Beschreibung:
<jats:title>Abstract
</jats:title><jats:p>The cyclic depsipeptide FR900359 (FR) is derived from the soil bacterium <jats:italic>Chromobacterium vaccinii</jats:italic> and known to bind G<jats:sub>q</jats:sub> proteins of mammals and insects, thereby abolishing the signal transduction of their G<jats:sub>q</jats:sub> protein-coupled receptors, a process that leads to severe physiological consequences. Due to their highly conserved structure, G<jats:sub>q</jats:sub> family of proteins are a superior ecological target for FR producing organisms, resulting in a defense towards a broad range of harmful organisms. Here, we focus on the question whether bacteria like <jats:italic>C. vaccinii</jats:italic> are important factors in soil in that their secondary metabolites impair, e.g., plant harming organisms like nematodes. We prove that the G<jats:sub>q</jats:sub> inhibitor FR is produced under soil-like conditions. Furthermore, FR inhibits heterologously expressed Gα<jats:sub>q</jats:sub> proteins of the nematodes <jats:italic>Caenorhabditis elegans</jats:italic> and <jats:italic>Heterodera schachtii</jats:italic> in the micromolar range. Additionally, <jats:italic>in vivo</jats:italic> experiments with <jats:italic>C. elegans</jats:italic> and the plant parasitic cyst nematode <jats:italic>H. schachtii</jats:italic> demonstrated that FR reduces locomotion of <jats:italic>C. elegans</jats:italic> and <jats:italic>H. schachtii</jats:italic>. Finally, egg-laying of <jats:italic>C. elegans</jats:italic> and hatching of juvenile stage 2 of <jats:italic>H. schachtii</jats:italic> from its cysts is inhibited by FR, suggesting that FR might reduce nematode dispersion and proliferation. This study supports the idea that <jats:italic>C. vaccinii</jats:italic> and its excreted metabolome in the soil might contribute to an ecological equilibrium, maintaining and establishing the successful growth of plants.</jats:p>