Integrating landscape ecology and the assessment of ecosystem services in the study of karst areas

Landscape Ecology - A landscape is defined as a “system of ecosystems” and this is a model in which karst areas can easily be integrated. In karst areas, much of the connectivity...     

A methodological approach to estimate the geogenic contribution in soils potentially polluted by trace elements. Application to a case study

Purpose

The determination of the contribution of background values in a potentially polluted soil is very important in defining the contamination extension, in particular in areas of geological complexity and long-term economic development, where mining and industry have been traditional activities and soils are showing both geogenic and anthropogenic contributions. Some approaches have been proposed for the estimation of the anthropogenic input vs. the background; in this paper we present a more robust approach.

Materials and methods

The proposed methodological approach includes the following steps. The first step consists of the comparison among the trace element contents in potentially polluted soils (PPS) and the reference and threshold values calculated both for the same geotectonic unit. A second stage is the calculation of the reference and threshold values for the surrounding area (LTV), natural setting, of the PPS with similar lithological characteristics. The final step is based on the analysis of the results by comparison of the PPS with LTV. On the other hand, the definition of a new pollution factor allows to grade the pollution and to classify the pollution importance.

Results and discussion

The protocol proposed was applied to PPS from a potentially polluted area of SW Spain. The anthropogenic vs. geogenic anomalies and the pollution grade of the three PPS were assessed, which is important to establish the priority to further actions. In addition, this study makes clear that the use of the enrichment factors to estimate the pollution of soils is not advisable. On the other hand, in this study, new areas close to the PPS were defined as potentially polluted because of the high trace element concentration.

Conclusions

The methodological approach proposed can be considered as a good indicator for evaluating the geogenic vs. anthropogenic contribution in polluted soils and for classifying the pollution importance in a more robust way than the use of other previous indexes. The proposal methodology could be used also by the administration to detect other PPS in a study area, which a priori were not considered as contaminated.     

Trichoderma–plant–pathogen interactions

Biological control involves the use of beneficial organisms, their genes, and/or products, such as metabolites, that reduce the negative effects of plant pathogens and promote positive responses by the plant. Disease suppression, as mediated by biocontrol agents, is the consequence of the interactions between the plant, pathogens, and the microbial community. Antagonists belonging to the genus Trichoderma are among the most commonly isolated soil fungi. Due to their ability to protect plants and contain pathogen populations under different soil conditions, these fungi have been widely studied and commercially marketed as biopesticides, biofertilizers and soil amendments. Trichoderma spp. also produce numerous biologically active compounds, including cell wall degrading enzymes, and secondary metabolites. Studies of the three-way relationship established with Trichoderma, the plant and the pathogen are aimed at unravelling the mechanisms involved in partner recognition and the cross-talk used to maintain the beneficial association between the fungal antagonist and the plant. Several strategies have been used to identify the molecular factors involved in this complex tripartite interaction including genomics, proteomics and, more recently, metabolomics, in order to enhance our understanding. This review presents recent advances and findings regarding the biocontrol-resulting events that take place during the Trichoderma–plant–pathogen interaction. We focus our attention on the biological aspects of this topic, highlighting the novel findings concerning the role of Trichoderma in disease suppression. A better understanding of these factors is expected to enhance not only the rapid identification of effective strains and their applications but also indicate the potentials for improvement of natural strains of Trichoderma.     

Efficiency of DNA typing methods for detection of smoked paprika "pimenton de la vera" adulteration used in the elaboration of dry-cured Iberian pork sausages

The purpose of this work was to develop a PCR method for the identification of smoked paprika "Pimento?n de la Vera" adulteration with paprika elaborated from varieties of pepper foreign to the la Vera region, in central western Spain. Three autochthonous varieties of pepper, Jaranda, Jariza, and Bola, and the varieties Papri Queen, Papri King, Sonora, PS9794, and Papri Ace, foreign to the La Vera region, were used in the study. Analyses of the ITS and 5.8S rDNA, RAPD-PCR, SSR, and ISSR were tested. RAPD-PCR, SSR, and ISSR analyses allowed differentiation among the varieties of paprika analyzed. There was no difference in the sequence of ITS1-5.8S rDNA-ITS2. In addition, with the RAPD-PCR primers S13 and S22, two molecular markers were obtained of 641 and 704 bp, respectively, which allowed all of the smoked paprika varieties to be differentiated from paprikas elaborated with the five foreign varieties. These two molecular markers were investigated as a basis for detecting the adulteration of smoked paprika with paprika elaborated from foreign varieties of pepper.     

Performance of diagnostic tests for the detection and identification of <Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv. <Emphasis Type="Italic">actinidiae</Emphasis> (Psa) from woody samples

The aim of this study was to characterise the performance of new molecular methods for the detection and identification of Pseudomonas syringae pv. actinidiae (Psa) and to provide validation data in comparison to the assays mentioned in official diagnostic protocols and being currently used. Eleven molecular tests for the Psa detection were compared in an inter-laboratory comparison where each laboratory had to analyse the same panel of samples consisting of thirteen Psa-spiked kiwifruit wood extracts. Laboratories had to perform also isolation from the wood extracts. Data from this interlaboratory test performance study (TPS) was statistically analysed to assess the performance of each method. In order to provide complete validation data, both for detection and identification, this TPS was supplemented by a further study of identification from pure culture of phylogenetically closely related Pseudomonas spp., Psa, and bacterial strains associated with kiwifruit. The results of both these studies showed that simplex-PCRs gave good results, whereas duplex-PCR and real-time PCR were the most reliable tools for detection and identification of Psa. Nested and multiplex-PCR gave false-positive results. The use of the most reliable detection test is suggested for routine analyses, but when Psa-free status needs to be accurately assessed, it is recommended that at least two detection tests are used. This work provides a wide comparison of the available diagnostic methods, giving new information for a possible revision of the official diagnostic protocols (e.g. European and Mediterranean Plant Protection Organization (EPPO) protocol PM7/120 for the detection of Psa).