Deciphering Molecular Mechanisms involved in the Interaction of Banana, Cosmopolites sordidus and Fusarium oxysporum

Banana is the most popular fruit worldwide and an important staple food in tropical and subtropical regions where most bananas are produced. More than 40% of world production and virtually all export trade is based on Cavendish bananas. However, the Cavendish banana is threatened by a virulent banana wilt fungus (FWB), Fusarium oxysporum f. sp. tropical cubense race 4 (TR4), for which no acceptable resistant variety has been identified. The spread of FWB occurs through the contact of contaminated plants or pathogen structures with healthy plants, and due to the large volume of exports and infected productive regions, the pathogen disperses rapidly, complicating the adaptation of disease management to different circumstances. FWB management strategies currently aim to prevent the spread of TR4 by focusing on the use of clean planting material and machinery and the quarantining of infested farms. However, the ongoing global spread shows that FWB successfully disseminates despite extensive prevention strategies. Reduced susceptibility of alternative banana germplasm seems inadequate to manage FWB. Complete resistance is required as shown by the Cavendish varieties that are globally cultivated on Race 1, infested soils for over 70 years without any decline of resistance. Any level of resistance to TR4 that does not meet this standard is insufficient and can contribute to further dissemination of TR4. In a recent discovery, the hypothesis was raised of a new mechanism of dissemination caused by the main pest of the banana crop, Cosmopolites sordidus. This weevil carries the pathogen in its digestive system and is attracted to volatiles from wounds on banana pseudostems. Thus, this insect pest can be a potential vector of the disease, requiring a rapid search for mechanisms of control and/or resistance. In view of this scenario, the present work seeks for mechanisms of resistance and control, in addition to a more in-depth and comprehensive knowledge of these organisms, with the objective of exploring the banana-F. oxysporum-banana weevil interaction, evaluating: 1) Identification of volatile compounds emitted by bananas infected by F. oxysporum; and 2) Behavioral study of the insect pest by banana volatiles infected by F. oxysporum.