Natural variation in antimicrobial activity and composition of the secreted metabolomes of the model moss Ceratodon purpureus.

Bryophytes have recently emerged as potentially promising producers of bioactive metabolites with multiple applications in biomedicine and biotechnology. Our previous studies have established that the model moss Ceratodon purpureus produces novel compounds with potent antimicrobial activities against Gram-positive bacteria. Here, we conducted a comparative analysis of metabolites produced by four different natural isolates of C. purpureus and observed considerable variation in the composition of antibacterial compounds. Next, we partially purified bioactive compounds from extracellular exudates produced by the two model C. purpureus lines, GG1 and R40. Untargeted metabolomic analysis revealed that GG1 isolate secreted a much more diverse set of metabolome components, including various amines, fatty acids, lactones, quinones and terpenoids, in comparison to the R40 isolate. However, the relative percentages of nitrogen-, phosphorus- and sulfur-containing compounds were notably similar in both metabolomes. Importantly, our analysis predicted the presence of several classes of potentially bioactive metabolites in metabolomes of both moss isolates. Taken together, our experiments provided an important evidence that extracellular metabolomes of the model moss Ceratodon purpureus are characterized by a remarkable intraspecific variability in the secretion, composition and abundance of different extracellular compounds.