Gram-negative bacterial flora on the root surface of wheat (Triticum aestivum) grown under different soil conditions

Sato, Katsutoshi; Jiang, Hong-Ying

doi:10.1007/bf00335955

Cited by 26 publications

(11 citation statements)

References 11 publications

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“…Bacteroidetes are known for their utilization of macromolecules, including proteins and polysaccharides such as cellulose and chitin (6, 26, 32, 41). Bacteroidetes, including Chryseobacterium spp., have been previously detected in composted materials (1,12,21,37), in soil environments (52,54), and in association with plant surfaces (22,26,27,29,30,33,36,40,44,45). We have consistently recovered Chryseobacterium sequences directly from these and other cow manure composts produced in the same location (Ohio Agriculture Research and Development Center, Ohio State University, Wooster).…”

Section: Discussionmentioning

confidence: 58%

Succession of Bacterial Communities during Early Plant Development: Transition from Seed to Root and Effect of Compost Amendment

Green

Inbar

Michel³

et al. 2006

Appl Environ Microbiol

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Compost amendments to soils and potting mixes are routinely applied to improve soil fertility and plant growth and health. These amendments, which contain high levels of organic matter and microbial cells, can influence microbial communities associated with plants grown in such soils. The purpose of this study was to follow the bacterial community compositions of seed and subsequent root surfaces in the presence and absence of compost in the potting mix. The bacterial community compositions of potting mixes, seed, and root surfaces sampled at three stages of plant growth were analyzed via general and newly developed Bacteroidetes-specific, PCR-denaturing gradient gel electrophoresis methodologies. These analyses revealed that seed surfaces were colonized primarily by populations detected in the initial potting mixes, many of which were not detected in subsequent root analyses. The most persistent bacterial populations detected in this study belonged to the genus Chryseobacterium (Bacteroidetes) and the family Oxalobacteraceae (Betaproteobacteria). The patterns of colonization by populations within these taxa differed significantly and may reflect differences in the physiology of these organisms. Overall, analyses of bacterial community composition revealed a surprising prevalence and diversity of Bacteroidetes in all treatments.

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Section: Discussionmentioning

confidence: 58%

Succession of Bacterial Communities during Early Plant Development: Transition from Seed to Root and Effect of Compost Amendment

Green

Inbar

Michel³

et al. 2006

Appl Environ Microbiol

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“…Typically, rhizosphere soil is collected by shaking soil that is loosely adhering to the roots, and then the soil is used to prepare serial dilutions in water that are plated onto selective agar media. Individual isolates are then identified by using metabolic tests (32) or procedures such as metabolic fingerprinting (5, 13), fatty acid methyl ester analysis (20), and genetic analysis of individual isolates by 16S rDNA gene sequencing (26). Often several hundred to more than 1,000 isolates are analyzed in an analysis of one sample.…”

Section: Discussionmentioning

confidence: 99%

Rhizosphere Microbial Community Structure in Relation to Root Location and Plant Iron Nutritional Status

Yang

Crowley

2000

Appl Environ Microbiol

474

229

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Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.Root exudates selectively influence the growth of bacteria and fungi that colonize the rhizosphere by altering the chemistry of soil in the vicinity of the plant roots and by serving as selective growth substrates for soil microorganisms. Microorganisms in turn influence the composition and quantity of various root exudate components through their effects on root cell leakage, cell metabolism, and plant nutrition. Based on differences in root exudation and rhizodeposition in different root zones, rhizosphere microbial communities can vary in structure and species composition in different root locations or in relation to soil type, plant species, nutritional status, age, stress, disease, and other environmental factors (8,16,22,23). During the growth of new roots, exudates secreted in the zone of elongation behind the root tips support the growth of primary root colonizers that utilize easily degradable sugars and organic acids. In the older root zones, carbon is deposited primarily as sloughed cells and consists of more recalcitrant materials, including lignified cellulose and hemicellulose, so that fungi and bacteria in these zones are presumably adapted to crowded, oligotrophic conditions. Other nutritionally distinct sites include the sites of lateral root emergence and the secondary, ...

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“…O. anthropi LMG 5140 has been isolated from arsenical cattle dipping fluid (Holmes et al, 1988) and is described as identical to O. anthropi strains LMG 2134 and LMG 2320(t1). There are some reports on the presence of O. anthropi in soil, on wheat roots and in internal root tissues of different plants (Aguillera et al, 1993 ;McInroy & Kloepper, 1994 ;Sato & Jiang, 1996), but identification was based only on phenotypic characters. O. intermedium LMG 3306 has been isolated from a French soil (Holmes et al, 1988) and other O. intermedium strains are from human blood (Velasco et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

Taxonomic characterization of Ochrobactrum sp. isolates from soil samples and wheat roots, and description of Ochrobactrum tritici sp. nov. and Ochrobactrum grignonense sp. nov.

Lebuhn¹,

Achouak²,

Schloter³

et al. 2000

International Journal of Systematic and Evolutionary Microbiology

166

125

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A large collection of bacterial strains, immunotrapped from soil and from the wheat rhizoplane, was subjected to polyphasic taxonomy by examining various pheno-and genotypic parameters. Strains were grouped on (inter) repetitive extragenic palindromic DNA (REP) PCR profiles at the intraspecies level. Pheno-and genotypic characters were assessed for representatives from 13 different REP groups. Strains of nine REP groups constituting two physiological BIOLOG clusters fell in the coherent DNA-DNA reassociation group of Ochrobactrum anthropi. Strains of two REP groups constituting a separate BIOLOG cluster fell in the coherent DNA-DNA reassociation group of Ochrobactrum intermedium. Additional phenotypic characters differentiating O. anthropi and O. intermedium were found. REP group K strains constituted a different BIOLOG cluster, a separate DNA-DNA reassociation group and a distinct phylogenetic lineage in 16S rDNA homology analysis, indicating that REP group K strains represent a new species. Diagnostic phenotypic characters were found. Closest relatives were Ochrobactrum species. The name Ochrobactrum grignonense sp. nov. is proposed (type strain OgA9a T l LMG 18954 T l DSM 13338 T ). REP group J strains again constituted a different BIOLOG cluster, a separate DNA-DNA reassociation group and showed, as a biological particularity, a strict preference for the rhizoplane as habitat. Diagnostic phenotypic characters were found. This indicated that REP group J strains represent a further new species, although phylogenetic analyses using 16S rDNA homology were not able to separate the cluster of REP group J sequences significantly from 16S rDNA sequences of Ochrobactrum anthropi. The name Ochrobactrum tritici sp. nov. is proposed (type strain SCII24 T l LMG 18957 T l DSM 13340 T ).

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Gram-negative bacterial flora on the root surface of wheat (Triticum aestivum) grown under different soil conditions

Cited by 26 publications

References 11 publications

Succession of Bacterial Communities during Early Plant Development: Transition from Seed to Root and Effect of Compost Amendment

Succession of Bacterial Communities during Early Plant Development: Transition from Seed to Root and Effect of Compost Amendment

Rhizosphere Microbial Community Structure in Relation to Root Location and Plant Iron Nutritional Status

Taxonomic characterization of Ochrobactrum sp. isolates from soil samples and wheat roots, and description of Ochrobactrum tritici sp. nov. and Ochrobactrum grignonense sp. nov.

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