Site-specific field resistance of grapevine to <Emphasis Type="Italic">Plasmopara viticola</Emphasis> correlates to altered gene expression and was not modulated by the application of organic amendments

The influence of site on resistance of grapevine (cv. Chasselas) to Plasmopara viticola was evaluated. Grapevine leaves from three vineyards in the region of Lake Neuchatel (Switzerland) were tested for their susceptibility to P. viticola in the lab in five successive years (2004–2008), and the expression levels of four selected defence-related genes (Glucanase, Lipoxygenase 9, 9-cis epoxycarotenoid dioxygenase, Stilbene synthase) were studied in 1 year. In all 5 years of examination, differences between sites were substantial. In four out of 5 years, plants from site Hauvernier were much less susceptible to P. viticola than plants from site Auvernier. In another year, differences were less pronounced but still significant for one leaf age. Susceptibility of plants from a third site (Concise) varied from year to year. Differences in the genetic background were excluded by microsatellite analysis. Differences in susceptibility were mirrored in the constitutive expression pattern of four defence-related genes, with samples from the Hauterive site clearly separated from samples of the other two sites in redundancy analysis. Furthermore, it was evaluated whether site-specific resistance can be modulated by agronomic practices such as the application of organic amendments. In two commercial vineyards (cv. Pinot noir), soils had either not (control) or yearly (compost) been amended with a compost for the last 9 years. Leaves from plants grown in any of the two treatments did not differ in their susceptibility to P. viticola in both years of examination. Additionally, under controlled conditions, none of 19 different composts amended to the substrate of grapevine seedlings or cuttings affected their susceptibility to P. viticola, but 8 out of 19 composts reduced severity in the control bioassay Arabidopsis thaliana—Hyaloperonospora arabidopsidis, indicating that a modulation of site-specific susceptibility of grapevine plants by organic amendments is at the very least, difficult.     

Dry‐matter losses and changes in nutrient concentrations in grass and maize silages stored in bunker silos

To reduce losses and improve forage use efficiency in dairy farming systems, mass and nutrient flows during silage production have to be measured from the field to feed bunk. However, data on these losses at the farm scale are scarce. Thus, we examined dry‐matter (DM) losses and changes in nutrient concentrations (proximate constituents, nitrogen [N], phosphorus [P]) and energy values (net energy for lactation [NEL]) of silages on three experimental farms from ensiling to feed‐out. The investigated material included forages from permanent grassland and whole‐crop maize that were stored in 64 side‐walled bunker silos. To determine DM losses, the total‐in versus total‐out method was applied. Additionally, the changes in the nutrient concentrations were measured by comparing the concentrations before and after ensiling. Data analyses were carried out by using ANOVA, and the means across groups were compared via multiple contrast tests. On average, the farms had good silage production management. Average values showed a trend towards higher DM losses during the ensiling process with grass (9%) than maize (7%). The N and P concentrations of the silages remained mainly unchanged during the ensiling process, suggesting that the total losses of N and P were also low (<10%). Regarding the fibre fractions, ensiling resulted in a significant reduction in the concentration of amylase‐treated ash‐excluded neutral detergent fibre (aNDFom) for grass (11%) and maize (15%), while ash‐excluded acid detergent fibre (ADFom) was not affected by the ensiling process. These changes resulted in slightly improved energy values in the silages.     

Structure and chemical composition of bast fibers isolated from developing hemp stem

Microscopic and chemical changes of hemp bast fibers were studied during the maturation from vegetative to grain maturity stages at both apical and basal regions of the stems. The content of protein was the main factor related to fiber maturation, whereas increased proportions of mannose and glucose and decreasing levels of galactose were also highly significant. Enhanced glucose deposition in apical fibers could be related to the gradual thickening of the fibers, whereas in basal regions the thickness of the fibers nearly reached the maximum at vegetative stages. In contrast, the extent of lignification remained close to 3-4% during plant growth. Hemp fiber lignins were rich in guaiacyl units and would be rather condensed in nature. In addition, the proportion of p-hydroxyphenyl units displayed a constant decline during maturation. A progressive chemical fractionation of hemp fibers provided further insights to the occurrence and nature of noncellulosic polysaccharides. Notably, these data pointed out that maturation is accompanied by a significant increase in water- and alkali-soluble components containing glucose- and mannose-related polymers and a decrease in arabinose and galactose components disrupted by diluted hydrochloric acid. Taken together, chemical features of the noncellulosic components suggest that the architecture of hemp fibers differs slightly from that of the more widely studied flax fibers.     

Temporal and Spatial Dynamics of Primary and Secondary Infection by Armillaria ostoyae in a Pinus pinaster Plantation

ABSTRACT Epidemiological investigations were performed in a 3-ha maritime pine (Pinus pinaster) plantation established on a site heavily infested by Armillaria ostoyae. Geostatistics were used to examine the density and the distribution of the initial inoculum. Disease dynamics were monitored for 17 years after planting. On the whole site, the cumulative mortality rate reached 35% over this period, plateauing at 12 years. Disease progress curves differed according to the density of the initial inoculum, although in all the cases, the Gompertz model described the epidemics well. The epidemiological contributions of both primary (initially colonized stumps) and secondary inoculum (newly dead pines) were evaluated by analyzing their spatial relation to annual mortality. Newly dead pines acted as secondary inoculum from year 3 and their role increased with time. When the initial inoculum density was low, the contribution of secondary inoculum to epidemic development increased faster and halted sooner than when the density of primary inoculum was high. Regardless of its density, the primary inoculum acted throughout the dynamic phase of the epidemic. When the inoculum density was low, the probability of mortality during the first 6 years of the epidemic depended on the tree distance from the nearest stumps colonized by Armillaria sp. When the inoculum density was high, the probability of mortality was higher and not related to the distance between trees and colonized stumps.     

Biological activity of volatiles from marine and terrestrial bacteria

The antiproliferative activity of 52 volatile compounds released from bacteria was investigated in agar diffusion assays against medically important microorganisms and mouse fibroblasts. Furthermore, the activity of these compounds to interfere with the quorum-sensing-systems was tested with two different reporter strains. While some of the compounds specific to certain bacteria showed some activity in the antiproliferative assay, the compounds common to many bacteria were mostly inactive. In contrast, some of these compounds were active in the quorum-sensing-tests. γ-Lactones showed a broad reactivity, while pyrazines seem to have only low intrinsic activity. A general discussion on the ecological importance of these findings is given.     

Sulfates in Martian layered terrains: the OMEGA/Mars Express view

The OMEGA/Mars Express hyperspectral imager identified hydrated sulfates on light-toned layered terrains on Mars. Outcrops in Valles Marineris, Margaritifer Sinus, and Terra Meridiani show evidence for kieserite, gypsum, and polyhydrated sulfates. This identification has its basis in vibrational absorptions between 1.3 and 2.5 micrometers. These minerals constitute direct records of the past aqueous activity on Mars.     

Arbuscular mycorrhizal fungal colonization of GlycyrrhJza glabra roots enhances plant biomass,phosphorus uptake and concentration of root secondary metabolites

Arbuscular mycorrhizal(AM)fungi penetrate the cortical cells of the roots of vascular plants,and are widely distributed in soil.The formation of these symbiotic bodies accelerates the absorption and utilization of mineral elements,enhances plant resistance to stress,boosts the growth of plants,and increases the survival rate of transplanted seedlings.We studied the effects of various arbuscular mycorrhizae fungi on the growth and development of licorice(Glycyrrhiza glabra).Several species of AM,such as Glomus mosseae,Glomus intraradices,and a mixture of fungi(G.mosseae,G.intraradices,G.cladoideum,G.microagregatum,G.caledonium and G.etunicatum)were used in our study.Licorice growth rates were determined by measuring the colonization rate of the plants by the fungi,plant dry biomass,phosphorus concentration and concentration of secondary metabolites.We established two cloned strains of licorice,clone 3(C3)and clone 6(C6)to exclude the effect of genotypic variations.Our results showed that the AM fungi could in fact increase the leaf and root biomass,as well as the phosphorus concentration in each clone.Furthermore,AM fungi significantly increased the yield of certain secondary metabolites in clone 3.Our study clearly demonstrated that AM fungi play an important role in the enhancement of growth and development of licorice plants.There was also a significant improvement in the secondary metabolite content and yield of medicinal compounds from the roots.     

A survey on biosecurity and management practices in selected Belgian cattle farms

The shift from cure towards prevention in veterinary medicine involves the implementation of biosecurity, which includes all measures preventing pathogens from entering a herd and reducing the spread of pathogens within a herd. In Belgium no studies have considered the implementation of biosecurity measures in the daily management of cattle farms. Therefore the aim of the study was to map the current application of biosecurity measures in Belgian cattle farms in the prevention of disease transmission within and between farms.