Use of nodulation pattern, stress tolerance, nodC gene amplification, RAPD-PCR and RFLP-16S rDNA analysis to discriminate genotypes of Rhizobium leguminosarum biovar viciae.
Twenty-seven new Rhizobium isolates were obtained from root nodules of wild and crop legumes belonging to the genera Vicia, Lathyrus and Pisum from different agroecological areas in central and southern Italy. A polyphasic approach including phenotypic and genotypic techniques was used to study their diversity and their relationships with other biovars and species of rhizobia. Analysis of symbiotic properties and stress tolerance tests revealed that wild isolates showed a wide spectrum of nodulation and a marked variation in stress tolerance compared with reference strains tested in this study. All rhizobial isolates (except for the isolate CG4 from Galega officinalis) were presumptively identified as Rhizobium leguminosarum biovar viciae both by their symbiotic properties and the specific amplification of the nodC gene. In particular, we found that the nodC gene could be used as a diagnostic molecular marker for strains belonging to the bv. viciae. RFLP-PCR 16S rDNA analysis confirms these results, with the exception of two strains that showed different RFLP-genotypes from those of the reference strains of R. leguminosarum bv. viciae. Analysis of intraspecies relationship among strains by using the RAPD-PCR technique showed a high level of genetic polymorphism, grouping our isolates and reference strains into six different major clusters with a similarity level of 20%. Data from seven parameters of phenotypic and genotypic analyses were evaluated by using principal component analysis which indicated the differences among strains and allowed them to be divided into seven different groups.
Moschetti
Giancarlo
G
Dipartimento di Scienza degli Alimenti, Sezione di Microbiologia Agraria, Alimnentare ed Ambientale e di Igiene, Università degli Studi di Napoli Federico II, I 80055 Portici, Italy. moschett@unina.it
Peluso
AnnaLucia
A
Protopapa
Andrea
A
Anastasio
Marilena
M
Pepe
Olimpia
O
Defez
Roberto
R
D001426:Bacterial Proteins; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000737:chemistry; D004275:DNA, Ribosomal / Q000737:chemistry; D007887:Fabaceae / Q000382:microbiology; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics*; D021141:Nucleic Acid Amplification Techniques; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D025341:Principal Component Analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D019105:Random Amplified Polymorphic DNA Technique; D016961:Rhizobium leguminosarum / Q000145:classification* / Q000235:genetics* / Q000502:physiology; D013559:Symbiosis
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D017351:N-Acetylglucosaminyltransferases; C060771:NodC protein, Rhizobiales