Genetic diversity and population structure of a large collection of Magnaporthe oryzae isolates from italian rice field

Blast, caused by the filamentous ascomycete fungus Magnaporthe oryzae , is the most severe disease of rice worldwide, causing yield loss to rice cultivation up to 50 - 70%. To investigate rice - Magnaporthe interaction is crucial to understand the molecular mechanisms underlying durable blast resistance and establish improved rice protection strategies. However, durable resistance is a difficult task to achieve due to the high degree of pathogenic variability of host populations and large number of fungal races co - existing.. The study of the genetic diversity and definition of the structure of existing populations are necessary to overcome this hurdle and identify new virulent genotypes. Therefore, the development of robust and reliable molecular markers allowing to monitor the dynamics of Magnaporthe populations is a crucial goal to design strategies for rice blast control. During the last 20 years, the diversity and structure of M. oryzae populati ons on rice were described using different molecular techniques such as RFLP, rep - PCR markers, RAPD or AFLP. Simple Sequence Repeat (SSR) has become the most popular marker system used in genetic mapping, diversity studies and pedigree analysis, since are highly informative and highly reproducible. SSR have been only recently developed to analyze Magnaporthe genetic diversity, but studies have been carried out only at European or worldwide scale. The main goal of this study was to investigate the genetic di versity of Italian Magnaporthe oryzae strains to implement national rice breeding program for durable resistance towards blast population inhabiting Italian ricegrowing areas. To this aim, in the framework of the RISINNOVA project we created a large Magnap orthe collection constituted of 293 Italian strains isolated in the period 1998 - 2011, different locations in Italy and plant organs. To classify the biodiversity of RISINNOVA Magnaporthe collection a molecular characterization was carried out by a set of selected informative SSR and p reliminary results of the phylogenetic analyses will be presented. (Texte Intégral

Plant biostimulants from cyanobacteria: An emerging strategy to improve yields and sustainability in agriculture

Cyanobacteria can be considered a promising source for the development of new biostimulants as they are known to produce a variety of biologically active molecules that can positively affect plant growth, nutrient use efficiency, qualitative traits of the final product, and increase plant tolerance to abiotic stresses. Moreover, the cultivation of cyanobacteria in controlled and confined systems, along with their metabolic plasticity, provides the possibility to improve and standardize composition and effects on plants of derived biostimulant extracts or hydrolysates, which is one of the most critical aspects in the production of commercial biostimulants. Faced with these opportunities, research on biostimulant properties of cyanobacteria has undergone a significant growth in recent years. However, research in this field is still scarce, especially as regards the number of investigated cyanobacterial species. Future research should focus on reducing the costs of cyanobacterial biomass production and plant treatment and on identifying the molecules that mediate the biostimulant effects in order to optimize their content and stability in the final product. Furthermore, the extension of agronomic trials to a wider number of plant species, different application doses, and environmental conditions would allow the development of tailored microbial biostimulants, thus facilitating the diffusion of these products among farmers

High pressure and thermal processing on the quality of zucchini slices

In response to the market demand for low processed vegetables, high-pressure treatments (400,600 MPa; 1,5 min) were applied on zucchini slices and compared to a traditional blanching treatment. Histological observations, texture and color analysis, pectinmethylesterase (PME) and antioxidant (DPPH) activities were measured and compared to untreated samples. The histological observations revealed that the longer high-pressure treatments (5 min) led to more extended cell lysis and dehydration than the shorter ones (1 min) and blanching. High-pressure treatments resulted less effective than blanching on PME inactivation, with the best results obtained at 400 MPa for 1 min. Comparable texture parameters were observed for high-pressured and blanched samples. The negative correlation found between PME activity and the texture parameter ‘distance of the first peak force’ revealed an effect of PME on the texture recovery after treatments. High pressure led to a general browning of zucchini parenchyma and to DPPH drop. The correlations found between DPPH and color suggest the common nature of the phenomena. The influence of pressure and time on the studied parameters was revealed by two-way ANOVA. Principal component analysis clustered together the four high-pressure-treated samples, being clearly divided by blanched and untreated ones

Comparison of physical, microstructural, antioxidant and enzymatic properties of pineapple cubes treated with conventional heating, ohmic heating and high-pressure processing

Pineapple cubes in sugar syrup were treated with high-pressure processing (HPP), conventional (DIM) heating and ohmic heating (OHM). Samples were compared in terms of microstructural, physical (total soluble solids, sieve analysis, texture and colour) and residual pectin methylesterase activity (PME) and total antioxidant capacity. OHM yielded relevant changes in cellular microstructure and electroporation of the cell wall. The HPP treatment favoured the presence of soluble solids in the syrup, and the samples were less damaged in terms of shape and microstructure. in the samples were harder following HPP than they were with OHM and DIM, while HPP showed the highest colorimetric (ΔE) differences compared with RAW samples. The PME residual activity was the lowest in pineapple treated by DIM, while the antioxidant capacity was comparable among treated samples

Assessment of gully erosion using photogrammetric techniques. A case study of upper Mbuluzi river, Swaziland

Resumen del trabajo presentado al IV International Symposium on Gully Erosion, celebrado en la Universidad Pública de Navarra del 17 al 19 de septiembre de 2007.Swaziland is severely affected by gully erosion contributing to a sediment budget up to 250,000 m3 y-1 (WMS Associates, 1988). This type is more important than inter-rill and rill erosion. Severe gully erosion is mainly in the Middleveld especially on communal land highly populated (43.65 inhabitants km-2) and with high livestock concentrations. Here, the calculated carrying capacities are 0.27 LSU ha-1 (Livestock Units) vs. stocking rates 0.87 LSU ha-1. In general, to assess gully erosion, numerous investigators have made use of aerial photos and GIS to predict the morphometric conditions that favoured gulling (Nachtergaele and Poesen, 1999). In Swaziland, from 1947 to 1987, the WMS Associates (1988) established gully erosion rates from aerial stereo photos. Subsequently, Mushala et al., 1994 analyzed the gullies distribution and their relationship to lithology and land tenure. In the present research long terms rates of gully erosion have been measured by aerial photos taken from 1947 to 1996. Particular attention was focused on two dendritic gully systems. One of them is dynamically evolving, whereas the other one is in a static phase (Sidorchuk, 1999). The objectives of this research were to calculate the historical development of the morphology of gully as input data to the gully erosion model (Sidorchuk et al., 2001) and to predict hillslope area susceptible to gulling. A High Digital Terrain Models (HDTMs) with 1-m resolution were devised for this purpose.Part of this work was supported by the European Union, INCO-DC, contract nr. IC18-CT97-0144

The Effect of Diel Temperature and Light Cycles on the Growth of Nannochloropsis oculata in a Photobioreactor Matrix

A matrix of photobioreactors integrated with metabolic sensors was used to examine the combined impact of light and temperature variations on the growth and physiology of the biofuel candidate microalgal species Nannochloropsis oculata. The experiments were performed with algal cultures maintained at a constant 20u C versus a 15°C to 25°C diel temperature cycle, where light intensity also followed a diel cycle with a maximum irradiance of 1920 μmol photons m-2 s-1. No differences in algal growth (Chlorophyll a) were found between the two environmental regimes; however, the metabolic processes responded differently throughout the day to the change in environmental conditions. The variable temperature treatment resulted in greater damage to photosystem II due to the combined effect of strong light and high temperature. Cellular functions responded differently to conditions before midday as opposed to the afternoon, leading to strong hysteresis in dissolved oxygen concentration, quantum yield of photosystem II and net photosynthesis. Overnight metabolism performed differently, probably as a result of the temperature impact on respiration. Our photobioreactor matrix has produced novel insights into the physiological response of Nannochloropsis oculata to simulated environmental conditions. This information can be used to predict the effectiveness of deploying Nannochloropsis oculata in similar field conditions for commercial biofuel production. © 2014 Tamburic et al

Energy balance of algal biomass production in a 1-ha "Green Wall Panel" plant: How to produce algal biomass in a closed reactor achieving a high Net Energy Ratio

The annual productivity of Tetraselmis suecica in a 1-ha Green Wall Panel-II (GWP-II) plant in Tuscany (Italy) is 36 t (dry weight) ha-1 year-1, which corresponds to an energy output of 799 GJ ha-1 year-1. The energy inputs necessary to attain that productivity amount to 1362 GJ ha-1 year-1, mainly given by the embodied energy of the reactor (about 30%), mixing (about 40%), fertilizers (11%) and harvesting (10%). The Net Energy Ratio (NER) of T. suecica production is thus 0.6. In a more suitable location (North Africa) productivity nearly doubles, reaching 66 t ha-1 year-1, but the NER increases only by 40% and the gain (difference between output and inputs) remains negative. In a GWP-II integrated with photovoltaics (PV), the NER becomes 1.7 and the gain surpasses 600 GJ ha-1 year-1. Marine microalgae cultivation in a GWP plant, in a suitable location, can attain high biomass productivities and protein yields 30 times higher than those achievable with traditional crops (soya). When the GWP reactor is integrated with PV, the process attains a positive energy balance, which substantially enhances its sustainability

Análisis integrado de las condiciones de amenaza natural en el medio ambiente costero semiárido de Chile. La Serena, Coquimbo

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