Multiple alleles for resistance and susceptibility modulate the defense response in the interaction of tetraploid potato (Solanum tuberosum) with Synchytrium endobioticum pathotypes 1, 2, 6 and 18

The obligate biotrophic, soil-borne fungus Synchytrium endobioticum causes wart disease of potato (Solanum tuberosum), which is a serious problem for crop production in countries with moderate climates. S. endobioticum induces hypertrophic cell divisions in plant host tissues leading to the formation of tumor-like structures. Potato wart is a quarantine disease and chemical control is not possible. From 38 S. endobioticum pathotypes occurring in Europe, pathotypes 1, 2, 6 and 18 are the most relevant. Genetic resistance to wart is available but only few current potato varieties are resistant to all four pathotypes. The phenotypic evaluation of wart resistance is laborious, time-consuming and sometimes ambiguous, which makes breeding for resistance difficult. Molecular markers diagnostic for genes for resistance to S. endobioticum pathotypes 1, 2, 6 and 18 would greatly facilitate the selection of new, resistant cultivars. Two tetraploid half-sib families (266 individuals) segregating for resistance to S. endobioticum pathotypes 1, 2, 6 and 18 were produced by crossing a resistant genotype with two different susceptible ones. The families were scored for five different wart resistance phenotypes. The distribution of mean resistance scores was quantitative in both families. Resistance to pathotypes 2, 6 and 18 was correlated and independent from resistance to pathotype 1. DNA pools were constructed from the most resistant and most susceptible individuals and screened with genome wide simple sequence repeat (SSR), inverted simple sequence region (ISSR) and randomly amplified polymorphic DNA (RAPD) markers. Bulked segregant analysis identified three SSR markers that were linked to wart resistance loci (Sen). Sen1-XI on chromosome XI conferred partial resistance to pathotype 1, Sen18-IX on chromosome IX to pathotype 18 and Sen2/6/18-I on chromosome I to pathotypes 2,6 and 18. Additional genotyping with 191 single nucleotide polymorphism (SNP) markers confirmed the localization of the Sen loci. Thirty-three SNP markers linked to the Sen loci permitted the dissection of Sen alleles that increased or decreased resistance to wart. The alleles were inherited from both the resistant and susceptible parents

The system methane-water as a geologic thermometer and barometer from the external part of the Central Alps

Fluid inclusion studies from syncinematic quartz crystals gave new insights into the fluid composition and P-T distribution of the external part of the Central Alps. Knowing the densities of methane and the minimum temperature of formation, fluid inclusions of the system CH4-H2O and CH4 have been used as geothermometers and barometers. For the regional distribution the following conclusions can be drawn : 1. Fluids trapped in inclusions define zones of different fluid composition related to the zones of metamorphism : — non-metamorphic zone : > 1 mol-% higher hydrocarbons, CH4, H2O, CO2, ... — low and medium grade anchizone : CH4, < 1 mol-% higher hydrocarbons, H2O, CO2, ... — high grade anchizone and epimetamorphic zone : H2O, CO2, ... 2. The minimum conditions of formation for mineral clefts and their quartz crystals from the low and medium grade anchizone are 200-270° C — 1,200-1,700 bar, with geothermal gradients of 25-45° C/km. 3. From the fluid inclusion studies the following minimum P-T conditions were deduced with respect to metamorphic grade : — non-metamorphic zone — low grade anchizone : T > 200° C — P > 1,200 bar — medium grade anchizone — high grade anchizone : T > 270° C — P > 1,700 bar 4. The evolution of the fluids is a product of the progressive metamorphism. But the fluids were trapped in quartz crystals towards the end of the nappe overthrust and during the uplift of the Alps (middle to final Miocene era). As rocks with fluid inclusions of higher grade metamorphism are found above rocks with fluid inclusions of lower grade metamorphism, their metamorphism must have taken place before the final transport of the nappes.L'étude des inclusions fluides des cristaux de quartz syncinématiques donne un éclairage nouveau sur la composition des fluides et la distribution des températures et des pressions dans la région externe des Alpes centrales. A partir de la densité du méthane et des températures minimales de formation, les inclusions fluides des systèmes CH4-H2O et CH4 ont été utilisées comme thermomètres et baromètres. Les conclusions suivantes peuvent être tirées à l'échelle régionale : 1. Les fluides piégés dans les inclusions définissent des zones dont la composition varie suivant les zones métamorphiques : — zone non métamorphique : > 1 mole % hydrocarbures plus lourds que le méthane, CH4, H2O, CO2,... — anchizone supérieure et moyenne : CH4, < x mole % hvdrocarbures plus lourds que le méthane H2O, CO2, ... — anchizone profonde et épizone : H2O, CO2, ... 2. Les conditions minimales de formation des fentes à minéraux et de leurs cristaux de quartz sont pour l'anchizone supérieure et moyenne : 200-270° C — 1 200-1 700 bars, avec des gradients géothermiques de 25-45° C/km. 3. A partir de l'étude des inclusions fluides, les conditions minimales de température et pression suivantes ont été trouvées pour le métamorphisme : — transition entre zone non métamorphique et anchizone supérieure : T > 200° C — P > 1 200 bars — transition entre anchizone moyenne et anchizone profonde : T > 270° C — P > 1 700 bars 4. L'évolution des fluides est un produit du métamorphisme progressif. Les fluides ont été piégés dans les cristaux de quartz à. la fin du charriage des nappes et durant la surrection des Alpes (Miocène moyen à terminal). Comme des unités tectoniques contenant des fluides de métamorphisme plus intense se trouvent au-dessus d'unités tectoniques contenant des fluides de métamorphisme plus faible, on en déduit que le métamorphisme des unités transportées s'est produit avant la mise en place finale des nappes.Mullis Josef. The system methane-water as a geologic thermometer and barometer from the external part of the Central Alps. In: Bulletin de Minéralogie, volume 102, 5-6, 1979. Minéraux et minerais

The first petrographic characterisation of a prehistoric rock crystal mine in the Swiss Alps

Abstract Over the past decades, there has been increasing evidence for the prehistoric use of rock crystal in mountainous environments, including craft specialisation and long-distance exchange. Yet there are only a few known sites where the mineral was quarried in sustainable quantities. One of them is situated near Fiescheralp in the Upper Valais (Switzerland) and dates to the Early Mesolithic and a final stage of the Neolithic. Here we present the first petrographic characterisation of a prehistoric rock crystal mine in the Swiss Alps, involving a combination of different methods. The article provides a detailed description of the fluid inclusions within the quartz crystals and an overview over the related mineral paragenesis. This gives interesting new insights into the formation of the analysed fissure and allows comparing rock crystal artefacts found in other archaeological sites to this particular source. The results form the basis for further investigations concerning the circulation and distribution of the raw material in the past

Reconnaissance par microspectrométrie Raman, dans les inclusions fluides, de H2S et CO2 solides à domaine de fusion comparable

In fluid inclusions from Lastourville (Gabon), Col d'Allos (France), Perry County (USA) and Val d'Illiez (Switzerland), melting of a solid phase was observed between —92 °C and —103 °C. Identification by Raman microspectrometry shows these phases are solid CO2 or solid H2S. These spectroscopic determinations are necessary for interpretations of microthermometric measurements.Dans des inclusions fluides de Lastourville (Gabon), du Col d'Allos (France), de Perry County (USA) et du Val d'Illiez (Suisse) la fusion d'un solide a été observée entre —92 °C et — 103 °C. Par microspectrométrie Raman, ces solides ont été identifiés comme étant soit CO2 solide, soit H2S solide. Ces caractérisations spectroscopiques sont essentielles pour l'interprétation des mesures microthermométriques.Dubessy Jean, Guilhaumou Nicole, Mullis Josef, Pagel Maurice. Reconnaissance par microspectrométrie Raman, dans les inclusions fluides, de H2S et CO2 solides à domaine de fusion comparable. In: Bulletin de Minéralogie, volume 107, 2, 1984. Inclusions fluides

Mesures quantitatives de Composition, Pression et Densité des Microvolumes des Mélanges de gaz de CO2-N2 par Spectroscopie Raman

International audienceQuantitative analysis of gases by Raman spectroscopy is based on relative Raman scattering cross-sections (RRSCS) and the evolution of different spectral parameters (peak position, peak area, peak intensity, etc.). However, most of the calibration data were established at low pressure (low density) and without evaluating the effect of the composition. Using these data may lead to considerable errors, especially when applied to gas mixtures at high pressure as found in natural fluid inclusions. The aim of this study is to reevaluate the RRSCS of CO 2 and to establish new calibration data based on the variation of CO 2 Fermi diad splitting as a function of pressure (density) and composition over a pressure range of 5 to 600 bars at 22 and 32 °C. A high-pressure optical cell system (HPOC) and a heating-cooling stage were used for Raman in-situ analyses at controlled PTX conditions. Our experimental results show that the RRSCS of CO 2 varies slightly with pressure but can be considered constant over the studied pressure range. It can be used to measure the proportion of CO 2 in gas mixtures with an uncertainty of about ± 0.5 mol%. Different polynomial equations were provided to calculate pressure and density of CO 2-N 2 gas mixtures with an uncertainty of ± 20 bar or 0.01 g.cm-3. A comparison of PVTX properties of natural CO 2-N 2 fluid inclusions hosted in quartz from the Central Alps (Switzerland) obtained by Raman measurement and as derived from phase transition temperatures by microthermometry experiments shows comparable values