Sea Grant

The Diversity and Role of Root-Associated Fungi in Saltmarsh and Seagrass Plants and Implications for Restoration Success

Nutrients taken up by mycorrhizal fungi can lead to improved plant growth and reproduction. The benefits for plants with mycorrhizal symbioses can be characterized either agronomically by increased growth and yield, or ecologically by improved fitness (i.e., reproductive ability). Mycorrhizal plants are often more competitive and better able to tolerate environmental stresses than are non-mycorrhizal plants. This interaction between plants and fungi is well understood and documented in terrestrial plants, but the knowledge of mycorrhizae in salt marshes and seagrasses is scarce. Of the few studies undertaken it was determined that the presence of mycorrhizal fungi in several wetland plant species ranged from 0 to 61.5% and it was suggested that wetlands with a lower nutrient availability may be more dependent on mycorrhizal fungi for nutrient uptake. Additionally, mycorrhizal fungi are an important factor in the tolerance of saltmarsh plants to seawater tidal flooding, and improved plant nitrogen acquisition. Mycorrhizal associations are important in understanding plant nutrient uptake efficiency, and this may be a causal mechanism for the poor restoration success of saltmarsh and seagrass plants. The main objective is to investigate the presence and ecological role of mycorrhizal fungi in estuarine plant habitats found along the Mississippi coastline, and to determine the effect of the presence of mycorrhizal fungi on seagrass and salt marsh restoration, survival, and function. The diversity of mycorrhizal fungi will be identified and classified using morphological and molecular methods (including molecular phylogeny and DGGE). The health of plants with mycorrhizae in relation to plants without mycorrhizae will be determined across a salinity gradient found in coastal waters of the Northern Gulf of Mexico.

This work is funded by SeaGrant.

The Master's theses resulting from this research are available as:

Pratt-Zossoungbo, Melissa (2008) Mycorrhizal fungal associations with salt marsh species Juncus roemerianus, Spartina alterniflora, Schoenoplectus robustus, and Schoenoplectus americanus. M.S. Thesis. USM Coastal Sciences

Walker, Allison Kennedy (2007) Assessment of fungal diversity of Gulf Coast saltmarshes and seagrass beds using morphological, molecular and biochemical methods. M.S. Thesis. USM Coastal Sciences