Identification of Azospirillum Strains at the Genome Level with Total DNA Restriction Pattern Analysis

Giovannetti, Luciana; Fedi, Stefano; Gori, Alessio; Montaini, P.; Ventura, Stefano

doi:10.1016/s0723-2020(11)80135-9

Cited by 11 publications

(6 citation statements)

References 13 publications

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“…In the present study, we describe the phenotypic switching in A. lipoferum. In the genus Azospirillum, DNA restriction pattern analysis [19], RFLP [20] and plasmid-pro¢ling techniques [14,21] are considered strain-speci¢c. PCR-RFLP analysis of the 16S2 3S rDNA intergenic spacer region and comparison of partial 16S rDNA sequences allow discrimination between closely related strains of the same species [7,22].…”

Section: Discussionmentioning

confidence: 99%

Emergence of a laccase-positive variant of Azospirillum lipoferum occurs via a two-step phenotypic switching process

Alexandre

1999

FEMS Microbiology Letters

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Two variants have been isolated from the wild-type Azospirillum lipoferum strain 4B. The first variant, 4V s , spontaneously emerged from the wild-type at frequencies in the order of 10 3R to 10 3Q per cell generation. Compared to the wild-type, the 4V s variant gained (production of a carotenoid-like pigment, assimilation of certain carbohydrates) and lost (swimming motility, reduction of triphenyl tetrazolium chloride, acid production from certain sugars) apparently unrelated phenotypic characteristics. Only from the 4V s variant, a second atypical stable form, variant 4V ss , which acquired laccase activity and ability to produce melanin, appeared under very specific conditions, namely growth at extremely low oxygen concentrations. Neither of the variants was able to revert to the parental phenotype. The results suggest that atypical non-motile laccasepositive isolates of A. lipoferum that are found in the rice rhizosphere originate from wild-type (motile, laccase-negative) cells via a two-step phenotypic switching event, a non-motile laccase-negative variant being an intermediate phase. z 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

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Section: Discussionmentioning

confidence: 99%

Emergence of a laccase-positive variant of Azospirillum lipoferum occurs via a two-step phenotypic switching process

Alexandre

1999

FEMS Microbiology Letters

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“…That is why we decided to consider the DNA content of the strain in order to develop a strain‐specific molecular tool. The effectiveness of the method we employed to characterize a strain specific DNA fragment is not surprising insofar as previous studies have shown that Azospirillum strains are correlated at low similarity coefficients [25] and DNA/DNA hybridization values among strains of A. lipoferum are low [26].…”

Section: Discussionmentioning

confidence: 99%

“…The plasmid‐profiling technique was discriminant enough to be considered also as strain specific. Other methods like restriction fragment length polymorphism [30], DNA restriction pattern analysis [25] and pulsed‐field gel electrophoresis [31] can differentiate Azospirillum strains. However, the important drawback of all these methods is that they need a preliminary step: isolation and DNA extraction from the tested isolates.…”

Section: Discussionmentioning

confidence: 99%

Development of a strain-specific probe to follow inoculated Azospirillum lipoferum CRT1 under field conditions and enhancement of maize root development by inoculation

Jacoud

Faure

Wadoux³

et al. 1998

FEMS Microbiology Ecology

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In order to develop a reliable and specific tool for the detection of Azospirillum lipoferum CRT1, randomly cloned DNA fragments from this strain were used as hybridization probes to differentiate A. lipoferum CRT1 from 29 closely related Azospirillum strains. Two cloned fragments hybridizing only with DNA from A. lipoferum CRT1 (CRT1‐5 and CRT1‐7) were considered as specific probes of this strain. CRT1‐7 fragment (1.4 kb) was further tested for purity control of the inoculant Azogreen‐m by colony hybridization. The sequence of the CRT1‐7 fragment has been determined and compared with those present in databases: no significant similarity with other sequences was detected. This probe permitted us to count specifically A. lipoferum CRT1 cells on maize roots during a field trial. During the first two weeks, A. lipoferum CRT1 remained at 107 CFU plant−1. Afterwards, bacterial concentration sharply decreased. We could not detect any CRT1 cells on maize roots 28 days after sowing. Concurrently, three plant parameters were estimated (plant height, primary root length and root fresh weight). The results showed that A. lipoferum CRT1 growth promotion effect began early on (from day 14) in plant development and increased in spite of a rapid decrease of bacterial density.

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“…Surprisingly, the N 2 -fixing, anoxygenic phototroph Rhodospirillum centenum, isolated from a hot spring (Favinger et al, 1989), was also grouped within the Azospirillum cluster close to A. irakense. In addition to ribosomal RNA sequence analysis, the DNA restriction profiles also support the subgeneric classification of Azospirillum (Giovanetti et al, 1990(Giovanetti et al, , 1992Fani et al, 1991).…”

Section: Introductionmentioning

confidence: 69%

Taxonomic and Ecologic Studies of Diazotrophic Rhizosphere Bacteria Using Phylogenetic Probes

Hartmann

Baldani

Kirchhof

et al. 1995

Azospirillum VI and Related Microorganisms

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The phylogenetic relationships between diazotrophic rhizosphere bacteria were studied using 16S and 23S ribosomal RNA sequences. Certain stretches of the rRNA sequences are variable enough to provide information for the development of diagnostic probes at the species level for the five Azospirillum spp., Acetobacter diazotrophicus, Herbaspirillum seropedica, H rubrisubalbicans and "isolate E"-bacteria. The brasilian "isolate E"-type bacteria, which reside inside roots, stems and leaves of several plants, could be grouped into the betasubgroup of prot eo bacteria. According to their 16S rRNA sequences they belong to the genus Oligonucleotide probes were successfully used for a specific fluorescence-labelling of single cells in situ. Azospirillum brasilense strains Sp7, Sp245, and Wa3 could be identified and localized in the rhizosphere of wheat plants. Scanning confocal laser microscopy allowed to image the three-dimensional structure of colonized roots and to characterize a different localization pattern of these strains.

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Identification of Azospirillum Strains at the Genome Level with Total DNA Restriction Pattern Analysis

Cited by 11 publications

References 13 publications

Emergence of a laccase-positive variant of Azospirillum lipoferum occurs via a two-step phenotypic switching process

Emergence of a laccase-positive variant of Azospirillum lipoferum occurs via a two-step phenotypic switching process

Development of a strain-specific probe to follow inoculated Azospirillum lipoferum CRT1 under field conditions and enhancement of maize root development by inoculation

Taxonomic and Ecologic Studies of Diazotrophic Rhizosphere Bacteria Using Phylogenetic Probes

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