Honey-killers were the largest organisms in Earth’s history
An international group of scientists found that mushrooms have a specific DNA that makes them “serial killers” trees. These genes contribute to the fact that mushrooms can grow to giant size.
So, the largest organism on Earth is a dark Armillaria (Armillaria ostoyae). This mushroom grows in the forest preserve, Malur U.S. state of Oregon. Preprint of a study published in the repository bioRxiv.
Mycelium (mycelium) is an underground part of a mushroom and looks like a network of thin branched filaments. It is known that the mycelium of Armillaria ostoyae in Oregon, does not form separate clusters, as a single organism with a mass of 600 tons and covers an area of 8.4 square kilometers. Scientists estimate that the age of this largest living creature on the planet is more than two thousand years.
Another major body is the Tolstonogov Armillaria (Armillaria gallica), growing in Michigan. It covers an area of 0.37 square kilometers.
To understand what makes Armillaria such a unique and successful species, biologists have analyzed the genome of different mushrooms, finding out their origins and evolutionary development. They compared the DNA of species such as A. ostoyae, A. cepistipes, A. gallica and A. solidipes, with the genes of other fungi. It turned out that honey is characterized by a significant increase in the genome that led to the emergence of specific genes associated with pathogenicity of fungi and also contribute to the formation of rhizomorphs.
Isomorphy — plexus of fungal threads that penetrate trees and transportyou the water and nutrients to fruit bodies. They also spread from diseased plants, contributing to healthy infection. This parasitism leads to mass death of trees.