Featured Research

from universities, journals, and other organizations

Symbiosis in Fungi: Enforced surrender?

Date:
May 20, 2014
Source:
INRA-France
Summary:
A key mechanism in the symbiosis between fungi and trees has been uncovered by researchers. During this mutually beneficial interaction, the fungus takes control of its host plant by injecting a small protein that neutralizes its immune defenses thereby allowing the fungus to colonize the plant. This finding is a major advance in our understanding of the evolution and functioning of symbiotic interactions between fungi and plants - relationships that play a significant role in supporting the health and sustainability of our natural ecosystems.

Laccaria bicolor.
Credit: INRA/F. Martin

Scientists from INRA and Lorraine University in France unraveled a key mechanism in the symbiosis between fungi and trees. During this mutually beneficial interaction, the fungus takes control of its host plant by injecting a small protein that neutralizes its immune defenses thereby allowing the fungus to colonize the plant. This finding is a major advance in our understanding of the evolution and functioning of symbiotic interactions between fungi and plants -- relationships that play a significant role in supporting the health and sustainability of our natural ecosystems. These results are published in the advance online edition of the PNAS on 19 May 2014.

In the complex world of the rhizosphere -- the soil surrounding plant roots -- thousands of species of bacteria and fungi compete for resources released by plants. Some fungi, such as truffles and boletus, are able to live in symbiosis with plants through their roots, by-passing their competitors to obtain sugars directly from their host. In return, symbiotic fungi allow plant roots to absorb mineral nutrients; this improves the plant's health, vigor and productivity. Mycorrhizal fungi are one class of symbiotic fungi that make their way to plant roots where they negotiate for housing and all-you-can-eat sugar services. But how does this negotiation play out? Is the host plant able to distinguish between beneficial and parasitic fungi? How does the fungus avoid the plant's immune defenses during the interaction?

It's all about biochemical dialogue

Thanks to a global collaboration between INRA, Lorraine University, Oak Ridge National Laboratory and the University of Western Sydney, part of the molecular language used by mycorrhizal fungi was partially deciphered.

Plant roots are constantly releasing a diverse set of 'signal' molecules into their surrounding soil environment. Scientists studied a specific fungus, Laccaria bicolor, which perceives these molecules in the soil and enables fungal growth toward the plant root. The presence of a plant root also triggers the release of small proteins by the fungus. Generically called 'effectors', these small fungal proteins are bioactive molecular signals that prepare plant tissues for a symbiotic relationship. How these molecular signals prepare the plant host for symbiosis with a mycorrhizal fungus has remained clouded in mystery -- until now.

Effectors block the plant's immune defenses

The research consortium identified one of these effectors, MiSSP7, that binds a molecular switch which controls plant immunity. Normally, when a plant is attacked by a disease-causing microbe, jasmonic acid is one of the main hormones that immediately triggers a battery of defense reactions to kill off the invading organism. MiSSP7 neutralizes this defensive response by directly targeting the jasmonic acid-associated control switch of plant immunity. By hindering the plants ability to generate an immune response, MiSSP7 allow the fungus to develop within plant tissue where it can establish a fair trade for nutrients.

These findings show that beneficial microbes, rather than playing nice, are forcing themselves into the plant enacting a symbiotic relationship with the plant nefariously. Research is underway to identify if the other effectors of mycorrhizal fungi act similarly to control the host plant and force symbiosis.


Story Source:

The above story is based on materials provided by INRA-France. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jonathan M. Plett, Yohann Daguerre, Sebastian Wittulsky, Alice Vayssieres, Aurelie Deveau, Sarah J. Melton, Annegret Kohler, Jennifer Morrell-Falvey, Annick Brun, Claire Veneault-Fourrey, Francis Martin. The Effector MiSSP7 of the Mutualistic Fungus Laccaria bicolor Stabilizes the Populus JAZ6 Protein and Represses JA-responsive Genes. PNAS, May 2014

Cite This Page:

INRA-France. "Symbiosis in Fungi: Enforced surrender?." ScienceDaily. ScienceDaily, 20 May 2014. <www.sciencedaily.com/releases/2014/05/140520093444.htm>.
INRA-France. (2014, May 20). Symbiosis in Fungi: Enforced surrender?. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2014/05/140520093444.htm
INRA-France. "Symbiosis in Fungi: Enforced surrender?." ScienceDaily. www.sciencedaily.com/releases/2014/05/140520093444.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
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