Fertility of CMS wheat is restored by two Rf loci located on a recombined acrocentric chromosome

Cytoplasmic male sterility (CMS) results from incompatibility between nuclear and cytoplasmic genomes, and is characterized by the inability to produce viable pollen. The restoration of male fertility generally involves the introgression of nuclear genes, termed restorers of fertility (Rf). CMS has been widely used for hybrid seed production in many crops but not in wheat, partly owing to the complex genetics of fertility restoration. In this study, an acrocentric chromosome that restores pollen fertility of CMS wheat in Hordeum chilense cytoplasm (msH1 system) is studied. The results show that this chromosome, of H. chilense origin and named Hchac, originated from a complex reorganization of the short arm of chromosomes 1Hch (1HchS) and 6Hch (6HchS). Diversity arrays technology (DArT) markers and cytological analysis indicate that Hchac is a kind of 'zebra-like′ chromosome composed of chromosome 1HchS and alternate fragments of interstitial and distal regions of chromosome 6HchS. PCR-based markers together with FISH, GISH, and meiotic pairing analysis support this result. A restorer of fertility gene, named Rf 6H ch S, has been identified on the short arm of chromosome 6HchS. Moreover, restoration by the addition of chromosome 1HchS has been observed at a very low frequency and under certain environmental conditions. Therefore, the results indicate the presence of two Rf genes on the acrocentric chromosome: Rf 6H ch S and Rf 1H ch S, the restoration potential of Rf 6H ch S being greater. The stable and high restoration of pollen fertility in the msH1 system is therefore the result of the interaction between these two restorer genes.Results have been achieved within the framework of the Transnational (Germany, France, Spain, Portugal and Canada) Cooperation within the PLANT-KBBE Initiative, with funding from Spanish Ministerio de Economía y Competitividad project PIM2010PKB-00703  “Hybrid Wheat for Reduced Inputs and Sustainable Yield”. This research was partly supported by grant (to S.G. Atienza) 200840I137 from CSIC and FEDER.Peer Reviewe

Genome-Wide Association Analysis for Stem Cross Section Properties, Height and Heading Date in a Collection of Spanish Durum Wheat Landraces

Durum wheat landraces have a high potential for breeding but they remain underexploited due to several factors, including the insufficient evaluation of these plant materials and the lack of efficient selection tools for transferring target traits into elite backgrounds. In this work, we characterized 150 accessions of the Spanish durum wheat collection for stem cross section, height and heading date. Continuous variation and high heritabilities were recorded for the stem area, pith area, pith diameter, culm wall thickness, height and heading date. The accessions were genotyped with DArTSeq markers, which were aligned to the durum wheat ‘Svevo’ genome. The markers corresponding to genes, with a minor allele frequency above 5% and less than 10% of missing data, were used for genome-wide association scan analysis. Twenty-nine marker-trait associations (MTAs) were identified and compared with the positions of previously known QTLs. MTAs for height and heading date co-localized with the QTLs for these traits. In addition, all the MTAs for stem traits in chromosome 2B were located in the corresponding synteny regions of the markers associated with lodging in bread wheat. Finally, several MTAs for stem traits co-located with the QTL for wheat stem sawfly (WSS) resistance. The results presented herein reveal the same genomic regions in chromosome 2B are involved in the genetic control of stem traits and lodging tolerance in both durum and bread wheat. In addition, these results suggest the importance of stem traits for WSS resistance and the potential of these landraces as donors for lodging tolerance and WSS resistance enhancement. In this context, the MTAs for stem-related traits identified in this work can serve as a reference for further development of markers for the introgression of target traits into elite materialThis research was funded by the Instituto de Investigación y Formación Agraria y Pesquera (IFAPA), Junta de Andalucía, grant number AVA-AVA2019.020 cofounded at 80% by FEDER. C.M.A., J.S. and S.G.A. are members of the FiRCMe Network, funded by Ministerio de Economía, Industria y Competitividad (AGL2016-81855-REDT). M.D.R.-R. was the recipient of a fellowship from the Ministerio de Ciencia, Innovación y Universidades (PRE2018-084037)

Exploitation of nuclear and cytoplasm variability in Hordeum chilense for wheat breeding

Hordeum chilense Roem. et Schultz. is a diploid wild barley native to Chile and Argentina. The high crossability of this species with other members of the Triticeae tribe promoted the development of the new species × Tritordeum Ascherson et Graebner. Hexaploid tritordeum was developed from the hybrid derived from the cross between H. chilense (used as female parent) and durum wheat. The interest of H. chilense is based on the presence of traits potentially useful for wheat breeding, including high endosperm carotenoid content, septoria tritici blotch resistance and abiotic stress tolerance. Besides, the variability at cytoplasm level is also important in this species. The development of common wheat-H. chilense alloplasmic lines (nucleus from wheat and cytoplasm from H. chilense) results in fertile or male sterile genotypes, depending on the accession donating the cytoplasm. Furthermore, these alloplasmic lines constitute an ideal system for deepening our knowledge on nuclear-cytoplasm interactions. In conclusion, H. chilense is an interesting source of variability for wheat breeding. © 2011 NIAB.Our work in this area is supported by grants (to S. G. A.) AGL2008-03720, and P09-AGR-4817 from Spanish Ministry of Science and Innovation, Junta de Andalucía and FEDER. C. R.-S. acknowledges financial support from CSIC (JAE-Doc program).Peer Reviewe

Mapping quantitative trait loci controlling fatty acid composition in olive

22 Páginas; 3 Tablas; 2 FigurasFatty acids are the main components of the olive oil and their composition has a critical influence on the oil quality. However, oil quality evaluation has not been frequently included in the selection of new bred cultivars. This can be due to the difficulties in analyzing oil quality in large set of genotypes and also to the long juvenile period of olive seedlings. Therefore, the identification of molecular markers associated to olive oil quality traits could facilitate their selection in breeding programs of this species. In the present work, the identification of the first QTLs for fatty acids on olive oil is reported. They have been located in a linkage map of a ‘Picual’ × ‘Arbequina’ progeny of the olive breeding program of Córdoba. Correlations among fatty acids are in agreement with previous reports of breeding progenies. QTLs found for oleic and linoleic acids explained 41.1 and 69.7% of the total variability, respectively, and were co-localized in the same linkage groups. In the same region, QTLs for monounsaturated, polyunsaturated and oleic/linoleic ratio were also identified. In other linkage groups, three QTLs for linolenic and one for palmitoleic acid were also located explaining 15.0–28.0% of the total variability. These results could be useful to increase the efficiency of breeding programs aimed at selecting new cultivars with high oleic acid content, and, therefore, with enhanced nutritional properties and oxidative stability of the olive oil.This work was partly supported by OLEAGEN Project funded by the Fundación Genoma España, Junta de Andalucía through Instituto de Investigación y Formación Agraria y Pesquera (IFAPA) and Corporación Tecnológica de Andalucía (CTA).Peer reviewe

Cytoplasmic genome substitution in wheat affects the nuclear-cytoplasmic cross-talk leading to transcript and metabolite alterations

Abstract Background Alloplasmic lines provide a unique tool to study nuclear-cytoplasmic interactions. Three alloplasmic lines, with nuclear genomes from Triticum aestivum and harboring cytoplasm from Aegilops uniaristata, Aegilops tauschii and Hordeum chilense, were investigated by transcript and metabolite profiling to identify the effects of cytoplasmic substitution on nuclear-cytoplasmic signaling mechanisms. Results In combining the wheat nuclear genome with a cytoplasm of H. chilense, 540 genes were significantly altered, whereas 11 and 28 genes were significantly changed in the alloplasmic lines carrying the cytoplasm of Ae. uniaristata or Ae. tauschii, respectively. We identified the RNA maturation-related process as one of the most sensitive to a perturbation of the nuclear-cytoplasmic interaction. Several key components of the ROS chloroplast retrograde signaling, together with the up-regulation of the ROS scavenging system, showed that changes in the chloroplast genome have a direct impact on nuclear-cytoplasmic cross-talk. Remarkably, the H. chilense alloplasmic line down-regulated some genes involved in the determination of cytoplasmic male sterility without expressing the male sterility phenotype. Metabolic profiling showed a comparable response of the central metabolism of the alloplasmic and euplasmic lines to light, while exposing larger metabolite alterations in the H. chilense alloplasmic line as compared with the Aegilops lines, in agreement with the transcriptomic data. Several stress-related metabolites, remarkably raffinose, were altered in content in the H. chilense alloplasmic line when exposed to high light, while amino acids, as well as organic acids were significantly decreased. Alterations in the levels of transcript, related to raffinose, and the photorespiration-related metabolisms were associated with changes in the level of related metabolites. Conclusion The replacement of a wheat cytoplasm with the cytoplasm of a related species affects the nuclear-cytoplasmic cross-talk leading to transcript and metabolite alterations. The extent of these modifications was limited in the alloplasmic lines with Aegilops cytoplasm, and more evident in the alloplasmic line with H. chilense cytoplasm. We consider that, this finding might be linked to the phylogenetic distance of the genomes.The authors thank Prof. S.S. Maan (North Dakota State University, USA) for providing the alloplasmic lines T183 and T195 and Dr. Alessio Aprile (University of Salento, Lecce, Italy) for help in data analysis. LQ was partly supported by grant # 2770367, the Chief Scientist Fund, the Ministry of Agriculture, Israel.Peer Reviewe

Allelic Variation, Alternative Splicing and Expression Analysis of Psy1 Gene in Hordeum chilense Roem. et Schult

Background: The wild barley Hordeum chilense Roem. et Schult. is a valuable source of genes for increasing carotenoid content in wheat. Tritordeums, the amphiploids derived from durum or common wheat and H. chilense, systematically show higher values of yellow pigment colour and carotenoid content than durum wheat. Phytoene synthase 1 gene (Psy1) is considered a key step limiting the carotenoid biosynthesis, and the correlation of Psy1 transcripts accumulation and endosperm carotenoid content has been demonstrated in the main grass species. Methodology/Principal findings: We analyze the variability of Psy1 alleles in three lines of H. chilense (H1, H7 and H16) representing the three ecotypes described in this species. Moreover, we analyze Psy1 expression in leaves and in two seed developing stages of H1 and H7, showing mRNA accumulation patterns similar to those of wheat. Finally, we identify thirtysix different transcripts forms originated by alternative splicing of the 59 UTR and/or exons 1 to 5 of Psy1 gene. Transcripts function is tested in a heterologous complementation assay, revealing that from the sixteen different predicted proteins only four types (those of 432, 370, 364 and 271 amino acids), are functional in the bacterial system. Conclusions/Significance: The large number of transcripts originated by alternative splicing of Psy1, and the coexistence of functional and non functional forms, suggest a fine regulation of PSY activity in H. chilense. This work is the first analysis of H. chilense Psy1 gene and the results reported here are the bases for its potential use in carotenoid enhancement in duru

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

Carotenoid evolution during postharvest storage of durum wheat (Triticum turgidum conv. durum) and tritordeum (×Tritordeum Ascherson et Graebner) grains

27 páginas, 3 figuras, 2 tablasThe process of in vivo esterification of xanthophylls has proven to be an important part of the post-carotenogenesis metabolism which mediates their accumulation in plants. The biochemical characterization of this process is therefore necessary for obtaining new and improved crop varieties with higher carotenoid contents. This study investigates the impact of postharvest storage conditions on carotenoid composition, with special attention to the esterified pigments (monoesters, diesters and their regioisomers), in durum wheat and tritordeum, a novel cereal with remarkable carotenoid content. For tritordeum grains, the total carotenoid content decreased during the storage period in a clear temperature-dependent manner. On the contrary, carotenoid metabolism in durum wheat was very much dependent on the physiological adaptation of the grains to the imposed conditions. Interestingly, when thermal conditions were more intense (37 °C), a higher carotenoid retention was observed for tritordeum, and was directly related to the de novo esterification of the lutein induced by temperature. The profile of lutein monoester regioisomers was constant during storage, indicating that the regioisomeric selectivity of the XAT enzymes was not altered by temperature. These data can be useful for optimizing the storage conditions of grains favoring a greater contribution of carotenoids from these staple foods.This work was supported by funding from the Ministerio de Ciencia e Innovación (Spanish Government, Projects AGL2010-14850/ALI, AGL2008-03720) and the Consejería de Economía, Innovación, Ciencia y Empleo (Junta de Andalucía, Project P08-AGR-03477). EMO was the recipient of a JAE-Predoctoral grant (CSIC) co-financed by the ESF. DHM and EMO are members of the IBERCAROT Network, funded by CYTED (ref. 112RT0445).Peer reviewe

Legumes in sustainable agriculture

Foreword.Agriculture faces unprecedented demands for food and feed production due to the increase in world population predicted forthenextdecades.Thegrowingconcernsonenvironmental and food security make necessary to face these demands with more sustainable and environmentally friendly agricultural practices which constitute a high challenge for researchers and farmers all over the world.Peer reviewe

Carotenoids in tritordeum (Tritordeum Ascherson et Graebner). Effect of storage conditions on their content

The hexaploid tritordeum (Tritordeum Ascherson et Graebner) (Figure 1), is the fertile amphiploid (2n=6x=42, AABBHchHch) resulting from the cross between a wild barley (Hordeum chilense) and durum wheat (Triticum turgidum Desf) (1). The agronomic, morphological, chemical, physico-chemical and rheological characteristics of this new crop, similar to bread wheat, indicate that tritordeum is a promising cereal for agriculture and food processing (2). Moreover, there is a huge genetic variability available for breeding this new crop as a consequence of the synthesis of hundreds of different amphiploids, becoming tritordeum a potentially donor of useful traits to wheat. Previous studies (3), carried out in our laboratories, have demonstrated that lutein is the major carotenoide present in tritordeum lines, and at much higher concentration (more than 5 times) than in durum wheat, which suggests a high potential of this crop to become a functional food. In addition, it was found that in the case of tritordeum, lutein shows a characteristic esterification with fatty acids, which is absent or at very low levels in durum wheat grains. In the present study, the effect of storage of grains (temperature and time) on the carotenoid content of three advanced tritordeum lines and three commercial durum wheat varieties has been investigated. The role of esterification on the stability of lutein is also discussed.This work was supported by the Project AGL2007-60092/ALI, Ministerio de Ciencia e Innovación (Spanish Government) and by the Project P08-AGR3477, Consejería de Economía, Innovación y Ciencia (Junta de Andalucía)