Kandalepas, Demetra , Arnold, A.E. , Shaffer, Gary P. , Platt, William .
Mycophylla Communities are Influenced by the Interaction between Plant Host and Environmental Conditions.
When plants experience stress, they become more susceptible to disease, but mycophyllas -- endophytic fungi that live within plant leaves -- may ameliorate some of these negative effects. Thus, determining the effects of sea-level rise and storms on mycophylla communities may be important in understanding plant community dynamics in coastal systems in the context of global change. Using mesocosms in which we manipulated flooding, salinity, and sediment load, we asked whether coastal processes simulating storm surges affect community structure of mycophylla communities in two focal wetland plants (Taxodium distichum and Sagittaria lancifolia). Twenty weeks after the onset of treatment, we surface-sterilized mature leaves produced under mesocosm conditions and incubated small tissue fragments on 2% malt extract agar to isolate fungal endophytes. Isolates were classified into morphospecies and data from the nuclear ribosomal internal transcribed spacer and large subunit (ca. 1000bp) were used to estimate species boundaries. Overall, mycophylla diversity in T. distichum exceeded that in S. lancifolia. When conditions were favorable for the host, rare fungal species were present at the expense of common species. Sediment addition was the most important factor affecting community structure in each plant host, influencing fungal species composition in T. distichum but not changing the diversity of mycophylla assemblages in that species. Conversely, sediment addition affected mycophylla diversity, but not composition, in S. lancifolia, with increased diversity in plants with freshwater and fertilized soil, and decreased diversity in saline water and unfertilized soil. Treatment combinations simulating storm surges (flooded conditions, increased salinity, and added sediment) indicate that host identity interacts with environmental conditions to alter the community structure of leaf-symbiotic fungi: mycophylla community response to sea level rise and storms may depend on the host they inhabit.
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1 - Louisiana State University, Biological Sciences, Rm. 107 Life Sciences Bldg., Baton Rouge, LA, 70803, USA
2 - The University of Arizona, Department of Plant Sciences, Division of Plant Pathology and Microbiology, 1140 E. South Campus Drive, Forbes 303, Tucson, AZ, 85721, USA
3 - Southeastern Louisiana University, Biological Sciences, Hammond, LA, 70402, USA
4 - Louisiana State University, Biological Sciences, Baton Rouge, LA, 70803, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch A/Cliff Lodge - Level C
Date: Wednesday, July 29th, 2009
Time: 4:45 PM