Did you know that the bananas you eat today are different from the bananas people ate generations ago? The banana you might eat for breakfast today is a Cavendish banana variety; the one found in grocery stores until the 1950s was a variety called Gros Michel, which was wiped out by a disease called Fusarium banana wilt, or FWB.

FWB Gros Michel was called up Fusarium oxysporum race 1, a fungal pathogen that affects bananas. This fungal infection kills the plant by taking over the plant’s vascular system, preventing the transport of water and minerals.

Plant biologists have developed a hardy Cavendish cultivar. FusariosisIt will replace Gros Michel. But in the last few decades, a resurgence of FWB, caused by another strain of the same fungus called tropical race 4 or TR4, has once again threatened global banana production. Fusarium oxysporum Have you gained the ability to overcome resistance and infect many different plants?

The bipartite genome of F. oxysporum

I am a genomic scientist who has spent the last ten years researching genetic evolution. Fusarium oxysporum. As a species complex, F. oxysporum It can cause wilt and root rot diseases in more than 120 plant species. Some species can also infect humans.

In 2010, my lab started to analyze every genome F. oxysporum can be divided into two parts: a core genome shared by all strains that encodes important host functions, and an additional genome that encodes specialized functions that vary from strain to strain, such as the ability to infect a particular host plant.

Each plant species has a complex immune response to protect against microbial invasion, so each strain has the ability to establish an infection. F. oxysporum uses its accessory genome to suppress the plant’s unique defense system. This functional compartmentalization F. oxysporum significantly expand the circle of its owners.

In our recently published research, my team and colleagues in China and South Africa found that the TR4 strain that kills Cavendish bananas has a different evolutionary origin and different sequences in its complementary genome compared to the strain that kills Gros Michel bananas.

When we looked at the interface where the TR4 strain fights its Cavendish banana host, we found that some of the activated accessory genes secrete nitric oxide, a gas that is harmful to Cavendish bananas. This sudden release of toxic gases neutralizes the plant’s defenses, encouraging infection. The fungus also protects itself by increasing production of chemicals that scavenge nitric oxide.

Increasing banana diversity

Stay tuned for the global rollout of this new version Fusarium oxysporumWe realized that the main reason for the recent re-emergence of this fungal infection is the dominance of a single banana clone in the international banana industry.

Breeding different banana varieties can make agriculture more sustainable and reduce disease pressure on a single crop. Farmers and researchers can control Fusarium wilt in bananas by identifying or breeding banana varieties tolerant or resistant to TR4.

Our findings suggest that another way to protect Cavendish bananas is to develop effective nitric oxide scavengers that would reduce the toxic pressure of the gas explosion. It is hard to imagine how a consumer who simply enjoys eating bananas could help combat a disease that is destroying banana crops. But consumers determine the market, and farmers have to grow what the market demands.

You can help increase the variety of bananas in your supermarket by deliberately trying one or more of the hundreds of other banana varieties available as they become available. You can also buy local varieties of other fruits and crops to help preserve plant diversity and support local producers.

Collaboration between scientists, farmers, industry and consumers worldwide could help prevent future shortages of bananas and other crops.