Featured Research

from universities, journals, and other organizations

Ants protect acacia plants against pathogens

Date:
January 15, 2014
Source:
Max Planck Institute for Chemical Ecology
Summary:
The presence of mutualistic ants greatly reduces bacterial abundance on surfaces of acacia leaves and has a visibly positive effect on plant health. Study results indicate that symbiotic bacteria colonizing the ants inhibit pathogen growth on the leaves.

Mutualistic Pseudomyrmex ferrugineus ants on an acacia plant. The ants love nectar from the plant's extrafloral nectaries.
Credit: Martin Heil, CINVESTAV, Irapuata, Mexico

The biological term "symbiosis" refers to what economists and politicians usually call a win-win situation: a relationship between two partners which is beneficial to both. The mutualistic association between acacia plants and the ants that live on them is an excellent example: The plants provide food and accommodation in the form of food bodies and nectar as well as hollow thorns which can be used as nests. The ants return this favor by protecting the plants against herbivores. Researchers at the Max Planck Institute for Chemical Ecology in Jena, Germany, have now found that ants also keep harmful leaf pathogens in check. The presence of ants greatly reduces bacterial abundance on surfaces of leaves and has a visibly positive effect on plant health. Study results indicate that symbiotic bacteria colonizing the ants inhibit pathogen growth on the leaves.

Related Articles


Myrmecophytes are plants which live in a symbiotic relationship with ants. The acacia species Acacia hindsii, which is native to tropical dry forests in Central America, is such a myrmecophyte. Its inhabitants are ants of the genus Pseudomyrmex. The ants depend completely on their host plants for nectar and the food bodies rich in proteins and lipids which they require. The acacia also provides shelter, the so-called domatia, in the hollows of its swollen thorns. In return for room and board, mutualistic Pseudomyrmex ferrugineus ants become bodyguards, protecting their host against herbivores and competing plants. However, some ants also benefit from the plant's services without giving anything in return, such as the parasitic ant species Pseudomyrmex gracilis.

Scientists at the Max Planck Institute for Chemical Ecology have now looked more deeply into the insect-plant interaction, asking whether the tiny bodyguards also provide protection against microbial pathogens. They compared the leaves of acacia plants which were inhabited by either mutualistic or parasitic ants to leaves from which ants had been removed. Intriguingly, the leaves of acacia colonized by parasitic ants showed more leaf damage from herbivores and microbial pathogens than did the leaves that had mutualistic ants. The presence of the right symbiotic partner seemed to have a positive effect on the plant's health.

Analysis of the surfaces of the leaves revealed that the number of plant pathogens as well as of necrotic plant tissues increased considerably when mutualistic Pseudomyrmex ferrugineus ants were absent. These plants also showed strong immune responses in the form of an increased concentration of salicylic acid, a plant hormone which regulates defense against pathogens. Detailed analysis of the bacterial composition on the surfaces of the leaves suggested that the presence of mutualistic ants changed the bacterial populations and reduced harmful pathogens. Although far less pronounced, this effect could also be observed in parasitic ants.

How antimicrobial protection is transferred from ants to plant is still unclear. Chilean researcher Marcia Gonzαlez-Teuber, first author of the publication, suspected that microorganisms associated with the ants might play a role. Because acacia leaves are touched mainly by ants' legs, she extracted the legs of mutualistic and parasitic ants and tested the effect of the extracts on the growth of bacterial pathogens in the lab. Plant pathogen Pseudomonas syringae was sensitive to the application of leg extracts of both ant species and its growth was inhibited. In the next step, the scientist isolated and identified bacteria from the legs of the ants. In lab tests, bacterial strains of the genera Bacillus, Lactococcus, Pantoea and Burkholderia effectively inhibited the growth of Pseudomonas bacteria isolated from infected acacia leaves. Interestingly, some of the bacterial genera associated with the ants are known to produce antibiotic substances.

The Jena researchers have thus added another level of interaction to the symbiosis between ants and their host plants. "Such mutualistic relationships are much more complex than previously thought. In the future, we will have to include bacteria and other microorganisms in our considerations," says Wilhelm Boland, head of the Department of Bioorganic Chemistry at the Max Planck Institute. Studies on symbiotic relationships between ants and myrmecophytic plants should not overlook the role of bacterial partners that help the ants protect "their" plants.


Story Source:

The above story is based on materials provided by Max Planck Institute for Chemical Ecology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Marcia Gonzαlez-Teuber, Martin Kaltenpoth, Wilhelm Boland. Mutualistic ants as an indirect defence against leaf pathogens. New Phytologist, 2014; DOI: 10.1111/nph.12664

Cite This Page:

Max Planck Institute for Chemical Ecology. "Ants protect acacia plants against pathogens." ScienceDaily. ScienceDaily, 15 January 2014. <www.sciencedaily.com/releases/2014/01/140115113243.htm>.
Max Planck Institute for Chemical Ecology. (2014, January 15). Ants protect acacia plants against pathogens. ScienceDaily. Retrieved December 17, 2014 from www.sciencedaily.com/releases/2014/01/140115113243.htm
Max Planck Institute for Chemical Ecology. "Ants protect acacia plants against pathogens." ScienceDaily. www.sciencedaily.com/releases/2014/01/140115113243.htm (accessed December 17, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Wednesday, December 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

When You Lose Weight, This Is Where The Fat Goes

When You Lose Weight, This Is Where The Fat Goes

Newsy (Dec. 17, 2014) — Can fat disappear into thin air? New research finds that during weight loss, over 80 percent of a person's fat molecules escape through the lungs. Video provided by Newsy
Powered by NewsLook.com
Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) — NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com
Ivory Trade Boom Swamps Law Efforts

Ivory Trade Boom Swamps Law Efforts

Reuters - Business Video Online (Dec. 17, 2014) — Demand for ivory has claimed the lives of tens of thousands of African elephants and now a conservation report says the illegal trade is overwhelming efforts to enforce the law. Amy Pollock reports. Video provided by Reuters
Powered by NewsLook.com
Uphill Battle to Tackle Indonesian Shark Fishing

Uphill Battle to Tackle Indonesian Shark Fishing

AFP (Dec. 17, 2014) — Sharks are hauled ashore every day at a busy market on the central Indonesian island of Lombok, the hub of a booming trade that provides a livelihood for local fishermen but is increasingly alarming environmentalists. Duration: 00:42 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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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