A Killer Fungi Could Wipe Out the World’s Banana Supply

Unrivaled potassium source, great elevenses snack, fodder for endless comedy skits, and handy cocaine-smuggling tool … The humble banana is many things to many people.

But all these things could become half-remembered tales to tell your grandchildren (maybe leave out the cocaine one), as new research from the University of California, Davis (UC Davis) predicts that fast-evolving fungal diseases could obliterate the world's banana supply in five to ten years.

The study, which was published last week in science journal PLOS Genetics, looked into the genome sequences of two of the three most lethal fungal diseases known to banana plants. The researchers found that these diseases "have become more virulent by increasing their ability to manipulate the banana's metabolic pathways and make use of its nutrients."

The Sigatoka virus—described by the scientists as a "three-fungus disease complex"—is to blame for the potential impending wipe out, with black Sigatoka and Eumusae leaf spot being the two most damaging to banana plants.

The researchers explained in a press release on the study that the fungal diseases not only shut down a banana plant's immune system but also adapted to mimic its metabolism, which "allows the fungi to feed on the plant's sugars and other carbohydrates."

How delightful.

In addition, the researchers found that frequent fungicide application, which currently accounts for up to 35 percent of banana production costs, contributes to the "rapid evolution of fungicide-resistant strains within populations causing disease-control failures throughout the world."

It's not the first instance of a banana plant facing death by fungi. In the 1950s, the Gros Michel banana was wiped out by Panama disease and growers had to turn to the Cavendish banana, which is the most prominent breed of the fruit in the world today.

Speaking to MUNCHIES, John Carr, head of the plant virology and pathology research group at Cambridge University and a board member of the British Society for Plant Pathology, explained why bananas are particularly at risk from disease.

He said: "Nearly all bananas are called 'Cavendish' because they are clones (effectively genetically identical cuttings) from a plant that grown a long time ago in a glasshouse in Derbyshire. Clonal crops can be bad news in agriculture since all individuals are genetically identical, all are susceptible to the same diseases."

But Carr—agreeing with the conclusions drawn by the UC Davis researchers—added that knowing more about the genome sequences of the fungi could now lead to better breeding of new banana plants. He said: "The main hope for preserving world banana production is the discovery of new resistance genes for breeding into the population."

Better start stockpiling those bananas now though, just in case.