Study in California grassland expands understanding of biodiversity and management of emerging diseases
On Earth Day, a study of disease dynamics in a California grassland has revealed fundamental principles underlying the spread of pathogens, or disease-causing microbes, among species.
Wild radishes are surrounded by abundant diseased grasses.
Credit: Bruce Lyon
The results, announced today in the journal Nature, have implications for the maintenance of biodiversity and for addressing practical problems related to plant disease.
Researchers at the University of California, Santa Cruz, studied the phenomenon of "pathogen spillover" in grassland species on the UC Santa Cruz campus.
They found that the amount of disease present on each species could be predicted by the abundance of its close relatives in the grassland. When there were many individuals of the same or similar species living close together, pathogens spread more quickly.
Perhaps unexpectedly, that in turn promotes biodiversity by creating openings for less common species that are not attacked by these same pathogens.
Link between community structure and individual disease vulnerability
The findings reveal a tight link between the structure of a plant community and the vulnerability of individual species to disease.
"These scientists demonstrate that the relatedness of species in communities is an important predictor of disease prevalence," said Alan Tessier, acting director of the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.
The researchers were able to predict which plant species introduced into the grassland would be most strongly affected by naturally-occurring diseases.
Ingrid Parker, an ecologist and evolutionary biologist at UC Santa Cruz and first author of the paper, said the study adds an important new dimension to a longstanding concept in ecology known as the "rare species advantage."
Diseases take greater toll on common species
"The rare species advantage is thought to be a major driver of biodiversity in natural ecosystems," Parker said. "Most pathogens are not host specialists--they can easily move from one species to another. Whether pathogens 'spill over' depends on how closely related other species nearby are.
"Our study shows that it's the structure of the whole community around a species that affects its vulnerability to disease."
Large-scale experiment with 44 plant species
In a large-scale experiment, the researchers introduced 44 plant species from outside California. (The plants were removed before they reproduced.)
The biologists found that species with few close relatives in the grassland escaped disease, while those closely related to many resident species always showed high levels of disease.
The researchers were able to make surprisingly accurate predictions of disease in introduced species based on their phylogenetic, or evolutionary, distance from local species.
"It was kind of shocking how well we were able to predict disease at a local scale," Parker said.
To incorporate the phylogenetic distance between species into their predictions of disease dynamics, the researchers used a "PhyloSusceptibility model" developed by scientist Gregory Gilbert at UC Santa Cruz and two other paper co-authors, Roger Magarey and Karl Suiter of North Carolina State University, who work with the U.S. Department of Agriculture's (USDA) Animal and Plant Health Inspection Service.
The model is based on USDA's global database of fungal pathogens and host plants, and can be used to predict the probability of two species sharing a pathogen.
"If a plant pathogen from Brazil suddenly shows up in southern California, you want to know what plants in California are most likely to be attacked," Gilbert said.
By showing that the PhyloSusceptibility model makes accurate predictions, the results suggest a range of potential applications.
The PhyloSusceptibility model could help avoid disease problems affecting proposed horticultural imports or reforestation projects.
It could also be used in agriculture to design intercropping or rotation systems to decrease crop disease.
Vulnerability of local species to "pathogen spillover"
Imported plants can bring new pathogens and pests into an area. The PhyloSusceptibility model could be used to assess the vulnerability of local species to pathogen spillover from such plant introductions, the scientists say.
While the PhyloSusceptibility model used in this study was based on data for fungal pathogens, Gilbert said the team has also created versions based on data for eight other groups of pests and pathogens, including insects, nematodes, bacteria and viruses.
In addition to Parker, Gilbert, Magarey and Suiter, the co-authors of the study include UC Santa Cruz researchers Megan Saunders, Megan Bontrager, Andrew Weitz and Rebecca Hendricks.
USDA also funded the work.
Cheryl Dybas | EurekAlert!
Climate change weakens Walker circulation
20.10.2017 | MARUM - Zentrum für Marine Umweltwissenschaften an der Universität Bremen
Shallow soils promote savannas in South America
20.10.2017 | Senckenberg Forschungsinstitut und Naturmuseen
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research