High frequency of HMW-GS sequence variation through somatic hybridization between Agropyron elongatum and common wheat

Insulin Resistance and Hypertension: Mechanisms Involved and Modifying Factors for Effective Glucose Control

Factors such as aging, an unhealthy lifestyle with decreased physical activity, snacking, a standard Western diet, and smoking contribute to raising blood pressure to a dangerous level, increasing the risk of coronary artery disease and heart failure. Atherosclerosis, or aging of the blood vessels, is a physiological process that has accelerated in the last decades by the overconsumption of carbohydrates as the primary sources of caloric intake, resulting in increased triglycerides and VLDL-cholesterol and insulin spikes. Classically, medications ranging from beta blockers to angiotensin II blockers and even calcium channel blockers were used alone or in combination with lifestyle modifications as management tools in modern medicine to control arterial blood pressure. However, it is not easy to control blood pressure or the associated complications. A low-carbohydrate, high-fat (LCHF) diet can reduce glucose and insulin spikes, improve insulin sensitivity, and lessen atherosclerosis risk factors. We reviewed articles describing the etiology of insulin resistance (IR) and its impact on arterial blood pressure from databases including PubMed, PubMed Central, and Google Scholar. We discuss how the LCHF diet is beneficial to maintaining arterial blood pressure at normal levels, slowing down the progression of atherosclerosis, and reducing the use of antihypertensive medications. The mechanisms involved in IR associated with hypertension are also highlighted.

Molecular Characterization and Marker Development of the HMW-GS Gene from Thinopyrum elongatum for Improving Wheat Quality

The quality of wheat primarily depends on its storage protein quality, especially in regards to gluten content and high-molecular-weight glutenin subunits (HMW-GS). The number of HMW-GS alleles is limited in bread wheat (Triticum aestivum L.), whereas it is abundant in wheat relatives. Therefore, HMW-GS alleles from wheat relatives could provide a potential for improving quality in wheat breeding. Thinopyrum elongatum (EE) is one of the relatives of wheat. The E genome is closely related to the ABD genome in wheat; therefore, Th. elongatum is often used as an excellent exogenous gene donor for wheat genetic improvement. In this study, the high-molecular glutenin subunit gene was cloned and sequenced from Th. elongatum. A specific molecular marker for identifying the Glu-1Ey subunit gene was developed and applied to detected wheat-Th. elongatum alien introgression lines. Quality analysis indicated that the substitution and addition lines containing Th. elongatum alleles significantly (p < 0.05) increased grain protein content by 3.76% to 5.11%, wet-gluten content by 6.55% to 8.73%, flour 8-MW by 0.25% to 6.35%, and bread volume value by 33.77 mL to 246.50 mL, in comparing it with Chinese Spring. The GMP content and lactic acid SRC showed significant positive correlations with flour processing quality and might be used as indicators for wheat quality. The results were expected to provide a novel route for improving processing quality in wheat quality breeding.

The production of wheat - Aegilops sharonensis 1Ssh chromosome substitution lines harboring alien novel high-molecular-weight glutenin subunits

In our previous work, a novel high-molecular-weight glutenin subunit (HMW-GS) with an extremely large molecular weight from Aegilops sharonensis was identified that may contribute to excellent wheat (Triticum aestivum) processing quality and increased dough strength, and we further generated HMW-GS homozygous lines by crossing. In this study, we crossed the HMW-GS homozygous line 66-17-52 with 'Chinese Spring' Ph1 mutant CS ph1b to induce chromosome recombination between wheat and Ae. sharonensis. SDS-PAGE was used to identify 19 derived F₂ lines with the HMW-GSs of Ae sharonensis. The results of non-denaturing fluorescence in situ hybridization (ND-FISH) indicated that lines 6-1 and 6-7 possessed a substitution of both 5D chromosomes by a pair of 1S^sh chromosomes. Further verification by newly developed 1S^sh-specific chromosome markers showed that these two lines amplified the expected fragment. Thus, it was concluded that lines 6-1 and 6-7 are 1S^sh(5D) chromosome substitution lines. The 1S^sh(5D) chromosome substitution lines, possessing alien subunits with satisfactory quality-associated structural features of large repetitive domains and increased number of subunits, may have great potential in strengthening the viscosity and elasticity of dough made from wheat flour. Therefore, these substitution lines can be used for wheat quality improvement and further production of 1S^sh translocation lines.

5-Azacytidine treatment and TaPBF-D over-expression increases glutenin accumulation within the wheat grain by hypomethylating the Glu-1 promoters

5-azaC treatment and TaPBF - D over-expression decrease C-methylation status of three Glu - 1 gene promoters, and aid in enhancing the expression of the Glu - 1 genes. The wheat glutenins exert a strong influence over dough elasticity, but the regulation of their encoding genes has not been firmly established. Following treatment with 5-azacytidine (5-azaC), both the weight and glutenin content of the developing and mature grains were significantly increased. The abundance of transcript produced by the Glu-1 genes (encoding high-molecular-weight glutenin subunits), as well as those encoding demethylases and transcriptional factors associated with prolamin synthesis was higher than in grain of non-treated plants. These grains also contained an enhanced content of the prolamin box binding factor (PBF) protein. Bisulfite sequencing indicated that the Glu-1 promoters were less strongly C-methylated in the developing grain than in the flag leaf, while in the developing grain of 5-azaC treated plants, the C-methylation level was lower than in equivalent grains of non-treated plants. Both Glu-1 transcript abundance and glutenin content were higher in the grain set by three independent over-expressors of the D genome homoeolog of TaPBF than in the grain set by wild type plants. When assessed 10 days after flowering, the Glu-1 promoters' methylation level was lower in the developing grains set by the TaPBF-D over-expressor than in the wild type control. An electrophoretic mobility shift assay showed that PBF-D was able to bind in vitro to the P-box of Glu-1By8 and -1Dx2, while a ChIP-qPCR analysis revealed that a lower level of C-methylation in the Glu-1By8 and -1Dx2 promoters improved the TaPBF binding. We suggest that promoter DNA C-methylation is a key determinant of Glu-1 transcription.

Cereal Crops Are not Created Equal: Wheat Consumption Associated with Obesity Prevalence Globally and Regionally

BACKGROUND

Cereals have been extensively advocated as the beneficial food group in terms of body weight management, but each staple cereal crop may contribute in different ways. Studies of the association between wheat availability and risk of obesity are controversial. This study aimed to test the global and regional association between wheat availability as reported by FAO and obesity prevalence at a population level. FAO does not distinguish between whole grain wheat and refined wheat.

METHODS

Population-specific data from 170 countries on prevalence of obesity, availabilities of mixed cereals, wheat, rice, maize, meat, sugar, fat, soy and calories and GDP are obtained from the UN agencies. All variables were measured as per capita per day (or per year). Each country is treated as an individual subject. SPSS v. 22 is used to analyse these data for all the 170 countries and official country groupings (regions) using non parametric and parametric correlations, including partial correlation analysis.

RESULTS

Pearson's correlation coefficient analysis showed that obesity prevalence is positively associated with wheat availability (r = 0.500, p < 0.001), but is inversely associated with availabilities of total cereals (r = -0.132, p = 0.087), rice (r = -0.405, p < 0.001) and maize (r = -0.227, p = 0.004). These associations remain in partial correlation model when we keep availabilities of meat, fat, sugar, soy, caloric intake and GDP statistically constant. Overall, positive associations between wheat availability and obesity prevalence remain in different regions. Maize and mixed cereal availabilities do not show independent associations with the obesity prevalence.

CONCLUSIONS

Our study suggests that wheat availability is an independent predictor of the obesity prevalence both worldwide and with special regard to the regions of Africa, Americas and Asia. Future studies should distinguish between possible influence of whole grain and ultra-processed refined wheat products.

Genetic and epigenetic changes in somatic hybrid introgression lines between wheat and tall wheatgrass

Broad phenotypic variations were induced in derivatives of an asymmetric somatic hybridization of bread wheat (Triticum aestivum) and tall wheatgrass (Thinopyrum ponticum Podp); however, how these variations occurred was unknown. We explored the nature of these variations by cytogenetic assays and DNA profiling techniques to characterize six genetically stable somatic introgression lines. Karyotyping results show the six lines similar to their wheat parent, but GISH analysis identified the presence of a number of short introgressed tall wheatgrass chromatin segments. DNA profiling revealed many genetic and epigenetic differences, including sequences deletions, altered regulation of gene expression, changed patterns of cytosine methylation, and the reactivation of retrotransposons. Phenotypic variations appear to result from altered repetitive sequences combined with the epigenetic regulation of gene expression and/or retrotransposon transposition. The extent of genetic and epigenetic variation due to the maintenance of parent wheat cells in tissue culture was assessed and shown to be considerably lower than had been induced in the introgression lines. Asymmetric somatic hybridization provides appropriate material to explore the nature of the genetic and epigenetic variations induced by genomic shock.

The detection of a de novo allele of the Glu-1Dx gene in wheat-rye hybrid offspring

This study provides a link between a de novo gene and novel phenotype in wheat-rye hybrids that can be used as a model for induced de novo genetic variation. Wide hybridization can produce de novo DNA variation that may cause novel phenotypes. However, there is still a lack of specific links between changed genes and novel phenotypes in wide hybrids. The well-studied high-molecular-weight glutenin subunit (HMW-GS) genes in tribe Triticeae provide a useful model for addressing this issue. In this study, we investigated the feasibility of a wheat-rye hybridization method for inducing de novo phenotypes using the Glu-1Dx2.2 subunit as an example. We developed three hexaploid wheat lines with normal fertility and a Glu-1Dx2.2 variant, named Glu-1Dx2.2 (v) , derived from three F1 hybrids. The wild-type Glu-1Dx2.2 has two direct repeats of 295 bp length separated by an intervening 101 bp in its central repetitive region. In the mutant Glu-1Dx2.2 (v) , one copy of the repeats and the intervening sequence were deleted, probably through homology-dependent illegitimate recombination (IR). This study provides a direct link between a de novo allele and novel phenotype. Our results indicate that the wheat-rye method may be a useful tool to induce de novo genetic variations that broaden the genetic diversity for wheat improvement.

Characterization of high-molecular-weight glutenin subunits from Eremopyrum bonaepartis and identification of a novel variant with unusual high molecular weight and altered cysteine residues

We characterized two high-molecular-weight glutenin subunit (HMW-GS) variants from Eremopyrum bonaepartis, determined their complete open reading frames, and further expressed them in a bacterial system. The variants have many novel structural features compared with typical subunits encoded by Glu-1 loci: 1Fx3.7 and 1Fy1.5 exhibit hybrid properties of x- and y-type subunits. In addition, unusual molecular mass and altered number and distribution of cysteine residues were unique features of HMW-GSs encoded by Glu-F1 from E. bonaepartis. The mature 1Fx3.7 subunit has a full length of 1,223 amino acid residues, making it the largest subunit found thus far, while 1Fy1.5 is just 496 residues. In addition, the mutated PGQQ repeat motif was found in the repetitive region of 1Fx3.7. Although it has a similar molecular mass to that previously reported for 1Dx2.2, 1Dx2.2* and 1S(sh)x2.9 subunits, 1Fx3.7 appears to have had a different evolutionary history. The N-terminal and repetitive regions have a total of four additional cysteine residues, giving 1Fx3.7 a total of eight cysteines, while 1Fy1.5 has only six cysteines because the GHCPTSPQQ nonapeptide at the end of the repetitive region is deleted. With its extra cysteine residues and the longest repetitive region, features that are relevant to good wheat quality, the 1Fx3.7 subunit gene could be an excellent candidate for applications in wheat quality improvement.

The place of asymmetric somatic hybridization in wheat breeding

Since its first development some 40 years ago, the application of the somatic hybridization technique has generated a body of hybrid plant material involving a wide combination of parental species. Until the late 1990s, the technique was ineffective in wheat, as regeneration from protoplasts was proving difficult to achieve. Since this time, however, a successful somatic hybridization protocol for wheat has been established and used to generate a substantial number of both symmetric and asymmetric somatic hybrids and derived materials, especially involving the parental combination bread wheat and tall wheatgrass (Thinopyrum ponticum). This review describes the current state of the art for somatic hybridization in wheat and focuses on its potential application for wheat improvement.

Introduction of chromosome segment carrying the seed storage protein genes from chromosome 1V of Dasypyrum villosum showed positive effect on bread-making quality of common wheat

Development of wheat- D. villosum 1V#4 translocation lines; physically mapping the Glu - V1 and Gli - V1 / Glu - V3 loci; and assess the effects of the introduced Glu - V1 and Gli - V1 / Glu - V3 on wheat bread-making quality. Glu-V1 and Gli-V1/Glu-V3 loci, located in the chromosome 1V of Dasypyrum villosum, were proved to have positive effects on grain quality. However, there are very few reports about the transfer of the D. villosum-derived seed storage protein genes into wheat background by chromosome manipulation. In the present study, a total of six CS-1V#4 introgression lines with different alien-fragment sizes were developed through ionizing radiation of the mature female gametes of CS--D. villosum 1V#4 disomic addition line and confirmed by cytogenetic analysis. Genomic in situ hybridization (GISH), chromosome C-banding, twelve 1V#4-specific EST-STS markers and seed storage protein analysis enabled the cytological physical mapping of Glu-V1 and Gli-V1/Glu-V3 loci to the region of FL 0.50-1.00 of 1V#4S of D. villosum. The Glu-V1 allele of D. villosum was Glu-V1a and its coded protein was V71 subunit. Quality analysis indicated that Glu-V1a together with Gli-V1/Glu-V3 loci showed a positive effect on protein content, Zeleny sedimentation value and the rheological characteristics of wheat flour dough. In addition, the positive effect could be maintained when specific Glu-V1 and Gli-V1/Glu-V3 loci were transferred to the wheat genetic background as in the case of T1V#4S-6BS · 6BL, T1V#4S · 1BL and T1V#4S · 1DS translocation lines. These results showed that the chromosome segment carrying the Glu-V1 and Gli-V1/Glu-V3 loci in 1V#4S of D. villosum had positive effect on bread-making quality, and the T1V#4S-6BS · 6BL and T1V#4S · 1BL translocation lines could be useful germplasms for bread wheat improvement. The developed 1V#4S-specific molecular markers could be used to rapidly identify and trace the alien chromatin of 1V#4S in wheat background.

Gluten and wheat intolerance today: are modern wheat strains involved?

Celiac disease is a food-induced enteropathy resulting from exposure to gluten in genetically predisposed individuals. The non-celiac gluten sensitivity (NCGS) is a less known syndrome whose prevalence is under-estimated. The last decades have seen changes in the clinical presentation of both diseases. One possible explanation is that changes in the gluten-rich cereals themselves were the principal causes. Celiac-triggering gluten proteins are indeed expressed to higher levels in modern cereals while non-triggering proteins are expressed less. Sophisticated hybridization techniques have been used to produce new strains of modern wheat, the most high-yielding of which have since made their way into human foods in the absence of animal or human safety testing. The dramatic changes in the clinical presentation of celiac disease and NCGS have taken place when new cereal hybrids were introduced into human foods. This is a critical medical and environmental issue which needs to be investigated by appropriate studies.

LcSAIN1, a novel salt-induced gene from sheepgrass, confers salt stress tolerance in transgenic Arabidopsis and rice

Previously, we identified >1,500 genes that were induced by high salt stress in sheepgrass (Leymus chinensis, Gramineae: Triticeae) when comparing the changes in their transcription levels in response to high salt stress by next-generation sequencing. Among the identified genes, a gene of unknown function (designated as Leymus chinensis salt-induced 1, LcSAIN1) showed a high sequence identity to its homologs from wheat, Hordeum vulgare and Oryza sativa, but LcSAIN1 and its homologs produce hypothetical proteins with no conserved functional domains. Transcription of the LcSAIN1 gene was up-regulated by various stresses. The overexpression of LcSAIN1 in Arabidopsis and rice increased the greening rate of cotyledons, the fresh weight, root elongation, plant height and the plant survival rate when compared with control plants and conferred a tolerance against salt stress. Subcellular localization analysis indicated that LcSAIN1 is localized predominantly in the nucleus. Our results show that the LcSAIN1 gene might play an important positive modulation role in increasing the expression of transcription factors (MYB2 and DREB2A) and functional genes (P5CS and RAB18) in transgenic plants under salt stress and that it augments stress tolerance through the accumulation of compatible solutes (proline and soluble sugar) and the alleviation of changes in reactive oxygen species. The LcSAIN1 gene could be a potential resource for engineering salinity tolerance in important crop species.

A transcriptomic analysis reveals the nature of salinity tolerance of a wheat introgression line

The bread wheat cultivar Shanrong No.3 (SR3) is a salinity tolerant derivative of an asymmetric somatic hybrid between cultivar Jinan 177 (JN177) and tall wheatgrass (Thinopyrum ponticum). To reveal some of the mechanisms underlying its elevated abiotic stress tolerance, both SR3 and JN177 were exposed to iso-osmotic NaCl and PEG stress, and the resulting gene expression was analysed using a customized microarray. Some genes associated with stress response proved to be more highly expressed in SR3 than in JN177 in non-stressed conditions. Its unsaturated fatty acid and flavonoid synthesis ability was also enhanced, and its pentose phosphate metabolism was more active than in JN177. These alterations in part accounted for the observed shift in the homeostasis related to reactive oxygen species (ROS). The specific down-regulation of certain ion transporters after a 0.5 h exposure to 340 mM NaCl demonstrated that Na(+) uptake occurred rapidly, so that the early phase of salinity stress imposes more than simply an osmotic stress. We discussed the possible effect of the introgression of new genetic materials in wheat genome on stress tolerance.

Hybrid inflorescences derived from gamma-fusion of Arabidopsis thaliana with Bupleurum scorzonerifolium

In our early experiments, a variety of Bupleurum scorzonerifolium-like somatic hybrid plants were obtained from protoplast fusion between Arabidopsis thaliana and UV-treated/untreated B. scorzonerifolium. To compare the effects of UV and γ-ray irradiation on the B. scorzonerifolium partner and obtain Arabidopsis-like hybrids, we designed a novel combination of somatic hybridization between A. thaliana and B. scorzonerifolium. Before protoplast isolation and fusion, the suspension cells of B. scorzonerifolium were irradiated by gamma ray ((60)Co, 50 Gy with 1.3 Gy min(-1)). Both parental protoplasts lost regeneration capacity, but over 100 somatic hybrids restored the capacity and developed to Arabidopsis-like inflorescences and flowers with some characteristics of B. scorzonerifolium. Some hybrid flowers showed yellow sepal, petal, or carpel, whose color was similar to the petal of B. scorzonerifolium; the others had silique of Arabidopsis with angularity of B. scorzonerifolium, and their parts possessed five stamens, the same as B. scorzonerifolium. Cytological analysis showed that three hybrids had Arabidopsis-like karyotypes. Random Amplified Polymorphic DNA (RAPD) and Simple Sequence Repeats (SSR) profiles revealed that both parental fragments were amplified from these hybrids. These results indicated chromatin introgression from B. scorzonerifolium to A. thaliana, which may be related to the complementation of hybrid inflorescence and flower generation.