Key resources table.

Reagent type (species) or resource	Designation	Source or reference	Identifiers	Additional information
Strain, strain background (Psychrobacter sp.)	D2	This study;Zhang Laboratory		Wild-type isolate; Available from Zhang lab
Strain, strain background (Psychrobacter sp.)	ΔdddX	This study;Zhang Laboratory		the dddX gene deletion mutant of Psychrobacter sp. D2; Available from Zhang lab
Strain, strain background (Psychrobacter sp.)	ΔdddX/pBBR1MCS-dddX	This study;Zhang Laboratory		ΔdddX containing pBBR1MCS-dddX plasmid; Available from Zhang lab
Strain, strain background (Psychrobacter sp.)	ΔdddX/pBBR1MCS	This study;Zhang Laboratory		ΔdddX containing pBBR1MCS plasmid; Available from Zhang lab
Strain, strain background (Escherichia coli)	WM3064	Dehio and Meyer, 1997		Conjugation donor strain
Strain, strain background (Escherichia coli)	DH5α	Vazyme Biotech company (China)		Transformed cells for gene cloning
Strain, strain background (Escherichia coli)	BL21(DE3)	Vazyme Biotech company (China)		Transformed cells for gene expression
Recombinant DNA reagent	pK18mobsacB-Ery	Wang et al., 2015b		Gene knockout vector
Recombinant DNA reagent	pK18Ery-dddX	This study;Zhang Laboratory		pK18mobsacB-Ery containing the homologous arms of the dddX gene of Psychrobacter. sp. D2; Available from Zhang lab
Recombinant DNA reagent	pBBR1MCS	Kovach et al., 1995		Broad-host-range cloning vector
Recombinant DNA reagent	pBBR1MCS-dddX	This study;Zhang Laboratory		pBBR1MCS containing the dddX gene and its promoter of Psychrobacter. sp. D2; Available from Zhang lab
Recombinant DNA reagent	pET-22b-dddX	This study;Zhang Laboratory		Used for dddX expression; Available from Zhang lab
Commercial assay or kit	Pierce BCA Protein Assay Kit	Thermo, USA		Protein assay
Commercial assay or kit	Bacterial genomic DNA isolation kit	BioTeke Corporation, China		DNA extraction
Commercial assay or kit	RNeasy Mini Kit	QIAGEN, America		RNA extraction
Commercial assay or kit	PrimeScript RT reagent Kit	Takara, Japan		Reverse transcription
Commercial assay or kit	Genome sequencing of Psychrobacter sp. D2	Biozeron Biotechnology Co., Ltd, China	NCBI: JACDXZ000000000
Commercial assay or kit	Transcriptome sequencing of Psychrobacter sp. D2	BGI Tech Solutions Co., Ltd, China	NCBI: PRJNA646786
Software, algorithm	HKL3000 program	Minor et al., 2006		Diffraction data analysis
Software, algorithm	CCP4 program Phaser	Winn et al., 2011		Diffraction data analysis
Software, algorithm	Coot	Emsley et al., 2010		Diffraction data analysis
Software, algorithm	Phenix	Adams et al., 2010		Diffraction data analysis
Software, algorithm	PyMOL	Schrödinger, LLC		http://www.pymol.org/
Software, algorithm	MEGA 7	Kumar et al., 2016		Phylogenetic analysis