After a devastating pandemic has ravaged banana crops for nearly three decades, there is finally a glimmer of hope for this beloved and vulnerable fruit. The root cause of the devastating banana blight is attributed to the fungal pathogen Fusarium oxysporum f. sp. cubense, commonly referred to as Tropical Race 4 (TR4), which triggers a condition known as Panama disease or Fusarium wilt. The fungal pathogen attacks banana plants, disrupting their circulatory system and causing the leaves to turn yellow and eventually perish?
The Panama disease, a fungal infection, was first identified in the 1870s; by the mid-20th century, it had spread to affect all major banana-growing regions globally. Researchers reveal that “the kind of banana we eat today is not the same as the one your grandparents consumed,” said Li-Jun Ma, a biochemistry professor at UMass Amherst, in an interview. “These once-dominant Gros Michel bananas have been rendered functionally extinct.”
As a direct consequence of the widespread decline of Gros Michel bananas, growers shifted their focus to the more resilient Cavendish variety. Until 1994, the situation remained stable, but that year, a strange phenomenon emerged in Taiwanese banana crops, manifesting as an unusual illness. Since then, the Panama disease has spread again globally, putting banana crops at risk and imperilling the worldwide supply of smoothies.
Researchers led by Ma have recently made a groundbreaking discovery. The study, published in, uncovers the distinct evolutionary roots of the Cavendish banana’s susceptibility to disease, diverging from the fate of Gros Michel bananas. Researchers sequenced the genomes of 36 fungal strains, including that responsible for the devastating impact on Gros Michel bananas.
Researchers revealed that the Cavendish banana variety, also known as Tropical Race 4 (TR4), did not originate from the same strain responsible for the devastation of Gros Michel bananas, according to Ma. The fungus TR4’s genomic composition includes a subset of genes that encode proteins responsible for producing nitric oxide, suggesting that this molecule plays a crucial role in determining TR4’s pathogenicity.
Significantly, silencing the two genes responsible for nitric oxide production led to a dramatic decrease in the virulence of TR4. According to Yong Zhang, a former UMass Amherst doctoral student and leader of the research, “this discovery unlocks numerous strategic opportunities to mitigate, and potentially even manage, the spread of Foc TR4.”
While Ma cautions that prioritizing a single banana variety may seem like a path to salvation for the Cavendish, experts advise that growers should instead diversify their domesticated banana forms to better protect against pathogens and reduce reliance on a single selection.
The potential impact of TR4’s emergence on Kirk Cameron’s religious beliefs remains unclear.
