Function-related replacement of bacterial siderophore pathways

TitleFunction-related replacement of bacterial siderophore pathways
Publication TypeJournal Article
Year of Publication2018
AuthorsBruns H., Crusemann M., Letzel A.C, Alanjary M., McInerney J.O, Jensen PR, Schulz S., Moore BS, Ziemert N.
JournalIsme Journal
Volume12
Pagination320-329
Date Published2018/02
Type of ArticleArticle
ISBN Number1751-7362
Accession NumberWOS:000422779100003
Keywordsactinomycete genus salinispora; biosynthesis; clusters; coordination; discovery; Environmental Sciences & Ecology; evolution; iron acquisition; microbiology; natural-products; pathogenic bacteria; secondary metabolism
Abstract

Bacterial genomes are rife with orphan biosynthetic gene clusters (BGCs) associated with secondary metabolism of unrealized natural product molecules. Often up to a tenth of the genome is predicted to code for the biosynthesis of diverse metabolites with mostly unknown structures and functions. This phenomenal diversity of BGCs coupled with their high rates of horizontal transfer raise questions about whether they are really active and beneficial, whether they are neutral and confer no advantage, or whether they are carried in genomes because they are parasitic or addictive. We previously reported that Salinispora bacteria broadly use the desferrioxamine family of siderophores for iron acquisition. Herein we describe a new and unrelated group of peptidic siderophores called salinichelins from a restricted number of Salinispora strains in which the desferrioxamine biosynthesis genes have been lost. We have reconstructed the evolutionary history of these two different siderophore families and show that the acquisition and retention of the new salinichelin siderophores co- occurs with the loss of the more ancient desferrioxamine pathway. This identical event occurred at least three times independently during the evolution of the genus. We surmise that certain BGCs may be extraneous because of their functional redundancy and demonstrate that the relative evolutionary pace of natural pathway replacement shows high selective pressure against retention of functionally superfluous gene clusters.

DOI10.1038/ismej.2017.137
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