JUL 26, 2016 10:53 AM PDT

Lichen's third wheel

WRITTEN BY: Kerry Evans
Researchers have known for a long time (we’re talking 150 years) that lichens exist as part of a symbiotic relationship - fungus and algae or cyanobacteria living in harmony. Just recently, however, Purdue mycologists identified a third partner in this relationship - yeast.

Lichens are composite organisms made up of a fungus and algae or cyanobacteria (sometimes both). The algae and cyanobacteria produce food for the fungus through photosynthesis. The fungus, in turn, gives the algae and cyanobacteria a safe place to live.
 
Lichens are composite organisms.
All of that is still true, except study author M. Catherine Aime has identified a third wheel in the relationship. According to Aime, “these yeasts comprise a whole lineage that no one knew existed, and yet they are in a variety of lichens on every continent as a third symbiotic partner. This is an excellent example of how things can be hidden right under our eyes and why it is crucial that we keep studying the microbial world.”

Aime and colleagues found that two seemingly identical lichens behaved quite differently. The lichens Bryoria tortuosa and B. fremontii are composed of the same fungus and alga, but B. tortuosa is yellow and produces vulpinic acid, while B. fremontii is brown and does not produce the acid.

The group took samples from 15 lichens in western Montana and performed mRNA transcriptome sequencing. When they compared the data, they found sequences from a basidiomycete. Basidiomycota is a phylum that includes both filamentous fungi and yeast.

The Purdue researchers dug a little deeper and looked for the basidiomycetes in different lichens that were growing adjacent to those initially sampled. Each of these adjacent lichens housed genetically distinct strains of Basidiomycota. Eventually, they identified 52 genera of lichens from 6 continents that have a symbiotic relationship with the yeast!

So, what do the yeast bring to the symbiotic equation? Aime predicts that they are the source of vulpinic acid, which probably helps protect the lichen from invading microbes.
 


Sources: Science, Purdue University, Wikipedia
 
About the Author
  • Kerry received a doctorate in microbiology from the University of Arkansas for Medical Sciences.
You May Also Like
AUG 23, 2020
Microbiology
How Microbes Can Help Clean a Toxic River
AUG 23, 2020
How Microbes Can Help Clean a Toxic River
Some places in the United States have become dangerously polluted with hazardous waste. The EPA oversees a program that ...
AUG 29, 2020
Cell & Molecular Biology
Together, Two Gut Microbes Have a Nasty Effect
AUG 29, 2020
Together, Two Gut Microbes Have a Nasty Effect
The microbes in the human gut play important roles in our physiology, and they can also contribute to disease. But they ...
SEP 01, 2020
Cell & Molecular Biology
Smell Cells Are Especially Good at Fighting the Flu
SEP 01, 2020
Smell Cells Are Especially Good at Fighting the Flu
All over the body, cells line organs and vessels, forming protective barriers. But pathogens like the flu have gained th ...
SEP 11, 2020
Microbiology
Bat Ticks Are Discovered in New Jersey
SEP 11, 2020
Bat Ticks Are Discovered in New Jersey
While only about 25 of 900 species of tick spread disease, ticks are responsible for an estimated 95 percent of vector-b ...
NOV 19, 2020
Immunology
Parasitic Worms Help Unravel the Immune Mechanisms Underlying Chronic Disease
NOV 19, 2020
Parasitic Worms Help Unravel the Immune Mechanisms Underlying Chronic Disease
Parasitic worms known as helminths have a complicated relationship with the immune systems of the hosts they invade. Ter ...
NOV 17, 2020
Drug Discovery & Development
Antibiotics Before Age 2 Linked to Childhood Health Conditions
NOV 17, 2020
Antibiotics Before Age 2 Linked to Childhood Health Conditions
Researchers from Mayo Clinic have found a link between children aged two and under taking antibiotics and an increased r ...
Loading Comments...