U.S. EPA regulation of plant-incorporated protectants: assessment of impacts of gene flow from pest-resistant plants

The U.S. Environmental Protection Agency licenses pesticide-expressing plants under the authority of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). Transgenes and their pesticidal products represent pesticides under FIFRA and are referred to as plant-incorporated protectants (PIPs). When sexually compatible wild relatives (SCWR) are sympatric with PIP crops, there is a need to assess the potential for adverse effects to man and the environment resulting from transgene introgression in accord with FIFRA requirements. Genetic compatibility, introgression, weediness of SCWR × PIP hybrids, seed dispersal, and dormancy, among other parameters, as well as effects on other species (herbivores and beneficial insects), all need to be considered as part of the risk assessment for experimental use under Section 5 or registration under Section 3 of FIFRA. EPA is currently developing data requirements and guidance toward addressing potential gene flow impacts from PIPs.     

Dynamics of symbiotic establishment between an IAA-overproducing mutant of the ectomycorrhizal fungus Hebeloma cylindrosporum and Pinus pinaster

To clarify the early steps of symbiotic establishment, we studied the dynamics of Pinus pinaster (Ait.) Sol. tap root colonization and mycorrhiza formation by an IAA-overproducing mutant of the ectomycorrhizal fungus Hebeloma cylindrosporum Romagnesi and by the corresponding wild type strain. Differences between wild type and mutant strains were quantitative rather than qualitative and were detected two days after inoculation. Both fungal strains established a typical Hartig net when they colonized the tap roots. Consequently, colonized tap roots exhibited features of a true mycorrhiza and fungal colonization enhanced plant growth. Fungal colonization and Hartig net formation were more rapid with the mutant than with the wild type. Colonization, especially with the mutant strain, increased rhizogenesis and the production of mycorrhizas. The mutant formed a hypertrophic Hartig net in tap roots and mycorrhizal short roots and we obtained evidence that the process of short root transformation into mycorrhiza started before their emergence from the tap root. Hyphae of the Hartig net in the tap root penetrated the cortex of young lateral roots at the beginning of their elongation, after the endodermis layer broke under the pressure of the elongating lateral root. Colonization was inhibited when triiodobenzoic acid was added to the culture medium, providing circumstantial evidence that auxin is involved in mycorrhiza formation.     

dSarm/Sarm1 is required for activation of an injury-induced axon death pathway

Axonal and synaptic degeneration is a hallmark of peripheral neuropathy, brain injury, and neurodegenerative disease. Axonal degeneration has been proposed to be mediated by an active autodestruction program, akin to apoptotic cell death; however, loss-of-function mutations capable of potently blocking axon self-destruction have not been described. Here, we show that loss of the Drosophila Toll receptor adaptor dSarm (sterile α/Armadillo/Toll-Interleukin receptor homology domain protein) cell-autonomously suppresses Wallerian degeneration for weeks after axotomy. Severed mouse Sarm1 null axons exhibit remarkable long-term survival both in vivo and in vitro, indicating that Sarm1 prodegenerative signaling is conserved in mammals. Our results provide direct evidence that axons actively promote their own destruction after injury and identify dSarm/Sarm1 as a member of an ancient axon death signaling pathway.     

Viral encephalopathy and retinopathy of Dicentrarchus labrax and Sparus aurata farmed in Tunisia

Viruses belonging to the Nodaviridae family cause disease worldwide among a large number of species of marine fish, and have been described in all continents. In the present study, a total of 69 farmed Tunisian sea bass (Dicentrarchus labrax) and 24 sea bream (Sparus aurata) samples were tested monthly for the detection of betanodavirus. The virus was identified in both species using indirect immunofluorescence assays (IFAT) and RT-PCR. In addition sequence analysis of part of the coat protein gene indicated that both species were infected by highly related, but distinct, strains belonging to the RGNNV genotype. The sequence of the coat protein gene of several strains was identical but up to 9 different sequences were detected in a single farm. In addition, viral sequences obtained from fish that were held at lower temperature (<20°C) were distinct from the rest of the sequences.     

Detection of European bat lyssavirus 2 (EBLV-2) in a Daubenton's bat (Myotis daubentonii) from Magdeburg, Germany

In Europe bat rabies in Daubenton's bats (Myotisdaubentonii) and in Pond bats (Myotis dasycneme) caused by the European bat lyssavirus 2 (EBLV-2) has been confirmed in less than 20 cases to date. Here we report the second encounter of this virus species in Germany. A Daubenton's bat found grounded in the zoological garden in Magdeburg died shortly after. In the frame of a retrospective study the bat carcass was eventually transferred to the national reference laboratory for rabies at the Friedrich-Loeffler-Institute for rabies diagnosis. Lyssavirus was isolated and characterized as EBLV-2.     

In vivo and in vitro propagation and transmission of Toggenburg orbivirus

The Toggenburg orbivirus (TOV), a recently discovered virus related to bluetongue virus (BTV), has been identified in goats in Switzerland, Italy and Germany. Isolation of TOV in vitro has not yet been achieved and the transmission mechanisms are still unknown. In the experimental infection of pregnant goats described here, TOV could not be detected in secretion/excretion samples or fetal blood. Material from the goat experiment was used as inoculum for propagating the virus in vitro. To enhance the infectivity of TOV several modified protocols, e.g. pretreatment of the virus with trypsin, polyethylene glycol-mediated infection and lipofection were applied. Isolation of TOV, attempts to infect Culicoides nubeculosus by feeding TOV-positive blood and intracerebral inoculation of newborn mice were unsuccessful. The results of these studies suggest that TOV requires specific but different factors than other BTVs for infection and replication outside of its natural caprine host.     

Seaweed polysaccharides and derived oligosaccharides stimulate defense responses and protection against pathogens in plants

Plants interact with the environment by sensing "non-self" molecules called elicitors derived from pathogens or other sources. These molecules bind to specific receptors located in the plasma membrane and trigger defense responses leading to protection against pathogens. In particular, it has been shown that cell wall and storage polysaccharides from green, brown and red seaweeds (marine macroalgae) corresponding to ulvans, alginates, fucans, laminarin and carrageenans can trigger defense responses in plants enhancing protection against pathogens. In addition, oligosaccharides obtained by depolymerization of seaweed polysaccharides also induce protection against viral, fungal and bacterial infections in plants. In particular, most seaweed polysaccharides and derived oligosaccharides trigger an initial oxidative burst at local level and the activation of salicylic (SA), jasmonic acid (JA) and/or ethylene signaling pathways at systemic level. The activation of these signaling pathways leads to an increased expression of genes encoding: (i) Pathogenesis-Related (PR) proteins with antifungal and antibacterial activities; (ii) defense enzymes such as pheylalanine ammonia lyase (PAL) and lipoxygenase (LOX) which determine accumulation of phenylpropanoid compounds (PPCs) and oxylipins with antiviral, antifugal and antibacterial activities and iii) enzymes involved in synthesis of terpenes, terpenoids and/or alkaloids having antimicrobial activities. Thus, seaweed polysaccharides and their derived oligosaccharides induced the accumulation of proteins and compounds with antimicrobial activities that determine, at least in part, the enhanced protection against pathogens in plants.     

Nutrient digestibility and prediction of metabolizable energy in total mixed rations for ruminants.

The aim of the present study was to determine equations that predict ME in total mixed rations (TMR) based on routine methods. The ME content of 30 TMR for dairy cows was determined based on digestible crude nutrients obtained with wether sheep. Concentrations in the TMR (in g/kg DM) varied between 118 and 234 for crude protein, 26 and 48 for crude lipid, 131 and 250 for crude fibre, 281 and 488 for NDF, and 173 and 304 for ADF. Gas production ranged from 40.7 to 54.1 ml/200 mg DM, and enzymatically degraded organic matter from 652 to 800 g/kg DM. Digestibility [%] ranged from 68.6 to 84.0 for organic matter, from 55.6 to 84.3 for crude lipid, from 55.0 to 77.8 for crude fibre, from 57.6 to 77.0 for NDF and from 53.1 to 79.6 for ADF. ME ranged from 9.6 to 11.9 MJ/kg DM, and NEL from 5.7 to 7.4 MJ/kg DM. ME content was highly correlated with the concentration of both crude fibre and enzymatically degradable organic matter as well as with organic matter digestibility. A multiple regression equation based on crude fibre and crude lipid predicted ME with a reasonable goodness of fit (r2 = 0.81; s(y.x) = 2.4%). The inclusion of other nutrients, of neutral and acid detergent fibre, neither of gas production did improve the goodness of fit. The best prediction was achieved with inclusion of enzymatically degraded organic matter (r2 = 0.90; s(y.x) = 1.7%).     

Ecosystem service supply and vulnerability to global change in Europe

Global change will alter the supply of ecosystem services that are vital for human well-being. To investigate ecosystem service supply during the 21st century, we used a range of ecosystem models and scenarios of climate and land-use change to conduct a Europe-wide assessment. Large changes in climate and land use typically resulted in large changes in ecosystem service supply. Some of these trends may be positive (for example, increases in forest area and productivity) or offer opportunities (for example, "surplus land" for agricultural extensification and bioenergy production). However, many changes increase vulnerability as a result of a decreasing supply of ecosystem services (for example, declining soil fertility, declining water availability, increasing risk of forest fires), especially in the Mediterranean and mountain regions.