Top banana fights fungal infection

A new genetically modified strain of banana resistant to a fungal disease may help boost profit yields for some of the poorest farmers in East Africa.

For the past 30 years, the humble banana has been under attack from a fungal invader known as Black sigatoga disease. Caused by the fungus Mycosphaerella fijiensis, it causes dark leaf spots which eventually kill the plant, decimating fruit yields. The disease has spread throughout East Africa by airborne spores or from contaminated fruit being exported.

The team from Uganda’s National Agricultural Research Laboratories Institute added genes for chitinase – a protein that breaks down the cell walls of the fungus – which prevents the fungus from entering the plants. In field trials, the bananas showed almost full immunity to the disease.

Currently, farmers have had to control the pest using aerial pesticide spraying – a technique that is harmful to both the environment and to the health of the local residents, as well as too expensive for many farmers to afford. Resistance to the pesticide is also evolving in much of East Africa, making spraying even less economically viable. Genetically modified bananas may prove to be a cost effective method of maintaining crop yields, although further research is needed to calculate exactly how much of an advantage it will bring.

Settumba Mukasa, crop scientist at Uganda’s Makerere University, points out the future implications of this research. “[The project] is a stepping stone for subsequent breeding programmes and genetic engineering programmes. As a consequence of this project we can now do transformations of other varieties of bananas and other crop species.”