Bananas Facing Extinction Because Of Fungal Threat

Bananas are at risk of extinction due to a fungal disease. Fortunately, a study published in Nature Microbiology reveals that scientists may have a solution. Researchers isolated specific genes in the fungus that contribute to its deadliness. Increased crop diversity could further lessen the fungus’s impact.

Fungal Threat to Bananas

Bananas are increasingly affected by Fusarium wilt, caused by the fungal pathogen Fusarium oxysporum TR4. This is not the first instance where banana species have faced extinction due to similar issues.

Currently, the main type of banana provided to consumers is the Cavendish variety. This type emerged after the Gros Michel was decimated by an earlier fungus version, Fusarium oxysporum race 1. "The Cavendish was bred to replace the Gros Michel due to its disease resistance," as noted by Popular Science. However, an outbreak of banana wilt in the 1990s spread from Southeast Asia to Central America.

While both varieties encounter fungal issues, the TR4 species did not evolve from the earlier race, states lead researcher Li-Jun Ma. This new fungal variety possesses accessory genes that aid in producing nitric oxide, which contributes to TR4’s virulence. The nitric oxide gas is harmful to Cavendish bananas by disabling the plant’s defense mechanism. "This release of toxic gas fosters infection," Ma explained to The Conversation.

Further discovery revealed that removing genes regulating nitric oxide production drastically reduces TR4's intensity. Identifying these accessories paves the way for strategies to control and mitigate Foc TR4's spread, according to Yong Zhang, the study’s lead author. Additional studies are needed "to understand the fungus's gas production and explore approaches to inhibit nitric oxide synthesis," as stated by Popular Science.

Importance of Crop Diversity

A significant issue faced by banana crops is the dominance of a single variety. "The lack of diversity in a primary commercial crop exposes it to pathogens," notes Ma. Although Cavendish bananas are widespread, other varieties exist but are cultivated less due to consumer preference. Instead, planting diverse types fosters sustainable farming and limits disease propagation.

The public can advocate for diverse agriculture by purchasing various fruit and vegetable types and supporting local produce. "Combining the efforts of scientists, farmers, and consumers can help prevent potential shortages of bananas and other crops," Ma emphasized in The Conversation.

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