Venus flytrap microbiota withstand harsh conditions during prey digestion

Abstract

The carnivorous Venus flytrap (Dionaea muscipula) overcomes environmental nutrient limitation by capturing small animals. Such prey is digested with an acidic enzyme-containing mucilage that is secreted into the closed trap. Surprisingly little is known about associations with microorganisms, though. Therefore, we assessed microbiota of traps and petioles for the Venus flytrap by 16S amplicon meta-barcoding. We further performed time-series assessments of dynamics during digestion in traps and experimental acidification of petioles.We found that the traps hosted distinct microbiota that differed from adjacent petioles. Further, they showed a significant taxonomic turnover during digestion. Following successful catches, prey-associated bacteria had strong effects on overall composition. With proceeding digestion however, microbiota were restored to compositions resembling pre-digestion stages. A comparable, yet less extensive shift was found when stimulating digestion with coronatine. Artificial acidification of petioles did not induce changes towards trap-like communities.Our results show that trap microbiota were maintained during digestion despite harsh conditions and recovered after short-term disturbances through prey microbiota. This indicates trap-specific and resilient associations. By mapping to known genomes, we predicted putative adaptations and functional implications for the system, yet direct mechanisms and quantification of host benefits, like the involvement in digestion, remain to be addressed.

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