08-17-2024, 12:32 AM
This post was last modified 08-17-2024, 12:44 AM by Maxmars.
Edit Reason: added content
I love bananas. Always have.
But I recall being told, with some degree of certainty, that we are pretty much dependent on a single species of banana here in the US. It had been selected because it was resistant to a particularly nasty fungus that had threatened an old-time favorite many decades ago... that species had pretty much fallen into near extinction due to a fungus that our new species was able to resist.
This article filled in the gaps of my knowledge of bananas quite well...
From ZME Science: The banana apocalypse is coming. Can we stop it this time?
Humans love bananas. We eat around 100 billion bananas per year, or 273 million bananas a day. We also grow 1000 or so varieties of bananas — but there’s a catch; one of these varieties, the Cavendish banana, makes up around 50% of global production. Whenever you go to buy a banana, especially if it’s in a supermarket, it’s most likely a Cavendish banana.
It’s not the first dominant cultivar, either. Before the Cavendish, we had the Gros Michel banana, which dominated global markets. In the early 20th century, however, the Gros Michel banana was brought to its knees by a fungus: Fusarium oxysporum. Specifically, it was attacked by the R1 strain of this fungus. It caused Fusarium wilt, also known as Panama disease, leading to the near-extinction of the Gros Michel variety. The banana industry responded by adopting the Cavendish banana, which was resistant to R1.
Now a new threat has reared it's ugly head.. Our go-to strain, the Cavendish banana is now facing a new (genetically-unrelated) fungal strain to which it has no such resistance...
Now, the strain (called TR4) has been detected in banana plantations across Asia, Australia, Africa, and Latin America. Its spread has alarmed scientists and industry stakeholders as it seems to infect Cavendish bananas as well as a number of other cultivars.
As the history of the bananas we eat is fascinating... it concerns me that this new pathogen is setting the stage for genetic manipulation to be "the answer." And I can only pray that such a solution is not a "mistake."
“We have spent the last 10 years studying this new outbreak of banana wilt,” says Ma, who is an expert in Fusarium oxysporum, which is not a single species but a “species complex” with hundreds of different varieties that specialize in affecting different plant hosts. These varieties are determined by the acquisition of strain-specific accessory genes in addition to a shared core genome. “We now know that the Cavendish banana-destroying pathogen TR4 did not evolve from the race that decimated the Gros Michel bananas. TR4’s genome contains some accessory genes that are linked to the production of nitric oxide, which seems to be the key factor in TR4’s virulence.”
In the study, researchers identified the genetic and biochemical factors that underpin TR4’s virulence. Unlike its predecessor R1, TR4 lacks the accessory chromosomes that typically carry virulence genes in other Fusarium strains. However, it compensates with a suite of accessory genes embedded within its core chromosomes.
Upon infection, TR4 induces a burst of nitric oxide (NO) production within its mitochondria. This NO burst is believed to overwhelm the banana’s defense mechanisms. In particular, it may interfere with the plant’s ability to manage cellular stress.
I suspect that a genetic approach will be the knee-jerk response to the problem, leaving us in a position of changing one of nature's perfect foods...
A good read....
[edit to add] A research paper upon which the article is based from Nature Microbiology: Virulence of banana wilt-causing fungal pathogen Fusarium oxysporum tropical race 4 is mediated by nitric oxide biosynthesis and accessory genes
But I recall being told, with some degree of certainty, that we are pretty much dependent on a single species of banana here in the US. It had been selected because it was resistant to a particularly nasty fungus that had threatened an old-time favorite many decades ago... that species had pretty much fallen into near extinction due to a fungus that our new species was able to resist.
This article filled in the gaps of my knowledge of bananas quite well...
From ZME Science: The banana apocalypse is coming. Can we stop it this time?
Humans love bananas. We eat around 100 billion bananas per year, or 273 million bananas a day. We also grow 1000 or so varieties of bananas — but there’s a catch; one of these varieties, the Cavendish banana, makes up around 50% of global production. Whenever you go to buy a banana, especially if it’s in a supermarket, it’s most likely a Cavendish banana.
It’s not the first dominant cultivar, either. Before the Cavendish, we had the Gros Michel banana, which dominated global markets. In the early 20th century, however, the Gros Michel banana was brought to its knees by a fungus: Fusarium oxysporum. Specifically, it was attacked by the R1 strain of this fungus. It caused Fusarium wilt, also known as Panama disease, leading to the near-extinction of the Gros Michel variety. The banana industry responded by adopting the Cavendish banana, which was resistant to R1.
Now a new threat has reared it's ugly head.. Our go-to strain, the Cavendish banana is now facing a new (genetically-unrelated) fungal strain to which it has no such resistance...
Now, the strain (called TR4) has been detected in banana plantations across Asia, Australia, Africa, and Latin America. Its spread has alarmed scientists and industry stakeholders as it seems to infect Cavendish bananas as well as a number of other cultivars.
As the history of the bananas we eat is fascinating... it concerns me that this new pathogen is setting the stage for genetic manipulation to be "the answer." And I can only pray that such a solution is not a "mistake."
“We have spent the last 10 years studying this new outbreak of banana wilt,” says Ma, who is an expert in Fusarium oxysporum, which is not a single species but a “species complex” with hundreds of different varieties that specialize in affecting different plant hosts. These varieties are determined by the acquisition of strain-specific accessory genes in addition to a shared core genome. “We now know that the Cavendish banana-destroying pathogen TR4 did not evolve from the race that decimated the Gros Michel bananas. TR4’s genome contains some accessory genes that are linked to the production of nitric oxide, which seems to be the key factor in TR4’s virulence.”
In the study, researchers identified the genetic and biochemical factors that underpin TR4’s virulence. Unlike its predecessor R1, TR4 lacks the accessory chromosomes that typically carry virulence genes in other Fusarium strains. However, it compensates with a suite of accessory genes embedded within its core chromosomes.
Upon infection, TR4 induces a burst of nitric oxide (NO) production within its mitochondria. This NO burst is believed to overwhelm the banana’s defense mechanisms. In particular, it may interfere with the plant’s ability to manage cellular stress.
I suspect that a genetic approach will be the knee-jerk response to the problem, leaving us in a position of changing one of nature's perfect foods...
A good read....
[edit to add] A research paper upon which the article is based from Nature Microbiology: Virulence of banana wilt-causing fungal pathogen Fusarium oxysporum tropical race 4 is mediated by nitric oxide biosynthesis and accessory genes
