ANIMALS
Scientists Hope To Harness Virus To Combat Fungus Driving Frogs And Toads To Extinction
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A fungus that has been killing frogs and toads, driving dozens of species to possible extinction, may be susceptible to a virus scientists can harness to save the amphibians.
Batrachochytrium dendrobatidis, or Bd, is a fungus that severely damages the skin of frogs and toads, and ultimately leads to heart failure. Scientists say it has contributed to the decline of more than 500 amphibian species since the late 1990s, and the possible extinction of 90 species including yellow-legged mountain frogs in the Sierras and the Panamanian golden frog.
Researchers at University of California Riverside have discovered a virus that infects Bd, changing its behavior, and they say the virus could be engineered to control what they call a global amphibian pandemic.
“Frogs control bad insects, crop pests, and mosquitoes. If their populations all over the world collapse, it could be devastating,” said UCR microbiology doctoral student Mark Yacoub, lead author of the study published in the journal Current Biology.
“Theyre also the canary in the coal mine of climate change. As temperatures get warmer, UV light gets stronger, and water quality gets worse, frogs respond to that. If they get wiped out, we lose an important environmental signal,” Yacoub said.
The fungus was not widely prevalent until the late 1990s, when researchers noticed that all of a sudden frogs started dying,” Yacoub said.
Yacoub and UCR microbiology professor Jason Stajich were studying Bd genetics using DNA sequencing technology with the hope of learning how it is mutating. They discovered the virus when they found sequences that did not belong to the fungus.
“We realized these extra sequences, when put together, had the hallmarks of a viral genome,” Stajich said.
The virus had not been discovered until now because of the difficulty of keeping the fungus alive in a laboratory setting.
“It is also a hard fungus to keep track of because they have a life stage where theyre motile, they have a flagellus, which resembles a sperm tail, and they swim around,” Stajich said.
Unlike most fungus-infecting viruses, which are RNA viruses, the newly discovered virus is a single-stranded DNA virus. It appears some strains of Bd have the virus in their genome.
The researchers found that the infected fungus behaves differently than uninfected fungus.
“When these strains possess the virus they produce fewer spores, so it spreads more slowly. But they also might become more virulent, killing frogs faster,” Stajich said.
The researchers are hoping to clone the virus to see whether manually infected Bd also produces fewer spores.
“Because some strains of the fungus are infected and some are not, this underscores the importance of studying multiple strains of a fungal species,” Yacoub said.
“We dont know how the virus infects the fungus, how it gets into the cells,” Yacoub said. “If were going to engineer the virus to help amphibians, we need answers to questions like these.”
Some amphibian species also appear to be developing their own resistance to the fungus.
“Like with COVID, there is a slow buildup of immunity. We are hoping to assist nature in taking its course,” Yacoub said.
TMX contributed to this article.
