Interspecific and intergeneric hybridization as a source of variation for wheat grain quality improvement.

KEY MESSAGE: The hybridization events with wild relatives and old varieties are an alternative source for enlarging the wheat quality variability. This review describes these process and their effects on the technological and nutritional quality. Wheat quality and its end-uses are mainly based on variation in three traits: grain hardness, gluten quality and starch. In recent times, the importance of nutritional quality and health-related aspects has increased the range of these traits with the inclusion of other grain components such as vitamins, fibre and micronutrients. One option to enlarge the genetic variability in wheat for all these components has been the use of wild relatives, together with underutilised or neglected wheat varieties or species. In the current review, we summarise the role of each grain component in relation to grain quality, their variation in modern wheat and the alternative sources in which wheat breeders have found novel variation.

Diversification of the celiac disease α-gliadin complex in wheat: a 33-mer peptide with six overlapping epitopes, evolved following polyploidization.

The gluten proteins from wheat, barley and rye are responsible both for celiac disease (CD) and for non-celiac gluten sensitivity, two pathologies affecting up to 6-8% of the human population worldwide. The wheat α-gliadin proteins contain three major CD immunogenic peptides: p31-43, which induces the innate immune response; the 33-mer, formed by six overlapping copies of three highly stimulatory epitopes; and an additional DQ2.5-glia-α3 epitope which partially overlaps with the 33-mer. Next-generation sequencing (NGS) and Sanger sequencing of α-gliadin genes from diploid and polyploid wheat provided six types of α-gliadins (named 1-6) with strong differences in their frequencies in diploid and polyploid wheat, and in the presence and abundance of these CD immunogenic peptides. Immunogenic variants of the p31-43 peptide were found in most of the α-gliadins. Variants of the DQ2.5-glia-α3 epitope were associated with specific types of α-gliadins. Remarkably, only type 1 α-gliadins contained 33-mer epitopes. Moreover, the full immunodominant 33-mer fragment was only present in hexaploid wheat at low abundance, probably as the result of allohexaploidization events from subtype 1.2 α-gliadins found only in Aegilops tauschii, the D-genome donor of hexaploid wheat. Type 3 α-gliadins seem to be the ancestral type as they are found in most of the α-gliadin-expressing Triticeae species. These findings are important for reducing the incidence of CD by the breeding/selection of wheat varieties with low stimulatory capacity of T cells. Moreover, advanced genome-editing techniques (TALENs, CRISPR) will be easier to implement on the small group of α-gliadins containing only immunogenic peptides.

Wheat waxy proteins: polymorphism, molecular characterization and effects on starch properties.

The starch fraction, comprising about 70% of the total dry matter in the wheat grain, can greatly affect the end-use quality of products made from wheat kernels, especially Asian noodles. Starch is associated with the shelf life and nutritional value (glycaemic index) of different wheat products. Starch quality is closely associated with the ratio of amylose to amylopectin, the two main macromolecules forming starch. In this review, we briefly summarise the discovery of waxy proteins-shown to be the sole enzymes responsible for amylose synthesis in wheat. The review particularly focuses on the different variants of these proteins, together with their molecular characterisation and evaluation of their effects on starch composition. There have been 19 different waxy protein variants described using protein electrophoresis; and at a molecular level 19, 15 and seven alleles described for Wx-A1, Wx-B1 and Wx-D1, respectively. This large variability, found in modern wheat and genetic resources such as wheat ancestors and wild relatives, is in some cases not properly ordered. The proper ordering of all the data generated is the key to enhancing use in breeding programmes of the current variability described, and thus generating wheat with novel starch properties to satisfy the demand of industry and consumers for novel high-quality processed food.

Molecular characterization of novel LMW-i glutenin subunit genes from Triticum urartu Thum. ex Gandil.

KEY MESSAGE: A high level of genetic diversity was found in LMW-i genes from Triticum urartu, resulting in detection of 11 novel alleles. The variability detected could affect gluten quality. Low-molecular weight glutenin subunits are important in determining the viscoelastic properties of wheat dough. Triticum urartu Thum. ex Gandil., which is related to the A genome of polyploid wheat, has been shown as a good source of variation for these subunits. The present study evaluated the variability of LMW-i genes in this species. High polymorphism was found in the sequences analysed and resulted in the detection of 11 novel alleles, classified into two sets (Group-I and -II) showing unique SNPs and InDels. Both groups were associated with Glu-A3-1 genes from common wheat. In general, deduced proteins from Group-II genes possessed a higher proportion of glutamine and proline, which has been previously suggested to be related with good quality. Moreover, there were other changes compared to common wheat. This novel variation could affect dough quality. Additional epitopes for celiac disease were also detected, suggesting that these subunits could be highly reactive. The results showed that T. urartu could be an important source of genetic variability for LMW-i genes that could enlarge the genetic pool of modern wheat.

Molecular characterization of waxy alleles in three subspecies of hexaploid wheat and identification of two novel Wx-B1 alleles.

KEY MESSAGE: Two novel Wx - B1 null alleles that enlarge the genetic variability for this wheat gene were characterized, whose effects on wheat quality could be different to those of the Wx - B1b allele. The starch composition of wheat grain has a primary influence on flour quality. Wheat starch consists of two types of glucose polymers: amylose (22-35% of the total) and amylopectin (68-75% of the total). Amylose is synthesized by waxy proteins. Several studies have contributed to the catalogue of waxy alleles available for breeders, and the search for novel alleles of these and other proteins related to flour quality continues. In this report, we describe the characterization of two novel Wx-B1 alleles (Wx-B1k and Wx-B1m) in a collection of macha, Indian dwarf and club wheat. Several accessions lacking Wx-B1 protein were detected, and some were caused by the common Wx-B1b null allele. Of the other accessions, four from Indian dwarf wheat showed the insertion of 4 bp within the seventh exon, and one from club wheat had a deletion of four nucleotides in the second exon. These mutations were novel and provisionally catalogued as Wx-B1k and Wx-B1m, respectively, and could be used to enlarge the genetic variability for this gene.

Allelic diversity and molecular characterization of puroindoline genes in five diploid species of the Aegilops genus.

Grain hardness is an important quality trait in wheat. This trait is related to the variation in, and the presence of, puroindolines (PINA and PINB). This variation can be increased by the allelic polymorphism present in the Aegilops species that are related to wheat. This study evaluated allelic Pina and Pinb gene variability in five diploid species of the Aegilops genus, along with the molecular characterization of the main allelic variants found in each species. This polymorphism resulted in 16 alleles for the Pina gene and 24 alleles for the Pinb gene, of which 10 and 17, respectively, were novel. Diverse mutations were detected in the deduced mature proteins of these alleles, which could influence the hardness characteristics of these proteins. This study shows that the diploid species of the Aegilops genus could be a good source of genetic variability for both Pina and Pinb genes, which could be used in breeding programmes to extend the range of different textures in wheat.

Molecular characterisation of the amino- and carboxyl-domains in different Glu-A1x alleles of Triticum urartu Thum. ex Gandil.

The wild diploid wheat (Triticum urartu Thum. ex Gandil.) is a potential gene source for wheat breeding, as this species has been identified as the A-genome donor in polyploid wheats. One important wheat breeding trait is bread-making quality, which is associated in bread wheat (T. aestivum ssp. aestivum L. em. Thell.) with the high-molecular-weight glutenin subunits. In T. urartu, these proteins are encoded by the Glu-A1x and Glu-A1Ay genes at the Glu-A (u) 1 locus. The Glu-A1x genes of 12 Glu-A (u) 1 allelic variants previously detected in this species were analysed using PCR amplification and sequencing. Data showed wide diversity for the Glu-A1x alleles in T. urartu, which also showed clear differences to the bread wheat alleles. This variation could enlarge the high-quality genetic pool of modern wheat and be used to diversify the bread-making quality in durum (T. turgidum ssp. durum Desf. em. Husn.) and common wheat.

Genetic Variability for Grain Components Related to Nutritional Quality in Spelt and Common Wheat.

Spelt (Triticum aestivum ssp. spelta) is part of the so-called ancient wheats. These types of wheats are experiencing a revival as they have been proposed to be healthier than conventional wheat. However, the given healthier condition of spelt is not substantiated by solid scientific evidence. The objective of this study was to analyze the genetic variability for several grain components, related to nutritional quality (arabinoxylans, micronutrients, phytic acid) in a set of spelt and common wheat genotypes to determinate if spelt is potentially healthier than common wheat. The results obtained indicated that within the compared species, there is a significant variation in the nutritional compounds, and it is not truthful and accurate to state that one species is healthier than the other. Within both groups, genotypes showing outstanding values for some traits were detected, which could be used in breeding programs to develop new wheat cultivars with good agronomic performance and nutritional quality.

Processing and Bread-Making Quality Profile of Spanish Spelt Wheat.

Spelt wheat (Triticum aestivum L. ssp. spelta Thell.) is an ancient wheat that has been widely cultivated for hundreds of years. Recently, this species has been neglected in most of Europe; however, the desire for more natural and traditional foods has driven a revival of the crop. In the current study, eighty-eight traditional spelt genotypes from Spain, together with nine common wheat cultivars and one modern spelt (cv. Anna Maria) were grown during a period of two years in Andalucia (southern Spain). In each, several traits were measured in to evaluate their milling, processing, and end-use quality (bread-making). The comparison between species suggested that, in general, spelt and common wheat showed differences for most of the measured traits; on average, spelt genotypes had softer grains, higher protein content (14.3 vs. 11.9%) and gluten extensibility (alveograph P/L 0.5 vs. 1.8), and lower gluten strength (alveograph W 187 vs. 438 × 10-4 J). In the baking test, both species showed similar values. Nevertheless, the analysis of this set of spelt genotypes showed a wide range for all measured traits, with higher values than common wheat in some spelt genotypes for some traits. This opens up the possibility of using these materials in future breeding programs, to develop either new spelt or common wheat cultivars.

Molecular characterization of a new waxy allele with partial expression in spelt wheat.

Starch composition which is dependent on the waxy protein, the enzyme responsible for amylose synthesis in the grain, is an important aspect of the wheat quality. In this report, we describe the characterization of a novel Wx-A1 allele (Wx-A1g formerly known as -Wx-A1a) in Spanish spelt wheat lines which is responsible for a remarkable decline in the concentration of Wx-A1 protein found in the endosperm. Comparison of the DNA sequences in the Wx-A1a and Wx-A1g alleles showed the presence of a 160-bp insertion within the fourth intron in the latter. This insertion had some characteristics of a transposable-like element. RT-PCR analysis showed the presence of normal and aberrant mRNA transcripts in the Wx-A1g lines, indicating that the aberrant transcripts are un-spliced and contained the longer fourth intron. This may be related to the low level of Wx-A1 protein in these lines. In addition, a simple and fast PCR assay was designed for differentiating among different Wx-A1 alleles (a, b, f and g). The mutation described here is not related to either of the Wx-A1 mutations identified previously in common and durum wheats and could help to extend the range of amylose content of wheats.

Waxy genes from spelt wheat: new alleles for modern wheat breeding and new phylogenetic inferences about the origin of this species.

BACKGROUND AND AIMS: Waxy proteins are responsible for amylose synthesis in wheat seeds, being encoded by three waxy genes (Wx-A1, Wx-B1 and Wx-D1) in hexaploid wheat. In addition to their role in starch quality, waxy loci have been used to study the phylogeny of wheat. The origin of European spelt (Triticum aestivum ssp. spelta) is not clear. This study compared waxy gene sequences of a Spanish spelt collection with their homologous genes in emmer (T. turgidum ssp. dicoccum), durum (T. turgidum ssp. durum) and common wheat (T. aestivum ssp. aestivum), together with other Asian and European spelt that could be used to determine the origin of European spelt. METHODS: waxy genes were amplified and sequenced. Geneious Pro software, DNAsp and MEGA5 were used for sequence, nucleotide diversity and phylogenetic analysis, respectively. KEY RESULTS: Three, four and three new alleles were described for the Wx-A1, Wx-B1 and Wx-D1 loci, respectively. Spelt accessions were classified into two groups based on the variation in Wx-B1, which suggests that there were two different origins for the emmer wheat that has been found to be part of the spelt genetic make-up. One of these groups was only detected in Iberian material. No differences were found between the rest of the European spelt and the Asiatic spelt, which suggested that the Iberian material had a different origin from the other spelt sources. CONCLUSIONS: The results suggested that the waxy gene variability present in wheat is undervalued. The evaluation of this variability has permitted the detection of ten new waxy alleles that could affect starch quality and thus could be used in modern wheat breeding. In addition, two different classes of Wx-B1 were detected that could be used for evaluating the phylogenetic relationships and the origins of different types of wheat.

Amylose content and starch properties in emmer and durum wheat lines with different waxy proteins composition.

BACKGROUND: Emmer wheat is a neglected crop that can be used in the breeding of modern durum wheat for quality. One important aspect of this quality is the starch composition, which is related to the waxy proteins. A collection of emmer wheat was analysed previously for waxy protein composition, and two new Wx-B1 alleles were found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and DNA sequencing analysis. It is necessary to analyse the effect of these alleles in starch properties and compare them to durum wheat ones. RESULTS: In the current study, emmer lines carrying three different Wx-B1 alleles (Wx-B1b, -B1g, -B1c*), including one with the null allele (Wx-B1b), together with durum cultivars Langdon (Wx-B1a) and Mexicali (Wx-B1c'), were analysed for amylose content. Differences were detected between both species, and the line lacking Wx-B1 protein showed a remarkably low amylose content. In addition, data from blue value, swelling power and Rapid Visco Analyzer also suggested that there were differences in starch properties among the different Wx-B1 alleles. CONCLUSION: The present study suggests that the amylose content in emmer (Wx-B1g) and durum (Wx-B1a) standard materials is not the same; therefore some starch properties are different between the two species. The variation found could be used to enlarge the gene pool of durum wheat and design new materials with desirable amylose content.

Spanish Spelt Wheat: From an Endangered Genetic Resource to a Trendy Crop.

Spelt wheat (Triticum aestivum L. ssp. spelta Thell.) is an ancient wheat that was widely cultivated in the past. This species derived from a cross between emmer wheat (T. turgidum spp. dicoccum Schrank em. Thell.) and Aegilops tauschii Coss. Its main origin was in the Fertile Crescent (Near East), with a secondary center of origin in Europe due to a second hybridization event between emmer and hexaploid wheat. This species has been neglected in most of Europe; however, the desire for more natural foods has driven a revival in interest. Iberian spelt is classified as a geographical group differing to the rest of European spelt. In this review, the particularities, genetic diversity and current situation of Spanish spelt, mainly for quality traits, are discussed.

Molecular characterization of five novel Wx-A1 alleles in common wheat including one silent allele by transposon insertion.

Wheat starch is composed of two glucose polymers, amylose and amylopectin. Although several starch synthases are responsible for its synthesis, only the waxy protein is associated with the amylose synthesis. The waxy protein composition of 45 Spanish common wheat landraces from Andalusia (southern Spain) was evaluated. Within these materials, five novel alleles for the Wx-A1 gene were detected. Four of them showed functional proteins (Wx-A1p, Wx-A1q, Wx-A1r and Wx-A1s), although some amino acid changes were found in the mature protein sequence. However, one of them (Wx-A1t) exhibited loss of the Wx-A1 protein, and its base sequence contained one large insert (1,073 bp) in the tenth exon, that interrupted the ORF of the Wx-A1 gene. This insert exhibited the characteristics of a Class II transposon of the Mutator superfamily, which had not been described previously, and has been named Baetica. The conservation of such inserts could be related to their low effect on vital properties of the plants, as occurs with most of the genes associated with technological quality. In conclusion, the evaluation of old wheat landraces showed that, in addition to their use as alternative crops, these materials could be a useful source of interesting genes in wheat quality improvement.

Estudio del impacto de la pandemia por COVID-19 en las Urgencias Pediátricas de un hospital de tercer nivel / Study on the impact of COVID-19 pandemic on pediatric emergencies of a third level hospital

Introducción. En los últimos años, los servicios de urgencias hospitalarias han experimentado un aumento progresivo de la demanda asistencial, a expensas de patología banal. Esta tendencia cambia a partir del 14 de marzo, cuando se decreta el estado de alarma debido a la pandemia por COVID-19, lo que supone el confinamiento obligatorio poblacional. Objetivos. Determinar el impacto que este estado de alarma ha tenido en el volumen de las urgencias pediátricas de un hospital de tercer nivel. Material y métodos. Se ha realizado un estudio retrospectivo de cohortes y se han incluido los menores de 14 años que demandaron asistencia durante los meses del estado de alarma y durante los mismos meses en el año anterior. Se han analizado diferentes datos epidemiológicos y clínicos. Resultados. 3.371 pacientes acudieron a nuestro Servicio de Urgencias en 2019 y 650 lo hicieron en 2020, siendo la media de edad de los pacientes similar. Los grupos diagnósticos al alta más frecuentes en ambos periodos de tiempo fueron las patologías infecciosa y digestiva. En cuanto a los ingresos hospitalarios, en 2019 requirieron ingreso el 7,12%, y en 2020, el 13,69%. Respecto al servicio a cargo del paciente durante el ingreso, destaca que en 2020 el 27,72% lo hizo a cargo de Cirugía Pediátrica. Conclusiones. La actividad en las Urgencias Pediátricas de nuestro hospital ha variado notablemente durante el estado de alarma. Se ha producido una disminución considerable del número de pacientes que han demandado asistencia debido a la percepción de riesgo de contagio por parte de la población. Además, hemos percibido un aumento relativo de los ingresos hospitalarios y, en concreto, en la patología quirúrgica urgente con respecto al año anterior (AU)

Objectives. In recent years, hospital emergency departments have experienced a progressive increase in the demand for care, at the expense of trivial pathology. This trend changes from 14 March 2020, when the state of alarm was declared due to the COVID-19 pandemic, which led to the compulsory confinement of the population. The main objective of this study was to determine the impact that this state of alarm has had on the volume of paediatric emergencies in a third level hospital. Material and methods. A retrospective study of cohorts was carried out and included those under 14 years of age who demanded care during the months of the state of alarm and during the same months in the previous year. Different epidemiological and clinical data have been analysed. Results. 3,371 patients attended our Emergency Department in 2019, and 650 in 2020, with a similar average patient age. The most frequent diagnostic groups at discharge in both time periods were infectious and digestive diseases. In terms of hospital admissions, 7.12% required admission in 2019 and 13.69% in 2020. Regarding the department in charge of the patient during admission, in 2020 27.72% of patients were admitted by Paediatric Surgery. Conclusions. The activity in the paediatric emergency departments of our hospital varied considerably during the state of alarm. There has been a considerable decrease in the number of patients who have requested assistance due to the perceived risk of contagion by the population. In addition, we have perceived a relative increase in hospital admissions and, specifically, in urgent surgical pathology compared to the previous year (AU)