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
MAY 13, 2020
Microbiology
Low Vitamin D Levels Linked to COVID-19 Mortality
MAY 13, 2020
Low Vitamin D Levels Linked to COVID-19 Mortality
The COVID-19 pandemic has swept through various countries with widely discrepant mortality rates.
JUN 15, 2020
Microbiology
Research Shows Wearing a Face Mask Reduces the Risk of COVID-19 Infection
JUN 15, 2020
Research Shows Wearing a Face Mask Reduces the Risk of COVID-19 Infection
We've known that face masks can reduce the likelihood that asymptomatic people will spread the illness. But they are als ...
JUN 22, 2020
Cell & Molecular Biology
Viruses Can Create New Genes By Stealing Bits of Human DNA
JUN 22, 2020
Viruses Can Create New Genes By Stealing Bits of Human DNA
When viruses infect cells, they hijack the machinery inside and start to use it for their own purposes. This enables vir ...
JUL 13, 2020
Microbiology
New Gene Editor Can Alter Mitochondrial DNA
JUL 13, 2020
New Gene Editor Can Alter Mitochondrial DNA
There is intense competition for resources in the microbial world, and bacteria have an arsenal of weapons to help them ...
AUG 03, 2020
Cell & Molecular Biology
Gut Microbes & Diet Change the Behavior of a Cancer-Driving Protein
AUG 03, 2020
Gut Microbes & Diet Change the Behavior of a Cancer-Driving Protein
Clinicians and researchers have long wondered why cancer is the small intestine is rare while it's so common in the colo ...
AUG 05, 2020
Microbiology
Revealing the Secrets of a Symbiotic Relationship
AUG 05, 2020
Revealing the Secrets of a Symbiotic Relationship
Some salamanders (Ambystoma maculatum) have a strange relationship with a type of alga (Oophila amblystomatis): they are ...
Loading Comments...