Overview

Pathogens belonging to the Fursarium species are known to infect a wide range of crops and cause large losses in agriculture. In this project, we will concentrate on protecting bananas from Fusarium oxysporum f.sp. cubense using an engineered strain of the native soil bacterium Pseudomonas putida. At present commercially grown bananas for export are all the same species, known as Cavendish. Prior to the 1960s, though, the Gros Michel cultivar was the primary banana for export. This species was almost completely wiped out within a decade by the Panama disease that is caused by Fusarium. Recently a new strain of Fusarium has been infecting Cavendish plants and is spreading throughout the world.

The first and perhaps most important part is the production of fungal growth inhibitors. In order to prevent these fungal inhibitors from damaging the soil microbiome, their production will be coupled to the sensing of fusaric acid, a characteristic toxin produced by Fusarium. To help our host compete against the fungus, resistance against fusaric acid will also be incorporated.

Protecting the natural biodiversity is a big part of our project. When the Fusarium threat has been detected and subsequently cleaned up, the bacteria will activate a kill-switch. In addition to this, spread of the genetically modified material will be prevented by a double dependent plasmid system in which loss or gain of one of the two modified plasmids will cause the host to kill itself.