Abstract Detail

Symbioses: Plant, Animal, and Microbe Interactions

Croft, Abigail [1], Thomas, Duncan [2], Schenk, John [3].

Mycorrhizal relationship identified in an African aquatic Podostemaceae.

Mycorrhizal fungi form symbiotic relationships with most plant species and likely facilitated the evolutionary transition from aquatic to terrestrial ecosystems in land plants. Plants that have re-evolved back into aquatic ecosystems sometimes retain this important mutualistic relationship in their roots, but in aquatics that have evolved morphological reductions from having typical roots to hold-fasts, such as what is observed in Podostemaceae, it is unknown whether they retained mutualistic relationships with mycorrhizae or even how they uptake nutrients from their environment. A recent study identified mycelium between the hold-fast and the rock substrate in the African Podostemaceae genus Inversodicraea, and we hypothesize that the mycelium represents a mutualistic relationship between the plants and mycorrhizae. Alternatively, the fungi might be parasitic or opportunistically taking advantage of being shielded from the current by the plant. Using Trypan blue to stain hyphae in cleared plant tissues, we tested the hypothesis that the hyphae between the rock substrate and the Podostemaceae species are arbuscular mycorrhizae. Hyphae were observed both on the outside and inside of the tissues, rejecting the hypothesis that the fungi are opportunistically being shielded by water movement from the plant. We did not observe necrotic plant tissue as would be expected if the fungus was parasitic, but did observe arbuscules and vesicles within the plant tissue. Our results represent the first documented case of arbuscular mycorrhizae in Podostemaceae and might be a critical relationship that allows Podostemaceae species to facilitate nutrient uptake without the presence of roots or soils.

1 - Ohio University, Department of Environmental and Plant Biology, 22 Richland Ave., Athens, OH, 45701, USA
2 - Oregon State University, Department of Botany and Plant Pathology, 4575 SW Research Way, Corvallis, OR, 97333, USA
3 - Ohio University, Department Of Environmental And Plant Biology, 22 Richland Ave., 401 Porter Hall, Athens, OH, 45701, United States

Keywords:
Podostemaceae
Aquatic plants
African endemics
Mycorrhizae
roots.

Presentation Type: Poster
Number: PSM002
Abstract ID:1077
Candidate for Awards:None