Effect of herbivore stress on transgene behaviour in maize crosses with different genetic backgrounds: transgene transcription, insecticidal protein expression and bioactivity against insect pests.

Background: Decades after their first commercial release, many theoretical assumptions are still taken for granted in the deployment of genetically modified (GM) crops. Theoretically, in the case of maize, active transcription of the transgene would result in dose-dependent production of the insecticidal Cry1Ab protein, which would in turn induce dose-dependent mortality on lepidopteran pests. We produced data to realistically approach this question by using a model that includes two genetic background contexts from two geographical provenances in Brazil and South Africa, and two lepidopteran pests ( and ).

Transgene behavior in Zea mays L. crosses across different genetic backgrounds: Segregation patterns, cry1Ab transgene expression, insecticidal protein concentration and bioactivity against insect pests.

Brazil and South Africa, countries with economies in transition, are characterized by a dual agrarian structure co-occurring, sometimes, alongside in the same region. Large-scale commercial farming produces crops for export to global markets on the one hand, and small-scale farming, on the other hand, provides for subsistence and local markets. In both systems, maize (Zea mays) is a key crop for these two countries.

Teosinte in Europe - Searching for the Origin of a Novel Weed.

A novel weed has recently emerged, causing serious agronomic damage in one of the most important maize-growing regions of Western Europe, the Northern Provinces of Spain. The weed has morphological similarities to a wild relative of maize and has generally been referred to as teosinte. However, the identity, origin or genetic composition of 'Spanish teosinte' was unknown.

Loop-mediated isothermal amplification of single pollen grains.

The polymerase chain reaction (PCR) has been a reliable and fruitful method for many applications in ecology. Nevertheless, unavoidable technical and instrumental requirements of PCR have limited its widespread application in field situations. The recent development of isothermal DNA amplification methods provides an alternative to PCR, which circumvents key limitations of PCR for direct amplification in the field.

Phylogeography and evolution in matsutake and close allies inferred by analyses of ITS sequences and AFLPs.

Matsutake are commercially important ectomycorrhizal basidiomycetes in the genus Tricholoma. Despite their importance, the systematics of this species complex have remained elusive and little is known about their origin and biogeography. Using DNA analyses on a worldwide sample of matsutake, we present here the first comprehensive definition of natural groupings in this species complex.

Isotopic fractionation during ammonium assimilation by basidiomycete fungi and its implications for natural nitrogen isotope patterns.

•  N natural abundance was examined to determine the fractionation associated with ammonium assimilation into fungi. The importance of fungi to the movement of nitrogen (N) within soils and into plants highlights the need to consider such fractionations in the interpretation of ecosystem N distributions. •  To separate the influence of physiological fractionations from N source preferences on fungal δ N, both ectomycorrhizal (EM) and saprotrophic (SAP) fungi were grown in liquid culture containing (NH ) HPO of known δ N and harvested after 35 d.

Phylogenetics of Lophodermium from pine.

Lophodermium comprises ascomycetous fungi that are both needle-cast pathogens and asymptomatic endophytes on a diversity of plant hosts. It is distinguished from other genera in the family Rhytismataceae by its filiform ascospores and ascocarps that open by a longitudinal slit. Nucleotide sequences of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA were used to infer phylogenetic relationships within Lophodermium.

Growth-dependent stable carbon isotope fractionation by basidiomycete fungi: delta(13)C pattern and physiological process.

We grew 11 basidiomycetes in axenic culture to characterize their physiological capacities to fractionate stable C isotopes. Generally, delta(13)C values of the fungal biomass were (i) enriched in (13)C relative to the growth medium, (ii) variable among the isolates, and (iii) dependent on the growth rate and growth stage of the fungi. We found a multiphasic dynamic of fractionation for Cryptoporus volvatus and Marasmius androsaceus during various growth stages.

Ecophysiology of C and N isotopic fractionation in forest fungi and the roots of the saprotrophic-mycorrhizal divide.

To quantify and characterize N and C isotopic fractionation effects due to fungal transformation of organic substrates in forest ecosystems, we performed a field study in California and a meta-analysis of three additional studies conducted by others across the Northern Hemisphere. Basidiomycete fungal biomass was consistently enriched for the heavier isotope for C relative to substrate and either enriched or depleted for N relative to atmospheric N. Extent and pattern of fractionation was very variable, but the distinction between ectomycorrhizal and saprotrophic basidiomycetes was strongly supported, particularly when dual isotope analyses were performed.

The role of the extracellular sheath in recognition and attachment of conidia of Discula umbrinella (Berk. & Br.) Morelet to the host surface.

The role of the conidial sheath in the recognition process and in the attachment of conidia of the beech endophyte, Discula umbrinella, to the host surface was investigated. After treatment of conidia with different lectins the adhesion of conidia to the host surface was effectively inhibited. A strong fluorescence was observed after treatment of conidia with TRITC-labelled concanavalin A.