Bananas are inching towards extinction, but scientists have devised a neat trick to save the trusty fruit
Aug 20, 2024, 16:30 IST
You know things have taken a turn for the bleak when you hear that our beloved bananas have begun a slow trot towards extinction. What will the weary parent offer to their snack-hungry child? What are we to put in our smoothies and sundaes?
The world's most popular banana, the Cavendish, is under siege from a deadly fungal disease known as Fusarium wilt of banana (FWB). Caused by a pathogen called Fusarium oxysporum f.sp. cubense (Foc) tropical race 4 (TR4), this disease has devastated banana plantations worldwide. Once present in a field, Foc TR4 is nearly impossible to eradicate, making future production of Cavendish bananas highly uncertain.
Sadly, these bananas are hardly the first victims of a vicious fungal attack.
"The banana we eat today is not the same as the one our grandparents ate," explains Li-Jun Ma, a professor of biochemistry and molecular biology at UMass Amherst. "The Gros Michel bananas, which were popular in the 1950s, were essentially wiped out by a previous Fusarium outbreak."
The Cavendish banana, a disease-resistant variety bred in response to the Gros Michel extinction, has dominated the commercial market for decades. However, Foc TR4 has proven to be a formidable foe, spreading rapidly across the globe and threatening the banana industry.
However, a recent study led by scientists at the University of Massachusetts Amherst has shed new light on the disease and its origins. The researchers discovered that Foc TR4 is not a descendant of the strain that wiped out commercial banana crops in the 1950s. Instead, its virulence seems to be linked to certain accessory genes associated with the production of nitric oxide.
This groundbreaking finding opens the door to potential treatments and strategies to combat Foc TR4. By understanding the genetic mechanisms behind the disease's virulence, scientists may be able to develop targeted interventions to slow or even stop its spread.
"We have spent the last 10 years studying this new outbreak of banana wilt," says Ma. "We now know that the Cavendish banana-destroying pathogen TR4 did not evolve from the race that decimated the Gros Michel bananas."
The researchers sequenced and compared 36 different Foc strains, including those that attack Gros Michel bananas. They discovered that Foc TR4 possesses unique accessory genes that enable it to produce and detoxify nitric oxide, a key factor in its virulence.
While the exact mechanisms by which nitric oxide contributes to disease infestation remain to be fully understood, the study found that eliminating certain genes involved in nitric oxide production significantly reduced the virulence of Foc TR4.
"Identifying these accessory genetic sequences opens up many strategic avenues to mitigate or even control the spread of Foc TR4," says Yong Zhang, lead author of the study.
However, Ma emphasises that the ultimate solution to the banana crisis lies in diversifying banana production. Monocropping, the practice of cultivating a single crop over a large area, makes it easier for pathogens to spread. By planting a variety of banana cultivars, farmers can reduce their reliance on the vulnerable Cavendish and increase the resilience of the overall banana industry.
Advertisement
The world's most popular banana, the Cavendish, is under siege from a deadly fungal disease known as Fusarium wilt of banana (FWB). Caused by a pathogen called Fusarium oxysporum f.sp. cubense (Foc) tropical race 4 (TR4), this disease has devastated banana plantations worldwide. Once present in a field, Foc TR4 is nearly impossible to eradicate, making future production of Cavendish bananas highly uncertain.
Sadly, these bananas are hardly the first victims of a vicious fungal attack.
"The banana we eat today is not the same as the one our grandparents ate," explains Li-Jun Ma, a professor of biochemistry and molecular biology at UMass Amherst. "The Gros Michel bananas, which were popular in the 1950s, were essentially wiped out by a previous Fusarium outbreak."
The Cavendish banana, a disease-resistant variety bred in response to the Gros Michel extinction, has dominated the commercial market for decades. However, Foc TR4 has proven to be a formidable foe, spreading rapidly across the globe and threatening the banana industry.
However, a recent study led by scientists at the University of Massachusetts Amherst has shed new light on the disease and its origins. The researchers discovered that Foc TR4 is not a descendant of the strain that wiped out commercial banana crops in the 1950s. Instead, its virulence seems to be linked to certain accessory genes associated with the production of nitric oxide.
Advertisement
This groundbreaking finding opens the door to potential treatments and strategies to combat Foc TR4. By understanding the genetic mechanisms behind the disease's virulence, scientists may be able to develop targeted interventions to slow or even stop its spread.
"We have spent the last 10 years studying this new outbreak of banana wilt," says Ma. "We now know that the Cavendish banana-destroying pathogen TR4 did not evolve from the race that decimated the Gros Michel bananas."
The researchers sequenced and compared 36 different Foc strains, including those that attack Gros Michel bananas. They discovered that Foc TR4 possesses unique accessory genes that enable it to produce and detoxify nitric oxide, a key factor in its virulence.
While the exact mechanisms by which nitric oxide contributes to disease infestation remain to be fully understood, the study found that eliminating certain genes involved in nitric oxide production significantly reduced the virulence of Foc TR4.
"Identifying these accessory genetic sequences opens up many strategic avenues to mitigate or even control the spread of Foc TR4," says Yong Zhang, lead author of the study.
Advertisement
However, Ma emphasises that the ultimate solution to the banana crisis lies in diversifying banana production. Monocropping, the practice of cultivating a single crop over a large area, makes it easier for pathogens to spread. By planting a variety of banana cultivars, farmers can reduce their reliance on the vulnerable Cavendish and increase the resilience of the overall banana industry.