A5010344664- Legume Nitrogen Fixing Symbiosis
- Plant-Microbe Interactions and Immunity
- Microbial Community Ecology and Physiology
- Nematode management and characterization studies
- Genomics and Phylogenetic Studies
- Agronomic Practices and Intercropping Systems
- Agricultural pest management studies
- Plant nutrient uptake and metabolism
- Wastewater Treatment and Nitrogen Removal
- Plant Pathogens and Fungal Diseases
- Protist diversity and phylogeny
- Biofuel production and bioconversion
- Plant Pathogenic Bacteria Studies
- Coastal wetland ecosystem dynamics
- Photosynthetic Processes and Mechanisms
- Soil Carbon and Nitrogen Dynamics
- Algal biology and biofuel production
- Metalloenzymes and iron-sulfur proteins
- Microbial Metabolic Engineering and Bioproduction
- Mycorrhizal Fungi and Plant Interactions
- Microbial Fuel Cells and Bioremediation
- Plant and fungal interactions
- Plant tissue culture and regeneration
- Rice Cultivation and Yield Improvement
- Plant Disease Resistance and Genetics
University of Bremen
2016-2025
Stellenbosch University
2018
Saarland University
2017
GTx (United States)
1999-2007
Max Planck Institute for Terrestrial Microbiology
1995-2005
China Agricultural University
2002
Estación Experimental del Zaidín
2002
Max Planck Society
1998-2000
Plant Industry
1994
Commonwealth Scientific and Industrial Research Organisation
1994
Roots are the primary site of interaction between plants and microorganisms. To meet food demands in changing climates, improved yields stress resistance increasingly important, stimulating efforts to identify factors that affect plant productivity. The role bacterial endophytes reside inside remains largely unexplored, because analysis their specific functions is impeded by difficulties cultivating most prokaryotes. Here, we present first metagenomic approach analyze an endophytic community...
Summary Ammonia‐oxidizing archaea (AOA) play an important role in nitrification and many studies exploit their amoA genes as marker for diversity abundance. We present archaeal consensus phylogeny based on all publicly available sequences (status June 2010) provide evidence the diversification of AOA into four previously recognized clusters one newly identified major cluster. These clusters, which we suggest a new nomenclature, harboured 83 species‐level OTU (using inferred species threshold...
The invasive properties of Azoarcus sp. strain BH72, an endorhizospheric isolate Kallar grass, on gnotobiotically grown seedlings Oryza sativa IR36 and Leptochloa fusca (L.) Kunth were studied. Additionally, spp. localized in roots field-grown grass. To facilitate localization to assure identity bacteria, genetically engineered microorganisms expressing beta-glucuronidase also used as inocula. beta-Glucuronidase staining indicated that the apical region root behind meristem was most...
Burkholderia phytofirmans PsJN is a naturally occurring plant-associated bacterial endophyte that effectively colonizes wide range of plants and stimulates their growth vitality. Here we analyze whole genomes, eight other endophytic bacteria. This study illustrates spectrum life styles exists. Although postulate the existence typical traits, no unique gene cluster could be exclusively linked to lifestyle. Furthermore, our revealed high genetic diversity among endophytes as reflected in...
Six closely related N2-fixing bacterial strains were isolated from surface-sterilized roots and stems of four different rice varieties. The identified as Serratia marcescens by 16S rRNA gene analysis. One strain, IRBG500, chosen for further analysis showed acetylene reduction activity (ARA) only when inoculated into media containing low levels fixed nitrogen (yeast extract). Diazotrophy IRBG500 was confirmed measurement 15N2 incorporation sequence the PCR-amplified fragment nifH. To examine...
Among the nitrogen-fixing bacteria associated with roots of Leptochloa fusca (L.) Kunth in saline-sodic soils Punjab Pakistan, we repeatedly found yellow-pigmented, straight to curved, gram-negative rods. To group and identify these organisms, examined morphological, nutritional, biochemical features performed polyacrylamide gel electrophoretic analyses cellular proteins, gas chromatographic fatty acids, DNA-rRNA hybridizations, DNA-DNA hybridizations. Our results showed that 11 isolates...
The extent to which the N 2 -fixing bacterial endophyte Azoarcus sp. strain BH72 in rhizosphere of Kallar grass can provide fixed nitrogen plant was assessed by evaluating inoculated plants grown greenhouse and uninoculated taken from natural environment. inoculum consisted either wild-type bacteria or nifK¯ mutant BHNKD4. In -deficient conditions, with (N test plants) grew better accumulated more a lower δ 15 signature after 8 months than did (non-N control plants). Polyadenylated...
Azoarcus sp. strain BH72, a mutualistic endophyte of rice and other grasses, is agrobiotechnological interest because it supplies biologically fixed nitrogen to its host colonizes plants in remarkably high numbers without eliciting disease symptoms. The complete genome sequence 4,376,040-bp long contains 3,992 predicted protein-coding sequences. Genome comparison with the Azoarcus-related soil bacterium EbN1 revealed surprisingly low degree synteny. Coding sequences involved synthesis...
In this study, the effects of plant genotype, soil type and nutrient use efficiency on composition different bacterial communities associated with rice roots were investigated. Thus, total bacteria, Alpha- Betaproteobacteria, Pseudomonas Actinobacteria studied using PCR, followed by denaturing gradient gel electrophoresis (PCR-DGGE). Rice genotype determined, to a large extent, across cultivars. Several cultivars belonging Oryza sativa ssp. indica tended select similar communities, whereas...
Adherence of bacteria to eukaryotic cells is essential for the initiation infection in many animal and human pathogens, e.g. Neisseria gonorrhoeae Pseudomonas aeruginosa . Adhesion‐mediating type IV pili, filamentous surface appendages formed by pilin subunits, are crucial virulence factors. Here, we report that pilus‐dependent adhesion also involved plant–bacteria fungus–bacteria interactions. Nitrogen‐fixing, endophytic bacteria, Azoarcus sp., can infect roots rice spread systemically into...
Summary Terminal restriction fragment length polymorphism (T‐RFLP) analysis of PCR‐amplified nitrogenase gene ( nifH ) fragments is a rapid technique for profiling diazotrophic microbial communities without the necessity cultures study. Here, we examined impact N‐fertilization, plant genotype and environmental conditions on populations in association with roots rice Oryza species) by T‐RFLP community found marked effects composition community. We change population structure within 15 days...
The nitrogen-fixing endophyte Azoarcus sp. strain BH72 infects roots of Kallar grass and rice inter- intra-cellularly can spread systemically into shoots without causing symptoms plant disease. Although cellulose or its breakdown products do not support growth, this expresses an endoglucanase, which might be involved in infection. Sequence analysis eglA places the secreted 34-kDa protein glycosyl hydrolases family 5, with highest relatedness (40% identity) to endoglucanases phytopathogenic...
Marama bean (Tylosema esculentum) is an indigenous non-nodulating legume to the arid agro-ecological parts of Southern Africa. It a staple food for Khoisan and Bantu people from these areas. intriguing how it able synthesize high-protein content in seeds since its natural habitat nitrogen deficient. The aim study was determine presence seed transmittable bacterial endophytes that may have growth promoting effects, which be particularly important harsh conditions. were surface sterilized...
Comparative 16S rRNA gene sequence analysis and major physiological differences indicate two distinct sublineages within the genus Azoarcus: Azoarcus evansii lineage, comprising Azoarcusevansii (type strain KB740T=DSM 6898T=CIP 109473T=NBRC 107771T), Azoarcusbuckelii U120T=DSM 14744T=LMG 26916T), Azoarcusanaerobius LuFRes1T=DSM 12081T=LMG 30943T), Azoarcustolulyticus Tol-4T=ATCC 51758T=CIP 109470T), Azoarcustoluvorans Td21T=ATCC 700604T=DSM 15124T) Azoarcustoluclasticus MF63T=ATCC 700605T),...
Several diazotrophic species of Azoarcus spp. occur as endophytes in the pioneer plant Kallar grass. The purpose this study was to screen Asian wild rice and cultivated Oryza sativa varieties for natural association with these endophytes. Populations culturable diazotrophs surface‐sterilized roots were characterized by 16S rDNA sequence analysis, identified genomic fingerprints. A. indigens sp. group C detected only rarely, whereas D occurred frequently samples flooded plants: 75% rice, 80%...
Transcriptional fusions of gusA and gfp to the nifH gene as well immunogold labeling with antibodies against iron protein nitrogenase revealed high expression levels endophyte Azoarcus sp. strain BH72 inside infected rice roots (Oryza sativa) in laboratory. Thus, environmental conditions are permissive for endophytic nitrogen fixation bacterial microcolonies aerenchyma.
The taxonomic structure of members the genus Azoarcus sensu lato was reassessed in a polyphasic approach. Two species, communis and indigens, three unnamed species containing diazotrophs associated with Kallar grass roots (groups C, D) group strains (E) isolated from fungi were analysed. They compared by PAGE analyses cellular proteins, genomic fingerprints, morphological nutritional features to new isolates rice roots. All within groups D E 5-12 showed group-specific cell colony morphology...
Abstract Nitrogen-fixing bacteria colonize the roots of many gramineous plants from different geographic regions. The discovery that diazotrophs can be isolated surface-sterilized or other plant material led to studies their potential inhabit tissue. For some diazotrophs, endophytic character has been documented. This review summarizes current methods identify endophytes and characterize colonization by bacteria. Taxonomy, occurrence, diversity, mechanisms infection Azoarcus spp. is...
The endophyte Azoarcus sp. strain BH72 expresses nitrogenase (nif) genes inside rice roots. We applied a proteomic approach to dissect responses of roots toward bacterial colonization and jasmonic acid (JA) treatment. Two sister lineages Oryza sativa were analyzed with cv. IR42 showing less compatible interaction the resulting in slight root browning whereas IR36 was successfully colonized as determined by nifH::gusA activity. External addition JA inhibited caused contrast ethylene, ethephon...