The relationship between cutinases and the pathogenicity/virulence of Fusarium solani in potato tubers

Cutinase activity was spectrophotometrically determined in the culture supernatants of 40 isolates of Fusarium solani, obtained in Iran from various biological origins and grown in a minimal medium with 0.4% cutin as the only carbon source. Enzymatic activities, which ranged from 0 to 488 nmol min-1 mL-1, were related to the pathogenicity or virulence of the fungal isolates, determined on potato tubers using a 0–5 disease severity scale. Cutinase activity was either not detected at all or was very low in the non-pathogenic isolates, whereas it was directly correlated with the virulence of the pathogenic isolates (Radj 2 = 0.97), with an increase in cutinase activity of about 100 units corresponding to a one-point increase in the disease severity scale. SDS-PAGE analysis revealed that non-pathogenic F. solani isolates did not produce a cutinase band, while pathogenic isolates, with various degrees of virulence, produced single or double peptide bands with molecular weights of 20–23 kDa. We conclude that enzyme activity can be used as a predictive marker of the pathogenicity and virulence of F. solani isolates obtained from various hosts

Spatial patterns and temporal variability of drought in Western Iran

An analysis of drought in western Iran from 1966 to 2000 is presented using monthly precipitation data observed at 140 gauges uniformly distributed over the area. Drought conditions have been assessed by means of the Standardized Precipitation Index (SPI). To study the long-term drought variability the principal component analysis was applied to the SPI field computed on 12-month time scale. The analysis shows that applying an orthogonal rotation to the first two principal component patterns, two distinct sub-regions having different climatic variability may be identified. Results have been compared to those obtained for the largescale using re-analysis data suggesting a satisfactory agreement. Furthermore, the extension of the large-scale analysis to a longer period (1948–2007) shows that the spatial patterns and the associated time variability of drought are subjected to noticeable changes. Finally, the relationship between hydrological droughts in the two sub-regions and El Niño Southern Oscillation events has been investigated finding that there is not clear evidence for a link between the two phenomen

Characterising droughts in Central America with uncertain hydro-meteorological data

Central America is frequently affected by droughts that cause significant socio-economic and environmental problems. Drought characterisation, monitoring and forecasting are potentially useful to support water resource management. Drought indices are designed for these purposes, but their ability to characterise droughts depends on the characteristics of the regional climate and the quality of the available data. Local comprehensive and high-quality observational networks of meteorological and hydrological data are not available, which limits the choice of drought indices and makes it important to assess available datasets. This study evaluated which combinations of drought index and meteorological dataset were most suitable for characterising droughts in the region. We evaluated the standardised precipitation index (SPI), a modified version of the deciles index (DI), the standardised precipitation evapotranspiration index (SPEI) and the effective drought index (EDI). These were calculated using precipitation data from the Climate Hazards Group Infra-Red Precipitation with Station (CHIRPS), the CRN073 dataset, the Climate Research Unit (CRU), ECMWF Reanalysis (ERA-Interim) and a regional station dataset, and temperature from the CRU and ERA-Interim datasets. The gridded meteorological precipitation datasets were compared to assess how well they captured key features of the regional climate. The performance of all the drought indices calculated with all the meteorological datasets was then evaluated against a drought index calculated using river discharge data. Results showed that the selection of database was more important than the selection of drought index and that the best combinations were the EDI and DI calculated with CHIRPS and CRN073. Results also highlighted the importance of including indices like SPEI for drought assessment in Central America.Universidad de Costa Rica/[805-B0-810]/UCR/Costa RicaUniversidad de Costa Rica/[805-A9-532]/UCR/Costa RicaUniversidad de Costa Rica/[805-B3-600]/UCR/Costa RicaUniversidad de Costa Rica/[805-B0-065]/UCR/Costa RicaUniversidad de Costa Rica/[805-B3-413]/UCR/Costa RicaUniversidad de Costa Rica/[805-B4-227]/UCR/Costa RicaUniversidad de Costa Rica/[805-B4-228]/UCR/Costa RicaUniversidad de Costa Rica/[805-B5-295]/UCR/Costa RicaUppsala University/[54100006]//SueciaMarie Curie Intra-European Fellowship/[No.329762]//EuropaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Físic

The relationship between cutinases and the pathogenicity/virulence of <I>Fusarium solani</I> in potato tubers

Cutinase activity was spectrophotometrically determined in the culture supernatants of 40 isolates of Fusarium solani, obtained in Iran from various biological origins and grown in a minimal medium with 0.4% cutin as the only carbon source. Enzymatic activities, which ranged from 0 to 488 nmol min-1 mL-1, were related to the pathogenicity or virulence of the fungal isolates, determined on potato tubers using a 0–5 disease severity scale. Cutinase activity was either not detected at all or was very low in the non-pathogenic isolates, whereas it was directly correlated with the virulence of the pathogenic isolates (Radj 2 = 0.97), with an increase in cutinase activity of about 100 units corresponding to a one-point increase in the disease severity scale. SDS-PAGE analysis revealed that non-pathogenic F. solani isolates did not produce a cutinase band, while pathogenic isolates, with various degrees of virulence, produced single or double peptide bands with molecular weights of 20–23 kDa. We conclude that enzyme activity can be used as a predictive marker of the pathogenicity and virulence of F. solani isolates obtained from various hosts

Assessment of Climate Change Impacts on Water Resources in Zarrinehrud Basin Using SWAT Model

This paper evaluate impacts of climate change on temperature, rainfall and runoff in the future Using statistical model, LARS-WG, and conceptual hydrological model, SWAT. In order to the Zarrinehrud river basin, as the biggest catchment of the Lake Urmia basin was selected as a case study. At first, for the generation of future weather data in the basin, LARS-WG model was calibrated using meteorological data and then 14 models of AOGCM were applied and results of these models were downscaled using LARS-WG model in 6 synoptic stations for period of 2015 to 2030. SWAT model was used for evaluation of climate change impacts on runoff in the basin. In order to, the model was calibrated and validated using 6 gauging stations for period of 1987-2007 and the value of R2 was between 0.49 and 0.71 for calibration and between 0.54 and 0.77 for validation. Then by introducing average of downscaled results of AOGCM models to the SWAT, runoff changes of the basin were simulated during 2015-2030. Average of results of LARS-WG model indicated that the monthly mean of minimum and maximum temperatures will increase compared to the baseline period. Also monthly average of precipitation will decrease in spring season but will increase in summer and autumn. The results showed that in addition to the amount of precipitation, its pattern will change in the future period, too. The results of runoff simulation showed that the amount of inflow to the Zarrinehrud reservoir will reduce 28.4 percent compared to the baseline period