Molecular Biodiversity Group, Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Würzburg, Germany.
Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany.
FEMS Microbiol Ecol. 2019 Mar 1;95(3). doi: 10.1093/femsec/fiz010.
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. However, surprisingly little is known about associations with microorganisms. Therefore, we assessed microbiotas of traps and petioles for the Venus flytrap by 16S amplicon meta-barcoding. We also performed time-series assessments of dynamics during digestion in traps and experimental acidification of petioles. We found that the traps hosted distinct microbiotas 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, microbiotas 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.
捕蝇草（Dionaea muscipula）通过捕捉小动物来克服环境营养限制。这种猎物会被一种含有酸性酶的粘性物质消化，这种粘性物质会分泌到封闭的陷阱中。然而，人们对与微生物的关联知之甚少。因此，我们通过 16S 扩增子元条形码评估了捕蝇草的陷阱和叶柄的微生物组。我们还对陷阱中的消化动态进行了时间序列评估，并对叶柄的酸化进行了实验。我们发现陷阱拥有独特的微生物组，与相邻的叶柄不同。此外，它们在消化过程中表现出显著的分类学转变。成功捕捉猎物后，与猎物相关的细菌对整体组成有强烈影响。然而，随着消化的进行，微生物组恢复到类似于消化前阶段的组成。用冠菌素刺激消化时，会发现类似但不那么广泛的转变。人工酸化叶柄不会导致向类似陷阱的群落发生变化。我们的研究结果表明，尽管条件恶劣，但陷阱微生物组在消化过程中得以维持，并通过猎物微生物组在短期干扰后恢复。这表明存在特定于陷阱的和有弹性的关联。通过映射到已知的基因组，我们预测了该系统的潜在适应和功能意义，但直接的机制和宿主益处的量化，如参与消化，仍有待解决。
