Budahn, Holger

Marthe, Frank

Mosch, M.

Winter, H.

English

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S22 - POSTER -17Auxin signalling and homeostasis in Arabidopsisthaliana during Plasmodiophora brassicae infectionStefanie Mucha Cl). Sabine Bergmann 01. Linda Jahn (lJ(1) Te<hnische Univmital DresdenAuxin plays an essential role during plant growth anddevelopment In plant cells, the IAA signal is recognizedthrough two different types cf receptors. The first one,ABP1, is responsible for activation cf H"'"/ATPases leading toacidification, cell wall loosening and finally cell elongation.In the second signalling pathway IM binds to F-boxproteins, e.g. T1Rl, AFB1 and AFB2, which are part 01 anubiquitin ligase pathway that degrades AuxJIAA repressorproteins. This affects the expression cf auxin responsivegenes, among them members cf the GH3 family.ln additionto IM signalling. conjugation of rAA plays an importantrole during the regulation of auxin homeostasis. The GH3auxin conjugate synthetases remave active lAA from thetotal auxin pool and store it as amino acid conjugates. Weinvestigate the role of auxin signalling and conjugation inthe increased cell divisions and elongations taking placeduring the c1ubroot disease by expression analyses ofABP1,T1Rl, AFB2 and GH3s in Arabidopsis during the inlectionwith Plasmodiophora.lnfection tests with T4 0NA knockoutmutants for different GH3 genes show a higher susceptibilityagainst Plasmodiophora. In addition, experiments withselected promotor::GUS Hnes will examine the influence ofPlasmodiaphora on IAA homeostasis.S22 - POSTER -18Comparative study of monoculture and mixedculture of the green algae Ooeystis marsonii andthe cyanobacteria Microcystis aeruginosaSusanne Ounker (1), Christian Wilhelm (2)0) Plant Physiol09Y; (2) University of leipZigMany studies deal with the culture of two or more algalspecies for example to understand phytoplanktondynamics, to analyse ec0 4 toxicological effects or to optimisemass culture of algae. Promoted growth of one specie inphytoplankton community or a mixed culture of algae isstrongly dependent on light and/or nutrient usage butalso on the effect of info-chemicals. Therefore, the growthefficiency in a pluri-algal laboratory system can be studiedonly if the cell absorptivity is taken into account. Sincesmaller phytoplankton cells have a higher Chi a specificabsorption coefficient (all-Phy) and a larger cell surfacecomparing to volume, we have performed a study where thecompeting organisms had similar cell sizes to ensure equalamounts of photons in the culture. Furthermore, naturalChI a-concentration under replete nutrient conditions weresimulated to exclude as far as possible nutrient and lightlimitations. Interestingly, the study shows that growth ofthe Microcystis aeruginosa (cyanobacteria) squeezed outOocystis marsonii (green alga) and actually M. aeruginosagrew better in mixed culture as weil as in supernatant ofmixed culture than in mono-algal culture. With the useof a bio-optical-model we tried to quantify the involvedinhibiting effects.S22 - POSTER -1 gIron as a determinant of virulence and resistancein the Colletatriehum graminicola maizeinteractionfanghua Ye (1), Emad Albarouki (2), Holger Oeising (3), Nicolaus von Wiren (4)(l) Molecular Plant Nutrition, leibniz Institute ofPlant (jenetics and Crop Plant Research(IPK), Gatersleben, Germany; (2) Institute of Agricultural and Nlltritional Science5,Martin-luther·University Halle, Germany; (]) Institute of Agflcultural and NlitritionalSdence5, Martin-luther-University Halle; (4) Physiol09Y and (eil Biology, MolerularPlant Nutrition, leibniz Institute of Plant Gene!ics and (rop Plant Resealch (IPK),GatersJebenIran (Fe) is an essential element for any forms of Iife. In orderto overcome the low availability of Fe in hosts and to establishinfection, plant pathogens have developed multiple Feacquisition strategies. However, it is still unclear which plantFe pools are utilized by pathogens and how Fe is involvedin the plant immune system. The C. graminicola - maizesystem is used to uncover the plant resistance mechanismsand fungal virulence factors related to Fe. Our experimentsshowed that 3week-old (long-term) Fe-deficient maize plantsare more susceptible to C. graminicola than Fe-sufficientplants. Previous studies suggested that Fe deftciency canstrongly affeet the leaf structure of field-grown pear or peachby reduction of cuticle weight and soluble cuticular lipidswhich can play active roles in plant-pathogen interaetions.We are currently analyzing Fe nutritional dependent leafstructures and the components of cuticles and searchingfor a linkage between the change in Fe 4 dependent leafstrueture and susceptibility to pathogens. To minimize theeffect of changes in leaf strueture under Fe deficiency, we aredeveloping a short-term approach to assess the susceptibilityof excised leaves fed over night (short-term) with a range ofdifferent Fe binding forms.S22 - POSTER -20New resistances to blackleg (Leptosphaeriamaculans) transferred into Brassica napusHendrik Winter (1), Maja Mosch (1), Holger Budahn (2), Frank Marthe (2)(l) Technische Universitaet Dresden; (2) llllius Kuehn Institllte, Federal Research Centrefor Cultivated Plants, QuedlinburgBlackleg caused by Leptosphaeria maculans (Phomalingam) is the most significant disease affecting oilseedrape (Brassica napus) worldwide.To widen the narrowbase of oilseed rape resistance, offspring derived fromsomatic hybrids B. oferacea (+) B. nigra and B. oleraeea(+) B. carinata, respectively, are currently characterised anddeveloped towards the B. napus karyotype (genome AACC,2n=38).The focus of this study is on blackleg resistancebehaviour of selected selfing and backeross offspringproduced using embryo rescue techniques. Adult plantresistant individuals of different generations, along withsusceptible genotypes, were examined cytologically, e. g.by genomic in situ hybridisation (GISH). Furthermore, themost promising genotypes were self pollinated again andbackcrossed with B. napus to obtain resistant plants with anAACC background.Moreover, a complete set of nine disomicB. napus-Raphanus sativus addition lines (2n=3B""c+2.,Jhas been examined in blackleg resistance tests.GISH resultsare compared with those obtained earlier from blacklegresistant addition and putative recombination hnes derivedfrom interspecific, sexual hybrids between B. napus andSinapis arvensis, Coincya monensis and B. juncea,respectively.IBotanikertagung 201 1 1225

New resistances to blackleg (Leptosphaeria maculans) transferred into Brassica napus

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New resistances to blackleg (Leptosphaeria maculans) transferred into Brassica napus

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