Effects of Lagarosiphon major extracts on the metabolome and photosynthesis of Microcystis aeruginosa
Résumé
Over the last decades, Aquitaine lakes have been exposed to growing biomasses of invasive macrophytes, in particular Lagarosiphon major, and to frequent blooms of the cyanobacteria Microcystis aeruginosa. Our aim was to explore the potential role of L. major in the regulation of such blooms, through allelopathic interactions. Experiments consisted of exponential growth phase cells incubated for 96 h in L. major extracts at increasing concentrations. Our approach was based on untargeted metabolomics and photosynthetic activity measurements. We demonstrated the anticyanobacterial properties of L. major extracts. In particular, we reported that L. major extracts inhibited M. aeruginosa photosynthesis, and affected the production of various metabolite classes and pathways mainly involved in the secondary metabolism of the cyanobacteria.
We further provided clear evidence about the existence of metabolite classes in L. major that may be involved in allelopathic interactions with M. aeruginosa, such as caffeic acid.
