Symbiosis Driven Development

The importance of symbiosis is becoming increasingly evident, with microbes playing a role in diverse processes from animal nutrition to behavior. The symbiont can also initiate and regulate host-developmental processes. How the symbiont initiates development in the host, and the evolutionary mechanism that lead to alterations in gene regulatory networks remain largely unknown. I tackle these questions using the emerging model system Cassiopea xamachana.

Bacteria induced Settlement of Invertebrate Larvae

Bacterial cues initiate pelagic marine plankton to undergo settlement and metamorphosis, thus playing a major role in organismal life-history. Despite the ecological implications, the cue for settlement and metamorphosis has been characterized for a relatively small number of taxa. In the upside-down jellyfish, the larvae to polyp transition is triggered by bacteria associated with degrading leaves of shoreline plant species (i.e. mangrove leaves). By sequencing the genomes of bacterial isolates and taking a comparative genomics approach, I explore the mechanisms behind settlement and metamorphosis of Cassiopea xamachana larvae.

Intracellular Symbiont induced Metamorphosis

Cassiopea xamachana forms a symbiosis with photosynthetic dinoflagellates, similar to corals. While the jellyfish receive nutrients from its symbiont, it also requires the symbionts to transition from the polyp to adult medusa stage. Without the symbionts, the polyps can remain in the polyp stage indefinitely. I study this unique aspect of the jellyfish life-history to understand how gene regulatory networks evolve in symbiotic organisms.

Using both computational (RNAseq, comparative genomics) and lab based approaches, I am finding how symbiosis may have led to expressional changes in the RxR receptor signaling pathway, in addition to key enzymes that play a role in linking the symbiont to host development.