Genome Evolution Due to Allopolyploidization in Wheat

The wheat group has evolved through allopolyploidization, namely, through hybridization among species from the plant genera Aegilops and Triticum followed by genome doubling. This speciation process has been associated with ecogeographical expansion and with domestication. In the past few decades, we have searched for explanations for this impressive success. Our studies attempted to probe the bases for the wide genetic variation characterizing these species, which accounts for their great adaptability and colonizing ability. Central to our work was the investigation of how allopolyploidization alters genome structure and expression. We found in wheat that allopolyploidy accelerated genome evolution in two ways: (1) it triggered rapid genome alterations through the instantaneous generation of a variety of cardinal genetic and epigenetic changes (which we termed “revolutionary” changes), and (2) it facilitated sporadic genomic changes throughout the species’ evolution (i.e., evolutionary changes), which are not attainable at the diploid level. Our major findings in natural and synthetic allopolyploid wheat indicate that these alterations have led to the cytological and genetic diploidization of the allopolyploids. These genetic and epigenetic changes reflect the dynamic structural and functional plasticity of the allopolyploid wheat genome. The significance of this plasticity for the successful establishment of wheat allopolyploids, in nature and under domestication, is discussed.     

Assessing wheat (Triticum aestivum L.) genetic diversity using quality traits, amplified fragment length polymorphisms, simple sequence repeats and proteome analysis

The genetic diversity among 10 Iranian bread wheat (Triticum aestivum) genotypes was analysed using 12 quality traits, 320 amplified fragment length polymorphisms (AFLP) polymorphic fragments, 491 simple sequence repeats (SSR) alleles and 294 proteome markers. The results revealed that the genotypes differed for quality traits, AFLP, SSR and proteome markers. The average genetic diversity based on quality traits (0.684 with a range of 0.266–0.997) was higher than AFLP (0.502 with a range of 0.328–0.717), SSR (0.503 with a range of 0.409–0.595) and proteome (0.464 with a range of 0.264–0.870) markers. Although there were apparent similarities between the groupings of particular genotypes, the overall correspondence between the distance matrices appeared to be rather low. In this study, the cluster analysis based on AFLP data showed the closest agreement with genotypes’ regions of origin or pedigree information. In addition to the genetic diversity assessment, specific proteins with known function were detected uniquely for the studied genotypes. Our results suggest that the classification based on quality traits and genotypic markers of these wheat genotypes will be useful for wheat breeders to plan crosses for positive traits.     

Effect of psyllium husk and wheat mill bran fractions on the microstructure and mixograph characteristics of Arabic bread

When psyllium husk, wheat bran and germ was added, Incorporation of psyllium and wheat bran may affect the dough structure, dough rheology as well as the final quality of baked Arabic flat bread, which, thus, became important for this study. Scanning Electron Micrographs (SEM) taken on Arabic bread, depicted both intact small and the large starch granules on the outer crust area. This was mainly due to the rapid loss of moisture from the Arabic bread surface during intense baking operation leaving less moisture for gelatinization to take place. With psyllium added to WWF at 0, 3, and 5 % level, the peak time was increased from 3 to 4.5 min. The ascending and descending angle values were more or less identical in all the samples except with wheat germ addition, whereas much lower values (51 to 58°) for these parameters were observed, indicating a faster rate of dough breakdown. With psyllium, fine- and coarse bran addition to WWF, a corresponding increase in peak time was observed. Ascending and descending angles showed similar trends to that of the WWF and psyllium combinations. Use of falling number apparatus is an indirect method of measuring the diastatic enzyme activity in cereal flours. WGF showed lower falling-number values (502 s) than the WWF (607 s). Addition of fine bran to WWF lowered the falling number (607 to 563 s) whereas with coarse wheat bran and germ, these values were increased.     

Rye bread and synthetic bread odorants – effective trap bait and lure for German cockroaches

Bread‐in‐beer and bread‐in‐water are prevalent home recipe trap baits for attracting German cockroaches (GCRs), Blattella germanica (L.) (Dictyoptera: Blattellidae), which are significant urban pests. Our objectives were to (1) test the attractiveness of these baits, (2) study the underlying factors of GCR attraction, and (3) determine whether a blend of synthetic bread odorants could replace bread in a trap lure. In large‐arena laboratory experiments with laboratory‐reared GCR males, traps baited with rye bread not only captured eightfold more males than unbaited control traps but also most males released into bioassay arenas. Neither beer nor water enhanced the attractiveness of bread. Bread crust as a bait was more effective than bread crumbs. As Porapak Q headspace volatile extracts of rye bread attracted GCRs, all rye bread odorants in extracts were identified by gas chromatography‐mass spectrometry. Synthetic rye bread odorants and other known bread odorants were then assembled into a master blend. This master blend, and even partial blends lacking certain groups of organic volatiles such as aldehydes and ketones, proved very attractive to GCRs. We conclude that rye bread could be used as an effective bait in retainer traps or, laced with insecticide, as a food source in bait stations. A lure of synthetic bread odorants may eventually replace bread as bait, but the minimum number of essential odorants for that lure has yet to be determined.     

Floral resources and risk of exposure to pesticides for Melipona quadrifasciata anthidioides Lepeletier 1836 in a Cerrado of São Paulo (Brazil)

Honey and bee bread samples from storage pots of Melipona quadrifasciata anthidioides were collected monthly from April 2015 to May 2016 in the Mogi Guaçu Biological Reserve (22º 10? S, 47º 11? W). The flora in the site is characteristic of the Atlantic Forest with preserved areas of savanna-like vegetation surrounded by commercial forests, orchards and various crops of exotic and native plants. Samples were analysed with the use of melissopalynological methodology and 46 pollen types from 38 genera and 30 families were identified in 25 honey samples. Fabaceae, Asteraceae, Myrtaceae, Sapindaceae showed the greatest pollen richness in honey. Predominant nectariferous pollen types were Anadenanthera, Cordia, Eucalyptus, Mimosa scabrella, Schefflera, Sida, Serjania and Vernonia. Twenty-eight types of pollen from 21 genera and 19 families were identified in 22 bee bread samples. Fabaceae, Asteraceae and Myrtaceae showed the highest pollen richness. Anadenanthera, Cecropia, Eucalyptus, Melastomataceae, Mimosa scabrella, Mimosa verrucosa and Myrcia were the most frequent polliniferous pollen types. Principal component analysis (PCA) demonstrated that honey and pollen samples formed two main groups of similarity, mainly due to Eucalyptus’ nectar and pollen of Melastomataceae, respectively. Melipona quadrifasciata anthidioides collected nectar and pollen from the preserved areas as well as in the secondary and ‘ruderal’ vegetation and in cultivated forests/fields, suggesting their importance as pollinators both of native flora and exotic species. The use of trophic resources of plants grown with pesticides is a concern for the conservation of these species of bee and should be better studied.     

Effect of genome, induction medium and temperature pretreatment on green plant production in durum ( Triticum turgidum var. durum ) x bread wheat ( Triticum aestivum L. em Thell) crosses

The recalcitrancy of durum wheat (Triticum turgidum var. durum) to anther culture, was attempted to be overcome by transferring the responsible genes form bread wheat B-genome to the respective on durum wheat, determining an appropriate induction medium and clarifying the necessity of cold pretreatment. For this, three durum wheat cultivars were crossed to two bread wheat (Triticum aestivum L. em Thell) cultivars. The resulting F₁ plants and their original cultivars were grown in the field and anthers at the appropriate microspore stage were cultured on potato-2 and W₁₄ media with and without low temperature pretreatment. No green plants were produced from the parental durum wheat cultivars. In contrast, green plants were produced from the F₁ plants. The best results in three of the four F₁ hybrids were recorded when potato-2 was used as induction medium. A more variable response of the examined genotypes was noticed with respect to temperature pretreatment. Regarding green plant production, a negative effect of cold pretreatment was observed in two of the F₁ hybrids when they were cultured on potato-2. Chromosome counts on root tips from the resulting green plants revealed that they all carried D-genome chromosomes. The last observation could suggest that D-genome chromosomes are necessary for anther culture response in wheat. Yet, the production of one green plant with 15 chromosomes may indicate that the development of extracted durum genotypes from bread wheat genotypes with good response to in vitro anther culture might be possible. Further work however, is needed for this to be verified.     

Phytase production by Sporotrichum thermophile in a cost‐effective cane molasses medium in submerged fermentation and its application in bread

Aims: Phytase production by Sporotrichum thermophile in a cost‐effective cane molasses medium in submerged fermentation and its application in bread. Methods and Results: The production of phytase by a thermophilic mould S. thermophile was investigated using free and immobilized conidiospores in cane molasses medium in shake flasks, and stirred tank and air‐lift fermenters. Among surfactants tested, Tweens (Tween‐20, 40 and 80) and sodium oleate increased phytase accumulation, whereas SDS and Triton X‐100 inhibited the enzyme production. The mould produced phytase optimally at a_w 0·95, and it declined sharply below this a_w value. The enzyme production was comparable in air‐lift and stirred tank reactors with a marked reduction in fermentation time. Among the matrices tried, Ca‐alginate was the best for conidiospore immobilization, and fungus secreted sustained levels of enzyme titres over five cycles. The phytic acid in the dough was efficiently hydrolysed by the enzyme accompanied by the liberation of soluble phosphate in the bread. Conclusions: The phytase production by S. thermophile was enhanced in the presence of Tween‐80 in cane molasses medium. A peak in enzyme production was attained in 48 h in the fermenter when compared with that of 96 h in shake flasks. Ca‐alginate immobilized conidiospores germinated to produce fungal growth that secreted sustained levels of phytase over five cycles. The bread made with phytase contained reduced level of phytic acid and a high‐soluble phosphate. Significance and Impact of the Study: The phytase accumulation by S. thermophile was increased by the surfactants. The sustainability of enzyme production in stirred tank and air‐lift fermenters suggested the possibility for scaling up of phytase. The bread made with phytase contained low level of antinutrient, i.e. phytic acid.     

荞麦粉营养品质与加工特性研究

通过对荞麦粉营养品质和加工特性的测定分析,结果表明：荞麦粉必需氨基酸含量高,氨基酸组成优于小麦面粉,接近WHO／FAO建议模式;荞麦粉的淀粉酶活性远低于小麦粉,是荞麦粉粘度远大于小麦粉以及降落值(Falling number)远高于小麦粉的主要原因之一。营养成分在荞麦子粒的不同部位的分布很不均衡,外层麸粉的营养价值高于内层心粉,但内层心粉的加工性能优于外层麸粉。     

“Entombed Pollen”: A new condition in honey bee colonies associated with increased risk of colony mortality

Here we describe a new phenomenon, entombed pollen, which is highly associated with increased colony mortality. Entombed pollen is sunken, capped cells amidst “normal”, uncapped cells of stored pollen, and some of the pollen contained within these cells is brick red in color. There appears to be a lack of microbial agents in the pollen, and larvae and adult bees do not have an increased rate of mortality when they are fed diets supplemented with entombed pollen in vitro, suggesting that the pollen itself is not directly responsible for increased colony mortality. However, the increased incidence of entombed pollen in reused wax comb suggests that there is a transmittable factor common to the phenomenon and colony mortality. In addition, there were elevated pesticide levels, notably of the fungicide chlorothalonil, in entombed pollen. Additional studies are needed to determine if there is a causal relationship between entombed pollen, chemical residues, and colony mortality.