Development and use of anchored‐SSRs to study DNA polymorphism in bread wheat (Triticum aestivum L.)

In bread wheat, 21 anchored simple sequence repeat (SSR) primer pairs detecting SSR length polymorphism and 42 anchored SSR primers detecting microsatellite‐anchored fragment length polymorphisms (MFLPs) are reported. Eight bread wheat genotypes were used for detecting polymorphism. The number of alleles in SSR analysis ranged from two to six, with a mean of 2.9 alleles per SSR. The number of polymorphic bands in MFLP ranged from two to 40, with a mean of 12.74 polymorphic bands/primer combination, the SSRs with CT/GA motifs giving the highest level of polymorphism (a mean of 18.37 bands). The average value of polymorphic information content (PIC) was 0.473 for SSRs and 0.061 for MFLP.     

Identification and classification of genes required for tolerance to high-sucrose stress revealed by genome-wide screening of Saccharomyces cerevisiae

Yeasts used in bread making are exposed to high concentrations of sucrose during sweet dough fermentation. Despite its importance, tolerance to high-sucrose stress is poorly understood at the gene level. To clarify the genes required for tolerance to high-sucrose stress, genome-wide screening was undertaken using the complete deletion strain collection of diploid Saccharomyces cerevisiae. The screening identified 273 deletions that yielded high sucrose sensitivity, approximately 20 of which were previously uncharacterized. These 273 deleted genes were classified based on their cellular function and localization of their gene products. Cross-sensitivity of the high-sucrose-sensitive mutants to high concentrations of NaCl and sorbitol was studied. Among the 273 sucrose-sensitive deletion mutants, 269 showed cross-sensitivities to sorbitol or NaCl, and four (i.e. ade5,7, ade6, ade8, and pde2) were specifically sensitive to high sucrose. The general stress response pathways via high-osmolarity glycerol and stress response element pathways and the function of the invertase in the ade mutants were similar to those in the wild-type strain. In the presence of high-sucrose stress, intracellular contents of ATP in ade mutants were at least twofold lower than that of the wild-type cells, suggesting that depletion of ATP is a factor in sensitivity to high-sucrose stress. The genes identified in this study might be important for tolerance to high-sucrose stress, and therefore should be target genes in future research into molecular modification for breeding of yeast tolerant to high-sucrose stress.     

Comparison of media for their aptitude in wheat anther culture

Different media were evaluated with anthers of five spring wheat (Triticum aestivum L.) genotypes for their ability to produce embryos and green plants in anther culture. Our first experiment showed that the addition of a combination of 19 amino acids significantly increased the number of embryos and green plants obtained. The mean number of green plants per 100 anthers for the two genotypes in this experiment, HY320 and B723, went from 28.2 without amino acids in the medium, to 46.7 with addition of amino acids. Our second experiment with the genotypes HY320, Wim and Laval-19 showed that liquid medium with Ficoll is more efficient for anther culture (9.9 green plants/100 anthers) than solid (0 green plants), gelationous media (2.5 green plants/100 anthers) or liquid medium with Membrane Rafts (0 green plants; Hoechst Celanese Corp.). Our third experiment revealed that the effect of replacement of sucrose by maltose varied with the genotype of the donor plant. Maltose partially inhibited the androgenesis of three responsive genotypes, HY320, Wim and Reliance (40.3 green plants/100 anthers instead of 43.9 with sucrose), while maltose significantly increased the androgenesis of the recalcitrant genotype Laval-19 (10.8 green plants/100 anthers instead of 5.4 with sucrose). An amino acid x maltose interaction was also observed. Amino acids without maltose increased androgenesis, but the addition of maltose to the amino acid-enriched medium eliminated this positive effect of the amino acids.     

The Effect of Different Drying Methods on Bioactive and Nutrition Contents of Bee Bread and Mathematical Modeling of Drying Characteristics

In this study, the aim was to determine the effect of different drying methods (with microwave and hot air) on the color, nutrient and bioactive contents of fresh bee bread. Drying characteristics were also investigated. Microwave and hot air drying were applied at different microwave powers and temperatures, respectively. Lower moisture ratios and highest effective diffusion coefficients were obtained with microwave drying in a shorter time. The Midilli model was found to be the most suitable thin-layer drying model for both methods. Regardless of the drying conditions, moisture, ash, protein, carbohydrate, and lipid proportions were observed to vary in the ranges of 4.9–8.2 %, 1.61–2.67 %, 17.47–32.54 %, 39.92–60.84 %, and 7.10–8.89 %, respectively. The lowest color difference was obtained for the sample dried at 210 W. As a result, it was determined that microwave drying is more suitable for preserving the nutritional and bioactive content of bee bread during drying.     

Investigation of Botanical Origin,Phenolic Compounds,Carotenoids, and Antioxidant Properties of Monofloral and Multifloral Bee Bread

Bee bread is a unique natural product made by bees and good for human health. It has many bioactive molecules that can treat or prevent diseases. In this study, melissopalynological methods were used to examine five bee bread samples. Major plant sources found in bee bread were Lotus spp., Trifolium spp., and Xeranthemum spp., which are from the Fabaceae and Asteraceae families. Then, the amount of phenolic compounds and major carotenoids in bee bread (BB) samples were quantified. Gallic acid, caffeic acid, quercetin, and kaempferol were found in all BB samples, with β-carotene being the most abundant carotenoid in all but BB1. In addition, the total phenolic/flavonoid content and antioxidant activities of all BB samples were determined. Total flavonoid, total phenolic, DPPH⋅, and ABTS⋅⁺ values were varied between 5.6–10.00 mg GAE/g DW, 1.2–4.3 mg QE/g DW, 1.2–5.5 mg TEAC/g DW, and 2.6–15.4 mg TEAC/g DW, respectively.     

Hydrous and photosynthetic adaptations of common and durum wheat to saline stress

Seven varieties of bred wheat and seven varieties of durum wheat were cultivated in three different sites from the area of Errachidia (southeastern Morocco). These sites differ by the degree of salinity in the irrigation water. Results obtained showed that the reduction in leaf area is the principal strategy that makes it possible to attenuate the effects of the reduction in the availability of water under saline stress. Bread wheat, which limited the reduction in the leaf area, with the risk to undergo some hydrous problems, seems to better preserve its photosynthetic potentialities and grain productivity.     

Multiple displacement amplification of the DNA from single flow–sorted plant chromosome

A protocol is described for production of micrograms of DNA from single copies of flow‐sorted plant chromosomes. Of 183 single copies of wheat chromosome 3B, 118 (64%) were successfully amplified. Sequencing DNA amplification products using an Illumina HiSeq 2000 system to 10× coverage and merging sequences from three separate amplifications resulted in 60% coverage of the chromosome 3B reference, entirely covering 30% of its genes. The merged sequences permitted de novo assembly of 19% of chromosome 3B genes, with 10% of genes contained in a single contig, and 39% of genes covered for at least 80% of their length. The chromosome‐derived sequences allowed identification of missing genic sequences in the chromosome 3B reference and short sequences similar to 3B in survey sequences of other wheat chromosomes. These observations indicate that single‐chromosome sequencing is suitable to identify genic sequences on particular chromosomes, to develop chromosome‐specific DNA markers, to verify assignment of DNA sequence contigs to individual pseudomolecules, and to validate whole‐genome assemblies. The protocol expands the potential of chromosome genomics, which may now be applied to any plant species from which chromosome samples suitable for flow cytometry can be prepared, and opens new avenues for studies on chromosome structural heterozygosity and haplotype phasing in plants.     

Nutritional and technological assessment of durum wheat-faba bean enriched flours,and sensory quality of developed composite bread

Faba beans are acknowledged as a good source of proteins, minerals, fibers, vitamins and antioxidants. A blending study was undertaken in order to prepare naturally bread from enriched flours with added nutritional value, mainly in terms of Iron and proteins. Enriched flours were prepared with varied levels (25, 30, 35 and 40%) of whole faba bean flour to assess the effects of this substitution on their nutritional and technological properties. Then, whole durum wheat bread (regular) and enriched bread at 40% substitution level (composite bread) were prepared and subjected to sensory evaluation. The substitution level of composite bread was selected on the basis of Iron and proteins contents and technological results of the flour blends. Nutritionally, except for moisture, fibers, fat, zinc and sodium values, significant (p < 0.05) increases were showed in ash, proteins, minerals, total phenolic compounds, condensed tannins, total flavonoids and anti-radical activity values. Technologically, significant (p < 0.05) decreases were recorded for lightness and whiteness index. The gluten strength value revealed a significant (p < 0.05) decrease as whole faba bean flour was added. On the sensory level, the level of substitution (40%) chosen for the manufacture of composite bread resulted in acceptable bread by consumers. Moreover, composite bread was most preferred in aroma as it imparts a feeling of satiety. The observed nutritional improvements could be useful for malnourished people, including those having Iron and proteins deficiencies. Technologically, the observed changes didn’t present limitations since composite bread was accepted by consumers even at 40% substitution level. Besides, the slight preference of composite bread aroma might encourage its consumption by consumers. Also, its promotion of satiety is important for gluten sensitivity sufferers. Our results suggested that 40% is the appropriate ratio to increase, at the same time, Iron and proteins contents of enriched flours as well as their overall nutritional quality. Also it was possible to produce natural composite bread at this level (40%) while maintaining adequate technological and sensory quality.     

Influence of Protein Source on Growth-depressing Effect of Excess Amino Acids in Young Rats

The influence of protein quality on the growth-depressing effect of excessive amount of 12 individual essential and semiessential amino acids was examined. Growing rats were fed for 3 weeks diets containing either 10.5% egg albumin or 11.6% wheat gluten (equivalent to the protein content of a 10% casein diet) supplemented with 5% of each of the l-amino acids. In general, the pattern of growth depression produced by the addition of excess amino acids to the egg albumin or the wheat gluten diet was similar to that of the case of casein diet obtained previously under the same experimental conditions. However, the extent of these effects was dependent not only upon the kind of amino acid supplemented with but also upon the source of protein used, and the depressing effect of each of excess amino acids added to the wheat gluten diet was usually severer than those added to casein and egg albumin diets. No evidence was noted of any striking changes in the liver protein and nucleic acid concentrations by either diets, but total liver protein, RNA and DNA contents were decreased in some amino acid groups of the egg albumin diet and in all amino acid groups of the wheat gluten diet except the lysine addition. The free amino acid level in plasma generally showed extreme elevation for the amino acid supplemented in excess in the diet, and in most cases the extent of the elevation was correlated with the growth depression.     

基于DNA条形码的白斑切叶蜂粉源植物种类及多样性分析

利用人工蜂巢收集白斑切叶蜂(Megachile strupigera)蜂粮样本,并通过克隆测序方法,比较分析了新余市水北镇(XYSB)、吉安市戈坪乡(JAGP)、赣州市沙地镇(GZSD)和赣州市齐云山自然保护区(GZQYS)的4种不同林地类型的白斑切叶蜂粉源植物组成及多样性。共鉴定出粉源植物9科10属15种。其中黄荆Vitex negundo和山牡荆Vitex quinata为优势种。Chao1指数、Shannon-wiener指数和Simpson指数分析结果表明,4个样地粉源植物的丰富度和多样性依次为GZQYSGZSDXYSBJAGP。并且,4个样地七月上旬的物种丰富度均明显高于八月中旬。同一时期的粉源植物种类及多样性存在显著差异,表明不同林地利用方式对白斑切叶蜂粉源植物多样性的影响非常明显,并随人为干扰程度的增高而降低。相同样地中2个不同时期均呈现出粉源植物多样性随花期变化而降低的趋势,但其主要粉源植物种类没有发生改变,表明该蜂主要粉源植物没有受到花期变化的影响。因此,黄荆和山牡荆是白斑切叶蜂的主要粉源植物,对维持白斑切叶蜂种群的稳定具有重要作用。