Rearranged Biosynthetic Gene Cluster and Synthesis of Hassallidin E in Planktothrix serta PCC 8927.

Claire Pancrace (1, 2) , Jouni Jokela (3) , Nathalie Sassoon (1) , Christelle Ganneau (4) , Marie Desnos-Ollivier (5) , Matti Wahlsten (3) , Anu Humisto (3) , Alexandra Calteau (6) , Sylvie Bay (4) , David P. Fewer (3) , Kaarina Sivonen (3) , Muriel Gugger (1)

1 Collection des Cyanobactéries
2 UPMC - Université Pierre et Marie Curie - Paris 6
3 Helsingin yliopisto = Helsingfors universitet = University of Helsinki
4 Chimie des Biomolécules - Chemistry of Biomolecules
5 CNRMA - Centre National de Référence des Mycoses invasives et antifongiques - Mycologie moléculaire
6 UMR 8030 - Génomique métabolique

Cyanobacteria produce a wide range of natural products with antifungal bioactivity. The cyclic glycosylated lipopeptides of the hassallidin family have potent antifungal activity and display a great degree of chemical diversity. Here, we report the discovery of a hassallidin biosynthetic gene cluster from the filamentous cyanobacterium Planktothrix serta PCC 8927. The hassallidin gene cluster showed heavy rearrangement and marks of genomic plasticity. Nucleotide bias, differences in GC content, and phylogenetic incongruence suggested the acquisition of the hassallidin biosynthetic gene cluster in Planktothrix serta PCC 8927 by horizontal gene transfer. Chemical analyses by liquid chromatography and mass spectrometry demonstrated that this strain produced hassallidin E, a new glycosylated hassallidin variant. Hassallidin E was the only structural variant produced by Planktothrix serta PCC 8927 in all tested conditions. Further evaluated on human pathogenic fungi, hassallidin E showed an antifungal bioactivity. Hassallidin production levels correlated with nitrogen availability, in the only nitrogen-fixing Planktothrix described so far. Our results provide insights into the distribution and chemical diversity of cyanobacterial antifungal compounds as well as raise questions on their ecological relevance.

Domains: Microbiology and Parasitology

Claire Pancrace, Jouni Jokela, Nathalie Sassoon, Christelle Ganneau, Marie Desnos-Ollivier, et al.. Rearranged Biosynthetic Gene Cluster and Synthesis of Hassallidin E in Planktothrix serta PCC 8927.. ACS Chemical Biology, 2017, 12 (7), pp.1796-1804. ⟨10.1021/acschembio.7b00093⟩. ⟨pasteur-01535773⟩