Seasonal patterns of spore deposition of heterobasidion species in four forests of the Western alps

ABSTRACT Patterns of spore deposition by Heterobasidion species were studied between the spring of 1998 and December 2000 in four forests in the western Alps using woody traps. The maximum spore deposition rate (DR) ranged from 169 to 1,550 spores m(-2) h(-1). Although spores were captured from February to October at most sites, inoculum concentration consistently peaked in the late summer or early fall. In one of the four study sites, similar patterns of DR were recorded in 2 years of sampling. A significant correlation (r = 0.654, P = 0.001) was found between DR and the average minimum air temperature in the 4 weeks before sampling. Approximately 1,200 spores were isolated and identified at the species level by polymerase chain reaction-based methods. Single-spore isolates were consistently clampless, indicating the sampled airspora was almost exclusively composed of haploid basidiospores. No significant variations of basidiospore frequencies were detected for either H. abietinum or H. annosum among sampling periods. However, the frequency of H. parviporum spores was always significantly higher in the summer. These findings suggest different patterns of sporulation among Heterobasidion species.     

Post Hoc Assessment of Stand Structure Across European Wood-Pastures: Implications for Land Use Policy

Europe’s woodland and savanna rangelands, often part of silvopastoral systems known as wood-pastures, are deteriorating because of abandonment that leads to return to a forested state or lack of tree regeneration from overgrazing or tree and shrub removal. Despite numerous local studies, there has been no broader survey of the stand structure of European wood-pastures showing which systems are at risk of losing their semiopen character. This overview aims to 1) show some of the differences and similarities in wood-pastures from landscapes across Europe and 2) identify which of these wood-pastures are at risk of losing their semiopen character. We collated a dataset of 13 693 trees from 390 plots in wood-pastures from eight different European regions (western Estonia, eastern Greece, northern Germany, Hungary, northern Italy, southern Portugal, central Romania, and southern Sweden), including tree diameters at breast height, tree density, management type, and tree species composition. On the basis of their structural characteristics, we classified wood-pastures using principal component analysis (PCA) and cluster analysis. The PCA showed a gradient from dense wood-pastures with high levels of regeneration (e.g., in Estonia) to sparse wood-pastures with large trees but a lack of regeneration (e.g., in Romania). Along this gradient, we identified three main groups of wood-pastures: 1) sparse wood-pastures with mostly big trees; 2) dense wood-pastures composed of small trees, and 3) wood-pastures containing a wide range of tree ages. Our results show a large structural gradient in European wood-pastures, as well as regeneration problems varying in their severity, highlighting the importance of social-ecological context for wood-pasture conditions. To maintain the ecological and cultural integrity of European wood-pastures, we suggest 1) more comprehensively considering them in European policies such as the Common Agricultural Policy and EU Habitats Directive, while 2) taking into account their structural characteristics and social-ecological backgrounds.     

Unravelling landslide risk: soil susceptibility,agro‐forest systems and the socio‐economic profile of rural communities in Italy

Landslides are considered a form of physical soil degradation and are concentrated, especially in southern European countries, on inland and marginal rural areas. Low‐density, economically disadvantaged and poorly accessible areas are assumed to share a high landslide occurrence probability. However, an empirical verification of this assumption is still lacking for Mediterranean countries. This study investigates the spatial relation between a composite index of landslide risk and more than 100 indicators at the municipal level in Italy – a country with high landslide risk – exploring multiple territorial dimensions (population dynamics and settlements, job market and human capital, economic specialization and competitiveness, quality of life, agriculture and rural development, territory and environment). We combine nonparametric correlation, principal component analysis and hierarchical clustering, to profile municipalities according to their levels of landslide risk. The high landslide risk in certain areas of Italy is related to specific socio‐economic attributes (depopulation, ageing, tourism specialization, low density of economic activities, modest participation to the job market and crime intensity) and agro‐environmental features (low‐intensity cropping systems, natural landscapes and water resource availability).     

Changes in foliar carbon isotope composition and seasonal stomatal conductance reveal adaptive traits in Mediterranean coppices affected by drought

We estimated water-use efficiency and potential photosynthetic assimilation of Holm oak(Quercus ilex L.) on slopes of NW and SW aspects in a replicated field test examining the effects of intensifying drought in two Mediterranean coppice forests. We used standard techniques for quantifying gas exchange and carbon isotopes in leaves and analyzed total chlorophyll, carotenoids and nitrogen in leaves collected from Mediterranean forests managed under the coppice system. We postulated that responses to drought of coppiced trees would lead to differential responses in physiological traits and that these traits could be used by foresters to adapt to predicted warming and drying in the Mediterranean area. We observed physiological responses of the coppiced trees that suggested acclimation in photosynthetic potential and water-use efficiency:(1) a significant reduction in stomatal conductance(p0.01) wasrecorded as the drought increased at the SW site;(2) foliar δ13C increased as drought increased at the SW site(p0.01);(3) variations in levels of carotenoids and foliar nitrogen, and differences in foliar morphology were recorded, and were tentatively attributed to variation in photosynthetic assimilation between sites. These findings increase knowledge of the capacity for acclimation of managed forests in the Mediterranean region of Europe.     

Novel understanding of Trichoderma interaction mechanisms

Trichoderma- based biofungicides are a reality in commercial agriculture, with more than 50 formulations registered worldwide as biopesticides or biofertilizers. Several research strategies have been applied to identify the main genes and compounds involved in the complex, three-way interactions between fungal antagonists, plants and microbial pathogens. Proteome and genome analyses have greatly enhanced our ability to conduct targeted and genome-based functional studies. We have obtained repr…     

Susceptibility to flavescence dorée of different Vitis vinifera genotypes from north-western Italy

The aim of this work was to evaluate the susceptibility to flavescence dorée (FD) of 12 Vitis vinifera cultivars grown in Piedmont, and representative of the wine-making tradition of this area. The experiments were conducted under controlled conditions to ensure constant infection pressure. Test plants were ex vitro potted vines, singly inoculated with four Scaphoideus titanus infected by FD-C phytoplasma (FDp), under greenhouse conditions. Vines were tested for FDp at 5 and 8 weeks postinoculation (wpi) and the phytoplasma load was measured in leaves and roots at 8 wpi. Within the 14 V. vinifera accessions (belonging to 12 cultivars), three susceptibility clusters were identified. Cultivars within the low susceptibility group showed low phytoplasma loads and low percentages of infected plants, suggesting a tolerant behaviour. To confirm these results, four Vitis cultivars, representing extremes of FD susceptibility from low to high, were grafted onto Kober 5BB rootstocks and inoculated with laboratory-infected S. titanus, under semi-field conditions. The transmission experiments onto grafted cuttings confirmed that susceptibility to the disease depends on the scion genotype. The data indicated that none of the tested V. vinifera genotypes are resistant to FD, although some cultivars with low susceptibility are available, and can be explored for identifying genetic traits involved in disease tolerance/resistance. Moreover, ranking Vitis genotypes for their susceptibility to FD is in itself a valuable tool to support vine growers in their decision management, by helping them to choose the most appropriate varieties according to their specific FD epidemiological contexts.     

Studies on the effect of Amadoriase from Aspergillus fumigatus on peptide and protein glycation in vitro

Amadoriase I is a fructosyl amine oxidase from Aspergillus fumigatus that catalyzes the oxidation of Amadori products (APs) producing glucosone, H2O2, and the corresponding free amine. All the enzymes of this family discovered so far only deglycate small molecular weight products and are inactive toward large molecular weight substrates, such as glycated BSA or ribonuclease A. Therefore, they cannot be used to reverse protein glycation occurring in diabetes or in foods. In this paper, the effect of Amadoriase I added during the in vitro reaction between glucose and peptides having different polarities or proteins with molecular weights ranging from to 5 to 66 kDa was tested. The formation of APs was monitored by ESI-MS of intact glycated protein or peptides and by measuring the Nepsilon-(1-deoxy-d-fructos-1-yl)-L-lysine and furosine concentrations. Results showed that the formation of APs is reduced up to 80% when peptides and glucose are incubated in the presence of Amadoriase. The effect is more evident for hydrophobic peptides. In protein-glucose systems, the effect was dependent on the molecular weight and steric hindrance being negligible for BSA and at a maximum for insulin, where the formation of APs was reduced up to 60%. These findings indicate new potential applications of Amadoriase I as an efficient tool for inhibiting protein glycation in real food systems.     

Genetic variability of the prion protein gene (PRNP) in wild ruminants from Italy and Scotland

The genetics of the prion protein gene (PRNP) play a crucial role in determining the relative susceptibility to transmissible spongiform encephalopathies (TSEs) in several mammalian species. To determine the PRNP gene variability in European red deer (Cervus elaphus), roe deer (Capreolus capreolus) and chamois (Rupicapra rupicapra), the PRNP open reading frame from 715 samples was analysed to reveal a total of ten single nucleotide polymorphisms (SNPs). In red deer, SNPs were found in codons 15, 21, 59, 78, 79, 98, 136, 168 and 226. These polymorphisms give rise to 12 haplotypes, and one of which is identical to the PRNP of American wapiti (Rocky Mountain elk, Cervus elaphus nelsoni). One silent mutation at codon 119 was detected in chamois and no SNPs were found in roe deer. This analysis confirmed that European wild ruminants have a PRNP genetic background that is compatible with TSE susceptibility, including chronic wasting disease.