A high-density consensus map of A and B wheat genomes

A durum wheat consensus linkage map was developed by combining segregation data from six mapping populations. All of the crosses were derived from durum wheat cultivars, except for one accession of T. ssp. dicoccoides. The consensus map was composed of 1,898 loci arranged into 27 linkage groups covering all 14 chromosomes. The length of the integrated map and the average marker distance were 3,058.6 and 1.6 cM, respectively. The order of the loci was generally in agreement with respect to the individual maps and with previously published maps. When the consensus map was aligned to the deletion bin map, 493 markers were assigned to specific bins. Segregation distortion was found across many durum wheat chromosomes, with a higher frequency for the B genome. This high-density consensus map allowed the scanning of the genome for chromosomal rearrangements occurring during the wheat evolution. Translocations and inversions that were already known in literature were confirmed, and new putative rearrangements are proposed. The consensus map herein described provides a more complete coverage of the durum wheat genome compared with previously developed maps. It also represents a step forward in durum wheat genomics and an essential tool for further research and studies on evolution of the wheat genome. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00122-012-1939-y) contains supplementary material, which is available to authorized users

Common and durum wheat genetic materials for studying grain quality-related traits

LXVI SIGA Annual Congress “Climate-smart plants to feed the future”, 05-08 September 2023, Bari.Wheat is an important food crop worldwide. Climate change, disease and abiotic stresses can decrease yield and reduce grain quality, therefore search for useful alleles in wild accessions and subspecies could improve resilience and sustainability. Two genetic resources useful for studying grain quality-related traits were analyzed and characterized in the frame of the CEREALMED project. An introgression line population obtained by crossing a durum wheat cultivar, PR22D89, and an accession of Triticum dicoccoides, MG2323, was evaluated for protein content, SDS-sedimentation volume, beta-glucans and carotenoids in two different pedoclimatic environments to find genetic loci involved in these traits. Furthermore, a collection of 59 accessions of Triticum aestivum subspecies, including cultivars, breeding materials, landraces and wilds, previously characterized by SNP markers, was evaluated for carotenoid content. The variability present in this panel was partially overlapped with that observed in durum wheat and therefore useful in enlarging the total variation for wheat. Moreover, significant SNP markers putatively associated to this trait in common wheat were identified, providing the chance to identify novel useful alleles to further improve carotenoid content in both durum and bread wheat.Peer reviewe

Genome-Wide Identification, Characterization and Expression Pattern Analysis of the γ-Gliadin Gene Family in the Durum Wheat (Triticum durum Desf.) Cultivar Svevo

Very recently, the genome of the modern durum wheat cv. Svevo was fully sequenced, and its assembly is publicly available. So, we exploited the opportunity to carry out an in-depth study for the systematic characterization of the γ-gliadin gene family in the cv. Svevo by combining a bioinformatic approach with transcript and protein analysis. We found that the γ-gliadin family consists of nine genes that include seven functional genes and two pseudogenes. Three genes, Gli-γ1a, Gli-γ3a and Gli-γ4a, and the pseudogene Gli-γ2a* mapped on the A genome, whereas the remaining four genes, Gli-γ1b, Gli-γ2b, Gli-γ3b and Gli-γ5b, and the pseudogene Gli-γ4b* mapped on the B genome. The functional γ-gliadins presented all six domains and eight-cysteine residues typical of γ-gliadins. The Gli-γ1b also presented an additional cysteine that could possibly have a role in the formation of the gluten network through binding to HMW glutenins. The γ-gliadins from the A and B genome differed in their celiac disease (CD) epitope content and composition, with the γ-gliadins from the B genome showing the highest frequency of CD epitopes. In all the cases, almost all the CD epitopes clustered in the central region of the γ-gliadin proteins. Transcript analysis during seed development revealed that all the functional γ-gliadin genes were expressed with a similar pattern, although significant differences in the transcript levels were observed among individual genes that were sometimes more than 60-fold. A progressive accumulation of the γ-gliadin fraction was observed in the ripening seeds that reached 34% of the total gliadin fraction at harvest maturity. We believe that the insights generated in the present study could aid further studies on gliadin protein functions and future breeding programs aimed at the selection of new healthier durum wheat genotypes

Importance of Landraces in Cereal Breeding for Stress Tolerance

The renewed focus on cereal landraces is a response to some negative consequences of modern agriculture and conventional breeding which led to a reduction of genetic diversity. Cereal landraces are still cultivated on marginal lands due to their adaptability to unfavourable conditions, constituting an important source of genetic diversity usable in modern plant breeding to improve the adaptation to abiotic or biotic stresses, yield performance and quality traits in limiting environments. Traditional agricultural production systems have played an important role in the evolution and conservation of wide variability in gene pools within species. Today, on-farm and ex situ conservation in gene bank collections, together with data sharing among researchers and breeders, will greatly benefit cereal improvement. Many efforts are usually made to collect, organize and phenotypically and genotypically analyse cereal landrace collections, which also utilize genomic approaches. Their use in breeding programs based on genomic selection, and the discovery of beneficial untapped QTL/genes/alleles which could be introgressed into modern varieties by MAS, pyramiding or biotechnological tools, increase the potential for their better deployment and exploitation in breeding for a more sustainable agricultural production, particularly enhancing adaptation and productivity in stress-prone environments to cope with current climate changes

Effect of Sowing Date on Bioactive Compounds and Grain Morphology of Three Pigmented Cereal Species

Recently, the interest in improving the content of bioactive compounds for enhancing the nutritional value of cereal-based products has largely increased, and several strategies, both genetic and agronomic, were proposed. Here, we report the preliminary results of the effect of two sowing periods (winter and spring) on the accumulation of bioactive compounds (i.e., anthocyanins, carotenoids, minerals) and grain morphology in three pigmented cereal species (barley, bread and durum wheat). The results showed that with delayed sowing time, a significant reduction in yield was observed in all species, less in barley (50.4%) than in wheat (70.3% and 66.5% for bread and durum, respectively). On the contrary, the carotenoids accumulation was favored (increased by 12.2%, 15.7% and 27.8% for barley, bread and durum wheat, respectively), as well as those of anthocyanins although strongly dependent on the genotype (i.e., considering only the purple genotypes, the anthocyanins increase by 4.6%, 35.4% and 72.8% in barley, bread and durum wheat, respectively). For minerals compounds, our study highlighted a strong environmental influence even when the pigmented genotypes accumulated more minerals than commercial ones, while the morphometric seed traits were less influenced by this agronomic practice. Therefore, by exploiting the genetic variability for the accumulation of anthocyanins and carotenoids in the grain and by optimizing the sowing time, it could be possible to increase the nutritional value of the final cereal-based products

Characterization of wheat DArT markers: genetic and functional feature

Diversity array technology (DArT) markers are largely used for mapping, genetic diversity, and association mapping studies. For years, they have been used as anonymous genomic markers, as their sequences were not known. As the sequences of 2,000 wheat DArT clones are now available, this study was designed to analyze these sequences with bioinformatic approaches, and to study the genetic features of a subset of 291 markers positioned on the A and B genomes in three durum wheat genetic maps. A set of 1,757 non-redundant sequences was identified, and used as queries for similarity searches. Analysis of the genetic positions of markers corresponding to nearly identical sequences indicates that redundancy of sequences is one of the factors that explains the clustering of these markers in specific genomic regions. Of a total of 1,124 DArT clones (64 %) that represent putatively expressed sequences, putative functions are proposed for more than 700 of them. Of note, many clones correspond to genes that are related to disease resistance, as characterized by leucine-rich repeat domains, and 40 of these clones are positioned in the three genetic maps presented in this study. Finally, DArT markers have been used to find syntenic regions in the Brachypodium and rice genomes. In conclusion, the analyses herein presented contribute to explain the main features of DArT markers observed in genetic maps, as clustering in short chromosome regions. Moreover, the attribution of putative gene functions for more than 700 sequences makes these markers an optimal tool for collinearity studies or for the identification of candidate genes.This study was supported by the Italian Ministry of Agriculture (MiPAAF), with the special grants AGRO-NANOTECH and ESPLORA, and by the Ministry of Education, Universities and Research (MIUR), with the special grant AGRO-GEN.Peer Reviewe

Does Plant Breeding for Antioxidant-Rich Foods Have an Impact on Human Health?

Given the general beneficial effects of antioxidants-rich foods on human health and disease prevention, there is a continuous interest in plant secondary metabolites conferring attractive colors to fruits and grains and responsible, together with others, for nutraceutical properties. Cereals and Solanaceae are important components of the human diet, thus, they are the main targets for functional food development by exploitation of genetic resources and metabolic engineering. In this review, we focus on the impact of antioxidants-rich cereal and Solanaceae derived foods on human health by analyzing natural biodiversity and biotechnological strategies aiming at increasing the antioxidant level of grains and fruits, the impact of agronomic practices and food processing on antioxidant properties combined with a focus on the current state of pre-clinical and clinical studies. Despite the strong evidence in in vitro and animal studies supporting the beneficial effects of antioxidants-rich diets in preventing diseases, clinical studies are still not sufficient to prove the impact of antioxidant rich cereal and Solanaceae derived foods on huma