Thermal melting profiles of hybrids between 3 H-labeled rRNA of Rhizomonas suberifaciens, the causal agent of corky root of lettuce, and chromosomal DNAs from 27 species of gram-negative bacteria indicated that the genus Rhizomonas belongs to superfamily IV of De Ley. On the basis of the melting temperatures of DNA hybrids with rRNAs from the type strains of R. suberifaciens, Sphingomonas paucimobilis, and Sphingomonas capsulata, Rhizomonas strains constitute a separate branch in superfamily IV, which is closely related to but separate from branches containing Zymomonas mobilis, Sphingomonas spp., and S. capsulata. Sphingomonas yanoikuyae and Rhizomonas sp. strain WI4 are located toward the base of the Rhizomonas rRNA branch. DNA-DNA hybridization indicated that S. yanoikuyae is equidistant from Rhizomonas sp. strain WI4 and S. paucimobilis. Sequences of 270 bp of 16S ribosomal DNAs from eight strains of Rhizomonas spp., eight strains of Sphingomonas spp., and Agrobacterium tumefaciens indicated that S. yanoikuyae and Rhizomonas sp. strains WI4 and CA16 are genetically more closely related to R. suberifaciens than to Sphingomonas spp. Thus, S. yanoikuyae may need to be transferred to the genus Rhizomonas on the basis of the results of further study.
AusubelF. M.,
BrentR.,
KingstonR. E.,
MooreD. D.,
SeldmanJ. G.,
SmithJ. A.,
StruhlK.1987; Current protocols in molecular biology. p. 4.4.2–4.4.4 John Wiley and Sons; New York:
BallyR.,
Thomas-BauzonD.,
HeulinT.,
BalandreauJ.,
RichardC.,
De LeyJ.1983; Determination of the most frequent N2-fixing bacteria in a rice rhizosphere. Can.J. Microbiol 29:881–887
BauwensM.,
De LeyJ.1981; Improvements in the taxonomy of Flavobacterium by DNA-rRNA hybridizations. p. 27–31 In
ReichenbachH.,
WeeksO. B.The Fla-vobacterium-Cytophaga group. Proceedings of the International Symposium on Yellow-Pigmented Gram-Negative Bacteria of the Flavobacterium-Cytophaga Group. Gesellschaft fuer Bio- technologische Forschung mbH Braunschweig-Stoeckheim; Germany:
DeesS. B.,
MossC. W.,
WeaverR. E.,
HollisD.1979; Cellular fatty acid composition of Pseudomonas paucimobilis and groups Ilk-2, Ve-1, and Ve-2. J. Clin. Microbiol 10:206–209
De SmedtJ.,
De LeyJ.1977.; Intra- and intergeneric similarities of Agrobacterium ribosomal ribonucleic acid cis- trons. Int. J. Syst Bacteriol 27:222–240
De VosP.,
De LeyJ.1983.; Intra- and intergeneric similarities of Pseudomonas and Xanthomonas ribosomal ribonucleic acid cistrons. Int. J. Syst. Bacteriol 33:485–509
De VosP.,
van LandschootA.,
SegersP.,
TytgatR.,
GillisM.,
BauwensM.,
RossauR.,
GoorM.,
PotB.,
KerstersK.,
LizzaragaP.,
De LeyJ.1989; Genotypic relationships and taxonomic localization of unclassified Pseudomonas and Pseudomonas- like strains by deoxyribonucleic acid-ribosomal ribonucleic acid hybridizations. Int. J. Syst. Bacteriol 39:35–49
GillisM.,
De LeyJ.1980; Intra and intergeneric similarities of the ribosomal ribonucleic acid cistrons of Acetobacter and Gluconobacter. Int. J. Syst. Bacteriol 30:7–27
HolmesB.,
OwenR. J.,
EvansA.,
MalnickH.,
WillcoxW. R.1977; Pseudomonas paucimobilis, a new species iso-lated from human clinical specimens, the hospital environment, and other sources. Int. J. Syst. Bacteriol 27:133–146
KawaharaK.,
SeydelU.,
MatsuuraM.,
DanbaraH.,
RietchelE. T.,
ZaehringerU.1991; Chemical structure of gly- cosphingolipids isolated from Sphingomonas paucimobilis. FEBS Lett 292:107–110
LucasR. E.,
Guzman.V. L.1980; The incidence of corky root rot of lettuce due to soil moisture levels, nitrogen sources, and potash rates.A greenhouse study. Belle Glade ARFC Report EV-1980-10. University of Florida, Gainesville;
MooreR. L.,
McCarthy.B. J.1967; Comparative study of ribosomal ribonucleic acid cistrons in enterobacteria and myx- obacteria. J. Bacteriol 94:1066–1074
RichardsG. M.1974; Modifications of the diphenylamine reaction giving increased sensitivity and simplicity in the estimation of DNA. Anal. Biochem 57:369–376
StackebrandtE.,
MurrayR. G. E.,
TruperH. G.1988; Proteobacteria classis nov., a name for the phylogenetic taxon that includes the “purple bacteria and their relatives.”. Int. J. Syst. Bacteriol 38:321–325
van BruggenA. H.C.,
BrownP. R.,
JochimsenK. N.1989; Corky root of lettuce caused by strains of a gram-negative bacterium from muck soils of Florida. Wisconsin; New York: Appl. Environ. Microbiol552635–2640
van BruggenA. H. C.,
GroganR. G.,
BogdanoffC. P.,
WatersC. M.1988; Corky root of lettuce in California caused by a Gram-negative bacterium. Phytopathology 78:1139–1145
van BruggenA. H. C.,
Jochimsen.K. N.
Unpublished data
van BruggenA. H. C.,
JochimsenK. N.,
BenedictA. A.,
Pollard.L. W.1992; Monoclonal antibodies for the detection of Rhizomonas suberifaciens, causal agent of corky root of lettuce, with enzyme immunoassays. Food Agric. Immunol 4:27–40.
van BruggenA. H. C.,
JochimsenK. N.,
Brown.P. R.1990; Rhizomonas suberifaciens gen. nov., sp. nov., the causal agent of lettuce corky root. Int. J. Syst. Bacteriol 40:175–188
WoeseC. R.,
WinkerS.,
Gutell.R. R.1990; Architecture of ribosomal RNA: constraints on the sequence of “tetra-loops.”. Proc. Natl. Acad. Sci USA 87:8467–8471
YabuuchiE.,
YanoI.,
OyaizuH.,
HashimotoY.,
EzakiT.,
YamamotoH.1990; Proposals of Sphingomonas paucimobilis gen. nov. and comb, nov.,Sphingomonasparapaucimobilis sp. nov.,Sphingomonas yanoikuyae sp. nov.,Sphingomonas ad haesiva sp. nov.,Sphingomonas capsulata comb, nov., and two genospecies of the genus Sphingomonas. Microbiol. Immunol 34:99–110