Genetics of resistance to bean golden mosaic virus in Phaseolus vulgaris L.

Summary The genetics of resistance to bean golden mosaic virus (BGMV) was studied in an 8×8 complete diallel cross of common bean, Phaseolus vulgaris L. The 28F₁ hybrids, their reciprocals, and eight parents were artificially inoculated with BGMV under glasshouse conditions. Data were recorded and analyzed for foliar yellowing, plant dwarfing, flower abortion, and pod formation, using a randomized complete block design with two replications.General combining ability (GCA) mean squares were highly significant (P<0.01) and larger than values for specific combining ability for all traits. Reciprocal and maternal effects were nonsignificant. Cultivars Royal Red and Alubia Cerrillos possessed significant negative and positive GCA for all traits, respectively. Porrillo Sintetico also had negative GCA for all traits except plant dwarfing. None of the GCA effects were significant for Great Northern 31 and PVA 1111. Positive associations existed among all traits studied.     

Genetic-diversity assessed by microsatellites in tropical maize populations submitted to a high-intensity reciprocal recurrent selection

BR-105 and BR-106 are important tropical maize populations, which were submitted to a high-intensity reciprocal recurrent selection, generating the IG-3 and IG-4synthetics. Using 30-microsatellite loci,we measured and compared the genetic diversity of these populations and their synthetics. The populations did not differ significantly regarding the amount of genetic diversity. As a consequence of selection, genetic variability losses, in terms of mean number of alleles per locus,proportion of polymorphic loci, and gene diversity did occur and were greater in the synthetic IG-3 than IG-4. In the synthetics, the number of loci in adherence to Hardy-Weinberg proportions was superior to that observed in the populations. The Wright's mean fixation index was higher than the mean value expected for outcrossing species (5%) indicating as light excess of homozygotic individuals in both populations. The genetic distances confirmed the favourable effects of one cycle of recurrent selection, as the synthetics became more isolated in comparison to the original populations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Distortion of genetically modified organism quantification in processed foods: influence of particle size compositions and heat-induced DNA degradation

Milling fractions from conventional and transgenic corn were prepared at laboratory scale and used to study the influence of sample composition and heat-induced DNA degradation on the relative quantification of genetically modified organisms (GMO) in food products. Particle size distributions of the obtained fractions (coarse grits, regular grits, meal, and flour) were characterized using a laser diffraction system. The application of two DNA isolation protocols revealed a strong correlation between the degree of comminution of the milling fractions and the DNA yield in the extracts. Mixtures of milling fractions from conventional and transgenic material (1%) were prepared and analyzed via real-time polymerase chain reaction. Accurate quantification of the adjusted GMO content was only possible in mixtures containing conventional and transgenic material in the form of analogous milling fractions, whereas mixtures of fractions exhibiting different particle size distributions delivered significantly over- and underestimated GMO contents depending on their compositions. The process of heat-induced nucleic acid degradation was followed by applying two established quantitative assays showing differences between the lengths of the recombinant and reference target sequences (A, deltal(A) = -25 bp; B, deltal(B) = +16 bp; values related to the amplicon length of the reference gene). Data obtained by the application of method A resulted in underestimated recoveries of GMO contents in the samples of heat-treated products, reflecting the favored degradation of the longer target sequence used for the detection of the transgene. In contrast, data yielded by the application of method B resulted in increasingly overestimated recoveries of GMO contents. The results show how commonly used food technological processes may lead to distortions in the results of quantitative GMO analyses.     

Lipid composition of lees from Sherry wine

In this paper, we describe the study and characterization of the lipids from lees of Sherry wine, one of the main byproducts from the wine-making industry in the Jerez/Xeres/Sherry denomination of the origin zone in Jerez de la Frontera, Spain. The lipid content, extractability, classification, fatty acid composition, and its main chemical characteristics have been determined in order to evaluate their potential use as a food or food additive.     

Drought pretreatment increases the salinity resistance of tomato plants

Agricultural productivity is worldwide subjected to increasing salinity problems. Various strategies are applied to overcome the deleterious effects of salinity on plants. This study was conducted in order to determine whether drought pretreatment of seedlings or seed pretreatment with NaCl increases the long‐term salinity resistance of tomato (Solanum lycopersicum L.) and whether the adaptive response to salinity is accompanied by physiological changes throughout the plant‐growth cycle. When plants were pretreated at the five‐leaf growth stage, the plant dry weight was significantly higher in drought‐pretreated than in non‐pretreated plants after 50 d of salt treatment. The positive effect of drought pretreatment applied at the five‐leaf stage was maintained throughout the entire growth cycle, as fruit yield of drought‐pretreated plants was 40% higher than that of non‐pretreated plants at the end of the harvest period (150 d of 70 mM NaCl treatment). Moreover, the most productive plants maintained lower Na⁺ and Cl^– accumulation in their leaves until the end of the growth cycle, which shows that adaptation is a long‐term response during which the plants adjust their physiology to the environmental conditions. Salt resistance was also improved through seed pretreatment with NaCl. In conclusion, drought pretreatment applied at the five‐leaf stage or seed pretreatment with NaCl provide an alternative way to enhance salt resistance in tomato, and the increase in yield is associated with physiological changes throughout the plant‐growth cycle.     

Truffle aroma analysis by headspace solid phase microextraction

An experimental design has been used to optimize the extraction of volatile compounds from summer truffle aroma (Tuber aestivum) by using headspace solid phase microextraction. The extracted compounds have been analyzed by gas chromatography with a flame ionization detector and by gas chromatography-mass spectrometry (GC-MS). In an attempt to develop an objective method to fully characterize truffle aroma, a fiber of medium polarity (for flavors) was used to avoid discrimination toward very nonpolar and polar volatile compounds. To optimize the extraction conditions, a response surface experimental design was applied considering three factors such as extraction temperature, equilibrium time, and extraction time. From the statistical analysis of the experimental design, it was possible to determine that the most important factor influencing the abundance of aroma compounds was the extraction temperature. Optimal extraction temperature was established at approximately 50 degrees C. By using GC-MS, it was possible to identify 37 compounds, most of them previously described as responsible for truffle aroma.     

El Niño induced local extinction of coral reef bryozoan species from Northern Bahia, Brazil

The 1997-1998 El-Niño Southern Oscillation was the most severe on record and dramatically impacted corals worldwide. However, the effect of this event on the associated community of reef organisms has received much less attention. The composition of the bryozoan assemblage from the coral reefs of Northern Bahia, Brazil were monitored annually from 1995 to 2000, allowing the investigation of the effects of this large-scale stressor on an important, diverse, yet understudied component of the coral reef system. Bryozoan samples (35 replicates/reef) were collected during April/May from four shallow bank reefs (10-40 m depth) located a few kilometres off the coast, together with measurements of the associated environmental parameters. Currently 157 species have been recorded from the study area, but significant reductions in density and diversity were apparent between pre- and post El-Niño Southern Oscillation (ENSO) years, multivariate analysis denoting significant changes in assemblage composition. A total of 61 species were unrecorded following the 1997-1998 ENSO event (22 species from 1997; 25 further species from 1998 and 14 more from 1999). These included several species endemic to Brazil, suggesting that the 1997-1998 ENSO has had a marked influence on the reef bryozoan community, resulting in the local extinction of several species. Bryozoan mortalities were probably initiated by elevated temperatures, but continued disappearance of species for 2 years after ENSO suggests other indirect factors are also influential. These results demonstrate that ENSO events can have severe long-term impacts on the biodiversity of coral reefs, with important conservation consequences.     

Diurnal Macronutrients Uptake Patterns by Lettuce Roots under Various Light and Temperature Levels

In order to reduce nutrient wastes to the environment the supply should be in accordance to the demand for these. Two experiments were conducted to study and quantify the effect of temperature, irradiance, and plant age on the uptake of nitrate (NO₃^?), ammonium (NH₄⁺), dihydrogen phosphate ion (H₂PO₄^?), potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), and sulfate (SO₄²). In the first experiment, various levels of temperature and irradiance were applied to plants in a growth chamber, while in the second experiment the uptake was studied along the crop season under greenhouse conditions. The uptake rates were calculated at 2-hour intervals through sampling the nutrient solution and analyzing it by inductively coupled plasma atomic emission spectrometry (ICP-AES). Increasing light and temperature enhance the uptake rates, while the rates decrease with plant age. Nitrogen absorption was similar during the day as during the night. No differences were found in the absorption of H₂PO₄^?, K⁺, Ca²⁺, Mg²⁺, and SO₄^2? between day and night. Nitrate absorption was found to have a positive correlation with the absorption of all the ions except for NH₄⁺.     

Effect of red grapes co-winemaking in polyphenols and color of wines

The red grapes co-winemaking effect on phenolic fraction and wine color has been studied for the first time, where Monastrell was comacerated and cofermentated with Cabernet Sauvignon and Merlot. Changes in the relative abundance of anthocyanins were observed as well as hyperchromic shifts at 530 and 620 nm; these effects remain constant after aging. Co-winemaking also favored copigmentation, giving way to more stable anthocyanins and facilitating their polymerization. With regard to color evolution, the mixture of Monastrell with Merlot grapes was more appropriate than with Cabernet Sauvignon for aging wines in oak barrels. The extent of copigmentation was more important in young wines than in aged wines. This is mainly due to the self-anthocyanin monomer reactions in the case of young wines, whereas in aged wines copigmentation is mainly due to the reaction between the anthocyanins and other polyphenolic cofactors. Discriminant analysis showed the possibility of differentiating wines according to the aging time and the type of wine, with color parameters (color intensity, OD 620 nm, and OD 520 nm) being the most important discrimination variables in the first case and petunidin-3-glucoside and peonidin-3-glucoside contents in the second case.