Liquid culture and growth quantification of the seagrass pathogen, Labyrinthula spp.

Abstract

Symptoms characteristic of wasting disease, thought to result from infection by protozoan pathogens (i.e. Labyrinthula spp.), are a common phenomenon affecting seagrass species worldwide. However relatively little is known about factors that control the survival and success of Labyrinthula in part due to the difficulty associated with quantifying the growth of this organism. Here we describe a simple and inexpensive method for measuring growth of Labyrinthula in liquid culture that takes into consideration both cell density and areal spread. The technique allows for examination of the effects of both abiotic and biotic factors on the growth of Labyrinthula apart from its seagrass host, separating the effects of environmental condition on the host from their effects on the pathogen.

• die-off
• Thalassia testudinum
• wasting disease

The authors thank David Porter and Tim Sherman for comments and suggestions on techniques tested and Chris Tanner for assistance in the development of the crystal violet staining technique. Financial support for this work was provided by a NSF-RUI grant to AB (OCE-0117342) and by the Department of Biology, University of South Alabama.