Role of DKxanthenes in Myxococcus-Nematode Interactions.

Myxobacteria of the genus Myxococcus produce bioactive secondary metabolites known as DKxanthenes. When Myxococcus stipitatus DSM 14675T was co-cultured with the nematode Caenorhabditis elegans under conditions that induce DKxanthene production, nematode activity and survival were strongly suppressed, and nematodes progressively disappeared. In contrast, under conditions in which DKxanthenes were not produced, or when DKxanthene-deficient mutant strains were used, nematodes proliferated. Similarly, myxobacteria of the genus Corallococcus, which belong to the same family as Myxococcus but lack the DKxanthene biosynthetic gene cluster, supported robust nematode growth during co-cultivation with C. elegans. Assays using partially purified DKxanthene extracts demonstrated that DKxanthenes inhibit the growth of C. elegans, although they do not cause immediate nematode death. Together, these findings indicate that DKxanthenes function as key antinematodal metabolites that suppress nematode growth and viability and contribute to nematode resistance in Myxococcus under nutrient-limited conditions.