not an essential step in the replication cycle of pararetroviruses, it is assumed that under stress conditions some endogenous banana streak viruses could become infectious by reconstituting a complete replication-competent viral genome. Several serological and molecular tools have been developed to detect either virions or endogenous banana streak viruses. They specificity and potential to prevent and control outbreaks of banana streak disease is discussed. (Resume d'auteur)