Rhizobium sp. strain NGR234 possesses a remarkable number of secretion systems.
Rhizobium sp. strain NGR234 is a unique alphaproteobacterium (order Rhizobiales) that forms nitrogen-fixing nodules with more legumes than any other microsymbiont. We report here that the 3.93-Mbp chromosome (cNGR234) encodes most functions required for cellular growth. Few essential functions are encoded on the 2.43-Mbp megaplasmid (pNGR234b), and none are present on the second 0.54-Mbp symbiotic plasmid (pNGR234a). Among many striking features, the 6.9-Mbp genome encodes more different secretion systems than any other known rhizobia and probably most known bacteria. Altogether, 132 genes and proteins are linked to secretory processes. Secretion systems identified include general and export pathways, a twin arginine translocase secretion system, six type I transporter genes, one functional and one putative type III system, three type IV attachment systems, and two putative type IV conjugation pili. Type V and VI transporters were not identified, however. NGR234 also carries genes and regulatory networks linked to the metabolism of a wide range of aromatic and nonaromatic compounds. In this way, NGR234 can quickly adapt to changing environmental stimuli in soils, rhizospheres, and plants. Finally, NGR234 carries at least six loci linked to the quenching of quorum-sensing signals, as well as one gene (ngrI) that possibly encodes a novel type of autoinducer I molecule.
Schmeisser
Christel
C
Biozentrum Klein Flottbek, Abteilung für Mikrobiologie und Biotechnologie, Universität Hamburg, Germany.
Liesegang
Heiko
H
Krysciak
Dagmar
D
Bakkou
Nadia
N
Le Quéré
Antoine
A
Wollherr
Antje
A
Heinemeyer
Isabelle
I
Morgenstern
Burkhard
B
Pommerening-Röser
Andreas
A
Flores
Margarita
M
Palacios
Rafael
R
Brenner
Sydney
S
Gottschalk
Gerhard
G
Schmitz
Ruth A
RA
Broughton
William J
WJ
Perret
Xavier
X
Strittmatter
Axel W
AW
Streit
Wolfgang R
WR
D001692:Biological Transport; D004269:DNA, Bacterial / Q000235:genetics; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D010957:Plasmids; D012231:Rhizobium / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D026901:Membrane Transport Proteins