A chromosome level genome assembly of Pseudoroegneria Libanotica reveals a key Kcs gene involves in the cuticular wax elongation for drought resistance

BACKGROUND

The genus Pseudoroegneria (Nevski) Löve (Triticeae, Poaceae), whose genome symbol was designed as "St", accounts for more than 60% of perennial Triticeae species. The diploid species Psudoroegneria libanotica (2n = 14) contains the most ancient St genome, exhibited strong drought resistance, and was morphologically covered by cuticular wax on the aerial part. Therefore, the St-genome sequencing data could provide fundamental information for studies of genome evolution and reveal its mechanisms of cuticular wax and drought resistance.

RESULTS

In this study, we reported the chromosome-level genome assembly for the St genome of Pse. libanotica, with a total size of 2.99 Gb. 46,369 protein-coding genes annotated and 71.62% was repeat sequences. Comparative analyses revealed that the genus Pseudoroegneria diverged during the middle and late Miocene. During this period, unique genes, gene family expansion, and contraction in Pse. libanotica were enriched in biotic and abiotic stresses, such as fatty acid biosynthesis which may greatly contribute to its drought adaption. Furthermore, we investigated genes associated with the cuticular wax formation and water deficit and found a new Kcs gene evm.TU.CTG175.54. It plays a critical role in the very long chain fatty acid (VLCFA) elongation from C18 to C26 in Pse. libanotica. The function needs more evidence to be verified.

CONCLUSIONS

We sequenced and assembled the St genome in Triticeae and discovered a new KCS gene that plays a role in wax extension to cope with drought. Our study lays a foundation for the genome diversification of Triticeae species and deciphers cuticular wax formation genes involved in drought resistance.

Genome-wide identification of bHLH transcription factors and expression analysis under drought stress in Pseudoroegneria libanotica at germination

The basic helix-loop-helix (bHLH) transcription factor family is the second largest in plants. bHLH transcription factor is not only universally involved in plant growth and metabolism, including photomorphogenesis, light signal transduction, and secondary metabolism, but also plays an important role in plant response to stress. However, the function of bHLH TFs in Pseudoroegneria species has not been studied yet. Pseudoroegneria (Nevski) Á. Löve is a perennial genus of the Triticeae. Pseudoroegneria species are mostly distributed in arid/semi-arid areas and they show good drought tolerance. In this study, we identified 152 PlbHLH TFs in Pseudoroegneria libanotica, which could be classified into 15 groups. Collinearity analysis indicates that 122 PlbHLH genes share homology with wbHLH genes in wheat, and it has lower homology with AtbHLH genes in Arabidopsis. Based on transcriptome profiling under an experiment with three PEG concentrations (0%, 10%, and 20%), 10 up-regulated genes and 11 down-regulated PlbHLH genes were screened. Among them, PlbHLH6, PlbHLH55 and PlbHLH64 as candidate genes may be the key genes related to drought tolerance response at germination, and they have been demonstrated to respond to drought, salt, oxidative, heat, and heavy metal stress in yeast. This study lays the foundation for an in-depth study of the biological roles of PlbHLHs in Pse. libanotica, and discovered new drought-tolerance candidate genes to enhance the genetic background of Triticeae crops.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01433-w.

Cytogenetic and genomic characterization of a novel wheat-tetraploid Thinopyrum elongatum 1BS·1EL translocation line with stripe rust resistance

Stripe rust, caused by Puccinia striiformis f. sp tritici (Pst), is a destructive wheat disease pathogen. Thinopyrum elongatum is a valuable germplasm including diploid, tetraploid, and decaploid with plenty of biotic and abiotic resistance. In a previous study, we generated a stripe rust resistance wheat-tetraploid Th. elongatum 1E/1D substitution line K17-841-1. To further apply the wild germplasm for wheat breeding, we selected and obtained a new homozygous wheat-tetraploid Th. elongatum translocation line T1BS·1EL using genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), oligo-FISH-Painting, and the wheat 55K single nucleotide polymorphisms (SNPs) genotyping array. The T1BS·1EL is highly resistant to stripe rust at the seedling and adult stage. Pedigree and molecular marker analyses revealed that the resistance gene was located on chromosome arm 1EL of tetraploid Th. elongatum, tentatively named Yr1EL. Besides, we developed and validated 32 Simple Sequence Repeats (SSR) markers and two kompititive allele specific PCR (KASP) assays which were specific to tetraploid Th. elongatum chromosome arm 1EL to facilitate marker-assisted selection for alien 1EL stripe rust resistance breeding. This will help us explore and locate the stripe rust resistance gene mapping on the 1E chromosome and deploy it in the wheat breeding program.

Development, identification, and utilization of wheat-tetraploid Thinopyrum elongatum 4EL translocation lines resistant to stripe rust

KEY MESSAGE

The new stripe rust resistance gene Yr4EL in tetraploid Th. elongatum was identified and transferred into common wheat via 4EL translocation lines. Tetraploid Thinopyrum elongatum is a valuable genetic resource for improving the resistance of wheat to diseases such as stripe rust, powdery mildew, and Fusarium head blight. We previously reported that chromosome 4E of the 4E (4D) substitution line carries all-stage stripe rust resistance genes. To optimize the utility of these genes in wheat breeding programs, we developed translocation lines by inducing chromosomal structural changes through 60Co-γ irradiation and developing monosomic substitution lines. In total, 53 plants with different 4E chromosomal structural changes were identified. Three homozygous translocation lines (T4DS·4EL, T5AL·4EL, and T3BL·4EL) and an addition translocation line (T5DS·4EL) were confirmed by the genomic in situ hybridization (GISH), fluorescence in situ hybridization (FISH), FISH-painting, and wheat 55 K SNP array analyses. These four translocation lines, which contained chromosome arm 4EL, exhibited high stripe rust resistance. Thus, a resistance gene (tentatively named Yr4EL) was localized to the chromosome arm 4EL of tetraploid Th. elongatum. For the application of marker-assisted selection (MAS), 32 simple sequence repeat (SSR) markers were developed, showing specific amplification on the chromosome arm 4EL and co-segregation with Yr4EL. Furthermore, the 4DS·4EL line could be selected as a good pre-breeding line that better agronomic traits than other translocation lines. We transferred Yr4EL into three wheat cultivars SM482, CM42, and SM51, and their progenies were all resistant to stripe rust, which can be used in future wheat resistance breeding programs.

Integrated Transcriptome Analysis of miRNAs and mRNAs in the Skeletal Muscle of Wuranke Sheep

MicroRNAs (miRNAs) are regarded as important regulators in skeletal muscle development. To reveal the regulatory roles of miRNAs and their target mRNAs underlying the skeletal muscle development of Wuranke sheep, we investigated the miRNA and mRNA expression profiles in the biceps femoris of these sheep at the fetal (3 months of gestation) and 3- and 15-month-old postnatal stages. Consequently, a total of 1195 miRNAs and 24,959 genes were identified. Furthermore, 474, 461, and 54 differentially expressed miRNAs (DEMs) and 6783, 7407, and 78 differentially expressed genes (DEGs) were detected among three comparative groups. Functional analysis demonstrated that the target mRNAs of the DEMs were enriched in multiple pathways related to muscle development. Moreover, the interactions among several predicted miRNA-mRNA pairs (oar-miR-133-HDAC1, oar-miR-1185-5p-MYH1/HADHA/OXCT1, and PC-5p-3703_578-INSR/ACTG1) that potentially affect skeletal muscle development were verified using dual-luciferase reporter assays. In this study, we identified the miRNA and mRNA differences in the skeletal muscle of Wuranke sheep at different developmental stages and revealed that a series of candidate miRNA-mRNA pairs may act as modulators of muscle development. These results will contribute to future studies on the function of miRNAs and their target mRNAs during skeletal muscle development in Wuranke sheep.

Genome-Wide Association Study of Asian and European Common Wheat Accessions for Yield-Related Traits and Stripe Rust Resistance

Identifying novel loci of yield-related traits and resistance to stripe rust (caused by Puccinia striiformis f. sp. tritici) in wheat will help in breeding wheat that can meet projected demands in diverse environmental and agricultural practices. We performed a genome-wide association study with 24,767 single nucleotide polymorphisms (SNPs) in 180 wheat accessions that originated in 16 Asian or European countries between latitudes 30°N and 45°N. We detected seven accessions with desirable yield-related traits and 42 accessions that showed stable, high degrees of stripe rust resistance in multienvironment field assessments. A marker-trait association analysis of yield-related traits detected 18 quantitative trait loci (QTLs) in at least two test environments and two QTLs related to stripe rust resistance in at least three test environments. Five of these QTLs were identified as potentially novel QTLs by comparing their physical locations with those of known QTLs in the Chinese Spring (CS) reference genome RefSeq v1.1 published by the International Wheat Genome Sequencing Consortium; two were for spike length, one was for grain number per spike, one was for spike number, and one was for stripe rust resistance at the adult plant stage. We also identified 14 candidate genes associated with the five novel QTLs. These QTLs and candidate genes will provide breeders with new germplasm and can be used to conduct marker-assisted selection in breeding wheat with improved yield and stripe rust resistance.

[Clinical characteristics of COVID-19 Omicron variant infection in children with allergic diseases]

Objective: To analyze the clinical characteristics of infection of COVID-19 Omicron variants in children with allergic diseases. Methods: This was a cross-sectional retrospective study. A total of 657 pediatric patients with allergic diseases aged between 0-17 years confirmed with COVID-19 infection were enrolled from the Children's Hospital affiliated to Capital Institute of Pediatrics from January to March 2023. The median age was 6.6(4.7,9.9) years, with 443 males (67.4%) and 214 females (32.6%). Demographic data, vaccination status, clinical manifestations, therapeutic drugs, and other data were collected. The patients were then divided into different groups according to the age, type of allergic diseases and vaccination status, and their clinical characteristics were compared. Results: A total of 657 children with allergic diseases were included in this study, among them 568 with asthma. Fever is the most common symptoms after COVID-19 infection (627/657, 95.4%), and 509 children (77.5%) with high fever. Cough was observed in 446 (67.9%) and fatigue in 167 (25.4%) cases.10 cases (1.5%) were diagnosed as pneumonia. The proportion of pharyngalgia(22%,84/382, χ2=19.847, P<0.01), fatigue (31.7%, 121/382,χ2=23.831, P<0.01), headache(34.6%, 132/382,χ2=57.598, P<0.01), muscle joint pain(16.0%, 61/382,χ2=22.289, P<0.01) and vomiting(11.0%, 42/382,χ2=12.756, P<0.01) were highest in the>6 years group. Children younger than 3 years had the lowest proportion of runny nose(8.8%, 5/57,χ2=8.411, P<0.01), cough(45.6%, 26/57,χ2=6.287, P<0.05) and expectoration(7.0%, 4/57,χ2=5.950, P<0.05). 62.8%(137/218) of the patients in 3-6 year group had the highest rate of cough(χ2=6.287, P<0.05), with a higher proportion of wheezing (10.1%, 22/218). Cough and/or wheezing symptoms were most quickly relieved in the 6 year old group, who had a highest proportion of 68.8%(260/382) in duration of respiratory symptoms within 1 week compared with 52.2% (114/218)of 3-6 years group and 41.2% (22/57)of<3 year group, respectively(χ2=23.166, P<0.01). The asthma group had a significant higher proportion of cough(59.7% vs 41.6%, χ2=10.310, P<0.01), wheezing (8.5% vs 0.0%, χ2=8.114, P<0.01) and expectoration (19.2% vs 7.9%, χ2=10.310, P<0.01) than that of non-asthma group. Besides, patients with cough and/or wheezing in the asthma group had more impact on exercise and sleep (16.1% vs 0, χ2=5.436, P<0.05) and a longer duration over 4 weeks (25.1% vs 3.7%, χ2=6.244, P<0.05). Conclusions: The most common symptoms in children with allergy infected with COVID-19 Omicron variant were fever and cough. Children under 3 years of age had relatively fewer respiratory symptoms while those with asthma or aged 3-6 years were more likely to have cough and wheezing and longer duration of symptoms. The data suggested that the prevention and management of COVID-19 should be strengthened in children with allergy.

[Clinical characteristics of children with IgE-mediated cow's milk protein allergy]

Objective: To analyze the clinical characteristics of children with IgE-mediated cow's milk protein allergy (CMPA) and provide a basis for disease management and prevention. Methods: A cross-sectional study was conducted to analyze 142 children aged 0-12 years who were diagnosed with IgE-mediated CMPA in Capital Institute of Pediatrics Affiliated Children's Hospital from 2020 to 2022. There were 79 males (55.6%) and 63 females (44.4%), with an average age of 14 (8, 27) months. 61 cases (43.0%) were in the <1-year-old group, 54 cases (38.0%) in the 1-3-year-old group, and 27 cases (19.0%) in the >3-year-old group. Data on demographic data, clinical manifestations, mean wheel diameter of skin prick test and serum specific IgE level were collected. The serum cow's milk protein sIgE and component sIgE were measured by ImmunoCAP fully automated system of fluorescence enzyme-linked immunosorbent assay, and statistically analyzed using chi-square test, nonparametric tests, correlation. Results: Cutaneous symptoms were the first and most frequent in 142 children (97.9%, 139/142 cases), followed by digestive (29.6%, 42/142 cases) and respiratory symptoms (27.5%, 39/142 cases).The proportion of children with respiratory symptoms after consuming cow's milk was significantly higher in the>3 years age group than those in the infant and toddler groups(66.7% vs 19.7%,χ2=18.396,P<0.01;66.7% vs 16.7%,χ2=20.250,P<0.01), and the symptoms involving ≥3 systems were also significantly higher than those in the other two groups(37.0% vs 13.1%,χ2=6.597,P<0.05;37.0% vs 7.4%,χ2=12.120,P<0.01). The average cow's milk SPT diameter and serum sIgE levels in the>3 years age group were significantly higher than those in the infant and toddler groups (Z=-4.682, P<0.01; Z=-3.498, P<0.01); (Z=-4.463, P<0.01; Z=-6.463, P<0.01). The most common cow's milk component protein were β-lactoglobulin(65.1%,56/86 cases) and casein (57.0%, 49/86 cases). Multiple-sensitization rate of the patients were 54.9%. Egg white (43.7%, 62/142 cases) was the most common co-sensitization food allergen while mold (12.7%, 18/142 cases) and weed pollen (12.7%, 18/142 cases) were the main co-sensitization aeroallergens. The proportion of multiple-sensitization to aeroallergens in the children group was the highest (51.9%, 14/27 cases), followed by the toddler group (29.6%, 16/54 cases), and the infant group was the least (3.3%, 2/61 cases). There was a significant difference among these three groups (χ2=7.476, P<0.05). Conclusion: Skin and mucosal symptoms are the most common in CMPA patients. The proportion of respiratory symptoms and multisystem involvement increased with age as well as the wheal diameter in skin test and serum sIgE level elevated. CMPA patients older than 3 years had the highest proportion of aeroallergen sensitization and airway allergic diseases.

Chromosome-specific painting in Thinopyrum species using bulked oligonucleotides

Chromosome-specific painting probes were developed to identify the individual chromosomes from 1 to 7E in Thinopyrum species and detect alien genetic material of the E genome in a wheat background. The E genome of Thinopyrum is closely related to the ABD genome of wheat (Triticum aestivum L.) and harbors genes conferring beneficial traits to wheat, including high yield, disease resistance, and unique end-use quality. Species of Thinopyrum vary from diploid (2n = 2x = 14) to decaploid (2n = 10x = 70), and chromosome structural variation and differentiation have arisen during polyploidization. To investigate the variation and evolution of the E genome, we developed a complete set of E genome-specific painting probes for identification of the individual chromosomes 1E to 7E based on the genome sequences of Th. elongatum (Host) D. R. Dewey and wheat. By using these new probes in oligonucleotide-based chromosome painting, we showed that Th. bessarabicum (PI 531711, EbEb) has a close genetic relationship with diploid Th. elongatum (EeEe), with five chromosomes (1E, 2E, 3E, 6E, and 7E) maintaining complete synteny in the two species except for a reciprocal translocation between 4 and 5Eb. All 14 pairs of chromosomes of tetraploid Th. elongatum have maintained complete synteny with those of diploid Th. elongatum (Thy14), but the two sets of E genomes have diverged. This study also demonstrated that the E genome-specific painting probes are useful for rapid and effective detection of the alien genetic material of E genome in wheat-Thinopyrum derived lines.

Development and Characterization of a Novel Wheat-Tetraploid Thinopyrum elongatum 6E (6D) Disomic Substitution Line with Stripe Rust Resistance at the Adult Stage

Stripe rust, which is caused by Puccinia striiformis f. sp. tritici, is one of the most devastating foliar diseases of common wheat worldwide. Breeding new wheat varieties with durable resistance is the most effective way of controlling the disease. Tetraploid Thinopyrum elongatum (2n = 4x = 28, EEEE) carries a variety of genes conferring resistance to multiple diseases, including stripe rust, Fusarium head blight, and powdery mildew, which makes it a valuable tertiary genetic resource for enhancing wheat cultivar improvement. Here, a novel wheat-tetraploid Th. elongatum 6E (6D) disomic substitution line (K17-1065-4) was characterized using genomic in situ hybridization and fluorescence in situ hybridization chromosome painting analyses. The evaluation of disease responses revealed that K17-1065-4 is highly resistant to stripe rust at the adult stage. By analyzing the whole-genome sequence of diploid Th. elongatum, we detected 3382 specific SSR sequences on chromosome 6E. Sixty SSR markers were developed, and thirty-three of them can accurately trace chromosome 6E of tetraploid Th. elongatum, which were linked to the disease resistance gene(s) in the wheat genetic background. The molecular marker analysis indicated that 10 markers may be used to distinguish Th. elongatum from other wheat-related species. Thus, K17-1065-4 carrying the stripe rust resistance gene(s) is a novel germplasm useful for breeding disease-resistant wheat cultivars. The molecular markers developed in this study may facilitate the mapping of the stripe rust resistance gene on chromosome 6E of tetraploid Th. elongatum.

Manganese and copper additions differently reduced cadmium uptake and accumulation in dwarf Polish wheat (Triticum polonicum L.)

This study investigated the effects of manganese (Mn) and copper (Cu) on dwarf Polish wheat under cadmium (Cd) stress by evaluating plant growth, Cd uptake, translocation, accumulation, subcellular distribution, and chemical forms, and the expression of genes participating in cell wall synthesis, metal chelation, and metal transport. Compared with the control, Mn deficiency and Cu deficiency increased Cd uptake and accumulation in roots, and Cd levels in root cell wall and soluble fractions, but inhibited Cd translocation to shoots. Mn addition reduced Cd uptake and accumulation in roots, and Cd level in root soluble fraction. Cu addition did not affect Cd uptake and accumulation in roots, while it caused a decrease and an increase of Cd levels in root cell wall and soluble fractions, respectively. The main Cd chemical forms (water-soluble Cd, pectates and protein integrated Cd, and undissolved Cd phosphate) in roots were differently changed. Furthermore, all treatments distinctly regulated several core genes that control the main component of root cell walls. Several Cd absorber (COPT, HIPP, NRAMP, and IRT) and exporter genes (ABCB, ABCG, ZIP, CAX, OPT, and YSL) were differently regulated to mediate Cd uptake, translocation, and accumulation. Overall, Mn and Cu differently influenced Cd uptake and accumulation; Mn addition is an effective treatment for reducing Cd accumulation in wheat.

RNA-seq analysis revealed considerable genetic diversity and enabled the development of specific KASP markers for Psathyrostachys huashanica

Psathyrostachys huashanica, which grows exclusively in Huashan, China, is an important wild relative of common wheat that has many desirable traits relevant for wheat breeding. However, the poorly characterized interspecific phylogeny and genomic variations and the relative lack of species-specific molecular markers have limited the utility of P. huashanica as a genetic resource for enhancing wheat germplasm. In this study, we sequenced the P. huashanica transcriptome, resulting in 50,337,570 clean reads that were assembled into 65,617 unigenes, of which 38,428 (58.56%) matched at least one sequence in public databases. The phylogenetic analysis of P. huashanica, Triticeae species, and Poaceae species was conducted using 68 putative orthologous gene clusters. The data revealed the distant evolutionary relationship between P. huashanica and common wheat as well as the substantial diversity between the P. huashanica genome and the wheat D genome. By comparing the transcriptomes of P. huashanica and Chinese Spring, 750,759 candidate SNPs between P. huashanica Ns genes and their common wheat orthologs were identified. Among the 90 SNPs in the exon regions with different functional annotations, 58 (64.4%) were validated as Ns genome-specific SNPs in the common wheat background by KASP genotyping assays. Marker validation analyses indicated that six specific markers can discriminate between P. huashanica and the other wheat-related species. In addition, five markers are unique to P. huashanica, P. juncea, and Leymus species, which carry the Ns genome. The Ns genome-specific markers in a wheat background were also validated regarding their specificity and stability for detecting P. huashanica chromosomes in four wheat-P. huashanica addition lines. Four and eight SNP markers were detected in wheat-P. huashanica 2Ns and 7Ns addition lines, respectively, and one marker was specific to both wheat-P. huashanica 3Ns, 4Ns, and 7Ns addition lines. These markers developed using transcriptome data may be used to elucidate the genetic relationships among Psathyrostachys, Leymus, and other closely-related species. They may also facilitate precise introgressions and the high-throughput monitoring of P. huashanica exogenous chromosomes or segments in future crop breeding programs.

Determination of selected glucocorticoids in healthy foods by ultra-performance convergence chromatography-triple quadrupole mass spectrometry

The presence of glucocorticoids in healthy foods has recently become a topic of concern because of their side effects. In this study, we developed a method based on ultra-performance convergence chromatography-triple quadrupole mass spectrometry (UPC²-MS/MS) to detect 63 glucocorticoids in healthy foods. The analysis conditions were optimized, and the method was validated. We further compared the results of this method with those of the RPLC-MS/MS method. Glucocorticoids were separated on an Acquity Torus 2-picolylamine column (100 mm × 3.0 mm, 1.7 µm) and detected via MS/MS. CO₂ and methanol (containing 0.1% formic acid) were used as mobile phases. The method demonstrated good linear relationships between 1 and 200 µg·L^-1 (R² ≥ 0.996). The limits of detection in different types of samples were 0.3-1.5 µg·kg^-1 (S/N = 3). The average recoveries (n = 9) and RSDs in different types of samples were 76.6-118.2% and 1.1-13.1%, respectively. The matrix effect, calculated as the ratio between calibration curves built in matrix and pure solvent, was less than 0.21 for both a fish oil and a protein powder. This method exhibited better selectivity and resolution than RPLC-MS/MS method. Lastly, it could realize the baseline separation of 31 isomers of 13 groups, including four groups of eight epimers. This study provides new technical support for assessing the risk of exposure to glucocorticoids in healthy foods.

[Research advances in chest tightness variant asthma]

Chest tightness variant asthma (CTVA) is a special type of asthma with chest tightness as the only or main symptom. Due to the lack of typical asthma symptoms such as coughing, wheezing, shortness of breath, and positive signs in chest, it is easy to be missed or misdiagnosed in clinical practice. The onset of chest tightness variant asthma is insidious, and there is few research and attention both domestic and international, so there is no unified diagnosis and treatment standard especially in childhood asthma. This article expounds the related research advances in chest tightness variant asthma, in order to increase clinical attention and provide reference and basis for the prevention of the disease as well as the formulation of diagnosis and treatment strategies.

FeCl3 and Fe2(SO4)3 differentially reduce Cd uptake and accumulation in Polish wheat (Triticum polonicum L.) seedlings by exporting Cd from roots and limiting Cd binding in the root cell walls

Wheat grown in cadmium (Cd)-contaminated soils easily accumulates more Cd in edible parts than the Chinese safety limit (0.1 mg/kg). FeCl₃ and Fe₂(SO₄)₃ have been used to extract Cd from Cd-contaminated soils. Thus, we hypothesized that FeCl₃ and Fe₂(SO₄)₃, used as iron (Fe) fertilizers, can reduce Cd uptake and accumulation in wheat. Here, a hydroponic experiment was performed with three FeCl₃ and Fe₂(SO₄)₃ concentrations under 80 μM CdCl₂ stress on dwarf Polish wheat (Triticum polonicum L., 2n = 4x = 28, AABB) seedlings. Compared with Fe deficiency, FeCl₃ and Fe₂(SO₄)₃ additions competitively reduced Cd concentrations. The reductions were not associated with changes in dry weight and root morphological parameters. FeCl₃ and Fe₂(SO₄)₃ additions reduced Cd concentrations in the following order from smallest to largest reduction: 25 μM Fe₂(SO₄)₃ < 200 μM FeCl₃ < 50 μM FeCl₃ < 100 μM Fe₂(SO₄)₃. Investigation of subcellular distributions showed that the four Fe fertilizers differentially reduced Cd binding in the root cell walls and enhanced root sucrose and trehalose. Cd chemical form analysis revealed that Fe fertilizer addition also differentially reduced root F_E, F_W, and F_NaCl. Transcriptomic analysis revealed that addition of FeCl₃ and Fe₂(SO₄)₃ differentially up-regulated several genes that hydrolyze cell wall polysaccharides and metal transporter genes for Cd uptake (IRT1 and CAX19) and export (ZIP1, ABCG11, ABCG14, ABCG28, ABCG37, ABCG44, and ABCG48) reducing Cd uptake and accumulation. Our results demonstrated that FeCl₃ and Fe₂(SO₄)₃ can reduce Cd accumulation in wheat, and 50 μM FeCl₃ is the most effective treatment.

Pseudorogneria libanotica Intraspecific Genetic Polymorphism Revealed by Fluorescence In Situ Hybridization with Newly Identified Tandem Repeats and Wheat Single-Copy Gene Probes

The genus Pseudoroegneria (Nevski) Löve (Triticeae, Poaceae) with its genome abbreviated 'St' accounts for more than 60% of perennial Triticeae species. The diploid species Psudoroegneria libanotica (2n = 14) contains the most ancient St genome. Therefore, investigating its chromosomes could provide some fundamental information required for subsequent studies of St genome evolution. Here, 24 wheat cDNA probes covering seven chromosome groups were mapped in P. libanotica to distinguish homoelogous chromosomes, and newly identified tandem repeats were performed to differentiate seven chromosome pairs. Using these probes, we investigated intraspecific population chromosomal polymorphism of P. libanotica. We found that (i) a duplicated fragment of the 5St long arm was inserted into the short arm of 2St; (ii) asymmetrical fluorescence in situ hybridization (FISH) hybridization signals among 2St, 5St, and 7St homologous chromosome pairs; and (iii) intraspecific population of polymorphism in P. libanotica. These observations established the integrated molecular karyotype of P. libanotica. Moreover, we suggested heterozygosity due to outcrossing habit and adaptation to the local climate of P. libanotica. Specifically, the generated STlib_96 and STlib_98 repeats showed no cross-hybridization signals with wheat chromosomes, suggesting that they are valuable for identifying alien chromosomes or introgressed fragments of wild relatives in wheat.

MicroRNA and circular RNA profiling in the deposited fat tissue of Sunite sheep

As the most typical deposited fat, tail fat is an important energy reservoir for sheep adapted to harsh environments and plays an important role as a raw material in daily life. However, the regulatory mechanisms of microRNA (miRNA) and circular RNA (circRNA) in tail fat development remain unclear. In this study, we characterized the miRNA and circRNA expression profiles in the tail fat of sheep at the ages of 6, 18, and 30 months. We identified 219 differentially expressed (DE) miRNAs (including 12 novel miRNAs), which exhibited a major tendency to be downregulated, and 198 DE circRNAs, which exhibited a tendency to be upregulated. Target gene prediction analysis was performed for the DE miRNAs. Functional analysis revealed that their target genes were mainly involved in cellular interactions, while the host genes of DE circRNAs were implicated in lipid and fatty acid metabolism. Subsequently, we established a competing endogenous RNA (ceRNA) network based on the negative regulatory relationship between miRNAs and target genes. The network revealed that upregulated miRNAs play a leading role in the development of tail fat. Finally, the ceRNA relationship network with oar-miR-27a_R-1 and oar-miR-29a as the core was validated, suggesting possible involvement of these interactions in tail fat development. In summary, DE miRNAs were negatively correlated with DE circRNAs during sheep tail fat development. The multiple ceRNA regulatory network dominated by upregulated DE miRNAs may play a key role in this developmental process.

Fine mapping of the reduced height gene Rht22 in tetraploid wheat landrace Jianyangailanmai (Triticum turgidum L.)

Rht22 was fine mapped in the interval of 0.53-1.48 Mb on 7AS, which reduces cell number of internode to cause semi-dwarfism in Jianyangailanmai. As a valuable germplasm resource for wheat genetic improvement, tetraploid wheat has several reduced height (Rht) and enhanced harvest index genes. Rht22, discovered in Jianyangailanmai (JAM, Triticum turgidum L., 2n = 4x = 28, AABB), significantly increases the spikelet number per spike, but its accurate chromosomal position is still unknown. In this study, a high-density genetic map was constructed using specific-length amplified fragment sequencing in an F₇ RIL_DJ population, which was derived from a cross between dwarf Polish wheat (T. polonicum L., 2n = 4x = 28, AABB) and JAM. Two plant height loci, Qph.sicau-4B and Qph.sicau-7A, were mapped on chromosomes 4BS and 7AS, respectively. Qph.sicau-7A was mapped to the 0.33-4.46 Mb interval on 7AS and likely represents the candidate region of Rht22. Fine mapping confirmed and narrowed Rht22 on chromosome arm 7AS between Xbag295.s53 and Xb295.191 in three different populations. The physical region ranged from 0.53 to 1.48 Mb and included 18 candidate genes. Transcriptome analysis of two pairs of near-isogenic lines revealed that 135 differentially expressed genes (DEGs) were associated with semi-dwarfism. Of these, the expression of 83 annotated DEGs involved in hormones synthesis and signal transduction, cell wall composition, DNA replication, microtubule and phragmoplast arrays was significantly down-regulated in the semi-dwarf line. Therefore, Rht22 causes semi-dwarfism in JAM by disrupting these cellular processes, which impairs cell proliferation and reduces internode cell number.

Effect of nitrogen fertilizer on seed yield and quality of Kengyilia melanthera (Triticeae, Poaceae)

Widely distributed in the alpine sandy grassland in east Qinghai-Tibet Plateau (QTP), Kengyilia melanthera is considered as an ideal pioneer grass for the restoration of degraded and desertification grassland in the region. Under the special ecological and climatic conditions in the northwest Sichuan plateau located in east QTP, it is of great significance to optimize the amount of nitrogen fertilizer for the seed production of this species. The impact of nitrogen (N) fertilizer application on seed yield and quality of K. melanthera 'Aba', the only domesticated variety in the Kengyilia genus of Poaceae, was investigated based on two-year field experiments in the northwestern Sichuan plateau. The results showed that with the increase of N fertilizer application, the number of tillers, number of fertile tillers, 1,000-seed weight and seed yield of this species increased likewise. The optimum N fertilizer rate deduced in the present study was 180 kg·hm^-2, where the number of fertile tillers 1,000-seed weight and seed yield reached the peak values. Interestingly, the standard germination rate, germination energy, accelerated aging germination rate, dehydrogenase and acid phosphatase activity of seeds were not affected by the increasing the input of N fertilizer. The comprehensive evaluation of membership function showed that the optimal N fertilizer treatment was 180 kg·hm^-2 both for 2016 and 2017. This study provided a certain practical suggestion for the improvement of seed production of K. melanthera in the northwest Sichuan plateau.

Full-length transcriptome sequencing analysis and characterization, development and validation of microsatellite markers in Kengyilia melanthera

As a typical psammophyte of the Triticeae, Kengyilia melanthera possesses high feeding potential and great utilization values in desertification control in the Qinghai-Tibet Plateau. However, few gene function and genetic studies have been performed in K. melanthera. In this study, single-molecule real-time sequencing technology was used to obtain the full-length transcriptome sequence of K. melanthera, following the functional annotation of transcripts and prediction of coding sequences (CDSs), transcription factors (TFs), and long noncoding RNA (lncRNA) sequences. Meanwhile, a total of 42,433 SSR loci were detected, with 5'-UTRs having the most SSR loci and trinucleotide being the most abundant type. In total, 108,399 SSR markers were designed, and 300 SSR markers were randomly selected for diversity verification of K. melanthera. A total of 49 polymorphic SSR markers were used to construct the genetic relationships of 56 K. melanthera accessions, among which 21 SSR markers showed good cross-species transferability among the related species. In conclusion, the full-length transcriptome sequence of the K. melanthera will assist gene prediction and promote molecular biology and genomics research, and the polymorphic SSR markers will promote molecular-assisted breeding and related research of K. melanthera and its relatives.

[Characteristics and changes of sensitization patterns of major allergens in children from 2010 to 2020 in a hospital of pediatric in Beijing]

Objective: To analyze the sensitization characteristics and change of major allergens in children from 2010 to 2020 in Beijing, so as to provide basis for diagnosis, treatment and prevention of allergic diseases in children. Methods: A retrospective study was conducted to analyze the children who were suspected of allergic diseases and tested for serum immunoglobulin E (total IgE and specific IgE) in the children's Hospital Affiliated to the Capital Institute of Pediatrics from January 2010 to December 2020. A total of 45 746 children aged 0-17 years in Beijing were enrolled with a median (interquartile range) of 3.8 (2.5, 5.3) years. There were 28 918 boys (63.2%) and 16 828 girls (36.8%) and 14 984 cases (32.8%) in the infant group (<3 years old), 22 049 cases (48.2%) in the preschool group (3-6 years old), and 8 713 cases (19.0%) in the school-age group (6 years old and above). Immunocap allergen detection system (fluorescence enzyme-linked immunosorbent assay) was used to detect and the characteristics and change trend of allergens during 11 years were statistically analyzed by Chi square test. Results: The top three positive rates of single food allergens sIgE were egg white 42.6% (2 788/6 577 tests), milk 38.4% (2 606/6 782 tests) and wheat 31.8% (1 417/4 449 tests), and the sequence of single inhaled allergens were Ragweed 42.6% (440/1 034 tests), Artemisia 38.4% (1 045/3 191 tests) and Alternaria alternata 31.3% (3 358/10 725 tests). The positive detection rates of egg white 47.0%(1 904/4 048 tests), milk 41.9%(1 769/4 226 tests) and wheat 33.9%(973/2 870 tests) in the infant group were the highest, and there have statistically significant(χ²=91.495, 73.907, 16.966, P<0.05). The positive rates of fx1 (22.5%, 121/537 tests), peanut (24.9%, 111/446 tests), soybean (20.0%, 74/370 tests) and shrimp (7.48%, 44/588 tests) were the highest in the school-age group(χ²=14.436, 10.751, 11.569, 13.703, P<0.05). The most common inhaled allergens were Alternaria alternata (14.8%, 422/2 859 tests) in the infant group, Ambrosia (34.5%, 143/415 tests) and Alternaria alternata (33.5%, 1 762/5 254 tests) in the preschool group, while in the school-age group were Ambrosia (56.4%, 282/500 tests) and Artemisia (48.2%, 573/1 189 tests). The positive rates of egg white, milk, wheat, sesame seed and peanut varied from 2010 to 2020, showing a trend of falling first and then rising(χ²=10.293,χ²=12.066,χ²=7.402,χ²=32.458,χ²=31.747,P<0.05).The positive detection rates of soybean showed a significant downward trend (21.4%, 173/809 tests in 2010, 15.4%, 70/455 tests in 2020, χ²=6.751,P=0.009), while that of shrimp and crab were at a stable low level(χ²=0.263, 1.346;P>0.05). From 2010 to 2020, mold (26.7%, 1 066/3 998 tests in 2010, 40.2% 1 705/4 243 tests in 2020), grass pollen (19.8%, 259/1 308 tests in 2010, 39.3%, 1 472/3 746 tests in 2020), tree pollen(17%, 180/1 058 tests in 2010, 29.8%, 916/3 075 tests in 2020) and animal dander (18.5%, 111/601 tests in 2010, 26.6%, 672/2 522 tests in 2020) were all showed significant upward trend (χ²=168.600, 163.601, 65.931 and 17.271 respectively, P<0.001) but dust mites (30.7%, 1 270/4 132 tests in 2010, 26.7%, 1 126/4 221 tests in 2020) showed a significant downward trend(χ²=16.822,P<0.001).In 2010, the most common inhaled allergen was dust mite 30.7% (1 270/4 132 tests), followed by mold 26.7% (1 066/3 998 tests), while they were mold 40.2% (1 705/1 243 tests), and grass pollen 39.3% (1 472/3 746 texts) respectively in 2020. Conclusion: In the past 11 years, the main food allergens in children were still egg white and milk, wheat, but the mold and pollen gradually replaced dust mite as the most common inhaled allergen.

[Clinical characteristics of IgE-mediated cow's milk protein allergy in children]

Objective: To analyze the clinical features of IgE-mediated cow's milk protein allergy (CMPA) in children aged 0-5 years. Methods: This cross-sectional study collected the data on children diagnosed with CMPA in the Department of Allergy at the Children's Hospital of the Capital Institute of Pediatrics from October 2019 to November 2020 and improved peripheral blood routine,total IgE defection, milk specific IgE (sIgE) defection,SPT and milk component defection,diagnosis of severe anaphylaxis based on clinical manifestations. Rank-sum test and chi-square test are used for statistical analysis of clinical characteristics between groups. Results: A total of 106 children (67 boys and 39 girls) were enrolled with the age of 15 (8, 34) months, including 42 cases (≤ 1 year of age), 39 cases (>1-<3 years of age) and 25 cases(≥3 years of age), the onset age of 6 (5, 8) months. Among them, 95 cases (89.6%) were reacted after consuming milk or its products, 42 cases (39.6%) had reaction due to skin contact and 11 cases (10.4%) reacted after exclusive breastfeeding. The onset time of milk product consumption was 45 (1, 120) min, skin contact pathway was 10 (5, 30) min and symptoms in breastfeeding pathway was 121 (61, 180) min. There was statistical difference among the time of symptoms (χ²=77.01, P<0.001).The cutaneous reaction was most common (100 cases, 94.3%), followed by digestive (20 cases, 18.9%) and respiratory (16 cases, 15.1%), and the nervous symptoms (1 case, 0.9%) were uncommon and 24 cases (22.6%) had at least one episode of anaphylaxis. There were 87 cases (82.1%) also diagnosed with other food allergies, 94 cases (88.7%) with previous eczema, 57 cases (53.8%) with history of rhinitis, and 23 cases (21.7%) with history of wheezing. The total IgE level was 191.01 (64.71, 506.80) kU/L, and the cow's milk sIgE level was 3.03 (1.11, 15.24) kU/L. The maximum diameter of the wheal in SPT was 8.2 (4.0, 12.0) mm. Component resolved diagnosis showed that 77 cases (81.9%) were sensitized to at least one out of 4 main components, including casein, α lactalbumin, β lactoglobulin and bovine serum albumin.The possibility of anaphylaxis in children with milk sIgE grade Ⅳ-Ⅵ was higher than that in children with grade 0-Ⅲ (57.7% (15/26) vs. 12.5% (10/80), OR=9.545, 95%CI 3.435-26.523). Children with milk SPT ≥+++ had a higher probability of anaphylaxis than those with milk SPT ≤++ (34.4% (11/32) vs. 11.5% (3/26), OR=4.016, 95%CI 0.983-16.400). Anaphylaxis were more common in α lactalbumin positive children than in negative children (34.3% (13/38) vs. 14.2% (8/56), χ²=1.23，P=0.042). Conclusions: CMPA in children has early onset and diversified clinical manifestations, which are mainly cutaneous symptoms. Most children are sensitized to at least one allergen component. Serum sIgE level, SPT reaction and allergen components play important roles in the diagnosis and evaluation of CMPA, and higher milk sIgE level may predict a higher risk of anaphylaxis.

Development and Identification of a Novel Wheat-Thinopyrum scirpeum 4E (4D) Chromosomal Substitution Line with Stripe Rust and Powdery Mildew Resistance

Stripe rust caused by Puccinia striiformis f. sp. tritici and powdery mildew caused by Blumeria graminis f. sp. tritici are devastating diseases of wheat worldwide. Exploration of new disease-resistant genes from cultivated wheat and wild relatives are the most effective means of reducing the amounts of fungicides applied to combat these diseases. Thinopyrum scirpeum (2n = 4x = 28, EEEE) is an important promising reservoir of useful genes, including stripe rust and powdery mildew resistance, and may be useful for increasing wheat disease resistance. Here, we characterize a novel wheat-Th. scirpeum disomic substitution line, K16-730-3, and chromosome-specific markers were developed that can be used to trace the Th. scirpeum chromosome or chromosome segments transferred into wheat. Genomic in situ hybridization and fluorescence in situ hybridization analyses indicated that K16-730-3 is a new 4E (4D) chromosomal substitution line. Evaluation of seedling and adult disease responses revealed that K16-730-3 is resistant to stripe rust and powdery mildew. In addition, no obvious difference in grain yield was observed between K16-730-3 and its wheat parents. Genotyping-by-sequencing analyses indicated that 74 PCR-based markers can accurately trace chromosome 4E, which were linked to the disease resistance genes in the wheat background. Further marker validation analyses revealed that 13 specific markers can distinguish between the E-genome chromosomes of Th. scirpeum and the chromosomes of other wheat-related species. The new substitution line K16-730-3 carrying the stripe rust and powdery mildew resistance genes will be useful as novel germplasm in breeding for disease resistance. The markers developed in this study can be used in marker-assisted selection for increasing disease resistance in wheat.

Morphological, cytological, and molecular evidences for natural hybridization between Roegneria stricta and Roegneria turczaninovii (Triticeae: Poaceae)

Some plants with low fertility are morphologically intermediate between Roegneria stricta and Roegneria turczaninovii, and were suspected to be natural hybrids between these species. In this study, karyotype analysis showed that natural hybrids and their putative parents were tetraploids (2n = 4x = 28). Meiotic pairing in natural hybrids is more irregular than its putative parents. Results of genomic in situ hybridization and fluorescence in situ hybridization indicate that natural hybrids contain the same genome as their putative parents. The nuclear gene DNA meiotic recombinase 1 (DMC1) and the chloroplast gene rps16 of natural hybrids and their putative parents were analyzed for evidence of hybridization. The results from molecular data supported by morphology and cytology demonstrated that the plants represent natural hybrids between R. stricta and R. turczaninovii. The study is important for understanding species evolution in the genus since it demonstrates for the first time the existence of populations of natural homoploid hybrids in Roegneria. The study also reports for the first time that the composition of the genomic formula of R. turczaninovii is StY, confirming that the current taxonomic status is correct.

Identification of a Wheat-Psathyrostachys huashanica 7Ns Ditelosomic Addition Line Conferring Early Maturation by Cytological Analysis and Newly Developed Molecular and FISH Markers

Early maturation is an important objective in wheat breeding programs that could facilitate multiple-cropping systems, decrease disaster- and disease-related losses, ensure stable wheat production, and increase economic benefits. Exploitation of novel germplasm from wild relatives of wheat is an effective means of breeding for early maturity. Psathyrostachys huashanica Keng f. ex P. C. KUO (2n=2x=14, NsNs) is a promising source of useful genes for wheat genetic improvement. In this study, we characterized a novel wheat-P. huashanica line, DT23, derived from distant hybridization between common wheat and P. huashanica. Fluorescence in situ hybridization (FISH) and sequential genomic in situ hybridization (GISH) analyses indicated that DT23 is a stable wheat-P. huashanica ditelosomic addition line. FISH painting and PCR-based landmark unique gene markers analyses further revealed that DT23 is a wheat-P. huashanica 7Ns ditelosomic addition line. Observation of spike differentiation and the growth period revealed that DT23 exhibited earlier maturation than the wheat parents. This is the first report of new earliness per se (Eps) gene(s) probably associated with a group 7 chromosome of P. huashanica. Based on specific locus-amplified fragment sequencing technology, 45 new specific molecular markers and 19 specific FISH probes were developed for the P. huashanica 7Ns chromosome. Marker validation analyses revealed that two specific markers distinguished the Ns genome chromosomes of P. huashanica and the chromosomes of other wheat-related species. These newly developed FISH probes specifically detected Ns genome chromosomes of P. huashanica in the wheat background. The DT23 line will be useful for breeding early maturing wheat. The specific markers and FISH probes developed in this study can be used to detect and trace P. huashanica chromosomes and chromosomal segments carrying elite genes in diverse materials.

TpIRT1 from Polish wheat (Triticum polonicum L.) enhances the accumulation of Fe, Mn, Co, and Cd in Arabidopsis

Uptake and internal transport of micronutrients are essential for plant growth, development, and yield. In this regard, Iron Regulated Transporters (IRTs) from the Zinc Regulated Transporter (ZRT)/IRT-related protein (ZIP) family play an important role in transition metal uptake. Most studies have been focused on IRT1-like proteins in diploid species. Information on IRT1-like proteins in polyploids is limited. Here, we studied the function of TpIRT1A and TpIRT1B homoeologs in a tetraploid crop, Polish wheat (Triticum polonicum L.). Our results highlighted the importance of TpIRT1 in mediating the uptake and translocation of Fe, Mn, Co, and Cd with direct implications for wheat yield potential. Both TpIRT1A and TpIRT1B were located at the plasma membrane and internal vesicle-like organelle in protoplasts of Arabidopsis thaliana L. and increased Cd and Co sensitivity in yeast. The over-expression of TpIRT1B in A. thaliana increased Fe, Mn, Co, and Cd concentration in its tissues and improved plant growth under Fe, Mn, and Co deficiencies, while increased the sensitivity to Cd compared to wild type. Functional analysis of IRT1 homoeologs from tetraploid and diploid ancestral wheat species in yeast disclosed four distinct amino acid residues in TdiIRT1B (T. dicoccum L. (Schrank)) and TtuIRT1B (T. turgidum L.). Together, our results increase the knowledge of IRT1 function in a globally important crop, wheat.

Transcriptome analysis of messenger RNA and long noncoding RNA related to different developmental stages of tail adipose tissues of sunite sheep

The tail fat of sheep is the most typical deposited fat, and it can be widely used in human daily life, such as diet, cosmetics, and industrial raw materials. To understand the potential regulatory mechanism of different growth stages of tail fat in Sunite sheep, we performed high-throughput RNA sequencing to characterize the long noncoding RNA (lncRNA) and messenger RNA (mRNA) expression profiles of the sheep tail fat at the age of 6, 18, and 30 months. A total of 223 differentially expressed genes (DEGs) and 148 differentially expressed lncRNAs were found in the tail fat of 6-, 18-, and 30-month-old sheep. Based on functional analysis, we found that fat-related DEGs were mainly expressed at 6 months of age and gradually decreased at 18 and 30 months of age. The target gene prediction analysis shows that most of the lncRNAs target more than 20 mRNAs as their transregulators. Further, we obtained several fat-related differentially expressed target genes; these target genes interact with different differentially expressed lncRNAs at various ages and play an important role in the development of tail fat. Based on the DEGs and differentially expressed lncRNAs, we established three co-expression networks for each comparison group. Finally, we concluded that the development of the sheep tail fat is more active during the early stage of growth and gradually decreases with the increase in age. The mutual regulation of lncRNAs and mRNAs may play a key role in this complex biological process.

Ammonium-nitrogen addition at the seedling stage does not reduce grain cadmium concentration in two common wheat (Triticum aestivum L.) cultivars

High cadmium (Cd) concentration in common wheat (Triticum aestivum L.) grains poses potential health risks. Several management strategies have been used to reduce grain Cd concentration. However, limited information is available on the use of ammonium-nitrogen (NH₄⁺-N) as a strategy to manage Cd concentration in wheat grains. In this study, NH₄⁺-N addition at the seedling stage unchanged the grain Cd concentration in the high-Cd accumulator, Zhoumai 18 (ZM18), but dramatically increased that in the low-Cd accumulator, Yunmai 51 (YM51). Further analysis revealed that the effects of NH₄⁺-N addition on whole-plant Cd absorption, root-to-shoot Cd translocation, and shoot-to-grain Cd remobilization were different between the two wheat cultivars. In ZM18, NH₄⁺-N addition did not change whole-plant Cd absorption, but inhibited root-to-shoot Cd translocation and Cd remobilization from lower internodes, lower leaves, node 1, and internode 1 to grains via the down-regulation of yellow stripe-like transporters (YSL), zinc transporters (ZIP5, ZIP7, and ZIP10), and heavy-metal transporting ATPases (HMA2). This inhibition decreased the grain Cd content by 29.62%, which was consistent with the decrease of the grain dry weight by 23.26%, leading to unchanged grain Cd concentration in ZM18. However, in YM51, NH₄⁺-N addition promoted continuous Cd absorption during grain filling, root-to-shoot Cd translocation and whole-plant Cd absorption. The absorbed Cd was directly transported to internode 1 via the xylem and then re-transported to grains via the phloem by up-regulated YSL, ZIP5, and copper transporters (COPT4). This promotion increased the grain Cd content by 245.35%, which was higher than the increased grain dry weight by 132.89%, leading to increased grain Cd concentration in YM51. Our findings concluded that the addition of NH₄⁺-N fertilizer at the seedling stage is not suitable for reducing grain Cd concentration in common wheat cultivars.

Chloroplast Phylogenomic Analyses Resolve Multiple Origins of the Kengyilia Species (Poaceae: Triticeae) via Independent Polyploidization Events

Kengyilia is a group of allohexaploid species that arose from two hybridization events followed by genome doubling of three ancestral diploid species with different genomes St, Y, and P in the Triticeae. Estimating the phylogenetic relationship in resolution of the maternal lineages has been difficult, owing to the extremely low rate of sequence divergence. Here, phylogenetic reconstructions based on the plastome sequences were used to explore the role of maternal progenitors in the establishment of Kengyilia polyploid species. The plastome sequences of 11 Kengyilia species were analyzed together with 12 tetraploid species (PP, StP, and StY) and 33 diploid taxa representing 20 basic genomes in the Triticeae. Phylogenomic analysis and genetic divergence patterns suggested that (1) Kengyilia is closely related to Roegneria, Pseudoroegneria, Agropyron, Lophopyrum, Thinopyrum, and Dasypyrum; (2) both the StY genome Roegneria tetraploids and the PP genome Agropyron tetraploids served as the maternal donors during the speciation of Kengyilia species; (3) the different Kengyilia species derived their StY genome from different Roegneria species. Multiple origins of species via independent polyploidization events have occurred in the genus Kengyilia, resulting in a maternal haplotype polymorphism. This helps explain the rich diversity and wide adaptation of polyploid species in the genus Kengyilia.

Characterization of Each St and Y Genome Chromosome of Roegneria grandis Based on Newly Developed FISH Markers

The genera of the tribe Triticeae (family Poaceae), constituting many economically important plants with abundant genetic resources, carry genomes such as St, H, P, and Y. The genome symbol of Roegneria C. Koch (Triticeae) is StY. The St and Y genomes are crucial in Triticeae, and tetraploid StY species participate extensively in polyploid speciation. Characterization of St and Y nonhomologous chromosomes in StY-genome species could help understand variation in the chromosome structure and differentiation of StY-containing species. However, the high genetic affinity between St and Y genome and the deficiency of a complete set of StY nonhomologous probes limit the identification of St and Y genomes and variation of chromosome structures among Roegneria species. We aimed to identify St- and Y-enhanced repeat clusters and to study whether homoeologous chromosomes between St and Y genomes could be accurately identified due to high affinity. We employed comparative genome analyses to identify St- and Y-enhanced repeat clusters and generated a FISH-based karyotype of R. grandis (Keng), one of the taxonomically controversial StY species, for the first time. We explored 4 novel repeat clusters (StY_34, StY_107, StY_90, and StY_93), which could specifically identify individual St and Y nonhomologous chromosomes. The clusters StY_107 and StY_90 could identify St and Y addition/substitution chromosomes against common wheat genetic backgrounds. The chromosomes V_St, VII_St, I_Y, V_Y, and VII_Y displayed similar probe distribution patterns in the proximal region, indicating that the high affinity between St and Y genome might result from chromosome rearrangements or transposable element insertion among V_St/Y, VII_St/Y, and I_Y chromosomes during allopolyploidization. Our results can be used to employ FISH further to uncover the precise karyotype based on colinearity of Triticeae species by using the wheat karyotype as reference, to analyze diverse populations of the same species to understand the intraspecific structural changes, and to generate the karyotype of different StY-containing species to understand the interspecific chromosome variation.

Genetic diversity of Asian and European common wheat lines assessed by fluorescence in situ hybridization

Understanding the genetic diversity of wheat is important for wheat breeding and improvement. However, there have been limited attempts to evaluate wheat diversity using fluorescence in situ hybridization (FISH). In this study, the chromosomal structures of 149 wheat accessions from 13 countries located between the latitudes of 30°N and 45°N, the principal growing region for wheat, were characterized using FISH with pTa535 and pSc119.2 probes. The ranges of the numbers of FISH types in the A-, B-, and D-genome chromosomes were 2-8, 3-7, and 2-4, respectively, and the average numbers in the A and B genomes were greater than in the D genome. Chromosomal translocations were detected by these probes, and previously undescribed translocations were also observed. Using the FISH, the genetic relationships among the 149 common wheat lines were divided into three groups (G1, G2, and G3). G1 mainly consisted of southern European lines, G2 consisted of most lines from Japan and some lines from western Asia, China, and Korea, and G3 consisted of the other lines from southern Europe and most of the lines from western Asia, China, and Korea. FISH karyotypes of wheat chromosomes distinguished chromosomal structural variations, revealing the genetic diversity among wheat varieties. Furthermore, these results provide valuable information for the further genetic improvement of wheat in China.

The association of plasma acyl ghrelin level with alcohol craving in early abstinent alcohol dependent patients

Background

Craving plays an important role in maintenance of alcohol dependence. Earlier studies have analyzed the role of ghrelin in craving and their results have been heterogenous. Acyl ghrelin is its more active form as it crosses the blood brain barrier. Hence we aimed to examine the relationship between plasma acyl ghrelin and craving in Indian patients having alcohol dependence syndrome.

Methods

The present study was a hospital-based prospective study. A total of 60 drug-naive patients of alcohol dependence and 30 healthy controls were included. After taking informed consent fasting blood samples were collected from them on day 1 and tested for plasma acyl ghrelin level. Fasting blood samples were repeated in all cases on day 14. During this time, we also assessed the patients' cravings by obsessive compulsive drinking scale, and alcohol craving questionnaire; and withdrawal by clinical institute withdrawal assessment for alcohol scale. These scales were repeated on day 14. Data analysis was done by SPSS version 25.0.

Results

Plasma concentrations of acyl ghrelin increased significantly during early abstinence in patients from day 1 to day 14 (P < 0.0001). Pearson correlation test revealed a trend of positive correlation between plasma concentration of acyl ghrelin on day 14 and severity of craving on day 1.

Conclusion

Our results suggest the plasma concentration of acyl ghrelin may be a predictor of severity of alcohol craving during early abstinence. Anti-craving drugs acting on acyl ghrelin level in brain may open an innovative avenue for optimum treatment of alcohol dependence.

The semi-dwarfing gene Rht-dp from dwarf polish wheat (Triticum polonicum L.) is the "Green Revolution" gene Rht-B1b

Background

The wheat dwarfing gene increases lodging resistance, the grain number per spike and harvest index. Dwarf Polish wheat (Triticum polonicum L., 2n = 4x = 28, AABB, DPW), initially collected from Tulufan, Xinjiang, China, carries a semi-dwarfing gene Rht-dp on chromosome 4BS. However, Rht-dp and its dwarfing mechanism are unknown.

Results

Homologous cloning and mapping revealed that Rht-dp is the ‘Green Revolution’ gene Rht-B1b. A haplotype analysis in 59 tetraploid wheat accessions showed that Rht-B1b was only present in T. polonicum. Transcriptomic analysis of two pairs of near-isogenic lines (NILs) of DPW × Tall Polish wheat (Triticum polonicum L., 2n = 4x = 28, AABB, TPW) revealed 41 differentially expressed genes (DEGs) as potential dwarfism-related genes. Among them, 28 functionally annotated DEGs were classed into five sub-groups: hormone-related signalling transduction genes, transcription factor genes, cell wall structure-related genes, reactive oxygen-related genes, and nitrogen regulation-related genes.

Conclusions

These results indicated that Rht-dp is Rht-B1b, which regulates pathways related to hormones, reactive oxygen species, and nitrogen assimilation to modify the cell wall structure, and then limits cell wall loosening and inhibits cell elongation, thereby causing dwarfism in DPW.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07367-x.

Different nitrogen forms differentially affect Cd uptake and accumulation in dwarf Polish wheat (Triticum polonicum L.) seedlings

This study investigated the effects of different nitrogen (N) forms on Cadmium (Cd) uptake and accumulation in dwarf Polish wheat (DPW) seedlings, which were grown under Cd stress with N-Null, NH₄⁺-N, NO₃^--N and NH₄⁺-N + NO₃^--N. We measured plant growth and determined Cd uptake, translocation, accumulation, subcellular distribution and chemical forms in the roots and shoots of DPW seedlings. We also analyzed saccharide concentrations, and the transcript levels of genes encoding metal transporters in the roots of DPW seedlings. In the absence of NO₃^--N, addition of NH₄⁺-N reduced roots Cd concentration, F_CW (Cd in cell wall), F_S (Cd in soluble fraction) and F_E (inorganic Cd) concentrations, and induced the expression of four genes encoding metal transporters in roots, while it promoted Cd translocation to shoots. In the presence of NO₃^--N, addition of NH₄⁺-N increased roots Cd concentration, F_CW and F_W concentrations, and induced the expression of 22 genes encoding metal transporters in roots. Regardless of NH₄⁺-N level, addition of NO₃^--N increased roots Cd concentration, F_CW, F_S, F_W (water-soluble Cd), F_NaCl (pectates and protein Cd), F_HAc (undissolved Cd phosphate) and lactose concentrations, and also induced the expression of genes encoding metal transporters in roots. Overall, NH₄⁺-N differently regulated Cd uptake and accumulation in DPW seedlings in the absence or presence of NO₃^--N, while NO₃^--N greatly increased Cd uptake and accumulation in the presence of NH₄⁺-N compared to the absence of NH₄⁺-N. These patterns of Cd alteration likely arose due to different N forms altering Cd subcellular distribution and chemical forms, lactose concentration and the expression of metal transporter genes.

Genetic Diversity and Population Structure of Asian and European Common Wheat Accessions Based on Genotyping-By-Sequencing

Obtaining information on the genetic diversity and population structure of germplasm facilitates its use in wheat breeding programs. Recently, with the development of next-generation sequencing technology, genotyping-by-sequencing (GBS) has been used as a high-throughput and cost-effective molecular tool for examination of the genetic diversity of wheat breeding lines. In this study, GBS was used to characterize a population of 180 accessions of common wheat originating from Asia and Europe between the latitudes 30° and 45°N. In total, 24,767 high-quality single-nucleotide polymorphism (SNP) markers were used for analysis of genetic diversity and population structure. The B genome contained the highest number of SNPs, followed by the A and D genomes. The polymorphism information content was in the range of 0.1 to 0.4, with a mean of 0.26. The distribution of SNPs markers on the 21 chromosomes ranged from 243 on chromosome 4D to 2,337 on chromosome 3B. Structure and cluster analyses divided the panel of accessions into two subgroups (G1 and G2). G1 principally consisted of European and partial Asian accessions, and G2 comprised mainly accessions from the Middle East and partial Asia. Molecular analysis of variance showed that the genetic variation was greater within groups (99%) than between groups (1%). Comparison of the two subgroups indicated that G1 and G2 contained a high level of genetic diversity. The genetic diversity of G2 was slightly higher as indicated by the observed heterozygosity (H o) = 0.23, and unbiased diversity index (uh) = 0.34. The present results will not only help breeders to understand the genetic diversity of wheat germplasm on the Eurasian continent between the latitudes of 30° and 45°N, but also provide valuable information for wheat genetic improvement through introgression of novel genetic variation in this region.

Molecular cytogenetic characterization of wheat-Elymus repens chromosomal translocation lines with resistance to Fusarium head blight and stripe rust

BACKGROUND

Fusarium head blight (FHB) caused by the fungus Fusarium graminearum Schwabe and stripe rust caused by Puccinia striiformis f. sp. tritici are devastating diseases that affect wheat production worldwide. The use of disease-resistant genes and cultivars is the most effective means of reducing fungicide applications to combat these diseases. Elymus repens (2n = 6x = 42, StStStStHH) is a potentially useful germplasm of FHB and stripe rust resistance for wheat improvement.

RESULTS

Here, we report the development and characterization of two wheat-E. repens lines derived from the progeny of common wheat-E. repens hybrids. Cytological studies indicated that the mean chromosome configuration of K15-1192-2 and K15-1194-2 at meiosis were 2n = 42 = 0.86 I + 17.46 II (ring) + 3.11 II (rod) and 2n = 42 = 2.45 I + 14.17 II (ring) + 5.50 II (rod) + 0.07 III, respectively. Genomic and fluorescence in situ hybridization karyotyping and simple sequence repeats markers revealed that K15-1192-2 was a wheat-E. repens 3D/?St double terminal chromosomal translocation line. Line K15-1194-2 was identified as harboring a pair of 7DS/?StL Robertsonian translocations and one 3D/?St double terminal translocational chromosome. Further analyses using specific expressed sequence tag-SSR markers confirmed that the wheat-E. repens translocations involved the 3St chromatin in both lines. Furthermore, compared with the wheat parent Chuannong16, K15-1192-2 and K15-1194-2 expressed high levels of resistance to FHB and stripe rust pathogens prevalent in China.

CONCLUSIONS

Thus, this study has determined that the chromosome 3St of E. repens harbors gene(s) highly resistant to FHB and stripe rust, and chromatin of 3St introgressed into wheat chromosomes completely presented the resistance, indicating the feasibility of using these translocation lines as novel material for breeding resistant wheat cultivars and alien gene mining.

Characterization of a wheat-tetraploid Thinopyrum elongatum 1E(1D) substitution line K17-841-1 by cytological and phenotypic analysis and developed molecular markers

Background

Tetraploid Thinopyrum elongatum (2n = 4x = 28) is a promising source of useful genes, including those related to adaptability and resistance to diverse biotic (Fusarium head blight, rust, powdery mildew, and yellow dwarf virus) and abiotic (cold, drought, and salt) stresses. However, gene transfer rates are low for this species and relatively few species-specific molecular markers are available.

Results

The wheat-tetraploid Th. elongatum line K17–841-1 derived from a cross between a hexaploid Trititrigia and Sichuan wheat cultivars was characterized based on sequential genomic and fluorescence in situ hybridizations and simple sequence repeat markers. We revealed that K17–841-1 is a 1E (1D) chromosomal substitution line that is highly resistant to stripe rust pathogen strains prevalent in China. By comparing the sequences generated during genotyping-by-sequencing (GBS), we obtained 597 specific fragments on the 1E chromosome of tetraploid Th. elongatum. A total of 235 primers were designed and 165 new Th. elongatum-specific markers were developed, with an efficiency of up to 70%. Marker validation analyses indicated that 25 specific markers can discriminate between the tetraploid Th. elongatum chromosomes and the chromosomes of other wheat-related species. An evaluation of the utility of these markers in a F₂ breeding population suggested these markers are linked to the stripe rust resistance gene on chromosome 1E. Furthermore, 28 markers are unique to diploid Th. elongatum, tetraploid Th. elongatum, or decaploid Thinopyrum ponticum, which carry the E genome. Finally, 48 and 74 markers revealed polymorphisms between Thinopyrum E-genome- containing species and Thinopyrum bessarabicum (E^b) and Pseudoroegneria libanotica (St), respectively.

Conclusions

This new substitution line provide appropriate bridge–breeding–materials for alien gene introgression to improve wheat stripe rust resistance. The markers developed using GBS technology in this study may be useful for the high-throughput and accurate detection of tetraploid Th. elongatum DNA in diverse materials. They may also be relevant for investigating the genetic differences and phylogenetic relationships among E, E^b, St, and other closely-related genomes and for further characterizing these complex species.

Protective effect of different forms of nitrogen application on cadmium-induced toxicity in wheat seedlings

Therefore, applying NH₄⁺-N tp PHW-SA caused greater tolerance to Cd toxicity by higher biomass production, photosynthetic capacity, Ca and Cu accumulation, better root development and lower translocation factor of Cd as well as Cd concetration in organelle fraction. The Cd stress inhibited the growth performance of wheat seedlings, the mineral nutrient accumulation, and nitrogen uptake and distribution, and different forms of nitrogen have different protective effects on wheat. In PHW-SA, ANCd treatment caused lower reduction in biomass accumulation, photosynthesis, isotope stable N content, Ca and Cu accumulation, root development inhibition, tissue Cd concentration, and transfer factor, which even led to lower concentrations of Cd in F_co than those in F_cw and F_s in comparison with NNCd treatment. On the other hand, the converse growth performance was recorded in J-11 under ANCd treatment. Meanwhile, the nitrogen absorption preference in PHW-SA was altered along with the enhanced absorption efficiency of nitrogen. Therefore, applying NH₄⁺-N to PHW-SA caused greater tolerance to Cd toxicity by higher biomass production, photosynthetic capacity, Ca and Cu accumulation, better root development and lower translocation factor of Cd as well as Cd concetration in organelle fraction..

Genome constitution and evolution of Elytrigia lolioides inferred from Acc1, EF-G, ITS, TrnL-F sequences and GISH

BACKGROUND

Elytrigia lolioides (Kar. et Kir.) Nevski, which is a perennial, cross-pollinating wheatgrass that is distributed in Russia and Kazakhstan, is classified into Elytrigia, Elymus, and Lophopyrum genera by taxonomists on the basis of different taxonomic classification systems. However, the genomic constitution of E. lolioides is still unknown. To identify the genome constitution and evolution of E. lolioides, we used single-copy nuclear genes acetyl-CoA carboxylase (Acc1) and elongation factor G (EF-G), multi-copy nuclear gene internal transcribed space (ITS), chloroplast gene trnL-F together with fluorescence and genomic in situ hybridization.

RESULTS

Despite the widespread homogenization of ITS sequences, two distinct lineages (genera Pseudoroegneria and Hordeum) were identified. Acc1 and EF-G sequences suggested that in addition to Pseudoroegneria and Hordeum, unknown genome was the third potential donor of E. lolioides. Data from chloroplast DNA showed that Pseudoroegneria is the maternal donor of E. lolioides. Data from specific FISH marker for St genome indicated that E. lolioides has two sets of St genomes. Both genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) results confirmed the presence of Hordeum genome in this species. When E genome was used as the probe, no signal was found in 42 chromosomes. The E-like copy of Acc1 sequences was detected in E. lolioides possibly due to the introgression from E genome species. One of the H chromosomes in the accession W6-26586 from Kazakhstan did not hybridize H genome signals but had St genome signals on the pericentromeric regions in the two-color GISH.

CONCLUSIONS

Phylogenetic and in situ hybridization indicated the presence of two sets of Pseudoroegneria and one set of Hordeum genome in E. lolioides. The genome formula of E. lolioides was designed as StStStStHH. E. lolioides may have originated through the hybridization between tetraploid Elymus (StH) and diploid Pseudoroegneria species. E and unknown genomes may participate in the speciation of E. lolioides through introgression. According to the genome classification system, E. lolioides should be transferred into Elymus L. and renamed as Elymus lolioidus (Kar. er Kir.) Meld.

The polish wheat (Triticum polonicum L.) TpSnRK2.10 and TpSnRK2.11 meditate the accumulation and the distribution of cd and Fe in transgenic Arabidopsis plants

Background

The SnRK2s (Plant specific protein kinase) are involved in various biological processes, such as plant defense and environmental challenges. In Arabidopsis, AtSnRK2s regulate the expression of some metal transporters. For example, AtSnRK2.4 plays a role in the regulation of Arabidopsis tolerance to Cd; AtSnRK2.2 and AtSnRK2.3 are involved in Cd uptake and translocation. However, the functions of their homologs, TpSnRK2.10 and TpSnRK2.11 from dwarf Polish wheat are unknown.

Results

TpSnRK2.11 encodes a cytoplasmic protein. TpSnRK2.10 and TpSnRK2.11 have different expression patterns at different growth stages. Expression of TpSnRK2.10 increased yeast’s sensitivity to Cd; conversely, expression of TpSnRK2.11 enhanced yeast’s tolerance to Cd. Overexpression of TpSnRK2.10 or TpSnRK2.11 did not affect Cd sensitivity in Arabidopsis, but significantly increased Cd accumulation in roots and shoots, and Cd translocation from roots to shoots. While, Fe accumulation was significantly increased in roots but decreased in shoots by overexpression of TpSnRK2.10; opposite results were observed in TpSnRK2.11-overexpressing lines. Subcellular distribution analysis found that overexpression of TpSnRK2.10 and TpSnRK2.11 increased Cd concentration in cell wall and organelle fractions of roots and shoots; meanwhile, they also differentially influenced Fe distribution.

Conclusions

These results indicated that TpSnRK2.10 and TpSnRK2.11 are involved in the uptakes and the translocations of Cd and Fe, possibly by regulating the expression of AtNRAMP1 and AtHMA4, and other genes involved in the synthesis of phytochelatins or hemicellolosic polysaccharides.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5589-1) contains supplementary material, which is available to authorized users.

[A follow-up study of six years' outcome of children with asthma in urban area of Beijing]

Objective: To understand the outcome of asthma in children from urban area of Beijing and the factors associated with the outcome. Methods: A total of 497 children with asthma diagnosed in the epidemiological survey of childhood asthma in urban area of Beijing in 2010 were selected in this study. Telephone follow-up was conducted in 2016 to obtain information about asthma attack, emergency visit, hospitalization, medication and disease control, and data of comorbidities of allergic diseases from 1 year earlier. Enumeration data were compared using chi-square test, measurement data were compared by rank sum test. The multi-factor logistic regression analysis was employed for the relationship between the related factors and asthma, Kaplan-Meier survival analysis and COX regression was employed to understand the relationship between the related factors and the course of the disease. Results: Questionnaires were conducted in 366 children, of whom 66.7% (244/366) were male, and 33.3% (122/366) were female.Compared with 2010, the rate of asthma attack and emergency room visits in children in last 12 months were significantly lower (19.1%(70/366) vs. 57.1%(284/497), and 3.0% (11/366) vs.19.7% (98/497), χ(2)=125.910 and 53.352, both P<0.01). There was no significant change in the proportion of allergic rhinitis and atopic dermatitis in last 12 months compared with that 6 years ago (both P>0.05). The number of children with clinical remission (2 years and above) was 75.4% (276/366). The number of children without remission within 2 years was 24.6% (90/366). The majority of children without remission were less than 12 years old boys (52.4% (33/63) vs. 30.9% (56/181) , χ(2)=9.273, P<0.01) . The proportion of children without remission associated with allergic rhinitis (67.8%(61/90)), atopic dermatitis (30.0%(27/90)), first-degree relatives with asthma (68.9%(62/90)) was higher than that of children with remission (51.8%(143/276), 17.0%(47/276), and 54.7%(151/276), respectively, χ(2)=7.013, 7.079, 5.608, respectively, all P<0.05). The proportion of children without remission who used control drugs was (33.3%(30/90)), which was higher than that in children with remission (7.2%(20/276), χ(2)=39.158, P<0.01). Multiple logistic regression showed that boy (OR=2.402 (1.611-3.580), P<0.05), later onset (OR=4.339 (>3-6 years old vs. 0-3 years old), OR=2.630(>6 years old vs. 0-3 years old), χ(2)=18.512, 31.371, 6.510, all P<0.05) were independent risk factors for asthma remission. COX regression analysis showed that the use of control drugs (HR=0.705 (0.515-0.964), χ(2)=4.795, P<0.05) was the relevant factor in the course of the disease. Conclusions: With the increase of age, the incidence of asthma in children in Beijing city in recent 12 months reduced. Male and late onsets were independent risk factors for asthma remission. The use of control drugs was the relevant factor in the course of the disease.

Expression of TpNRAMP5, a metal transporter from Polish wheat (Triticum polonicum L.), enhances the accumulation of Cd, Co and Mn in transgenic Arabidopsis plants

TpRNAMP5 is mainly expressed in the plasma membrane of roots and basal stems. It functions as a metal transporter for Cd, Mn and Co accumulation. Numerous natural resistance-associated macrophage proteins (NRAMPs) have been functionally identified in various plant species, including Arabidopsis, rice, soybean and tobacco, but no information is available on NRAMP genes in wheat. In this study, we isolated a TpNRAMP5 from dwarf Polish wheat (DPW, Triticum polonicum L.), a species with high tolerance to Cd and Zn. Expression pattern analysis revealed that TpNRAMP5 is mainly expressed in roots and basal stems of DPW. TpNRAMP5 was localized at the plasma membrane of Arabidopsis leaf protoplast. Expression of TpNRAMP5 in yeast significantly increased yeast sensitivity to Cd and Co, but not Zn, and enhanced Cd and Co concentrations. Expression of TpNRAMP5 in Arabidopsis significantly increased Cd, Co and Mn concentrations in roots, shoots and whole plants, but had no effect on Fe and Zn concentrations. These results indicate that TpNRAMP5 is a metal transporter enhancing the accumulation of Cd, Co and Mn, but not Zn and Fe. Genetic manipulation of TpNRAMP5 can be applied in the future to limit the transfer of Cd from soil to wheat grains, thereby protecting human health.

FISH-Based Markers Enable Identification of Chromosomes Derived From Tetraploid Thinopyrum elongatum in Hybrid Lines

Tetraploid Thinopyrum elongatum, which has superior abiotic stress tolerance characteristics, and exhibits resistance to stripe rust, powdery mildew, and Fusarium head blight, is a wild relative of wheat and a promising source of novel genes for wheat improvement. Currently, a high-resolution Fluorescence in situ hybridization (FISH) karyotype of tetraploid Th. elongatum is not available. To develop chromosome-specific FISH-based markers, the hexaploid Trititrigia 8801 and two accessions of tetraploid Th. elongatum were characterized by different repetitive sequences probes. We found that all E-genome chromosomes could be unambiguously identified using a combination of pSc119.2, pTa535, pTa71, and pTa713 repeats, and the E-genome chromosomes of the wild accessions and the partial amphiploid failed to exhibit any significant variation in the probe hybridization patterns. To verify the validation of these markers, the chromosome constitution of eight wheat- Th. elongatum hybrid derivatives were analyzed. We revealed that these probes could quickly detect wheat and tetraploid Th. elongatum chromosomes in hybrid lines. K16-712-1-2 was a 1E (1D) chromosome substitution line, K16-681-4 was a 2E disomic chromosome addition line, K16-562-3 was a 3E, 4E (3D, 4D) chromosome substitution line, K15-1033-8-2 contained one 4E, two 5E, and one 4ES⋅1DL Robertsonian translocation chromosome, and four other lines carried monosomic 4E, 5E, 6E, and 7E chromosome, respectively. Furthermore, the E-genome specific molecular markers analysis corresponded perfectly with the FISH results. The developed FISH markers will facilitate rapid identification of tetraploid Th. elongatum chromosomes in wheat improvement programs and allow appropriate alien chromosome transfer.

Cytogenetics and stripe rust resistance of wheat-Thinopyrum elongatum hybrid derivatives

BACKGROUND

Amphidiploids generated by distant hybridization are commonly used as genetic bridge to transfer desirable genes from wild wheat species into cultivated wheat. This method is typically used to enhance the resistance of wheat to biotic or abiotic stresses, and to increase crop yield and quality. Tetraploid Thinopyrum elongatum exhibits strong adaptability, resistance to stripe rust and Fusarium head blight, and tolerance to salt, drought, and cold.

RESULTS

In the present study, we produced hybrid derivatives by crossing and backcrossing the Triticum durum-Th. elongatum partial amphidiploid (Trititrigia 8801, 2n = 6× = 42, AABBEE) with wheat cultivars common to the Sichuan Basin. By means of cytogenetic and disease resistance analyses, we identified progeny harboring alien chromosomes and measured their resistance to stripe rust. Hybrid progenies possessed chromosome numbers ranging from 40 to 47 (mean = 42.72), with 40.0% possessing 42 chromosomes. Genomic in situ hybridization revealed that the number of alien chromosomes ranged from 1 to 11. Out of the 50 of analyzed lines, five represented chromosome addition (2n = 44 = 42 W + 2E) and other five were chromosome substitution lines (2n = 42 = 40 W + 2E). Importantly, a single chromosome derived from wheat-Th. elongatum intergenomic Robertsonian translocations chromosome was occurred in 12 lines. Compared with the wheat parental cultivars ('CN16' and 'SM482'), the majority (70%) of the derivative lines were highly resistant to strains of stripe rust pathogen known to be prevalent in China.

CONCLUSION

The findings suggest that these hybrid-derivative lines with stripe rust resistance could potentially be used as germplasm sources for further wheat improvement.

Ammonium N influences the uptakes, translocations, subcellular distributions and chemical forms of Cd and Zn to mediate the Cd/Zn interactions in dwarf polish wheat (Triticum polonicum L.) seedlings

Ammonium (NH₄⁺) would influence the uptake and translocation of Cd and Zn to mediate their interactions in wheat. Thus, the effects of NH₄⁺ on Cd and Zn uptake, translocation, subcellular distributions and Cd chemical forms in dwarf polish wheat (DPW, Triticum polonicum L.) under Cd, Zn and Cd + Zn stresses with lack or supply of NH₄⁺ was investigated. The biomasses of root and shoot were reduced by NH₄⁺. NH₄⁺ enhanced Cd and Zn uptakes, but inhibited their translocations. Under lack and supply of NH₄⁺, Zn inhibited Cd uptakes, but promoted Cd translocations. Meanwhile, NH₄⁺ reinforced the inhibition of Cd uptake and the promotion of Cd translocation caused by Zn. Cd inhibited Zn uptake and promoted Zn translocation under lack of NH₄⁺. Meanwhile, Cd slightly reduced the Zn uptake, but did not affect the translocation under supply of NH₄⁺. Therefore, NH₄⁺ alleviated the inhibition of Zn uptake and partly reduced the promotion of Zn translocation stimulated by Cd. NH₄⁺ and Zn changed the subcellular distributions and chemical forms of Cd. NH₄⁺ and Cd also influenced the subcellular distributions of Zn. The changed subcellular distributions and chemical forms were associated with Cd and Zn uptakes and translocations, which physiologically revealed and illustrated NH₄⁺ participates in Cd/Zn interactions.

Cloning and Characterization of TpNRAMP3, a Metal Transporter From Polish Wheat (Triticum polonicum L.)

Essential transition metals and non-essential metals often co-exist in arable soils. In plants, some transition metal transporters, such as the natural resistance-associated macrophage proteins (NRAMPs), poorly selectively transport metals with similar chemical properties whether they are essential or non-essential. In this study, a member of the NRAMP transporter family, TpNRAMP3, was identified from dwarf Polish wheat (Triticum polonicum L.). TpNRAMP3 encodes a plasma membrane-localized protein and was highly expressed in leaf blades and roots at the jointing and booting stages, and in the first nodes at the grain filling stage. Expression of TpNRAMP3 increased sensitivity to Cd and Co, but not Zn, and increased the Cd and Co concentrations in yeast. TpNRAMP3 expression in Arabidopsis increased concentrations of Cd, Co, and Mn, but not Fe or Zn, in roots, shoots, and whole plant. However, TpNRAMP3 did not affect translocation of Cd, Co, or Mn from roots to shoots. These results suggest that TpNRAMP3 is a transporter for Cd, Co, and Mn accumulation, but not for Fe or Zn. However, Cd and Co are non-essential toxic metals; selective genetic manipulation of TpNRAMP3 will help breed low Cd- and Co-accumulating cultivars.

Physiological and transcriptome response to cadmium in cosmos (Cosmos bipinnatus Cav.) seedlings

To date, several species of Asteraceae have been considered as Cd-accumulators. However, little information on the Cd tolerance and associated mechanisms of Asteraceae species Cosmos bipinnatus, is known. Presently, several physiological indexes and transcriptome profiling under Cd stress were investigated. C. bipinnatus exhibited strong Cd tolerance and recommended as a Cd-accumulator, although the biomasses were reduced by Cd. Meanwhile, Cd stresses reduced Zn and Ca uptake, but increased Fe uptake. Subcellular distribution indicated that the vacuole sequestration in root mainly detoxified Cd under lower Cd stress. Whilst, cell wall binding and vacuole sequestration in root co-detoxified Cd under high Cd exposure. Meanwhile, 66,407 unigenes were assembled and 41,674 (62.75%) unigenes were annotated in at least one database. 2,658 DEGs including 1,292 up-regulated unigenes and 1,366 down-regulated unigenes were identified under 40 μmol/L Cd stress. Among of these DEGs, ZIPs, HMAs, NRAMPs and ABC transporters might participate in Cd uptake, translocation and accumulation. Many DEGs participating in several processes such as cell wall biosynthesis, GSH metabolism, TCA cycle and antioxidant system probably play critical roles in cell wall binding, vacuole sequestration and detoxification. These results provided a novel insight into the physiological and transcriptome response to Cd in C. bipinnatus seedlings.

High Nitrogen Supply Induces Physiological Responsiveness to Long Photoperiod in Barley

Photoperiod and nutrient nitrogen (N) supply influence the growth, development, and productivity of crops. This study examined the physiological, biochemical, and morpho-anatomical traits of NA5 and NA9, two barley cultivars with contrasting photoperiod lengths, under the combined treatment of photoperiod regime and N supply. Under long photoperiod, high N supply decreased net photosynthesis; decreased chlorophyll a and chlorophyll a/b; decreased ascorbate peroxidase (APX), catalase (CAT), and superoxide dismutase (SOD) activities; decreased ascorbate, glutathione, soluble protein, and soluble sugar; destroyed mesophyll cell integrity; and increased [Formula: see text], malondialdehyde, and proline in both NA5 and NA9. Under short photoperiod, high N content increased net photosynthesis; increased chlorophyll a and chlorophyll a/b; increased APX, CAT, and SOD activities; and increased antioxidants, soluble protein, and soluble sugar in NA9 but decreased the same parameters in NA5. These results indicated that N supply strongly affected photosynthetic capacity and the balance of reactive oxygen species in response to short and long photoperiod. High N supply enhanced the sensitivity of long-day barley to photoperiod change by inhibiting photosynthesis and decreasing antioxidant defense ability. High N mitigated the undesirable effects of shortened photoperiod in short-day barley. Therefore, the data from this study revealed that N status affects adaptation to photoperiod changes by maintaining redox homeostasis and photosynthetic capacity.

Transcriptomic Profiles Reveal the Interactions of Cd/Zn in Dwarf Polish Wheat (Triticum polonicum L.) Roots

Different intra- or interspecific wheat show different interactions of Cd/Zn. Normally, Zn has been/being widely utilized to reduce the Cd toxicity. In the present study, the DPW seedlings exhibited strong Cd tolerance. Zn and Cd mutually inhibited their uptake in the roots, showed antagonistic Cd/Zn interactions. However, Zn promoted the Cd transport from the roots to shoots, showed synergistic. In order to discover the interactive molecular responses, a transcriptome, including 123,300 unigenes, was constructed using RNA-Sequencing (RNA-Seq). Compared with CK, the expression of 1,269, 820, and 1,254 unigenes was significantly affected by Cd, Zn, and Cd+Zn, respectively. Only 381 unigenes were co-induced by these three treatments. Several metal transporters, such as cadmium-transporting ATPase and plant cadmium resistance 4, were specifically regulated by Cd+Zn. Other metal-related unigenes, such as ABC transporters, metal chelator, nicotianamine synthase (NAS), vacuolar iron transporters (VIT), metal-nicotianamine transporter YSL (YSL), and nitrate transporter (NRT), were regulated by Cd, but were not regulated by Cd+Zn. These results indicated that these transporters participated in the mutual inhibition of the Cd/Zn uptake in the roots, and also participated in the Cd transport, accumulation and detoxification. Meanwhile, some unigenes involved in other processes, such as oxidation-reduction, auxin metabolism, glutathione (GSH) metabolism nitrate transport, played different and important roles in the detoxification of these heavy metals.

St2-80: a new FISH marker for St genome and genome analysis in Triticeae

The St genome is one of the most fundamental genomes in Triticeae. Repetitive sequences are widely used to distinguish different genomes or species. The primary objectives of this study were to (i) screen a new sequence that could easily distinguish the chromosome of the St genome from those of other genomes by fluorescence in situ hybridization (FISH) and (ii) investigate the genome constitution of some species that remain uncertain and controversial. We used degenerated oligonucleotide primer PCR (Dop-PCR), Dot-blot, and FISH to screen for a new marker of the St genome and to test the efficiency of this marker in the detection of the St chromosome at different ploidy levels. Signals produced by a new FISH marker (denoted St₂-80) were present on the entire arm of chromosomes of the St genome, except in the centromeric region. On the contrary, St₂-80 signals were present in the terminal region of chromosomes of the E, H, P, and Y genomes. No signal was detected in the A and B genomes, and only weak signals were detected in the terminal region of chromosomes of the D genome. St₂-80 signals were obvious and stable in chromosomes of different genomes, whether diploid or polyploid. Therefore, St₂-80 is a potential and useful FISH marker that can be used to distinguish the St genome from those of other genomes in Triticeae.