Most of us cannot imagine the world without the banana; it is one of the globe’s most favorite fruits. In 2019 alone, over 115 million tonnes of bananas were produced. In addition to its delicious taste, bananas are rich with valuable nutrients such as potassium, vitamin B6, magnesium, and manganese. However, just as the COVID-19 pandemic is threatening humans’ lives, another pandemic is threatening this beloved fruit. It is not the first time for such a thing to happen; one previous pandemic was so close to wiping out the banana from our life!
The banana we know today is seedless; you just peel it and enjoy the delicious taste. Nevertheless, it was not always like that; wild bananas originally had seeds inside them, inedible, large, and numerous seeds. Thousands of years ago, however, humans domesticated the banana; farmers crossed different types of wild bananas, producing bananas that have no seeds.
There are numerous types of seedless bananas, but most of the world today consumes one type: the Cavendish banana. Nearly all the types are genetically identical and the reason for that is the way we produce them. Since bananas have nearly invisible seeds, they are cultivated using a method known as vegetative reproduction or vegetative propagation. In this method, cuttings from the plant are used to grow new ones. This is the reason for the genetic similarity of the bananas, and it is a double-edged sword!
Having genetically similar plants could prove advantageous; one example is that you can buy a large number of bananas knowing that every single one would be as sweet as you would love it to be. Yet, this genetic similarity is the reason the banana is at risk.
Going back to 1940, when the Gros Michel banana was the dominant cultivar, the Panama Disease—caused by the Fusarium fungus—wiped the Gros Michel bananas from the market. Within 20 years, farmers moved to the Cavendish banana that we know today. Despite the fact that it tasted different from the Gros Michel banana, it had one important advantage to farmers: it was resistant to Panama Disease.
Still, our beloved fruit is not safe yet! The fungus that caused the Gros Michel banana to go extinct was caused by a strain of Fusarium called Tropical Race 1; today, Tropical Race 4 is threatening banana farms, and the bad news is: Cavendish bananas are not resistant to it!
This time, scientists are thinking of genetic engineering as a possible solution to prevent the spread of the fungus, and save our beloved fruit. The key to saving the Cavendish banana lies within the wild ones that have resistance genes for the new Fusarium strain (Tropical Race 4). Biologists have identified some of those genes, and they are working on transferring them to the Cavendish banana.
References
fao.org
academic.oup.com
web.archive.org
nature.com