Pacific oyster holobiont in the changing environment :a microbial perspective

• Main Authors: Lokmer, A., Wegner, K.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Christian-Albrechts-Universität 2015
• Subjects: Crassostrea gigas; Pacific oyster
• Online Access: http://hdl.handle.net/21.11116/0000-000F-9874-3

Animal's fitness does not depend only on its own traits, as almost every aspect of animal's biology is profoundly affected by its associated microbiota. Among other, the microbiota play an important role in health and disease: they protect their host against infections as well as act as opportunistic pathogens. The latter usually occurs if host's immune defense has been compromised due to abiotic or biotic stress. Global climate change can promote such shifts towards pathogenicity, as rising temperatures impose stress on the host and at the same time may cause increase in virulence of microbes. One example of such environmentally-dependent disease outbreaks involving opportunistic pathogens are the summer mortalities of Pacific oysters (Crassostrea gigas). Although the climate change supported the spread of this invasive intertidal bivalve to coastal habitats all over the world, it also caused the mortality events to ocurr always farther north. Involved in these mortalities are the oyster commensals and opportunistic pathogens of the genus Vibrio sp., which impose strong selection pressure and thus cause rapid adaptation of Pacific oysters to their local Vibrio populations. The Pacific oyster is also an important aquaculture species that is being routinely translocated for commercial purposes to new habitats, where it is exposed to foreign microbes. Response of the oyster-associated microbial communities to this new biotic environment or to changes in abiotic conditions is largely unknown. However, understanding how the oyster microbiota are shaped by (a)biotic disturbances.