The Venus flytrap microbiota withstands extreme conditions during prey digestion

The carnivorous Venus flytrap (Dionaea muscipula) acquires nutrients via capture and digestion of insects. During digestion, hydrolytic enzymes are secreted as part of an acidic mucilage to break down prey. At present, it is unknown how these extreme conditions influence the surface microbiota of the trap. We analysed the bacterial community during both digestion of prey and artificially induced digestion after treatment with Coronatine by high-throughput 16s rDNA amplicon sequencing. We further compared the microbiota of inactive traps and petioles and determined whether treating petioles with acid causes similar community dynamics as acidification happening during digestion initiation. We found that the trap's microbiota was affected by the process of digestion, but that this effect was mostly caused by prey-induced bacteria. The bacterial community structure underwent a shift both when feeding an insect and when inducing the digestion with Coronatine, but the initial state was restored quickly. We further showed that the trap harbours a different microbiome than the petiole and that the acidification of petiole does not induce a change in bacterial community structure. Surprisingly, pH did not have much of an effect on the bacterial community. The trap microbiota is able to survive the digestion process relatively unharmed, whilst prey-associated bacteria are reduced. Together with the missing effect of pH, we conclude that the bacterial community can withstand the extreme conditions during prey digestion. The mechanism behind this remains to be identified in future.