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Horizontal Transmission of Symbiotic Green Algae Between Hydra Strains
The Biological Bulletin
|October 26, 2018
Summary
Green algae symbionts transmitted horizontally to new hydra hosts, establishing a stable symbiosis in Hydra vulgaris strain 105G. This novel symbiosis alters polyp behavior and morphology, offering insights into symbiosis origins.
Area of Science:
- Symbiosis research
- Hydra biology
- Algal symbiosis
Background:
- Some hydra strains exhibit symbiosis with green algae Chlorococcum sp.
- Symbiotic algae can escape hosts and form motile zoospores.
Purpose of the Study:
- Investigate horizontal transmission of algal symbionts in hydra.
- Characterize a novel, sustained symbiosis between Chlorococcum sp. and Hydra vulgaris strain 105.
- Explore the origin of symbiosis through a new experimental system.
Main Methods:
- Co-culture of symbiotic hydra polyps with non-symbiotic hydra strains.
- Long-term observation of symbiont transmission and establishment.
- Analysis of morphological and behavioral changes in the host hydra.
Main Results:
- Horizontal transmission of Chlorococcum sp. observed in non-symbiotic hydra strains.
- A stable symbiosis (strain 105G) formed between Chlorococcum sp. and Hydra vulgaris strain 105, lasting over five years.
- Strain 105G exhibited increased asexual proliferation under light, reduced feeding, and smaller polyp size.
Conclusions:
- A novel, stable hydra-algal symbiosis can be experimentally established.
- This sustained symbiosis induces significant host morphological and behavioral changes.
- Strain 105G provides a valuable model for studying symbiosis origins and evolution.
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