Complete genome of Phenylobacterium zucineum – a novel facultative intracellular bacterium isolated from human erythroleukemia cell line K562

Table 9 Distributions of proteins involved in environmental adaptation in P. zucineum and representative alphaproteobacteria with different living habitats

Species	S. meliloti	B. suis	C. crescentus	P. zucineum	R. conorii	G. oxydans
Genome size (Mb)	6.69	3.32	4.02	4.38	1.27	2.92
GC content (%)	62.2	57.3	67.2	71.1	32.4	60.8
Habitat	Multiple¹	Facultative¹	Aquatic¹	Facultative²	Obligate¹	Multiple³
ECF, extracytoplasmic function sigma factor (/Mb)	11 (1.6)	2 (0.6)	15 (3.7)	17 (3.9)	0 (0)	2 (0.7)
Transcriptional regulator (/Mb)	433 (64.7)	149(44.9)	183 (45.5)	170 (38.8)	11 (8.7)	89 (30.1)
Two-component signal transduction protein (/Mb)	113 (16.9)	44 (13.3)	111 (27.6)	102 (23.3)	7 (5.5)	41 (14.1)
molecular chaperone	23	12	14	33	8	14
Flagellar protein	41	37	42	43	10	40
Chemotaxis protein	42	4	48	41	0	11
Pilus protein	13	4	9	16	2	4
Sec-dependent secretion system	11	11	11	11	11	12
Sec-independent secretion system	4	4	4	4	3	4
Type II secretory protein	2	0	8	13	0	3
Type IV secretory protein	9	8	9	31	15	1

¹The habitats of S. meliloti, B. suis, and R. conorii were indicated in a recent publication [42].
²According to our recent publication [1], P. zucineum was classified as "facultative". ³Given that G. oxydans is often isolated from sugary niches (such as flowers and fruits) and associated soil (such as garden soil and baker's soil) [43], we classified G. oxydans as "multiple".

ISSN: 1471-2164