Transcriptomics of the flatworm Paracatenula sp. santandrea and its chemosynthetic symbiont Ca. Riegeria santandreae from the Bay of Sant´Andrea (Elba, Italy)

Paracatenula are marine catenulid flatworms occuring in shallow water sediments. Adult Paracatenula lack a mouth and a digestive system. Instead, a trophosome containing intracellular alphaproteobacterial symbionts, namely Ca. Riegeria fill most of the worm´s body. Transcriptomic analyses were performed to investigate (i) host and (ii) symbiont functions. The host transcriptome was studied with focus on understanding if the gutless host performs digestion of its symbionts. The symbiont transcriptome was studied to investigate whether genes revealing the symbiont´s functions in the host´ nutrition can be detected and are expressed.