CdgL is a degenerate nucleotide cyclase domain protein affecting flagellin synthesis and motility in Bacillus thuringiensis

Veronika Smith; Ida Kristine Bu Nilssen; Ida K Hegna; Bjørn Dalhus; Annette Fagerlund; Ole Andreas Økstad

doi:10.1016/j.resmic.2021.103850

CdgL is a degenerate nucleotide cyclase domain protein affecting flagellin synthesis and motility in Bacillus thuringiensis

Res Microbiol. 2021 Jun-Aug;172(4-5):103850. doi: 10.1016/j.resmic.2021.103850. Epub 2021 Jun 1.

Authors

Veronika Smith¹, Ida Kristine Bu Nilssen², Ida K Hegna³, Bjørn Dalhus⁴, Annette Fagerlund⁵, Ole Andreas Økstad⁶

Affiliations

¹ Laboratory for Microbial Dynamics (LaMDa), Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, PB 1068 Blindern, 0316, Oslo, Norway; Centre for Integrated Microbial Evolution (CIME), Faculty of Mathematics and Natural Sciences, University of Oslo, 0316, Oslo, Norway. Electronic address: veronis@farmasi.uio.no.
² Laboratory for Microbial Dynamics (LaMDa), Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, PB 1068 Blindern, 0316, Oslo, Norway; Centre for Integrated Microbial Evolution (CIME), Faculty of Mathematics and Natural Sciences, University of Oslo, 0316, Oslo, Norway. Electronic address: ida_kbn@hotmail.com.
³ Laboratory for Microbial Dynamics (LaMDa), Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, PB 1068 Blindern, 0316, Oslo, Norway; Centre for Integrated Microbial Evolution (CIME), Faculty of Mathematics and Natural Sciences, University of Oslo, 0316, Oslo, Norway. Electronic address: i.k.hegna@farmasi.uio.no.
⁴ Department of Medical Biochemistry, Institute of Clinical Medicine, University of Oslo, Postboks 4950 Nydalen, 0424, Oslo, Norway; Department of Microbiology, Division of Laboratory Medicine, Oslo University Hospital, Postboks 4950 Nydalen, 0424, Oslo, Norway. Electronic address: bjorn.dalhus@medisin.uio.no.
⁵ Department of Food Safety and Quality, Nofima - the Norwegian Institute of Food, Fisheries and Aquaculture Research, P.O. Box 210, NO-1431, Ås, Norway. Electronic address: Annette.Fagerlund@Nofima.no.
⁶ Laboratory for Microbial Dynamics (LaMDa), Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, PB 1068 Blindern, 0316, Oslo, Norway; Centre for Integrated Microbial Evolution (CIME), Faculty of Mathematics and Natural Sciences, University of Oslo, 0316, Oslo, Norway. Electronic address: aloechen@farmasi.uio.no.

PMID: 34082027
DOI: 10.1016/j.resmic.2021.103850

Abstract

In Bacillus subtilis, motility genes are expressed in a hierarchical pattern - governed by the σ^D transcription factor and other proteins such as the EpsE molecular clutch and SlrA/SlrR regulator proteins. In contrast, motile species in the Bacillus cereus group seem to express their motility genes in a non-hierarchical pattern, and less is known about their regulation, also given that no orthologs to σ^D, EpsE, SlrA or SlrR are found in B. cereus group genomes. Here we show that deletion of cdgL (BTB_RS26690/BTB_c54300) in Bacillus thuringiensis 407 (cry-) resulted in a six-to ten-fold downregulation of the entire motility locus, and loss of flagellar structures and swimming motility. cdgL is unique to the B. cereus group and is found in all phylogenetic clusters in the population except for group I, which comprises isolates of non-motile Bacillus pseudomycoides. Analysis of RNA-Seq data revealed cdgL to be expressed in a three-gene operon with a NupC like nucleoside transporter, and a putative glycosyl transferase for which transposon-based gene inactivation was previously shown to produce a similar phenotype to cdgL deletion. Interestingly, all three proteins were predicted to be membrane-bound and may provide a concerted function in the regulation of B. cereus group motility.

Keywords: Bacillus cereus group; Degenerate nucleotide cyclase domain; Flagellin; Swimming motility.

MeSH terms

Bacillus thuringiensis / enzymology
Bacillus thuringiensis / genetics*
Bacterial Proteins / genetics*
Bacterial Proteins / metabolism*
Flagellin / biosynthesis*
Flagellin / genetics*
Flagellin / metabolism
Gene Expression Regulation, Bacterial
Movement
Nucleotides*
Phylogeny

Substances

Bacterial Proteins
Nucleotides
Flagellin