Featured Research

from universities, journals, and other organizations

At The Fungal Farmer's Market, Only The Best Cyanobacteria Are For Sale

Date:
August 24, 2009
Source:
American Journal of Botany
Summary:
Lichens are the classic example of a symbiotic relationship. Both the fungal and photobiont components of the lichen benefit from the relationship and often are unable to survive without each other. Recent research has put a new spin on this relationship.

Cyanobacterial photobionts of tropical cyanolichens of the genera Acantholichen, Coccocarpia, Dictyonema, and Stereocaulon, belong to a previously unrecognized, exclusively lichenized, novel lineage with the name Rhizonema. These photobionts are shared between unrelated lichen mycobionts co-occurring in the same habitats, leading to improved strains by means of mycobiont and environmental selection, in a similar way as farmers domesticate and improve crops.
Credit: Courtesy of Robert K. Lucking

Lichens are the classic example of a symbiotic relationship. Both the fungal and photobiont components of the lichen benefit from the relationship and often are unable to survive without each other. Recent research by Dr. Robert Lücking (The Field Museum, Chicago), Dr. James Lawrey (George Mason University, Virginia) and a team of colleagues from around the world has put a new spin on this relationship.

In a paper published in the August 2009 issue of the American Journal of Botany, Lücking et al. explore the possibility of lichens as domesticators, similar to early farmers domesticating grains. By investigating the evolutionary history of a group of cyanobacteria associated with lichens, Lücking and Lawrey and their team have made some surprising conclusions.

Although lichen fungi represent more than 1000 genera, most are associated with photobionts that represent only four genera, one of them believed to be the common and widely distributed cyanobacterial genus Scytonema. However, the identity of photobionts thought to be Scytonema has never been confirmed. Lücking and his colleagues used DNA sequence data to reconstruct evolutionary relationships among free-living members of Scytonema and putative Scytonema photobionts associated with three major fungal lineages.

They discovered that these lichenized photobionts are not members of the genus Scytonema, but form a novel, previously unrecognized, entirely lichenized, lineage of cyanobacteria. The members of this novel lineage, which bears the name Rhizonema, physically appear very similar to free-living members of the genus Scytonema, and members of the two genera can be found close to each other—one lichenized, the other not. Apart from being the first discovery of a completely novel photobiont lineage in lichens using molecular phylogenetics, this find has important implications for ecosystem research because a large proportion of nitrogen-fixing cyanobacteria previously believed to occur in both lichenized and free-living forms now appear to be restricted to lichen symbioses.

Lücking et al. also found that a wide range of lichen fungi that are distantly related with each other but co-occur in the same habitats are associated with members of Rhizonema. This implies that the fungi "share" the cyanobacteria among them, as opposed to evolving in concert with the cyanobacteria, a process that would result in similar evolutionary patterns in the fungal and cyanobacterial components of the lichen.

The authors propose that photobionts are selected based on their compatibility with the mycobionts and their ability to contribute to the establishment and growth of the lichen. This results in an increase in the frequency of particular mycobiont-photobiont pairs, and likewise an increase in the frequency of particular photobionts, which then leads to an increase in the availability of these photobiont strains for other lichen associations. This process may be compared to crop domestication, where farmers develop improved crop varieties and share them with other farmers, leading to higher yields for the farmers and proliferation of the most widely-used varieties. Indeed, the North American lichenologist Trevor Goward has defined lichens as "fungi that discovered agriculture," and this study not only supports this view but adds a further dimension to it.


Story Source:

The above story is based on materials provided by American Journal of Botany. Note: Materials may be edited for content and length.


Journal Reference:

  1. Lucking, Robert, Lawrey, James D., Sikaroodi, Masoumeh, Gillevet, Patrick M., Chaves, Jose Luis, Sipman, Harrie J. M., Bungartz, Frank. Do lichens domesticate photobionts like farmers domesticate crops? Evidence from a previously unrecognized lineage of filamentous cyanobacteria. American Journal of Botany, 2009; 96 (8): 1409 DOI: 10.3732/ajb.0800258

Cite This Page:

American Journal of Botany. "At The Fungal Farmer's Market, Only The Best Cyanobacteria Are For Sale." ScienceDaily. ScienceDaily, 24 August 2009. <www.sciencedaily.com/releases/2009/08/090821163523.htm>.
American Journal of Botany. (2009, August 24). At The Fungal Farmer's Market, Only The Best Cyanobacteria Are For Sale. ScienceDaily. Retrieved August 27, 2014 from www.sciencedaily.com/releases/2009/08/090821163523.htm
American Journal of Botany. "At The Fungal Farmer's Market, Only The Best Cyanobacteria Are For Sale." ScienceDaily. www.sciencedaily.com/releases/2009/08/090821163523.htm (accessed August 27, 2014).

Share This




More Plants & Animals News

Wednesday, August 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Super Healthful Fruits and Vegetables: Which Are Best?

Super Healthful Fruits and Vegetables: Which Are Best?

Ivanhoe (Aug. 27, 2014) — We all know that it is important to eat our fruits and vegetables but do you know which ones are the best for you? Video provided by Ivanhoe
Powered by NewsLook.com
Raw: Firefighters Rescue Puppy Stuck in Tire

Raw: Firefighters Rescue Puppy Stuck in Tire

AP (Aug. 26, 2014) — It took Houston firefighters more than an hour to free a puppy who got its head stuck in a tire. (Aug. 26) Video provided by AP
Powered by NewsLook.com
Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Have You Ever Been 'Sleep Drunk?' 1 in 7 Has

Newsy (Aug. 26, 2014) — A study published in the journal "Neurology" interviewed more than 19,000 people and found 15 percent suffer from being "sleep drunk." Video provided by Newsy
Powered by NewsLook.com
Activists Urge NYC Mayor to Ban Carriage Horses

Activists Urge NYC Mayor to Ban Carriage Horses

AP (Aug. 26, 2014) — A group of New Yorkers are putting Mayor Bill de Blasio on notice for what they say is reneging on his campaign promise to ban carriage horses. They rallied Tuesday near the mayor's Gracie Mansion home. (Aug. 26) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins