Appendix 1—key resources table.

Reagent type (species) or resource	Designation	Source or reference	Identifiers	Additional information
Strain, Strain Background (Caulobacter crescentus NA1000)	Caulobacter crescentus NA1000	Evinger and Agabian, 1977; PMID:334726		See Supplementary file 2 Table S2
Antibody	CtrA Rabbit polyclonal	Domian et al., 1997; PMID:9267022	Home-made antibodies raised against full-length protein of C. crescentus	Immunoblot: 1/10000 dilution Figure 6, Figure 6—figure supplement 1
Antibody	FlgE Rabbit polyclonal	Hahnenberger and Shapiro, 1987; PMID:3039149	Home-made antibodies raised against FlgE protein of C. crescentus	Immunoblot: 1/50000 dilution Figure 1
Antibody	Flagellins Rabbit polyclonal	Hahnenberger and Shapiro, 1987; PMID:3039149	Home-made antibodies raised against purified flagellins from C. crescentus	Immunoblot: 1/20000 dilution Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6—figure supplement 1
Antibody	FljK Rabbit polyclonal	Ardissone et al., 2020	Home-made antibodies raised against full-length protein of C. crescentus	Immunoblot: 1/10000 dilution Figure 1, Figure 4, Figure 5, Figure 5—figure supplement 1
Antibody	NeuB Rabbit polyclonal	This paper	Home-made antibodies raised against full-length protein of C. crescentus	Immunoblot: 1/10000 dilution Figure 2, Figure 3, Figure 6—figure supplement 1
Antibody	FlmG Rabbit polyclonal	This paper	Home-made antibodies raised against FlmG (amino acids 301–500) of C. crescentus	Immunoblot: 1/10000 dilution Figure 6
Recombinant DNA reagent	Plasmids	This paper		See Supplementary file 2 Table S2
Sequence-based reagent	PCR primers	This paper		See Supplementary file 3 Table S3
Sequence-based reagent	FljK synthetic sequence	This paper	FljK coding sequence, codon-optimized for E. coli	See Supplementary file 3 Table S3
Sequence-based reagent	Pseudaminic acid biosynthesis operon synthetic sequence	This paper	FlmA, FlmB, FlmH, FlmD, NeuB and FlmC coding sequences, codon-optimized for E. coli	See Supplementary file 3 Table S3