Chapter 24
Coevolution of Molluscs and Their
Microbes
Aide Lasa and Jesús L. Romalde
Abstract Symbiotic associations between multicellular hosts and microbes are
widely distributed in nature, as they are essential for the ecological success and
evolutionary diversification of multicellular organisms. These associations form the
holobiont that, ultimately, represents the unit element for selection and evolution.
The impact of such interactions may even lead to the development of complex
structures in the host and microbe reprogramming based in intricated cell communications and signalling. However, the establishment and success of the holobiont
may be influenced by the surrounding microbial environment. In molluscs, the
environmental microbiome plays an important role in the establishment of
microbe-host symbiosis, especially in bivalves due to their filter-feeding habit.
One of the most studied symbiotic interactions between mollusc and marine bacteria
is the Euprymna scolopes-Aliivibrio fischeri association. The Hawaiian bobtail
squid, which is its common name, provides protection and nutrients to A. fischeri
and, in return, the marine bacteria produces light that makes the squid virtually
invisible to predators. The cooperation of these two organisms has been shaped and
evolved through time to forge one of the most elegant interactions between animal
and microbes. In bivalve molluscs, symbiotic bacteria have been found in the gills
using inorganic chemical energy for the synthesis of organic compounds for the
benefit of their hosts, such as the chemosymbiotic bacteria associated with
Bathymodiolus mussels or lucinid clams. On the other hand, vibrios and bivalves
have built an intimate association too, in which both partners have developed
different strategies to survive. In this chapter, the most relevant aspects of these
associations and the results of their coevolution will be summarised.
A. Lasa · J. L. Romalde (*)
Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología & Institute
CRETUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
e-mail: aide.lasa@usc.es; jesus.romalde@usc.es
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_24
513
Coevolution of Molluscs and Their
Microbes
Aide Lasa and Jesús L. Romalde
Abstract Symbiotic associations between multicellular hosts and microbes are
widely distributed in nature, as they are essential for the ecological success and
evolutionary diversification of multicellular organisms. These associations form the
holobiont that, ultimately, represents the unit element for selection and evolution.
The impact of such interactions may even lead to the development of complex
structures in the host and microbe reprogramming based in intricated cell communications and signalling. However, the establishment and success of the holobiont
may be influenced by the surrounding microbial environment. In molluscs, the
environmental microbiome plays an important role in the establishment of
microbe-host symbiosis, especially in bivalves due to their filter-feeding habit.
One of the most studied symbiotic interactions between mollusc and marine bacteria
is the Euprymna scolopes-Aliivibrio fischeri association. The Hawaiian bobtail
squid, which is its common name, provides protection and nutrients to A. fischeri
and, in return, the marine bacteria produces light that makes the squid virtually
invisible to predators. The cooperation of these two organisms has been shaped and
evolved through time to forge one of the most elegant interactions between animal
and microbes. In bivalve molluscs, symbiotic bacteria have been found in the gills
using inorganic chemical energy for the synthesis of organic compounds for the
benefit of their hosts, such as the chemosymbiotic bacteria associated with
Bathymodiolus mussels or lucinid clams. On the other hand, vibrios and bivalves
have built an intimate association too, in which both partners have developed
different strategies to survive. In this chapter, the most relevant aspects of these
associations and the results of their coevolution will be summarised.
A. Lasa · J. L. Romalde (*)
Departamento de Microbiología y Parasitología, CIBUS-Facultad de Biología & Institute
CRETUS, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
e-mail: aide.lasa@usc.es; jesus.romalde@usc.es
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_24
513