Photo/IllutrationThis mushroom, measuring about 1 centimeter in size, was grown from a fungus collected from a 20-million-year-old geological formation. (Provided by the Japan Agency for Marine-Earth Science and Technology)

  • Photo/Illustraion
  • Photo/Illustraion

Researchers said they have grown a mushroom from a fungus found in a 20-million-year-old geological formation under the Pacific seabed off Hachinohe, Aomori Prefecture.

The scientists with the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) are working to confirm their hypothesis that they have revived a mushroom that used to grow on land eons ago.

“What we have found may be ancient fungal species that were there even before humankind was born,” said Fumio Inagaki, deputy director of the JAMSTEC Research and Development Center for Ocean Drilling Science. “That could help elucidate evolution mechanisms of fungi.”

The geological stratum where the fungus was discovered is believed to have been a piece of land about 20 million years ago.

JAMSTEC in 2012 used its Chikyu deep-sea drilling vessel on the seabed about 80 kilometers off Hachinohe and 1,200 meters beneath the water surface. The researchers drilled into the seafloor to collect samples, such as rocks and sediments.

Sixty-nine species of fungi, or mushrooms and molds, were found in a specimen collected about 2,500 meters beneath the seafloor. They resembled land-based species, and one of them, when cultured in a lab, spread hyphae and grew into a mushroom about 1 centimeter in size.

The species is related to the Schizophyllum commune fungus, JAMSTEC officials said.

The geological formation is believed to have been part of the Eurasian landmass but was pushed beneath the seabed through crustal movements.

The JAMSTEC researchers hypothesize that land-based fungal species were buried underground but survived beneath the seafloor mainly in the form of spores.

How such fungi could survive remains a mystery. There is no ambient oxygen beneath the seabed, and temperatures there are high, at about 50 to 60 degrees.

The JAMSTEC officials said research papers published abroad argue that live bacteria were found in rock salt from a geological formation about 250 million years old. Critics, however, have pointed out that modern-day bacteria may have mixed into the sample.

JAMSTEC officials said they took sufficient care during the collection and culture of the latest specimen to prevent possible inclusion of modern-day, land-based fungi.

Researchers will study the fungi’s genes in more detail, Inagaki said.