Biosynthetic genes and activity spectrum of antifungal polyynes from C ollimonas fungivorans T er331

Abstract

Summary The antifungal activity of bacteria from the genus C ollimonas has been well documented, but the chemistry and gene functions that underlie this phenotype are still poorly understood. Screening of a random plasposon insertion library of C ollimonas fungivorans T er331 for loss‐of‐function mutants revealed the importance of gene cluster K , which is annotated to code for the biosynthesis of a secondary metabolite and which features genes for fatty acid desaturases and polyketide synthases. Mutants in gene cluster K had lost the ability to inhibit hyphal growth of the fungus A spergillus niger and were no longer able to produce and secrete several metabolites that after extraction and partial purification from wildtype strain T er331 were shown to share a putative ene‐triyne moiety. Some but not all of these metabolites were able to inhibit growth of A . niger , indicating functional variation within this group of C ollimonas ‐produced polyyne‐like ‘collimomycins’. Polymerase chain reaction analysis of isolates representing different C ollimonas species indicated that the possession of cluster K genes correlated positively with antifungal ability, further strengthening the notion that this cluster is involved in collimomycin production. We discuss our findings in the context of other bacterially produced polyynes and the potential use of collimomycins for the control of harmful fungi.

Bibliographic Information