Structure, Genetics and Function of an Exopolysaccharide Produced by a Bacterium Living within Fungal Hyphae. Issue 3 (21st December 2014)

• Record Type: Journal Article
• Authors: Uzum, Zerrin; Silipo, Alba; Lackner, Gerald; De Felice, Antonia; Molinaro, Antonio; Hertweck, Christian
• Is Part Of: Chembiochem. Volume 16:Issue 3(2015)
• Page Start: 387
• Page End: 392
• Publication Date: 2014-12-21
• Subjects: Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1002/cbic.201402488
• Languages: English
• ISSNs: 1439-4227

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The rice seedling blight fungus <italic>Rhizopus microsporus</italic> has an unusual symbiosis with a bacterium, <italic>Burkholderia rhizoxinica</italic>, which lives within the fungal cytosol and produces a potent phytotoxin that causes severe losses in agriculture. To gain insight into symbiosis factors we investigated the endosymbiont's exopolysaccharide (EPS), a secreted matrix that plays pivotal roles in mediating cell–environment interactions. By a combination of homo‐ and heteronuclear 2D NMR experiments, we elucidated a previously unknown EPS structure: a repeating tetrasaccharide unit bearing a nonstoichiometric acetyl group on a mannose residue. We also analyzed the EPS biosynthesis gene cluster and generated a targeted mutant to compare the phenotypes. Scanning electron microscope images revealed a reduced ability of the mutant to form extracellular polymers around cell aggregates. Phylogenetic analyses suggest that the symbiont's EPS genes are retained through evolutionary processes.</p> </abstract>