Bananas have been facing extinction. But maybe not for much longer.

The bananas we know and love have been at risk of extinction from a fungal disease. The good news is that scientists may have found a way to save them, according to a study published in the journal Nature Microbiology. The researchers isolated genes within the fungus that may be contributing to the disease's deadliness. Even with an avenue for controlling the disease, crop diversity could further reduce the fungus' virulence.

A banana bind

Bananas are being infected by a disease called Fusarium wilt of banana (FWB), caused by a fungal pathogen called Fusarium oxysporum TR4. This is not the first time a banana species has succumbed to the disease and gone extinct. 

Today, the main variety of bananas bred and sold is the Cavendish, however, this species was only bred after the Gros Michel was wiped out by a previous version of the fungus called Fusarium oxysporum race 1. "The Cavendish variety was bred to be a disease-resistant replacement for the Gros Michel," said Popular Science. "This worked for a while, but by the 1990s, there was another outbreak of banana wilt that spread from Southeast Asia to Central America."

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While bananas are facing the same variety of fungus, the TR4 species "did not evolve from the race that decimated the Gros Michel bananas," Li-Jun Ma, the senior author of the study, said in a press release. This new variety of the Fusarium fungus contains accessory genes "linked to the production of nitric oxide, which seems to be the key factor in TR4's virulence." The gas is toxic to the Cavendish banana. "This sudden burst of toxic gases facilitates infection by disarming the plant's defense system," Ma said in a piece for The Conversation. 

Researchers were also able to determine that the intensity of TR4 was "greatly reduced if the two genes that control nitric oxide production were eliminated," said the press release. "Identifying these accessory genetic sequences opens up many strategic avenues to mitigate, or even control, the spread of Foc TR4," study lead author Yong Zhang said in the release. More research needs to be done to "better understand how the fungus can produce such a harmful gas without hurting itself," and to "test various ways to interrupt the production of nitric oxide and explore genes that can take the gas away before it damages plant cells," said Popular Science.

Diversify the banana breeds

The biggest problem crops like the banana are facing is the overwhelming prevalence of one breed. "When there's no diversity in a huge commercial crop, it becomes an easy target for pathogens," Ma said. Cavendish bananas are not the only existing variety of the fruit, but because of their popularity, they are bred in much larger numbers than others. In reality, planting a variety of different types of bananas creates more sustainable agriculture as well as makes diseases more difficult to spread rapidly.

The public can also play a role in encouraging more diverse agricultural practices by opting to buy different varieties of fruits and vegetables as well as supporting local produce species. "Collaboration among scientists, farmers, industry and consumers around the world can help avoid future shortages of bananas and other crops," Ma said in The Conversation.