VAAM-Jahrestagung 2012 18.–21. März in Tübingen

222growing all over the North, Central and East India in a variety of habitatsand soil types. The capability of native bacterial strains from root nodulesto behave as plant growth promoting bacteria and biocontrol agents wasinvestigated.Methodology: Isolation of root-nodule symbiont (Palnaippan et al., 2010)Basic characters of isolate (Palnaippan et al., 2010)Genomic DNA isolation, 16S rRNA amplification, 16S rRNA sequencing,Phylogeny and accession number (Palnaippan et al., 2010)Plant Growth Promoting Characters (Li et al., 2008)Antagonistic characters (Senthilkumar et al., 2009)Germination AssayResults: One strain (RCP6) over 21 isolates from the root nodules of C.purpurea were able to grow on Ashby`s N free media over sevensuccessive generation indicative of presumptive N 2-fixation, an IAAproducer, solubilised organic P from calcium phytate, able to release watersoluble inorganic phosphate from tri-calcium phosphate, di-calciumphosphate and zinc phosphate with organic acid production on MM9medium, show halo on ZnPo 4 tris-minimal media indicative of zincsolubilisation apart from zone on Aleksandrov`s medium exhibitingsolubilisation of potassium. Isolate had the capability to antagonizeMacrophomina phaseolina, Fusarium udum, F. oxysporum, F. solani,Rhizoctania solani, Sclerotinia sclerotiorum in dual culture as well as cellfreeculture filtrate but show no activity against Colletotrichum spp.Conventional identification tests, Hi-media Carbokit TM indicated thatRCP6 behaves like the Paenibacillus genus. Molecular identication by16S rRNA sequence analysis identified the strain as Paenibacilluspolymyxa. The 1492 base pair sequence of P. polymyxa RCP6(GU369972) showed maximum similarity to P. polymyxa IAM 13419T(D16276). Strain also showed the ability to improve early vegetativegrowth of C. purpurea in germination assay.Conclusion: This study disclosed features of Plant growth promoting andantagonistic strain P.polymyxa RCP6 that deserve further studies aimed atconfirming its importance as a putative endophyte.Palaniappan, P., Chauhan, P. S., Saravanan, V. S., Anandham, R. and Sa, T.-M. (2010). Isolationand characterization of plant growth promoting endophytic bacterial isolates from root noduleofLespedezasp.Biol.Fert.Soil. 46: 807-816.Li, J. H., Wang, E. T., Chen, W. F. and Chen, W. X. (2008). Genetic diversity and potential forpromotion of plant growth detected in nodule endophytic bacteria of soybean grown inHeliongjiang province of China.Soil.Biol.Biochem. 40: 238-246.Senthilkumar, M., Govindasamy, V. and Annapurna, K. (2007). Role of antibiosis in suppression ofcharcoal rot disease by soybean endophytePaenibacillussp. HKA-15.Curr.Microbiol. 55: 25-29.SMP036Competition between subalpine plants and microbes fornitrogen under different redox conditions and nitrogenfertilization regimes - a greenhouse approachE.-M. Kastl* 1 , S. Gschwendtner 2 , J.C. Munch 2 , M. Schloter 11 Helmholtz Zentrum München, Research Unit Environmental Genomics,Neuherberg, Germany2 Technische Universität München, Chair of soil ecology, Neuherberg, GermanyNatural grasslands are important hotspots for biodiversity and otherecosystem services of soils. The gramineous species of these naturalgrasslands differ greatly in nitrogen uptake strategies: Whereasexploitative plants need high amounts of nitrogen compounds for growing,conservative plants require lower amounts. So far, the influence of plantnitrogen uptake strategies on microbial community is largely unknown.However, it can be hypothesized that the microbial rhizosphere communityof exploitative plants differ from that of conservative plants due to highcompetition between exploitative plants and microbes for availablenitrogen.The aim of this study was to investigate the microbial rhizospherecommunity of subalpine gramineous plants with different nitrogen uptakestrategies. Furthermore, the influence of low oxygen content due to highsoil water content was examined, as anoxic conditions are known to favourdenitrification processes and thus might facilitate microbes during thecompetition for nitrate. Therefore, a greenhouse experiment with Achilleamillefolium(exploitative), Bromus erectus (intermediary) and Brizamedia(conservative) was performed in sandy, nutrient poor soil. Plantsreceived 40 kg NH 4NO 3 ha -1 after 7 days and 60 kg NH 4NO 3 ha -1 after 21days of growth. After 28 days plants were sampled. The microbialrhizosphere community was investigated by quantification of functionalgenes involved in nitrification (bacterial and archaeal amoA) anddenitrification (nirK,nirS and nosZ) by real-time PCR. Soil ammonium andnitrate concentrations were determined. Furthermore potential enzymeactivities of nitrification and denitrification were analyzed. Thepresentation will give detailed results on the allocation pattern.SMP037Population analysis of iron depositing bacterial communitiesin technical water systemsJ. Schröder*, H. Danner, B. Braun, U. SzewzykTechnische Universität Berlin, Fachgebiet Umweltmikrobiologie, Berlin,GermanyThis subproject of the BMBF project „Antiocker“ focuses on theidentification and characterization of iron depositing bacteria under neutralpH. Iron bacteria have caused problems in water since the 19th century andthere have been many references to red water becoming undrinkablepresumably due to the growths of iron bacteria. The aim of this project isto identify the key bacteria which are involved in deposition of oxidizediron compounds. Their activity becomes a very important economicconcern as a result of the intense deposition of iron oxides in technicalwater systems. Examples are the processing of groundwater, drinkingwater production or operation of water wells. Therefore ochreous samplesfrom several technical water systems were examined to get an overview ofthe composition of the bacterial population.For this purpose, traditional cultivation techniques such as bacterialisolation and molecular methods like PCR-DGGE, FISH in combinationwith epifluorescence-and confocal laser scanning microscopy werecombined. The isolation of different iron precipitating bacteria has beensuccessful and their living conditions can be characterized now. In additionto that a 16S rDNA genomic clone library of seven different samples fromochreous water wells (opencast mine and well reactors) was generated. 384clones based on the 16S rDNA are available to make a molecularevolutionary analysis. Besides classical iron bacteria like Gallionella andLeptothrix, representatives of typical soil bacteria of the generaSphingomonas, Novosphingobium, Hyphomicrobium and Arthrobacterwere inside.Based on this data, different specific oligonucleotide probes and primerswill be developed for iron bacteria to detect them in their natural habitatand make a fast sample screening possible.SMP038Hydrolytic bacteria involved in degradation of plant biomassin the biogas processT. Köllmeier*, V.V. Zverlov, W.H. SchwarzTU München, Lehrstuhl für Mikrobiologie, Freising, GibraltarAs fossil energy supplies are on a decline, technologies that employregrowing resources have become of mutual interest. Biogas plants employsuch resources as substrate for microbial fermentation processes whichconverte the contained energy in the energy carrier biogas. Improvementof these processes is of general interest. The aim of this work is to getinsights into the composition of hydrolytic bacteria in biogas plants tooptimize the hydrolysis of lignocellulosic material. This leads to improvedmethan yield and increased efficiency of the biogas process. We focusedon the development of hydrolytic mixed cultures, their analysis and thedevelopment of monitoring methods to investigate the abundance ofhydrolytic bacteria in (inoculated) biogas fermenter. Another approach wasto purify cellulolytic cultures to investigate their capabilities.SMP039Selective transport of bacterial populations through thevadose zone during groundwater rechargeD. Dibbern* 1 , A. Schmalwasser 2 , K.U. Totsche 2 , T. Lueders 11 Helmholtz Center Munich, Institute of Groundwater Ecology, München,Germany2 University of Jena, Department of Hydrogeology, Jena, GermanyPlants introduce abundant carbon into soil, were it can be sequestered inmicrobial biomass and recalcitrant organic matter. However, proportionsof these pools can be relocated, by event-driven transport to deeper vadosezones and even to the groundwater during groundwater recharge, such asheavy rainfalls or after snowmelt. It is postulated that large fractions of thisefflux are biocolloids, or microbial biomass in specific. Relevant questionsare, whether only selected microbial populations are exported from topsoils and what is the fate of this biomass in deeper zones and groundwater.Is it merely a carbon input for subsurface microbial food webs or dotransported populations survive?Here, at an agricultural experimental field site, we analyzed thecomposition of mobile bacterial communities collected in seepage waterdirectly after recharge events at different depths (35 and 65 cm) andcompared it to the corresponding bacterial communities from soil andvadose depths. Using T-RFLP and high-throughput pyrotag sequencing,we reveal that top soil bacteria are washed out selectively, and that theirfate in deeper zones may be distinct, but taxon-specific. These findingsgreatly extend our understanding of the event-driven and organismic flowof carbon from soil into the subsurface.BIOspektrum | Tagungsband 2012