Aplanochytrium kerguelensis gen. nov. spec. nov., a new phycomycete from subantarctic marine waters

A new monocentric marine fungus, Aplanochytrium kerguelensis gen. nov. spec. nov., was recovered from water samples taken in the vicinity of the Kerguelen Islands in the South Indian Ocean during a cruise of the research vessel USNS “Eltanin”. Aplanochytrium is very similar to Thraustochytrium Sparrow (1936) in having a chytrid-like thallus and in being able to utilize pine pollen as a substrate to which it establishes contact by well-developed rhizoids. At maturity, however, only aplanospores are formed, as in Dermocystidium sensu Goldstein and Moriber (1966).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46151/1/203_2004_Article_BF00715023.pd

Nachweis der Gattung <em>Armillaria</em> (Fr.: Fr.) Staude und <em>Heterobasidion annosum</em> (Fr.) Bref. in Fichte (<em>Picea abies</em> [L.] Karst.) und Erfassung der klonalen ausbreitung von <em>A. ostoyae</em>-Genotypen unter Verwendung molekularer M

Methods based on the polymerase chain reaction (PCR) for generating molecular markers are illustrated by two important forest pathogens, Armillaria spp. and H. annosum. Using the primer pairs ARM-1/ARM-2 and HET-7/HET-8, derived from sequences of the &quot;internal transcribed spacer&quot; (ITS) regions of the rDNA repeat, Armillaria spp.- and H. annosum-specific DNA fragments were amplified by PCR. This PCR-based detection method allows a rapid and definite diagnosis of both important root and butt rot pathogens in different substrates or plant tissues, especially in early stages. Genetic variability among 20 A. ostoyae-isolates from different geographical origins was studied. UPGMA cluster analysis of random amplified polymorphic DNAs (RAPDs) profiles generated by 10 decamer random primers (OPA 01-10) grouped the isolates in subclusters at similarity levels between 40% and 96%, indicating high intraspecific genetic variation. The potential role of historical and current spread of spruce plants on the genetic variation of A. ostoyae in Europe is discussed. The established polymorphic DNA markers were used to determine the population structure, dynamics and spatial distribution of A. ostoyae-&quot;genets&quot; in areas colonized by the fungus. First investigations revealed different distribution strategies of A. ostoyae, which may be mediated by climatic factors, location (e.g., soil characters), and pollutants

Effects of abiotic and biotic stress on gene transcription in European beech: From samplings to mature trees.

Die Beitr&auml;ge eines internationalen Symposiums greifen den Konflikt auf, unterschiedliche &ouml;kophysiologische Anforderungen an Pflanzen im Prozessgeschehen der Ressourcenallokation auszubalancieren. Der Schwerpunkt liegt dabei auf dem Trade-off zwischen Wachstum und Stressabwehr mit jeweiligen Kosten-/Nutzen-Bewertungen. Wachstum stellt die Voraussetzung dar, um kompetitive Ressourcenakquirierung sicherzustellen, und Abwehr die Voraussetzung, um die Ressourcen nach Inkorporation f&uuml;r die Pflanze zu erhalten. Diese integrierte Betrachtungsweise erfordert in der Erkenntnis des intensiven Ressourcenaustausches der Pflanze mit ihrer abiotischen und biotischen Umwelt eine r&auml;umlich-zeitliche Prozessskalierung. Dies wird hinsichtlich des mechanistischen und zugleich &ouml;kologisch relevanten Kl&auml;rungspotenzials gepr&uuml;ft. Die Analyse der Prozessvernetzung zwischen funktionalen und strukturellen pflanzen- und &ouml;kosysteminh&auml;renten biologischen Organisationsebenen (Skalen) wird dabei als Voraussetzung f&uuml;r r&auml;umlich-zeitliche Musteraufdeckung im Allokationsgeschehen identifiziert. Die Beitr&auml;ge erreichen so eine neue Qualit&auml;t eines umfassenden, prozessbasiert integrierenden Verst&auml;ndnisses von &bdquo;Systembiologie&ldquo;

Identification techniques for <em>Armillaria spp.</em> and <em>Heterobasidion annosum </em>root and butt rot diseases: A critical review.

The need for a rapid and definite diagnosis of the Armillaria spp. and Heterobasidion annosum root and butt rot diseases as well as general requirements expected of a test to detect the pathogens are reviewed. As a spin‐off from more fundamental molecular biological research there has been a remarkable increase in newer methods for diagnosis (i.e., detection and identification) in recent years. These newer methods all have in common that they use structural elements of the target organisms such as proteins, polysaccharides, glycoproteins, nucleic acids, etc. for the construction of antibodies, probes and primers for detection, or to produce electrophoretic patterns to be used for classification and identification. The article presents a short description of principles, advantages, disadvantages and some perspectives of the new methods also developed for Armillaria spp. and H. annosum diagnosis compared with conventional ones, such as interfertility testing or visual inspection of the pathogens in situ and in vitro in pure culture. It will be noted that the specificity and reproducibility of the new techniques, which are closely linked with potential experimental error, lead to principal pitfalls which should always be kept in mind when conclusions are drawn on data generated by them. Even though PCR‐based methods become increasingly more widespread it is likely that most diagnostic methods will continue to be used or co‐exist in some form in the future