Eelgrass populations are currently infected with a disease that produces symptoms and epidemiology reminiscent of the famous eelgrass wasting disease of the 1930s. This disease virtually eliminated eelgrass (Zostera marina L.) in the North Atlantic for three decades. For 50 years scientists have speculated about the cause of the 1930s eelgrass decline. We have now proven that the causal organism of the present epidemic is a pathogenic strain of Labyrinthula, which was suspected, but never conclusively shown to cause the 1930s wasting disease. We have isolated the infectious form of Labyrinthula from eelgrass from Maine to North Carolina on the Atlantic coast, and from Puget Sound on the Pacific coast; disease-related dieoffs of eelgrass beds are confirmed in Maine, New Hampshire, and Massachusetts.
A marine epidemic of wasting disease decimated populations of eelgrass, Zostera marina L., in the early 1930s. Labyrinthula, a marine slime mold was the suspected pathogen, although the cause was never clearly determined. Presently, a recurrence of wasting disease of Z. marina was documented in populations along the coasts of North America and Europe. A pathogenic species of Labyrinthula, described as Labyrinthula zosterae Porter et Muehlstein, was identified as the primary microorganism causing the present wasting disease. Of all the microorganisms tested in laboratory disease tests, only L. zosterae caused disease symptoms. Direct microscopic observations revealed that Labyrinthula cells were found most frequently associated with marginal areas of disease symptoms and appeared to move rapidly through the tissue, directly penetrating cell walls. The ectoplasmic network that surrounds Labyrinthula cells appeared to have an important role in the enzymatic degradation of plant cell walls and presumably a role in the destruction of cytoplasmic contents of the plant cells. Direct contact of diseased leaves with healthy leaves was the mechanism of disease spread from plant to plant. Key words: Labyrinthula, Zostera marina, eelgrass wasting disease.
Early in the 1930's a major epidemic decimated populations of eelgrass Zostera manna L. along the Atlantic coast of North America and Europe. Over 90 % of the eelgrass populations disappeared, resulting in dramatic changes within the coastal ecosystem. There was much speculation about the possible causes of the wasting disease ranging from pathogen~c microorganisms to abiotic factors including changes in temperature, precipitation, salinity, and pollution In a critical review of the Literature, substantial research supported the view that a specles of the genus Labyrinthula, a marine slime mold, was the primary causative agent of the epidemic dlsease This hypothesis was consistently supported by data collected throughout the range of diseased eelgrass populations. In the present recurrence of eelgrass wasting disease, a pathogenic species, Labyrinthula zosterae has been identified as the causative agent of the disease. Similarities of past and present wasting disease episodes further support the hypothesis that Labyrinthula is the primary etiological agent.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.