The formation of the rodlet layer of streptomycetes is the result of the interplay between rodlins and chaplins

• Published in: Molecular microbiology 2004-07, Vol.53 (2), p.433-443
• Main Authors: Claessen, Dennis, Stokroos, Ietse, Deelstra, Heine J., Penninga, Nynke A., Bormann, Christiane, Salas, José A., Dijkhuizen, Lubbert, Wösten, Han A. B.
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biological and medical sciences; Cryoelectron Microscopy; DNA, Bacterial - chemistry; DNA, Bacterial - isolation & purification; Fundamental and applied biological sciences. Psychology; Gene Deletion; Gene Expression Regulation, Bacterial; Gene Order; Genes, Bacterial; Membrane Proteins - genetics; Membrane Proteins - metabolism; Microbiology; Molecular Sequence Data; Multigene Family; Mutagenesis, Insertional; RNA, Bacterial - analysis; RNA, Messenger - analysis; Sequence Analysis, DNA; Sequence Homology; Spores, Bacterial - chemistry; Streptomyces - chemistry; Streptomyces - genetics; Streptomyces - metabolism; Streptomyces - ultrastructure; Streptomyces coelicolor
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.2004.04143.x

Summary Streptomycetes form hydrophobic aerial hyphae that eventually septate into hydrophobic spores. Both aerial hyphae and spores possess a typical surface layer called the rodlet layer. We present here evidence that rodlet formation is conserved in the streptomycetes. The formation of the rodlet layer is the result of the interplay between rodlins and chaplins. A strain of Streptomyces coelicolor in which the rodlin genes rdlA and/or rdlB were deleted no longer formed the rodlet layer. Instead, these surfaces were decorated with fine fibrils. Deletion of all eight chaplin genes (strain ΔchpABCDEFGH) resulted in the absence of the rodlet layer as well as the fibrils at surfaces of aerial hyphae and spores. Apart from coating these surfaces, chaplins are involved in the escape of hyphae into the air, as was shown by the strong reduction in the number of aerial hyphae in the ΔchpABCDEFGH strain. The decrease in the number of aerial hyphae correlated with a lower expression of the rdl genes in the colony. Yet, expression per aerial hypha was similar to that in the wild‐type strain, indicating that expression of the rdl genes is initiated after the hypha has sensed that it has grown into the air.