Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Schreiter, Susanne  (9)
  • 1
    In: PLoS ONE, 2014, Vol.9(8)
    Description: Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10 6 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected the bottom rot disease severity.
    Keywords: Research Article ; Biology And Life Sciences
    E-ISSN: 1932-6203
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Language: English
    In: PLoS ONE, August 6, 2014, Vol.9(8)
    Description: Rhizosphere competence of bacterial inoculants is assumed to be important for successful biocontrol. Knowledge of factors influencing rhizosphere competence under field conditions is largely lacking. The present study is aimed to unravel the effects of soil types on the rhizosphere competence and biocontrol activity of the two inoculant strains Pseudomonas jessenii RU47 and Serratia plymuthica 3Re4-18 in field-grown lettuce in soils inoculated with Rhizoctonia solani AG1-IB or not. Two independent experiments were carried out in 2011 on an experimental plot system with three soil types sharing the same cropping history and weather conditions for more than 10 years. Rifampicin resistant mutants of the inoculants were used to evaluate their colonization in the rhizosphere of lettuce. The rhizosphere bacterial community structure was analyzed by denaturing gradient gel electrophoresis of 16S rRNA gene fragments amplified from total community DNA to get insights into the effects of the inoculants and R. solani on the indigenous rhizosphere bacterial communities. Both inoculants showed a good colonization ability of the rhizosphere of lettuce with more than 10.sup.6 colony forming units per g root dry mass two weeks after planting. An effect of the soil type on rhizosphere competence was observed for 3Re4-18 but not for RU47. In both experiments a comparable rhizosphere competence was observed and in the presence of the inoculants disease symptoms were either significantly reduced, or at least a non-significant trend was shown. Disease severity was highest in diluvial sand followed by alluvial loam and loess loam suggesting that the soil types differed in their conduciveness for bottom rot disease. Compared to effect of the soil type of the rhizosphere bacterial communities, the effects of the pathogen and the inoculants were less pronounced. The soil types had a surprisingly low influence on rhizosphere competence and biocontrol activity while they significantly affected the bottom rot disease severity.
    Keywords: RNA ; Biological Pest Control
    ISSN: 1932-6203
    Source: Cengage Learning, Inc.
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Plant and Soil, 2012, Vol.361(1), pp.343-357
    Description: Co-inoculation of biocontrol agents with different modes of action is assumed to improve biocontrol activity. The present study aimed to investigate the effects of single or co-inoculation of Trichoderma viride strain GB7 and Serratia plymuthica strain 3Re4-18 on microbial communities in the rhizosphere of lettuce and their ability to suppress Rhizoctonia solani AG1-IB.Growth chamber experiments with two different application modes were performed with single or co-inoculation of GB7 and 3Re4-18 in the presence or absence of R. solani. Biocontrol efficacy and plant growth parameters were assessed. Bacterial and fungal communities were analyzed by 16S rRNA gene and ITS fragments PCR-amplified from total community DNA of rhizosphere samples and analyzed by denaturing gradient gel electrophoresis.Compared to the single application, the co-inoculation of 3Re4-18 and GB7 resulted in an improved biocontrol efficacy. DGGE analysis revealed more pronounced effect on microbial community in co-inoculation treatment. The abundance of 3Re4-18 in the rhizosphere seemed to be increased in the presence of R. solani.The applied cultivation-independent methods provided insights into the complex interaction in response to the pathogen and the antagonists. Co-inoculation resulted in an improved biocontrol efficacy and an increased evenness of the microbial communities.
    Keywords: Biocontrol ; Co-inoculation ; Rhizosphere community ; 16S rRNA gene and ITS-based fingerprints
    ISSN: 0032-079X
    E-ISSN: 1573-5036
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Frontiers in Microbiology, 01 February 2018, Vol.9
    Description: Biocontrol inoculants often show inconsistency in their efficacy at field scale and the reason for this remains often unclear. A high rhizosphere competence of inoculant strains is assumed to be a key factor for successful biocontrol effects as the biocontrol strain has to compete with the indigenous microbial community in the rhizosphere. It is known that many factors, among them plant species and soil type shape the rhizosphere microbial community composition. However, microbial community composition in the rhizosphere can also be influenced by the presence of a pathogen. We hypothesized that plant species, soil type, and a pathogen affect the rhizosphere competence of a biocontrol strain and its biocontrol effect against a soil-borne pathogen. To test the hypothesis, we used an experimental plot system with three soil types (diluvial sand, alluvial loam, loess loam) kept under similar agricultural management at the same field site for 12 years. We investigate the rhizosphere competence of Pseudomonas sp. RU47 in two plant species (potato and lettuce) and its biocontrol effect against Rhizoctonia diseases. The colonization density of a rifampicin resistant mutant of RU47 in the rhizosphere of both crops was evaluated by plate counts. Bacterial community compositions were analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments amplified from total community DNA. The inoculant RU47 was able to colonize the rhizosphere of both model crops in a sufficient density and to reduce disease severity of black scurf on potato and bottom rot on lettuce in all three soils. DGGE indicated that RU47 affected the bacterial community composition stronger in the rhizosphere of lettuce than in the potato rhizosphere. In contrast, the effect of the pathogen Rhizoctonia solani on the bacterial community was much stronger in the rhizosphere of potato than in the lettuce rhizosphere. A significant effect of RU47 on the Pseudomonas-specific gacA fingerprints of the rhizosphere was only observed in lettuce in alluvial soil. The soil type and plant species independent biocontrol effects of RU47 and its minor influence on the indigenous bacterial community composition might be important criteria for the registration and use of RU47 as biocontrol strain.
    Keywords: Rhizoctonia Solani ; Plant Health ; Biocontrol ; Plant Disease ; Bacterial Community ; Dgge ; Biology
    E-ISSN: 1664-302X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Frontiers in microbiology, 2013, Vol.4, pp.420
    Description: Class 1 integrons contribute to the emerging problem of antibiotic resistance in human medicine by acquisition, exchange, and expression of resistance genes embedded within gene cassettes. Besides the clinical setting they were recently reported from environmental habitats and often located on plasmids and transposons, facilitating their transfer and spread within bacterial communities. In this study we aimed to provide insights into the occurrence of genes typically associated with the class 1 integrons in previously not studied environments with or without human impact and their association with IncP-1 plasmids. Total community DNA was extracted from manure-treated and untreated soils, lettuce and potato rhizosphere, digestates, and an on-farm biopurification system and screened by PCR with subsequent Southern blot hybridization for the presence of the class 1 integrase gene intI1 as well as qacE and qacEΔ 1 resistance genes. The results revealed a widespread dissemination of class 1 integrons in the environments analyzed, mainly related to the presence of qacEΔ 1 genes. All 28 IncP-1ε plasmids carrying class 1 integrons, which were captured exogenously in a recent study from piggery manure and soils treated with manure, carried qacEΔ 1 genes. Based on the strong hybridization signals in the rhizosphere of lettuce compared to the potato rhizosphere, the abundances of intI1, qacE/qacEΔ 1, and sul1 genes were quantified relative to the 16S rRNA gene abundance by real-time PCR in the rhizosphere of lettuce planted in three different soils and in the corresponding bulk soil. A significant enrichment of intI1 and qacE/qacEΔ 1 genes was confirmed in the rhizosphere of lettuce compared to bulk soil. Additionally, the relative abundance of korB genes specific for IncP-1 plasmids was enriched in the rhizosphere and correlated to the intI1 gene abundance indicating that IncP-1 plasmids might have contributed to the spread of class 1 integrons in the analyzed soils.
    Keywords: Incp-1 Korb ; Biofilter ; Digestates ; Inti1 ; Manured Soil and Rhizosphere ; Qace ; Qaceδ1 ; Sul1
    ISSN: 1664-302X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    In: FEMS Microbiology Ecology, 2014, Vol. 90(3), pp.718-730
    Description: Bacterial biocontrol strains used as an alternative to chemical fungicides may influence bacterial communities in the rhizosphere and effects might differ depending on the soil type. Here we present baseline data on the effects of Pseudomonas jessenii RU47 on the bacterial community composition in the rhizosphere of lettuce grown in diluvial sand, alluvial loam and loess loam at the same field site. 16S rRNA gene fragments amplified from total community DNA were analyzed by denaturing gradient gel electrophoresis (DGGE) and pyrosequencing. DGGE fingerprints revealed that in three consecutive years (2010–2012) RU47 had a slight but statistically significant effect on the bacterial community composition in one (2010), two (2011) or all the three soils (2012). However, these effects were much less pronounced compared with the influence of soil types. Additional pyrosequence analysis of samples from 2011 showed that significant changes in bacterial community compositions in response to RU47 inoculation occurred only in alluvial loam. Different taxonomic groups responded to the RU47 application depending on the soil type. Most remarkable was the increased relative abundance of OTUs belonging to the genera Bacillus and Paenibacillus in alluvial loam. Pyrosequencing allowed side-effects of the application of bacterial inoculants into the rhizosphere to be identified. The introduction of the potential biocontrol inoculant Pseudomonas jessenii RU47 into three soil types at the same field site had a negligible effect on the bacterial community in the rhizosphere of field-grown lettuce. The introduction of the potential biocontrol inoculant Pseudomonas jessenii RU47 into three soil types at the same field site had a negligible effect on the bacterial community in the rhizosphere of field-grown lettuce.
    Keywords: 16s Rrna Gene ; Biocontrol ; Denaturing Gradient Gel Electrophoresis ; Ru47 ; Pyrosequencing ; Total Community Dna
    ISSN: 01686496
    E-ISSN: 1574-6941
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: Plant and Soil, 1 January 2012, Vol.361, pp.343-357
    Description: Background and aims Co-inoculation of biocontrol agents with different modes of action is assumed to improve biocontrol activity. The present study aimed to investigate the effects of single or co-inoculation of Trichoderma viride strain GB7 and Serratia plymuthica strain 3Re4-18 on microbial communities in the rhizosphere of lettuce and their ability to suppress Rhizoctonia solani AG1-IB. Methods Growth chamber experiments with two different application modes were performed with single or co-inoculation of GB7 and 3Re4-18 in the presence or absence of R. solani. Biocontrol efficacy and plant growth parameters were assessed. Bacterial and fungal communities were analyzed by 16S rRNA gene and ITS fragments PCR-amplified from total community DNA of rhizosphere samples and analyzed by denaturing gradient gel electrophoresis. Results Compared to the single application, the co-inoculation of 3Re4-18 and GB7 resulted in an improved biocontrol efficacy. DGGE analysis revealed more pronounced effect on microbial community in co-inoculation treatment. The abundance of 3Re4-18 in the rhizosphere seemed to be increased in the presence of R. solani. Conclusions The applied cultivation-independent methods provided insights into the complex interaction in response to the pathogen and the antagonists. Co-inoculation resulted in an improved biocontrol efficacy and an increased evenness of the microbial communities.
    Keywords: Biological sciences -- Ecology -- Population ecology ; Biological sciences -- Biology -- Microbiology ; Biological sciences -- Biology -- Botany ; Health sciences -- Medical sciences -- Immunology ; Biological sciences -- Biology -- Mycology ; Biological sciences -- Biology -- Mycology ; Biological sciences -- Agriculture -- Farming ; Biological sciences -- Agriculture -- Agricultural sciences ; Biological sciences -- Biology -- Botany ; Biological sciences -- Biology -- Mycology
    ISSN: 0032079X
    E-ISSN: 15735036
    Source: Archival Journals (JSTOR)
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    In: Microbial Biotechnology, March 2017, Vol.10(2), pp.434-449
    Description: A statistical method was developed to test for equivalence of microbial communities analysed by next‐generation sequencing of amplicons. The test uses Bray–Curtis distances between the microbial community structures and is based on a two‐sample jackknife procedure. This approach was applied to investigate putative effects of the antifungal biocontrol strain 47 on fungal communities in three arable soils which were analysed by high‐throughput amplicon sequencing. Two contrasting workflows to produce abundance tables of operational taxonomic units from sequence data were applied. For both, the developed test indicated highly significant equivalence of the fungal communities with or without previous exposure to 47 for all soil types, with reference to fungal community differences in conjunction with field site or cropping history. However, minor effects of 47 on fungal communities were statistically significant using highly sensitive multivariate tests. Nearly all fungal taxa responding to 47 increased in relative abundance indicating the absence of ecotoxicological effects. Use of the developed equivalence test is not restricted to evaluate effects on soil microbial communities by inoculants for biocontrol, bioremediation or other purposes, but could also be applied for biosafety assessment of compounds like pesticides, or genetically engineered plants. A statistical method was developed to test for equivalence of microbial communities analysed by next generation sequencing of amplicons. The test uses Bray‐Curtis distances between the microbial community structures and is based on a two‐sample jackknife procedure. This approach was applied to investigate putative effects of the antifungal biocontrol strain RU47 on fungal communities in three arable soils which were analysed by high‐throughput ITS amplicon sequencing.
    Keywords: Antifungal Agents – Analysis ; Biosafety – Analysis ; Bioremediation – Analysis ; Soil Microbiology – Analysis ; Genetic Engineering – Analysis ; Soils – Analysis ; Genetically Modified Organisms – Analysis ; Biological Pest Control – Analysis;
    ISSN: 1751-7915
    E-ISSN: 1751-7915
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Frontiers in microbiology, 2014, Vol.5, pp.144
    Description: The complex and enormous diversity of microorganisms associated with plant roots is important for plant health and growth and is shaped by numerous factors. This study aimed to unravel the effects of the soil type on bacterial communities in the rhizosphere of field-grown lettuce. We used an experimental plot system with three different soil types that were stored at the same site for 10 years under the same agricultural management to reveal differences directly linked to the soil type and not influenced by other factors such as climate or cropping history. Bulk soil and rhizosphere samples were collected 3 and 7 weeks after planting. The analysis of 16S rRNA gene fragments amplified from total community DNA by denaturing gradient gel electrophoresis and pyrosequencing revealed soil type dependent differences in the bacterial community structure of the bulk soils and the corresponding rhizospheres. The rhizosphere effect differed depending on the soil type and the plant growth developmental stage. Despite the soil type dependent differences in the bacterial community composition several genera such as Sphingomonas, Rhizobium, Pseudomonas, and Variovorax were significantly increased in the rhizosphere of lettuce grown in all three soils. The number of rhizosphere responders was highest 3 weeks after planting. Interestingly, in the soil with the highest numbers of responders the highest shoot dry weights were observed. Heatmap analysis revealed that many dominant operational taxonomic units were shared among rhizosphere samples of lettuce grown in diluvial sand, alluvial loam, and loess loam and that only a subset was increased in relative abundance in the rhizosphere compared to the corresponding bulk soil. The findings of the study provide insights into the effect of soil types on the rhizosphere microbiome of lettuce.
    Keywords: 16s Rrna Gene Analysis ; Dgge ; Lactuca Sativa ; Bacterial Communities ; Pyrosequencing ; Rhizosphere Responders
    ISSN: 1664-302X
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages