Volatile lactone of Hymenoscyphus pseudoalbidus inhibits germination of ash seeds
The leaves wilt, the crown dies off, the bark exhibits lesions, the wood becomes discolored – the ash forests of Europe are under threat. The perpetrator is an Asian fungus, and its progress is unstoppable. In order to develop effective countermeasures, the transmission pathway, progression of the disease, and propagation of the fungus must be clarified. German researchers have now identified a metabolic product of this killer fungus that inhibits the germination of ash seeds. In the journal Angewandte Chemie, they report on possible mechanisms for this activity.
Hymenoscyphus pseudoalbidus looks almost identical to its harmless relative, Hymenoscyphus albidus, but it causes heavy damage to the common ash, Fraxinus excelsior. Over the last two decades, this killer fungus from the Far East has rapidly spread from east to west across Europe, reaching the British Isles in 2012. There is no decline of the disease in sight. Only a small subpopulation of European ash trees seems to be resistant to this fungus, but it is unclear whether this portion is large enough to ensure the survival of this ecologically and economically important tree species, which is found in nearly all of Europe and parts of Asia around the Black Sea.
A team led by Jeroen S. Dickschat at the Technische Universität Braunschweig has extracted the volatile and nonvolatile metabolic products of the fungus and studied them by spectroscopic methods. The researchers found a suspect among the volatile compounds: in laboratory experiments, the lactone 3,4-dimethylpentan-4-olide inhibits the germination of ash seeds and causes necrosis.
Surprisingly, this compound is also found in nonpathogenic fungi. “Metabolites from the plants may play a role here by regulating the production of the lactone differently in different species of fungus,” suggests Dickschat. “This could also explain why Japanese ash trees are not affected by this fungus and some individuals of the European ash are also relatively resistant.” Another explanation could be the interaction between the lactone and certain microorganisms that are found in the European ash. “Such a mechanism would allow endophytes to act as mediators between the plant and its pathogen,” explains Dickschat. “A comparable mechanism has previously been discovered in another case: Lactones in the smoke produced by burning plants promote germination through a process in which interactions with plant bacteria might play a critical role.”
These new discoveries are important milestones in understanding ash dieback and possible mechanisms of resistance in the unaffected populations of ash. Says Dickschat: “The identification of the lactone as the virulence factor will hopefully pave the way for control of a pathogen that currently threatens the entire population of ash trees in Europe.”
About the Author
Dr. Jeroen S. Dickschat is Assitant Professor of Organic Chemistry at the Technical University of Braunschweig and recipient of the Dechema Young Scientists' Award for Natural Product Research 2014. His research interests focus on the biosynthesis and function of volatile natural products from microorganisms.
Author: Jeroen S. Dickschat, Technische Universtiät Braunschweig (Germany), http://www.oc.tu-bs.de/dickschat/jdickschat_de.html
Title: A Volatile Lactone of Hymenoscyphus pseudoalbidus, Pathogen of European Ash Dieback, Inhibits Host Germination
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201402290
Jeroen S. Dickschat | Angewandte Chemie
Tiny songbird discovered to migrate non-stop, 1,500 miles over the Atlantic
01.04.2015 | University of Massachusetts at Amherst
The 'intraterrestrials': New viruses discovered in ocean depths
01.04.2015 | National Science Foundation
Spring is here and ectotherms, or animals dependent on external sources to raise their body temperature, are becoming more active. Recent studies have shown...
Glass-fronted office buildings are some of the biggest energy consumers, and regulating their temperature is a big job. Now a façade element developed by Fraunhofer researchers and designers for glass fronts is to reduce energy consumption by harnessing solar thermal energy. A demonstrator version will be on display at Hannover Messe.
In Germany, buildings account for almost 40 percent of all energy usage. Heating, cooling and ventilating homes, offices and public spaces is expensive – and...
Outstanding chemical, thermal and tribological properties predestine silicon carbide for the production of ceramic components of high volume. A novel method now overcomes the procedural and technical limitations of conventional design methods for the production of components with large differences in wall thickness and demanding undercuts.
Extremely hard as diamond, shrinking-free manufacturing, resistance to chemicals, wear and temperatures up to 1300 °C: Silicon carbide (SiSiC) bundles all...
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
01.04.2015 | Earth Sciences
01.04.2015 | Information Technology
01.04.2015 | Physics and Astronomy