The bananas we know and love are threatened with extinction by 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 Natural Microbiology. The researchers have isolated genes in the fungus that may contribute to the disease’s lethality. Even if there were a way to control the disease, the virulence of the fungus could be further reduced by the diversity of crops.
A banana binding
Bananas are infected by a disease called Fusarium wilt of banana (FWB), caused by a Fungal pathogens called Fusarium oxysporum TR4. This is not the first time that a banana species has succumbed to the disease and extinct.
Today, the Cavendish is the most widely cultivated and sold banana variety. However, this variety was only bred after the Gros Michel wiped out from an earlier version of the fungus called Fusarium oxysporum race 1. “The Cavendish variety was bred as a disease-resistant replacement for the Gros Michel variety,” said Popular Science“That worked for a while, but in the 1990s there was another outbreak of banana wilt that spread from Southeast Asia to Central America.”
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While bananas face the same type of fungus, the TR4 species “did not emerge from the race that decimated Gros Michel bananas,” said Li-Jun Ma, the study’s lead author, in a Press release. This new strain of the fungus Fusarium contains additional genes “related to the production of nitric oxide, which appears to be the key factor in the virulence of TR4.” The gas is toxic to the Cavendish banana. “This sudden explosion of toxic gases facilitates infection by disabling the plant’s defense system,” Ma said in an article for The conversation.
The researchers were also able to find that the intensity of TR4 “decreased sharply when the two genes controlling nitric oxide production were eliminated,” the press release said. “The identification of these additional genetic sequences opens up many strategic opportunities to contain or even control the spread of Foc TR4,” lead study author Yong Zhang said in the press release. Further research is needed to “better understand how the fungus can produce such a harmful gas without harming itself” and to “test different ways to interrupt nitric oxide production and explore genes that can remove the gas before it damages plant cells,” according to Popular Science.
Diversify banana varieties
The biggest problem with crops like bananas is the overwhelming prevalence of a single variety. “If there is no diversity in a large commercial crop, it becomes an easy target for pathogens,” Ma said. Cavendish bananas are not the only existing variety of this fruit, but because of their popularity, they are grown in much greater numbers than others. In fact, growing a variety of different banana varieties makes for more sustainable agriculture and makes it harder for diseases to spread quickly.
The public can also help encourage more diverse farming practices by choosing to buy different fruits and vegetables and supporting local fruit varieties. “Collaboration between scientists, farmers, industry and consumers around the world can help prevent future shortages of bananas and other crops,” Ma told The Conversation.
