A dangerous mix: Strain, dosage, and environment increase virulence of eelgrass wasting disease
Presentation Abstract
Seagrass wasting disease, caused by the opportunistic marine pathogen Labyrinthula zosterae, has the potential to devastate important eelgrass habitats worldwide, yet little is known about the host-pathogen interaction and how the disease will be impacted by climate change. L. zosterae is part of a diverse taxon of opportunistic invertebrate and plant pathogens, which directly threaten fisheries and critical fisheries habitat. An area of particular concern is the role of virulence, the degree of host damage caused by a pathogen, often the product of its growth rate. Recent data suggests that temperature increases the virulence of Labyrinthulas, providing a mechanism for climate sensitivity. In this study we investigate the effect of L. zosterae strain, pathogen dosage, and temperature on the pathogen virulence. We tested L. zosterae virulence in Zostera marina by inoculating plant tissue with strains collected from a range of eelgrass populations. The 11 strains tested displayed qualitatively different virulence, with infection rates ranging from 0 to 100%. Pathogen virulence increased with dosage. Growth rates at a range of temperatures were tested for a subset of these strains. Results suggest the temperature increases growth rates, but the degree differs between strains. We conducted a controlled temperature experiment in which Z. marina adults and seedlings were allowed to acclimate to low (11° C), high (18° C) and fluctuating (between 11 and 18° C) water temperatures and then half these individuals were exposed to L. zosterae. Disease occurred more rapidly and with higher severity in seedlings and at high temperatures. Our results show that pathogen virulence is impacted by strain, dosage, and environment and suggests L zosterae will cause increased damage to eelgrass beds as water temperatures warm.
Session Title
Kelp and Eelgrass
Conference Track
Habitat
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Location
2016SSEC
Type of Presentation
Oral
Genre/Form
presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Eelgrass--Diseases and pests--Salish Sea (B.C. and Wash.); Marina protozoa--Salish Sea (B.C. and Wash.); Virulence (Microbiology)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
A dangerous mix: Strain, dosage, and environment increase virulence of eelgrass wasting disease
2016SSEC
Seagrass wasting disease, caused by the opportunistic marine pathogen Labyrinthula zosterae, has the potential to devastate important eelgrass habitats worldwide, yet little is known about the host-pathogen interaction and how the disease will be impacted by climate change. L. zosterae is part of a diverse taxon of opportunistic invertebrate and plant pathogens, which directly threaten fisheries and critical fisheries habitat. An area of particular concern is the role of virulence, the degree of host damage caused by a pathogen, often the product of its growth rate. Recent data suggests that temperature increases the virulence of Labyrinthulas, providing a mechanism for climate sensitivity. In this study we investigate the effect of L. zosterae strain, pathogen dosage, and temperature on the pathogen virulence. We tested L. zosterae virulence in Zostera marina by inoculating plant tissue with strains collected from a range of eelgrass populations. The 11 strains tested displayed qualitatively different virulence, with infection rates ranging from 0 to 100%. Pathogen virulence increased with dosage. Growth rates at a range of temperatures were tested for a subset of these strains. Results suggest the temperature increases growth rates, but the degree differs between strains. We conducted a controlled temperature experiment in which Z. marina adults and seedlings were allowed to acclimate to low (11° C), high (18° C) and fluctuating (between 11 and 18° C) water temperatures and then half these individuals were exposed to L. zosterae. Disease occurred more rapidly and with higher severity in seedlings and at high temperatures. Our results show that pathogen virulence is impacted by strain, dosage, and environment and suggests L zosterae will cause increased damage to eelgrass beds as water temperatures warm.
