Publications by authors named "Silke Ruppel"

Background: Climate change and anthropogenic activities intensify salinity stress impacting significantly on plant productivity and biodiversity in agroecosystems. There are naturally salt-tolerant plants (halophytes) that can grow and withstand such harsh conditions. Halophytes have evolved along with their associated microbiota to adapt to hypersaline environments.

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The performance of two bio-inoculants either in single or in combined applications with organic fertilizer was tested to determine their effect on plant growth and yield under normal and unfavorable field conditions such as low pH value and low content of P. Arbuscular Mycorrhiza Fungi (AMF; three species of ) and the plant-growth-promoting bacterial strain were applied to barley in a two-year field experiment with different soil pH levels and available nutrients. Grain yield; contents of P, N, K, and Mg; and soil microbial parameters were measured.

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Soybean [ (L.) Merrill] cultivation is important for its dual role as rich source of dietary protein and soil fertility enhancer, but production is constrained by soil nutrient deficiencies. This is often resolved using chemical fertilizers that exert deleterious effects on the environment when applied in excess.

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Capturing the diverse microbiota from healthy and/or stress resilient plants for further preservation and transfer to unproductive and pathogen overloaded soils, might be a tool to restore disturbed plant-microbe interactions. Here, we introduce Aswan Pink Clay as a low-cost technology for capturing and storing the living root microbiota. Clay chips were incorporated into the growth milieu of barley plants and developed under gnotobiotic conditions, to capture and host the rhizospheric microbiota.

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Fungus-bacterium interactions are widespread, encompass multiple interaction types from mutualism to parasitism, and have been frequent targets for microbial inoculant development. In this study, using in vitro systems combined with confocal laser scanning microscopy and real-time quantitative PCR, we test whether the nitrogen-fixing bacterium can provide protection to the plant-beneficial fungus , which inhabits the rhizosphere and colonizes plants as an endophyte, from the fungus-feeding bacterium . We show that can protect fungal hyphae from bacterial feeding on solid agar medium, with probable mechanisms being quick hyphal colonization and biofilm formation.

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Plants are often challenged by multiple abiotic stresses simultaneously. The inoculation of beneficial bacteria is known to enhance plant growth under these stresses, such as phosphorus starvation or salt stress. Here, for the first time, we assessed the efficiency of selected beneficial bacterial strains in improving tomato plant growth to better cope with double stresses in salty and P-deficient soil conditions.

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The synergistic interaction between arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) can enhance growth and phosphorous uptake in plants. Since PSBs are well known hyphal colonizers we sought to understand this physical interaction and exploit it in order to design strategies for the application of a combined microbial inoculum. Phosphate-solubilizing bacteria strongly attached to the hyphae of Rhizoglomus irregulare were isolated using a two compartment system (root and hyphal compartments), which were separated by a nylon mesh through which AMF hyphae could pass but not plant roots.

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Salinity and phosphorus (P) deficiency are among the most serious soil factors constraining crop productivity. A proposed strategy for alleviating these stresses is supporting plants by inoculation with growth-promoting rhizobacteria (PGPR). Here, a comparison of the ability of two maize composite and two F1 hybrid varieties to tolerate a P deficiency in either a saline or a non-saline environment showed that the uptake of nutrients by all four entries was significantly reduced by the imposition of both soil salinity and P deficiency, and that their growth was compromised to a similar extent.

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Despite the benefits of bacterial endophytes, recent studies on the mostly Gram-negative bacteria lack of regard for formulation strategies. The encapsulation into biopolymeric materials such as amidated pectins hydrogels is a suitable alternative. Here, this research aimed at supporting the capability of the plant growth-promoting bacteria DSM16656 to endophytically colonize plant seedlings.

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High-throughput cultivation methods have recently been developed to accelerate the recovery of microorganisms reluctant to cultivation. They simulate environmental conditions for the isolation of environmental microbiota through the exchange of growth substrates during cultivation. Here, we introduce leaf-based culture media adopting the concept of the plant being the master architect of the composition of its microbial community.

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Kosakonia radicincitans is a species within the new genus Kosakonia. Many strains of this genus have been isolated from plants, but some strains are assumed to act as facultative human pathogens. In this study, an in-depth analysis of a Kosakonia isolate from human blood was performed.

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This study presents an anhydrobiotic engineering approach aiming at conferring a high degree of desiccation tolerance to the Gram-negative endophyte Kosakonia radicincitans. In particular, pre-conditioning of bacteria under high salinities provides a remarkable positive influence on drying survival. The endophytic bacteria accumulate exogenous hydroxyectoine > 500 µmol g dry weight cells exerted by osmotic stress at 4% NaCl.

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The recent introduction of plant-only-based culture media enabled cultivation of not-yet-cultured bacteria that exceed 90% of the plant microbiota communities. Here, we further prove the competence and challenge of such culture media, and further introduce "the inoculum-dependent culturing strategy, IDC". The strategy depends on direct inoculating plant serial dilutions onto plain water agar plates, allowing bacteria to grow only on the expense of natural nutrients contained in the administered inoculum.

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White asparagus is a high-value commodity of large economic importance in Germany. Its harvest period lasts only a limited part of the year, during which daily yield and also market demand are highly variable. Harvested asparagus is perishable; thus, quality control and shelf life must be ensured by proper handling, e.

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The plant phyllosphere is colonized by a complex ecosystem of microorganisms. Leaves of raw eaten vegetables and herbs are habitats for bacteria important not only to the host plant, but also to human health when ingested via meals. The aim of the current study was to determine the presence of putative probiotic bacteria in the phyllosphere of raw eaten produce.

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Gram-negative bacterial endophytes have attracted research interest caused by their advantageous over epiphytic bacteria in plant nutrition and protection. However, research on these typically Gram-negative endophytes has deficiencies concerning the role of cultivation and pre-formulation strategies on further plant colonisation capabilities. Besides, the influence of cultivation conditions and osmotic stress within bacterial endophytes on their phosphate solubilising ability has not yet been addressed.

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Type VI secretion systems and tailocins, two bacterial phage tail-like particles, have been reported to foster interbacterial competition. Both nanostructures enable their producer to kill other bacteria competing for the same ecological niche. Previously, type VI secretion systems and particularly R-type tailocins were considered highly specific, attacking a rather small range of competitors.

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Despite the great interest in using halophyte L. as a crop in extreme saline habitats, little is known about the role played by associated endophytic bacteria in increasing tolerance of the host-plant to nutrient deficiency. Main objectives of this study were to investigate the community composition of diazotrophic endophytes of grown under natural conditions, and determine the proportion of plant-growth promoting bacterial strains able to fix N.

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Improving cultivability of a wider range of bacterial and archaeal community members, living natively in natural environments and within plants, is a prerequisite to better understanding plant-microbiota interactions and their functions in such very complex systems. Sequencing, assembling, and annotation of pure microbial strain genomes provide higher quality data compared to environmental metagenome analyses, and can substantially improve gene and protein database information. Despite the comprehensive knowledge which already was gained using metagenomic and metatranscriptomic methods, there still exists a big gap in understanding microbial gene functioning , since many differentially expressed genes or gene families are not yet annotated.

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Natural control of phytopathogenic microorganisms is assumed as a priority function of the commensal plant microbiota. In this study, the suitability of fluorescent pseudomonads in the phyllosphere of crop plants as natural control agents was evaluated. Under field conditions, ears of winter wheat were found to be colonized with high consistency and at a high density by pseudomonads at the late milk dough stage.

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Bacteria, which establish positive interactions with plant roots, play a key role in agricultural environments and are promising for their potential use in sustainable agriculture. Many of these mutualistic bacteria provide benefits to plant hosts by facilitating soil mineral nutrient uptake, protecting plants from biotic and abiotic stresses and producing substances that promote growth. The dataset presented here, is related to the publication entitled "Community structure and plant growth-promoting potential of cultivable bacteria isolated from Cameroon soil" (Tchuisseu et al.

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The recent worldwide discovery of plant growth-promoting (PGP) in a large variety of crop plants suggests that this species confers significant influence on plants, both in terms of yield increase and product quality improvement. We provide a comparative genome analysis which helps to unravel the genetic basis for motility, competitiveness and plant growth-promoting capacities. We discovered that carries multiple copies of complex gene clusters, among them two flagellar systems and three type VI secretion systems (T6SSs).

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The rapid development of high-throughput techniques and expansion of bacterial databases have accelerated efforts to bring plant microbiomes into cultivation. We introduced plant-only-based culture media as a successful candidate to mimic the nutritional matrices of plant roots. We herein employed a G3 PhyloChip microarray to meticulously characterize the culture-dependent and -independent bacterial communities of the maize root compartments, the endo- and ecto-rhizospheres.

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This study demonstrates that the application of the PGPB strain, Kosakonia radicincitans enhances a plant's resistance against phloem-feeding and chewing insects in Arabidopsis thaliana. The plant growth-promoting bacterial strain K. radicincitans DSM 16656 applied to A.

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