SYMOBLIGA · Comparative genomics of host-symbiont dependency
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2018-09-01 → 2020-08-31
- EU contribution
- €183,455
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
Lines connect the coordinator with its partners.
Results in brief
Comparative genomics of host-symbiont dependency
Insects are frequently infected by bacteria. Some of them are obligate symbionts, providing functions essential to the survival and fitness of their hosts, while other are facultative. Aphids ancestrally harbour one obligate symbiont: Buchnera aphidicola. While this remain the most common situation, some clades of aphids transitioned to a state of co-obligate symbiosis, where they depend both on Buchnera and on an additional symbiont: Serratia symbiotica. The goal of the project is to understand how such evolutionary transitions occurred. Dependence on Serratia was previously reported only within an aphid clade known as the Lachninae subfamily. Our project focus on other aphid clades that independently evolved the same dependence on Serratia. The overall objectives were to identify the genomic and physiological bases of dependence to Serratia symbiotica in aphids. Taking advantage of the multiple independent origins of the same association (aphid-Buchnera-Serratia), we aimed at identifying the evolutionary processes that are shaping the evolution of symbioses. In particular: are they stochastic processes or rather deterministic, repeatable, ones? Do aphids evolve similar structures to host their newly obligate symbionts? Is Serratia always providing the same benefits to its host? As aphids are important agricultural pests, a better understanding of their biology is crucial to regulate them in efficient and sustainable ways.
Data: CORDIS, © European Union
Project objective
Organisms across the tree of life form partnerships with microbes for protection, metabolic and nutritional benefits. Symbiont acquisitions have allowed hosts to colonise ecological niches that they would otherwise be excluded from, use previously inaccessible resources and capture novel forms of energy. In some cases, host and symbiont become so tightly associated that dependency evolves and the two organisms integrate both physically and genomically. Understanding how organisms combine to perform new metabolic functions and capabilities is key to understanding the evolution of biological complexity. However, most permanent symbioses are ancient and independent evolutionary events, making it difficult to gain information about how dependency evolves. The symbiont Serratia symbiotica has relatively recently transitioned to an essential nutritional role in at least one subfamily of aphids. We provide evidence that dependency on Serratia’s has evolved not once, but several times independently in different aphid lineages. This provides a unique opportunity to explore how symbionts integrate with hosts both genomically and physiologically during the early stages of evolving dependency. We will use a state-of-the-art cross-species comparative genomic analysis in combinations with molecular cytogenetic experiments to determine whether dependency on Serratia has evolved through the same or different genetic mechanisms in the different aphid lineages. First, we will establish a timeline of when each aphid lineage evolved dependency on Serratia. Second, we will identify symbiont genomic rearrangements, the timing of losses and integration of host and symbiont metabolic pathways. Third, we will determine how physical integration evolves. Our findings will provide important information on how microbes and hosts evolve shared metabolic pathways and whether dependency evolves through parallel or convergent processes.
Original text from CORDIS.
Participants
- QUEEN MARY UNIVERSITY OF LONDON · LONDONCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union