Interspecific rDNA restriction fragment length polymorphism in Globodera species, parasites of Solanaceous plants

Le statut d'espèce au sein des #Globodera parasites des Solanacées est encore mal défini dû au faible polymorphisme morphologique détectable. Deux oligomères de 21 bases sont utilisés comme amorces pour amplifier la région non codante des ADN ribosomiques : "Internal Transcribed Spacers" (ITS) par réaction de polymérisation en chaîne (PCR). Le produit d'amplification obtenu mesure 1,2 Kb dans chacune des 26 populations étudiées. Trente-et-un enzymes de restriction sont testés sur les ITS pour la longueur des fragments de restriction; douze ont révélé du polymorphisme. Ces RFLP sont analysés, les distances génétiques sont calculées et un dendrogramme comportant quatre groupes est produit. Le polymorphisme intraspécifique est pratiquement inexistant; cependant le polymorphisme interspécifique apparaît clairement et permet une différenciation aisée des espèces. Les quatre groupes révélés correspondent aux groupes #G. tabacum sensu lato, #G. rostochiensis, #G. pallida et #G. "mexicana". Ces résultats confèrent un statut d'espèce à #G. "mexicana" dont l'identité génétique est peu précise. Ces résultats sont comparés à ceux des hybridations et aux résultats d'électrophorèse bidimensionnelle obtenus. Le séquençage des ITS a été réalisé pour rechercher un éventuel polymorphisme intraspécifique. La comparaison des séquences des ITS de trois populations de #G. rostochiensis et de cinq #Heterodera est réalisée puis comparée à la séquence publiée de #Caenorhabditis elegans$. (Résumé d'auteur

Intra- and interspecific variability in Globodera, parasites of Solanaceous plants, revealed by Random Amplified Polymorphic DNA (RAPD) and correlation with biological features

La variabilité inter et intraspécifique de #Globodera parasites des Solanacées est évaluée par leurs gammes d'hôtes et leurs profils RAPD. Divers espèces et cultivars de tabac sont testés vis-à-vis de #Globodera tabacum sensu lato et de #G. "mexicana". les profils RAPD sont étudiés sur 26 populations appartenant aux six espèces (publiées ou non) de #Globodera. De fortes différences dans la gamme d'hôtes permettent de classer les populations en groupes de virulence. Huit amorces Operon de dix bases (OPG-1, OPG-2, OPG-3, OPG-4, OPG-5, OPL-3, OPL-4, OPL-6) permettent d'identifier 222 marqueurs RAPD. Divers programmes d'analyses en grappes et en composante principale sont réalisés en utilisant ces marqueurs, avec de très faibles différences de classification entre programmes. Les dendrogrammes obtenus montrent l'existence de quatres unités taxinomiques, à savoir #G. rostochiensis, #G. pallida, #G. tabacum et #G. "mexicana". Ils sont semblables à ceux obtenus précédemmenet avec l'analyse de restriction des ITS. Ils révèlent des apparentements congruents avec ceux déterminés par la gamme d'hôtes et non contradictoires avec les barrières génétiques précédemment mises en évidence par les hybridations in vitro. (Résumé d'auteur

Real root finding for equivariant semi-algebraic systems

Let $R$ be a real closed field. We consider basic semi-algebraic sets defined by $n$-variate equations/inequalities of $s$ symmetric polynomials and an equivariant family of polynomials, all of them of degree bounded by $2d < n$. Such a semi-algebraic set is invariant by the action of the symmetric group. We show that such a set is either empty or it contains a point with at most $2d-1$ distinct coordinates. Combining this geometric result with efficient algorithms for real root finding (based on the critical point method), one can decide the emptiness of basic semi-algebraic sets defined by $s$ polynomials of degree $d$ in time $(sn)^{O(d)}$. This improves the state-of-the-art which is exponential in $n$. When the variables $x_1, \ldots, x_n$ are quantified and the coefficients of the input system depend on parameters $y_1, \ldots, y_t$, one also demonstrates that the corresponding one-block quantifier elimination problem can be solved in time $(sn)^{O(dt)}$

Grape variety affects larval performance and also female reproductive performance of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae)

For insect herbivores, the quality of the larval host plant is a key determinant of fitness. Therefore, insect populations are supposed to be positively correlated with the nutritional quality of their host plant. This study aimed to determine if and how different varieties of grapes (including the wild grape Lambrusque) affect both larval and adult performance of the polyphagous European grapevine moth Lobesia botrana (Denis & Schiffermüller). Significant differences were found in larval development time, but not in pupal mass, adult emergence rate, or sex ratio. Although the fecundity of females is not different among varieties, females fed on some varieties produced eggs of different sizes which are correlated to their fertility. Thus, females adapt resource allocation to eggs depending on their diet as larvae. Using a fitness index, the average reproductive output was found to be highest for females reared on cv. Chardonnay. Females reared on wild grape produced a fitness index identical to the cultivated grapes. However, Lambrusque and Gewurztraminer separate themselves from the cultivated varieties according to our discriminant analyses. It is emphasized, through this study, that cultivars fed on by larvae should be considered in the population dynamics of L. botrana and that egg number is insufficient to determine host plant qualit

Indigenous strains of Beauveria and Metharizium as potential biological control agents against the invasive hornet Vespa velutina

Alien species often miss parasites in their invaded area, and this is the case in Vespa velutina. This invasive hornet predator of bees was accidentally introduced in Europe from East China in 2004. The control of this species is still problematic. Indeed to destroy nests, applicators currently use large spectrum insecticides, which is too costly or dangerous to applicators and also to the environment, affecting non-targeted arthropods (one period). Studying the potential interest of biological control methods may help to propose alternatives in V. velutina control. We present here the bioassays in which we assessed the potential control efficiency of different indigenous French isolates of entomopathogenic fungi. We inoculated adults V. velutina by different ways: being directly, by walking on a contaminated surface, in the food, or by inter-individual transfers. We tested differences between the isolates and the application methods using two parameters mortality and LT50. The direct inoculation method was the most efficient modality, then the contact, transfer and food. Considering all contamination methods, there was no difference on susceptibility or mortality among different isolates. Still the LT50 was quite short in all isolates (average 5.8 ± 0.44d), and their virulence was quite high: we conclude that there is high potential in using such entomopathogens as a biological control agent against V. velutina.Fil: Poidatz, J.. Institut National de la Recherche Agronomique; FranciaFil: López Plantey, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Thiéry, D.. Institut National de la Recherche Agronomique; Franci

Résultats de croisements entre Globodera pallida stone et G. "mexicana" Campos-Vela : héritabilité du développement sur pomme de terre et notion d'espèce

Chez la pomme de terre, les juvéniles de #Globodera "mexicana" n'induisent pas de syncytium. Des hybridations de cinq populations de #G. "mexicana" et de deux populations de #G. pallida sont réalisées in vitro et les hybrides directs et les résultats de divers croisements en retour sont étudiés sur pomme de terre et sur tomate. Tous les hybrides F1 héritent de la capacité à induire des syncytia chez la pomme de terre. Selon le parent femelle #G. pallida utilisé, ces syncytia permettent le développement de mâles et de femelles ou seulement de mâles. Dans ce dernier cas, la capacité à produire des femelles apparaît progressivement après croisement en retour successifs sur femelle #G. pallida. L'incompatibilité cytoplasmique dépend également des couples utilisés. Avec #G. pallida Pa 1 Duddingston, cette incompatibilité est très atténuée. En fonction de ces résultats, la notion d'espèce et de coenospecies est discutée. (Résumé d'auteur

Exploration of finite dimensional Kac algebras and lattices of intermediate subfactors of irreducible inclusions

We study the four infinite families KA(n), KB(n), KD(n), KQ(n) of finite dimensional Hopf (in fact Kac) algebras constructed respectively by A. Masuoka and L. Vainerman: isomorphisms, automorphism groups, self-duality, lattices of coideal subalgebras. We reduce the study to KD(n) by proving that the others are isomorphic to KD(n), its dual, or an index 2 subalgebra of KD(2n). We derive many examples of lattices of intermediate subfactors of the inclusions of depth 2 associated to those Kac algebras, as well as the corresponding principal graphs, which is the original motivation. Along the way, we extend some general results on the Galois correspondence for depth 2 inclusions, and develop some tools and algorithms for the study of twisted group algebras and their lattices of coideal subalgebras. This research was driven by heavy computer exploration, whose tools and methodology we further describe.Comment: v1: 84 pages, 13 figures, submitted. v2: 94 pages, 15 figures, added connections with Masuoka's families KA and KB, description of K3 in KD(n), lattices for KD(8) and KD(15). v3: 93 pages, 15 figures, proven lattice for KD(6), misc improvements, accepted for publication in Journal of Algebra and Its Application

The Crustacean Fauna (Branchiopoda, Copepoda) of Shallow Freshwater Bodies in Iceland

A survey of shallow freshwaters of Iceland was conducted in June and July 1996. The 34 stations prospected were rainpools, ditches, wetlands. The composition of their crustacean communities, investigated by qualitative net samples, is discussed in relation to water characteristics. One notostracan, Lepidurus arcticus (Pallas, 1793), 17 cladoceran species (5 Daphniidae, 10 Chydoridae, 1 Macrothricidae, 1 Polyphemidae), and 12 copepods (2 Diaptomidae, 7 Cyclopidae, 3 Canthocamptidae) were identified. Two species are reported for the first time from Iceland: the diaptomid Diaptomus (Chaetodiaptomus) rostripes Herbst, 1955 and the chydorid Alona rustica Scott, 1895. Taxonomical comments about different species are added, and their ecological pecularities are given. The species richness as well as the biogeographical features of the freshwater zooplankton of Iceland are discussed in relation to neighbouring Greenland and Northern Europe.Обследование мелких пресных водоемов Исландии проведено в июне-июле 1996 г. Материал собирался в дождевых и талых лужах, канавах, болотах. Среди 30 обнаруженных видов отмечены 1 вид щитней Lepidurus arcticus (Pallas, 1793), 17 видов ветвистоусых ракообразных (5 представителей сем. Daphnidae, 10 Chydoridae, 1 Macrothricidae, 1 Polyphemidae), 12 видов веслоногих ракобразных (2 вида сем. Diaptomidae, 7 Cyclopidae, 3 Canthocamptidae). Два вида указаны впервые для фауны Исландии: Diaptomus (Chaetodiatomus) rostripes Herbst, 1955 и Alona rustica Scott, 1895. Состав ракообразных в водоемах обсуждается в связи с экологической характеристикой последних. Для отдельных видов представлены краткие таксономические и экологические замечания. Обсуждаются видовое разнообразие и биогеографические особенности Исландии в связи с фаунистическими контактами с Гренландией и северной Европой

A new integrative assessment indicator for damage caused by major pests and diseases in the vineyard

An original and integrative evaluation indicator has been developed to quantify the cumulated damage from major pests and diseases affecting grape bunches: downy mildew, powdery mildew, gray mould and tortricid moths. It made it possible to estimate the associated crop losses and to relate them to the plant protection strategy in different modes of production (organic farming, in-transition, conventional). Thus, overall plant losses were higher in 2012 than in 2011. The in-transition growers’ strategy, with reduced copper doses but increased numbers of sprays, led to a 20% increase in average severity on bunches (essentially due to Downy mildew). The more pragmatic approach of experienced organic growers and conventional ones (higher doses and fewer sprays) reduced the yield losses. The proposed indicator is used for two purposes, i) evaluating the quantitative losses due to pest attacks and ii) differentiating them from other non-pest ones. A more detailed analysis including the impact on performance will be achieved and published soon