Table 1.

Signal transducing two-component systems and their cognate posttranscriptional modules involving CsrA homologs and CsrA-antagonistic sRNAs in γ-proteobacteria.

Species	TCS	Stimulus	CsrA homolog*	Molecular mimic sRNA(s)*	Controlled phenotypes	References
Acinetobacter baumannii	GacS-GacA	Unkown	[CsrA]	[RsmX, RsmY, RsmZ]	Pili, motility, biofilm, metabolism of aromatic compounds, virulence	Kulkarni et al., 2006; Cerqueira et al., 2014
Azotobacter vinelandii	GacS-GacA	Unknown	RsmA	RsmZ1-7, RsmY1-2	Alginate, PHB and alkyl resorcinol lipid biosynthesis	Lopez-Pliego et al., 2018, 2020
Erwinia amylovora	GrrS-GrrA	Unknown	RsmA	RsmB	Flagella, T3SS, amylovoran biosynthesis	Ancona et al., 2016
Escherichia coli	BarA-UvrY	Acetate, formate	CsrA	CsrB, CsrC	Glycogen synthesis, gluconeogenesis, motility, biofilm	Chavez et al., 2010
Halomonas anticariensis	GacS-GacA	Unknown	[CsrA]	Unknown	Quorum sensing, exopolysaccharide, biofilm.	Tahrioui et al., 2013
Legionella pneumophila	LetS-LetA	Unknown	CsrA	RsmY, RsmZ	>40 effector proteins secreted by T4SS (cytotoxicity), motility	Nevo et al., 2014; Feldheim et al., 2018
Pectobacterium carotovorum	ExpS-ExpA	Unknown	RsmA	RsmB	Extracellular lytic enzymes, T3SS-secreted harpin	Cui et al., 2001
Salmonella enterica serovar Typhimurium	BarA-SirA	Acetate, formate	CsrA	CsrB, CsrC	Stress resistance, virulence (HilD), aerobic and nitrate respiration, motility, fimbriae	Lawhon et al., 2002; Zere et al., 2015
Serratia mascescems	GacS-GacA	Unknown	CsrA	CsrB, CsrC	Motility, biofilm, coral mucus utilization	Krediet et al., 2013; Ito et al., 2014
Vibrio cholerae	VarS-VarA	Unknown	CsrA	CsrB, CsrC, CsrD	Virulence, biofilm, quorum sensing	Lenz et al., 2005; Butz et al., 2019
Vibrio fischeri	GacS-GacA	Citrate?	CsrA	CsrB, CsrC, CsrD	Luminiscence, siderophores, motility	Septer et al., 2015
Vibrio tasmaniensis	VarS-VarA	Unknown	CsrA	CsrB1-4	Metalloproteases	Nguyen et al., 2018

^*Proteins or sRNAs between brackets were found by genome inspection and have not been experimentally characterized yet.