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New Insights in Plant Response to Viroid Infection by Differential Expression Analysis
Get PDFViroids are small circular RNA molecules, 246 to 400 nt long, which infect several crop plants and can cause diseases of economic importance. Citrus spp. are the hosts in which the highest number of viroids has been recovered. Citrus exocortis viroid (CEVd), causal agent of citrus exocortis disease, is responsible for several losses in citrus crops. Little is known about the molecular and cellular mechanisms by which viroids infect plants and produce symptoms. To deepen this knowledge, changes in the gene-expression profile during the early (pre–symptomatic) and the last (post-symptomatic) stage of Etrog citron infection by Citrus exocortis viroid (CEVd) were investigated using a citrus cDNA microarray. MaSigPro analysis was performed, and based on their expression profile along time, genes were divided into five clusters. These results will allow us to have a clearer idea about the changes in the plant transcriptome that are associated with symptom expression and/or with specific plant defense mechanisms
Comparative Analysis of the Volatile Fraction of Fruit Juice from Different Citrus Species
Get PDFThe volatile composition of fruit from four Citrus varieties (Powell Navel orange, Clemenules mandarine, and Fortune mandarine and Chandler pummelo) covering four different species has been studied. Over one hundred compounds were profiled after HS-SPME-GC-MS analysis, including 27 esters, 23 aldehydes, 21 alcohols, 13 monoterpene hydrocarbons, 10 ketones, 5 sesquiterpene hydrocarbons, 4 monoterpene cyclic ethers, 4 furans, and 2 aromatic hydrocarbons, which were all confirmed with standards. The differences in the volatile profile among juices of these varieties were essentially quantitative and only a few compounds were found exclusively in a single variety, mainly in Chandler. The volatile profile however was able to differentiate all four varieties and revealed complex interactions between them including the participation in the same biosynthetic pathway. Some compounds (6 esters, 2 ketones, 1 furan and 2 aromatic hydrocarbons) had never been reported earlier in Citrus juices. This volatile profiling platform for Citrus juice by HS-SPME-GC-MS and the interrelationship detected among the volatiles can be used as a roadmap for future breeding or biotechnological applications
Validation of a methodology for grouping intakes of pressurized irrigation networks into sectors to minimize energy consumption
Get PDFA methodology to optimise the amount of energy consumed in pressurized irrigation systems was presented by Jimenez-Bello et al. (2010a). These authors proposed grouping pressurized irrigation network intakes, each of the water turnouts resulting from a shared hydrant, into sectors via a genetic algorithm. In the present research, the methodology was applied and validated in a water users association. Several energy efficiency indicators were calculated and compared during five consecutive seasons (2006-2010). The first two seasons, when the methodology was not employed, were used as reference for the results obtained from 2008 onwards, when the methodology was applied to the management of irrigation network. Results obtained in seasons 2008-2010 showed that the average energy savings were 16% in comparisons to the 2006 season. However, it should be noted that the potential, theoretical savings, could have been as high as 22.3% if the modelled grouping networks would have been accurately followed. There was in fact some discrepancy between the theoretical model outputs and the final groupings due to some intake restrictions. In addition, during the irrigation campaigns, the number of irrigation intakes that operated within each sector was not always equal to the modelled sectoring, a fact that reduced the overall water users association energy efficiency. This occurred particularly during rainy periods, when some users deliberately decided to close their manual irrigation intakes valves. Overall, results showed the potential of the validated methodology for optimising energy use. However, the final overall system efficiency might depend on specific constraints that need to be taken into account when attempting to use model output predictions. (C) 2011 Elsevier B.V. All rights reserved
Spatial evaluation of soil salinity using the WET sensor in the irrigated area of the Segura river lowland
No full textThe electrical conductivity of the water within the soil pores (EC(p)) measured with the WET sensor, appears to be a reliable estimate of soil salinity. A methodology combining the use of the WET sensor along with geostatistics was developed to delimit and evaluate soil salinity within an irrigated area under arid to semiarid Mediterranean climate in SE Spain. A systematic random sampling of 104 points was carried out. The association between EC(p) and the saturation-extract electrical conductivity (EC(se)) was assessed by means of correlation analysis. The semivariograms for EC(p) were obtained at three different soil depths. Interpolation techniques, such as ordinary kriging and cokriging, were applied to obtain EC(p) levels in the unknown places. For each one of the soil depths, a model able to predict EC(se) from EC(p) was developed by means of ordinary least squares regression analysis. A good correlation (r = 0.818, p < 0.001) between EC(p) and EC(se) was found. Spherical spatial distribution was the best model to fit to experimental semivariograms of EC(p) at 10, 30, and 50 cm soil depths. Nevertheless, cokriging using the EC(p) of an adjacent soil depth as an auxiliary variable provided the best results, compared to ordinary kriging. An analytical propagation-error methodology was found to be useful to ascertain the contribution of the spatial interpolation and ordinary least squares analysis to the uncertainty of the EC(se) mapping. This methodology allowed us to identify 98% of the study area as affected by salinity problems within a rooting depth of 50 cm, with the threshold of EC(se) value at 2 dS m(-1). However, considering the crops actually grown and 10% potential reduction yield, the soil-salinity-affected area decreased to 83%. The use of sensors to measure soil salinity in combination with geostatistics is a cost-effective way to draw maps of soil salinity at regional scale. This methodology is applicable to other agricultural irrigated areas under risk of salinization
Evaluation of sludge from paper recycling as bedding material for broilers
Get PDFSeveral materials have been used as bedding substrates in broiler production. In this work, the sludge from paper recycling was tested for its potential use as litter material and was compared with wood shavings. Moisture content, apparent density, and water-holding capacity were measured and characterized in both materials. Later, 192 male broiler chickens were distributed among 16 experimental pens, 8 of which contained wood shavings as bedding material and 8 of which contained the sludge. growth rate, consumption, tonic immobility, gait score, breast lesions, foot pad dermatitis, hock burn, tibial dyschondroplasia, and metatarsal thickness were determined in the birds. Although the moisture content of the sludge was high, it decreased strongly after 7 d of drying, reaching lower values than those of wood shavings. In general, few differences were found between the materials in terms of bird performance and welfare and only the incidence of hock burn was higher in the sludge than in the wood shavings. Although further research is needed, sludge from paper recycling is a possible alternative to traditional bedding materials because it achieves most of the requirements for broiler bedding materials and does not show negative effects on the birds
Acta Horticulturae
No full textIrrigation of grapevines to meet the full seasonal water needs (ETc) usually negatively affects wine composition. In addition, our previous results showed that under Mediterranean climate replacing approximately 50% of full ETc ensures a substantial yield increase, compared with rain-fed conditions, with no detrimental effects on grape composition. The question then is whether it would be better to concentrate the water applications during the pre-veraison or during the postveraison period. A field experiment was carried out in a 'Tempranillo' vineyard during 2007 and 2008 where different irrigation strategies were applied at two crop levels (Normal and High). Rain-fed (NI) vines were compared with vines that were constantly irrigated at 75% of ETc (Control). Irrigation to the Control commenced when midday stem water potential (Psi(stem)) values reached -0.7 MPa. In addition, a spring water shortage strategy (ED) was applied by withholding irrigation until. stem Psi(stem) surpassed -1.0 MPa. After that, 75% of ETc was applied. Finally, a LD treatment was irrigated as per the Control up to veraison, and thereafter water application was reduced to approximately 2550% of ETc, trying to avoid. stem surpass -1.4 MPa. Results indicated that all irrigation regimes increased vine yield up to 50% with respect to the NI and no differences in yield among the irrigated treatments occurred. However, there were large differences in berry composition among the different irrigation strategies. The ED was more effective than LD in reducing berry growth leading to more concentrated berries in terms of anthocyanins. The LD impaired berry sugar accumulation due to the detrimental effect of water stress on leaf photosynthetic rate. Thus, in our conditions of scarce water resources, applying moderate water deficits before veraison and irrigating without considerable restriction afterwards, appears as the most convenient irrigation strategy. Crop level did not affect grape composition
Influence of mitochondria on gene expression in a citrus cybrid
No full textThe production of cybrids, combining nucleus of a species with alien cytoplasmic organelles, is a valuable method used for improvement of various crops. Several citrus cybrids have been created by somatic hybridization. These genotypes are interesting models to analyze the impact of cytoplasmic genome change on nuclear genome expression. Herein, we report genome-wide gene expression analysis in leaves of a citrus cybrid between C. reticulata cv ‘Willowleaf mandarin’ and C. limon cv ‘Eureka lemon’ compared with its lemon parent, using a Citrus 20K cDNA microarray. Molecular analysis showed that this cybrid possesses nuclear and chloroplast genomes of Eureka lemon plus mitochondria from Willowleaf mandarin and, therefore, can be considered as a lemon bearing foreign mitochondria. Mandarin mitochondria influenced the expression of a large set of lemon nuclear genes causing an over-expression of 480 of them and repression of 39 genes. Quantitative real-time RT–PCR further confirmed the credibility of microarray data. Genes over-expressed in cybrid leaves are predominantly attributed to the functional category “cellular protein metabolism” whereas in the down-regulated none functional category was enriched. Overall, mitochondria replacement affected different nuclear genes including particularly genes predicted to be involved in mitochondrial retrograde signaling. Mitochondria regulate all cell structures even chloroplast status. These results suggest that nuclear gene expression is modulated with respect to new information received from the foreign organelle, with the final objective to suit specific needs to ensure better cell physiological balance
Analysis of the Epitope Structure of Plum pox virus Coat Protein
Get PDFTyping of the particular Plum pox virus (PPV) strain responsible in an outbreak has important practical implications and is frequently performed using strain-specific monoclonal antibodies (MAbs). Analysis in Western blots of the reactivity of 24 MAbs to a 112-amino-acid N-terminal fragment of the PPV coat protein (CP) expressed in Escherichia coli showed that 21 of the 24 MAbs recognized linear or denaturation-insensitive epitopes. A series of eight C-truncated CP fragments allowed the mapping of the epitopes recognized by the MAbs. In all, 14 of them reacted to the N-terminal hypervariable region, defining a minimum of six epitopes, while 7 reacted to the beginning of the core region, defining a minimum of three epitopes. Sequence comparisons allowed the more precise positioning of regions recognized by several MAbs, including those recognized by the 5B-IV1A universal MAb (amino acids 94 to 100) and by the 4DG5 and 4DG11 D serogroup-specific MAbs (amino acids 43 to 64). A similar approach coupled with infectious cDNA clone mutagenesis showed that a V74T mutation in the N-terminus of the CP abolished the binding of the M serogroup-specific AL MAb. Taken together, these results provide a detailed positioning of the epitopes recognized by the most widely used PPV detection and typing MAbs
La caracterización de cepas de Staphylococcus aureus aisladas de nariz revela su potencial para causar enfermedad en conejos
Get PDFStaphylococcus aureus es una importante causa de mastitis, pododermatitis y abscesos subcutáneos en conejos.
Suele colonizar diferentes localizaciones, destacando la cavidad nasal por su frecuencia. Se examinaron 283 conejos
procedentes de 12 granjas con el objetivo de detectar S. aureus en nariz y lesiones. El estudio mostró que el
43,81% de los conejos portaba S. aureus en su nariz, con una mayor incidencia en los animales que presentaban
lesiones por S. aureus (75,75%) comparado con animales aparentemente sanos (15,89%). El tipado molecular de
las cepas aisladas de 65 animales portadores nasales con lesiones, reveló que en un 92% de los casos las cepas
eran iguales. Además, se estudió la presencia en dichas cepas de genes de virulencia, como toxinas exfoliativas,
leucotoxinas, superantígenos y MSCRAMMs. Los resultados mostraron que las cepas aisladas de nariz contenían la
misma combinación de factores de virulencia que las cepas aisladas de lesiones. Estos datos sugieren que la combinación
de genes necesaria para causar enfermedad podría ser también necesaria para la colonización nasal y,
además, el desarrollo de lesiones podría depender en mayor medida de factores del hospedador
Acta Horticulturae
No full textIn the old-world viticulture, there is a common but most often not scientifically proven consideration that supplemental irrigation should detrimentally affect berry and wine composition. In the semi-arid and warm climate of in-land Valencia, we tested the hypothesis that deficit irrigation might, not only improve yield, but also fruit composition. The experiment was performed with ‘Cabernet Sauvignon’ vines at the Celler del Roure SL vineyard, located in the D.O. Valencia. Rainfed vines were compared with three different post-veraison irrigation regimes with water application at either 10, 20, or 30% of reference evapotranspiration, resulting in water application of 26, 34 and 57, mm respectively. The experimental design was a randomised block with three replicates per treatment and 308 experimental vines per experimental plot. The experiment was conducted in a very dry and warm 2009 season, with substantial no rainfall from August up to harvest and average temperature during ripening of 24°C. Rainfed vines experienced quite severe plant water stress with an average midday stem water potential of -1.45 MPa. Supplemental irrigation improved plant water status and increased yield in proportion to the amount of water applied mostly because irrigation avoided berry and whole clusters dehydration that occurred in the rainfed vines during ripening. The most important effect of irrigation was to avoid the excessive increase in berry sugar content that, at the right phenolic ripening time, reached in the rainfed treatment up to 16.5° of probable alcohol. Irrigation did not affect must acidity and improved berry quality determined by a berry tasting panel. In addition the supplemental irrigation did not decrease total berry phenolic and anthocyanin potential. On the other hand irrigation slightly decreased the extractable values. This suggests that different maceration procedures should be applied depending on grape origin. Under very dry and warm seasons, irrigation can be used to mitigate the negative effect of low plant water status on berry dehydration and unbalanced ripening