Abstract Detail

Developmental and Structural Section

Sherman, Timothy D [1], Vaughn, Kevin C [2].

An ultrastructural overview of adaptations that make dodders (Cuscuta spp.) efficient parasites.

Dodder plants (Cuscuta spp.) germinate as seedlings with very limited chlorophyll content, and with only rudimentary leaves and a terminal, swollen, root-like structure. They apparently utilize this low level of photosynthetic capacity and nutrients, derived from the root-like structure, to sustain them for about 10 days until they can find a suitable host. Once the shoot makes contact with a compatible host species, a series of changes occurs in the region of contact between the dodder shoot and the host plant. Three phases of development occur in the dodder and host cells to establish a successful parasitism. These include: 1) recognition of the host and establishment of a firm contact between host and parasite; 2) penetration of the host by the hyphal system until contact is reached with the host xylem and phloem; 3) differentiation of the hyphae into modified xylem and phloem elements and their union between the host and parasite vascular systems. Because dodder requires a living host due to its own low levels of photosynthetic capacity, the parasitization of the host must be gentle enough so as not to disturb the host tissue in a way that would cause the quick death of the host. Rather, it must be done gently enough so that the host is sustained at least long enough to support the dodder plant through seed reproduction of the parasite. We will present ultrastructural data that demonstrates unique characteristics of dodder’s growth and development, which are responsible for the success of this parasite.

1 - University of South Alabama, Biological Sciences, Life Sciences Building #124, 307 University Blvd. North, Mobile, Alabama, 36688-0002, United States
2 - USDA-ARS, Southern Weed Science Research Unit, Stoneville, Mississippi, 38776, United States

Keywords:
parasite
cell wall
ultrastructure
photosynthesis
cytoskeleton
dodder
cuscuta.

Presentation Type: Poster
Session: 32-20
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM
Abstract ID:879