Abstract Detail

Developmental and Structural Section

Sherman, Timothy D [1], Evans, Kerry R [2], Vojvodic, Svjetlana [1].

Ultrastructural characterization of the infection process of two seagrass species by the protist Labyrinthula sp.

The subtropical seagrasses turtlegrass (Thalassia testudinum) and eelgrass (Zostera marina) are vulnerable to attack by the protist Labyrinthula sp. in varying degrees. On a macro-scale, the infection produces black necrotic lesions that spread out from the point of infection and eventually cover large portions of the leaf. Our interest in pathogenesis lies at the cellular level. When attacking, Labyrinthula must penetrate the cell wall of the seagrass in a fashion similar to that of fungal pathogenesis described in the terrestrial literature, which involves degrading the plant cell wall in order to access the cytoplasmic compartment. In order to study this process in Labyrinthula-related attacks, we used light, fluorescence, and transmission electron microscopy to examine the ultrastructural characteristics of the wall structure of the seagrass. This characterization was supplemented with an immunological characterization of the cell wall carbohydrate composition. We observed differential localization of the carbohydrates in the cell walls prior to infection. A comparison of uninfected and infected tissue may offer insight into the details of the attack at a cellular level, including the course of infection and the mechanisms occurring at the time of infection in one or both organisms.

1 - University of South Alabama, Biological Sciences, Life Sciences Building #124, 307 University Blvd. North, Mobile, Alabama, 36688-0002, United States
2 - Springhill College, Department of Biology, Mobile, Alabama, 36608, United States

Keywords:
Cell walls
ultrastructure
pathogen
cellulose
pectin
xyloglucan
immunolocalization
seagrass
callose.

Presentation Type: Poster
Session: 32-24
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:861