Bacterial Community Structure in Relation to the Carbon Environments in Lettuce and Tomato Rhizospheres and in Bulk Soil

Maloney, Patricia E.; Bruggen, A.H.C. van; Hu, Shengquan

doi:10.1007/s002489900040

Cited by 110 publications

(59 citation statements)

References 20 publications

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“…The roots of young barley seedlings were used as a model system, mainly because colonization of the young barley seedling root system by Pseudomonas cells has been studied in great detail (26,33,34). Although our conclusions cannot be directly applied to every other plant-bacterium system, as it is known that rhizosphere colonization is influenced by the nature of the microorganisms, the soil type, and the seeds used (37,39), they contribute to our understanding of the behavior of P. putida cells when these cells are used as a seed-applied inoculant.…”

Section: Discussionmentioning

confidence: 99%

Bacterial Activity in the Rhizosphere Analyzed at the Single-Cell Level by Monitoring Ribosome Contents and Synthesis Rates

Ramos

Mølbak

Molin

2000

Appl Environ Microbiol

162

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The growth activity of Pseudomonas putida cells colonizing the rhizosphere of barley seedlings was estimated at the single-cell level by monitoring ribosomal contents and synthesis rates. Ribosomal synthesis was monitored by using a system comprising a fusion of the ribosomal Escherichia coli rrnBP1 promoter to a gene encoding an unstable variant of the green fluorescent protein (Gfp). Gfp expression in a P. putida strain carrying this system inserted into the chromosome was strongly dependent on the growth phase and growth rate of the strain, and cells growing exponentially at rates of >0.17 h ؊1 emitted growth rate-dependent green fluorescence detectable at the single-cell level. The single-cell ribosomal contents were very heterogeneous, as determined by quantitative hybridization with fluorescently labeled rRNA probes in P. putida cells extracted from the rhizosphere of 1-day-old barley seedlings grown under sterile conditions. After this, cells extracted from the root system had ribosomal contents similar to those found in starved cells. There was a significant decrease in the ribosomal content of P. putida cells when bacteria were introduced into nonsterile bulk or rhizosphere soil, and the Gfp monitoring system was not induced in cells extracted from either of the two soil systems. The monitoring system used permitted nondestructive in situ detection of fast-growing bacterial microcolonies on the sloughing root sheath cells of 1-and 2-day-old barley seedlings grown under sterile conditions, which demonstrated that it may be possible to use the unstable Gfp marker for studies of transient gene expression in plant-microbe systems.

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Section: Discussionmentioning

confidence: 99%

Bacterial Activity in the Rhizosphere Analyzed at the Single-Cell Level by Monitoring Ribosome Contents and Synthesis Rates

Ramos

Mølbak

Molin

2000

Appl Environ Microbiol

162

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“…Examples of hypotheses under these themes, stated in a general way, include the following: there is no significant variation in the structure of the population of a given plant pathogen over time or between geographic regions (32,39), and plant species have a significant effect on the biodiversity of microorganisms in the rhizosphere (19,95,171,205,252). The test of such hypotheses necessitates well-developed experimental design leading to statistical tests.…”

Section: Approaches To Experimental Design and Hypothesis Testingmentioning

confidence: 99%

Microbial Biodiversity: Approaches to Experimental Design and Hypothesis Testing in Primary Scientific Literature from 1975 to 1999

Morris¹,

Bardin²,

Berge

et al. 2002

Microbiol Mol Biol Rev

103

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Research interest in microbial biodiversity over the past 25 years has increased markedly as microbiologists have become interested in the significance of biodiversity for ecological processes and as the industrial, medical, and agricultural applications of this diversity have evolved. One major challenge for studies of microbial habitats is how to account for the diversity of extremely large and heterogeneous populations with samples that represent only a very small fraction of these populations. This review presents an analysis of the way in which the field of microbial biodiversity has exploited sampling, experimental design, and the process of hypothesis testing to meet this challenge. This review is based on a systematic analysis of 753 publications randomly sampled from the primary scientific literature from 1975 to 1999 concerning the microbial biodiversity of eight habitats related to water, soil, plants, and food. These publications illustrate a dominant and growing interest in questions concerning the effect of specific environmental factors on microbial biodiversity, the spatial and temporal heterogeneity of this biodiversity, and quantitative measures of population structure for most of the habitats covered here. Nevertheless, our analysis reveals that descriptions of sampling strategies or other information concerning the representativeness of the sample are often missing from publications, that there is very limited use of statistical tests of hypotheses, and that only a very few publications report the results of multiple independent tests of hypotheses. Examples are cited of different approaches and constraints to experimental design and hypothesis testing in studies of microbial biodiversity. To prompt a more rigorous approach to unambiguous evaluation of the impact of microbial biodiversity on ecological processes, we present guidelines for reporting information about experimental design, sampling strategies, and analyses of results in publications concerning microbial biodiversity

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“…Regarding the sites of the root area, populated by microorganisms, some authors (Maloney et al 1997;Paul et al, 2010) showed an increased number of oligotrophic bacteria in the root peaks area, compared to the root base.…”

Section: Resultsmentioning

confidence: 99%

Plants Root Interference Area, A Benefit To The Microbial Community

Borozan¹,

Popescu²,

Boldura³

2017

BUASVMCN-HORT

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Part of byproducts synthesized by plants through photosynthesis reach the ground, where are creating selective microenvironments for micro-flora and associations of plant -microorganisms, being beneficial for plant growth. In this paper, the effect of the root interference area of vines and herbaceous plants and of radicular exudates from vine rhizosphere on microbial community was studied by estimating the present microbial population. Also, by molecular studies, the diversity of microbiological community was assessed.The microbiological study of biological samples was performed by classical and molecular methods. The biological material was represented by microbial communities from rhizosphere and phyllosphere areas of two varieties of vines White Romanian Tămâioasă and Black Romanian Tămâioasă cultivated in a soil that has never been chemically treated. Overall, bacteria had a significant presence in soil samples taken from the interference area of vines and herbaceous plants roots. Actinomycetes quantitatively dominated the root interference area of herbaceous plant with variety White Romanian Tămâioasă. The range of actinomycetes species and leaves microflora was found to be reduced. In this study we have shown that significant growth of microorganisms occurs in the interference area of vine with other herbal plants as a result of the cumulative effect of radicular exudates and that the surrounding microbial community differs among varieties, areas of interference and also is strongly influenced by the levels of tillage and fertilization of soil.

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Bacterial Community Structure in Relation to the Carbon Environments in Lettuce and Tomato Rhizospheres and in Bulk Soil

Cited by 110 publications

References 20 publications

Bacterial Activity in the Rhizosphere Analyzed at the Single-Cell Level by Monitoring Ribosome Contents and Synthesis Rates

Bacterial Activity in the Rhizosphere Analyzed at the Single-Cell Level by Monitoring Ribosome Contents and Synthesis Rates

Microbial Biodiversity: Approaches to Experimental Design and Hypothesis Testing in Primary Scientific Literature from 1975 to 1999

Plants Root Interference Area, A Benefit To The Microbial Community

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