We are interested in the genomic and chemical aspects underlying the evolution of symbiotic interactions.
Chelymorpha alternans on a sweet potato leave (Ipomoea batatas). Photograph by Aileen Berasategui.
A tripartite interaction in a changing world
The leaf beetle Chelymorpha alternans (Coleoptera: Cassidinae) engages in a symbiotic interaction with the ascomycete Fusarium oxysporum. The microbe rapidly proliferates at the onset of pupation, densely coating the pupal skin of its host. This ensures the protection of the beetle from predators during metamorphosis. In exchange, the beetle propagates its symbiont to its progeny, as well as its host plant (Ipomoea batatas). Like many members of the Fusarium genus, the symbiont causes yellow wilt disease in infected leaves, demonstrating that the microbe retained its pathogenic capacity despite its protective partnership with tortoise beetles.
We are interested in understanding how widespread these symbioses are and how they are established and maintained. Through a combination of genomics, transcriptomics, bioassays and analytical chemistry we characterize the molecules mediating these interactions. We also explore their resilience to rapid changes in abiotic factors and what their evolutionary responses are to a rapidly changing world.
Atta colombica ants in their nest. Photograph by Alex Wild.
The basis of host-parasite fidelity
There are more than 230 species of fungus-growing ants and all of them cultivate fungi (their “cultivar”) as their main food source. Each ant species cultivates a narrow range of cultivars. Like any crop, cultivars are susceptible to disease. One of their most important pathogens is Escovopsis, a genus of fungal parasites that attack and consume the cultivar of ants, and can consequently cause the death of the ant colony. These parasites show host-specificity, being able to infect their natural host and closely related cultivars, but not distantly related ones.
We use a diversity of techniques such as genomics, transcriptomics, bioassays and analytic chemistry to explore the genomic and chemical basis of this host-parasite specificity.
