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Reproductive stage frost poses a major constraint for wheat production in countries such as Australia. However, little progress has been made in identifying key genes to overcome the constraint. In the present study, a severe frost event hit two large-scale field trials consisting of six doubled haploid (DH) wheat populations at reproductive stage (young microspore stage) in Western Australia, leading to the identification of 30 robust frost QTL on 17 chromosomes. The major 18 QTL with the phenotype variation over 9.5% were located on 13 chromosomes including 2A, 2B, 2D, 3A, 4A, 4B, 4D, 5A, 5D, 6D, 7A, 7B and 7D. Most frost QTL were closely linked to the QTL of anthesis, maturity, Zadok stages as well as linked to anthesis related genes. Out of those, six QTL were repetitively detected on the homologous regions on 2B, 4B, 4D, 5A, 5D, 7A in more than two populations. Results showed that the frost damage is associated with alleles of Vrn-A1a, Vrn-D1a, Rht-B1b, Rht-D1b, and the high copy number of Ppd-B1. However, anthesis QTL and anthesis related genes of Vrn-B1a and TaFT3-1B on chromosomes 5B and 1B did not lead to frost damage, indicating that these early-flowering phenotype related genes are compatible with frost tolerance and thus can be utilised in breeding. Our results also indicate that wild-type alleles Rht-B1a and Rht-D1a can be used when breeding for frost-tolerant varieties without delaying flowering time.

Wheat pathogens, especially those causing powdery mildew and stripe rust, seriously threaten yield worldwide. Utilizing newly identified disease resistance genes from wheat relatives is an effective strategy to minimize disease damage. In this study, chromosome-specific molecular markers for the 3S

For improving lodging resistance and increasing grain yield in wheat in the Yellow-Huai River Basin in China, different sowing modes have been investigated. Conventionally, the small-flat-plot sowing mode has been adopted in wheat cultivation. However, this sowing mode leads to heavy lodging and low land use efficiency. In this study, a new sowing mode, high-low-plot sowing mode with two more rows sowed on the high plot, was investigated. Two cultivars, Hengguan 35 and Jimai 44 were used for two seasonal field experiments from 2018 to 2020. The results showed that grain yield improved with the high-low sowing mode by as much as 25% since more spikes per unit area were observed concomitant with reduced stem lodging. The grain yield increase was mainly due to the enhanced spike number per m2, while the lodging resistance was improved through the lowered plant height and the center of gravity height. This research proves that the high-low-plot sowing mode is an improved sowing mode for producing greater grain yield with better lodging resistance in the wheat production area in northern China.

Among yield contributing traits, the contribution of canopy activity related traits has been less studied. In this study, quantitative trait loci (QTL) for the normalized difference vegetation index (NDVI) at the seedling (NDVI-S) and grain filling (NDVI-10) stages and the chlorophyll (Chl) content at the grain filling stage (Chl-10) were mapped using three recombinant inbred line (RIL) populations of wheat derived from the following crosses: Doumai × Shi 4185 (D × S), Gaocheng 8901 × Zhoumai 16 (G × Z) and Linmai 2 × Zhong 892 (L × Z). In the three RIL populations, 6, 16 and 14 QTL were identified for NDVI-S, NDVI-10 and Chl-10, respectively. Furthermore, 6, 10 and 10 of the QTL were newly detected. Three QTL QNDVI-10.caas-4BS, QNDVI-10.caas-4DS and QChl-10.caas-4BS, were commonly detected in two populations. Twelve QTL clusters for both canopy activity related traits in the present study and grain yield (GY) related traits in our previous study were identified. NDVI-S is phenotypically and genetically correlated with thousand-kernel weight (TKW), which can be used to select lines with a high TKW. The QTL clusters harbouring QTL for canopy activity related traits and GY related traits are valuable in marker-assisted selection (MAS) of loci with pleiotropic effects. In addition, the stable QTL QNDVI-S.caas-1AL and QNDVI-10.caas-3B can be used to identify high NDVI lines at the seedling and grain filling stages, respectively. Our study provided new insight into the genetic architecture of the GY based on canopy activity related traits.

Background：To determine the grain proteome of the strong gluten wheat, TMT technology was used to analyze proteomic differences between the winter wheat varieties Jimai 44 and the strong gluten Jimai 229. Results：Comparisons were also made with the winter wheat Jimai 22 as a control. It was found that there were 120 differentially expressed proteins between Jimai 44 and Jimai 22, while 173 between Jimai 229 and Jimai 22. Among these, 27 proteins were up-regulated and 23 down-regulated in jimai 44 and in jimai 229. Conclusions：GO analysis and KEGG pathway analysis showed that the differentially expressed proteins were mainly enriched in cell functions relating to nutrient reservoir activity, metabolic processes, protein processing in endoplasmic reticulum, phenylpropane biosynthesis and nitrogen metabolism. Amongst the screened proteins, many differences were related to storage proteins. This study provides an important basis for further exploring the key factors of quality improvement and genetic variation of gluten protein expression.

We developed and validated 56 gene-specific semi-thermal asymmetric reverse PCR (STARP) markers for 46 genes of important wheat quality, biotic and abiotic stress resistance, grain yield, and adaptation-related traits for marker-assisted selection in wheat breeding. Development of high-throughput, low-cost, gene-specific molecular markers is important for marker-assisted selection in wheat breeding. In this study, we developed 56 gene-specific semi-thermal asymmetric reverse PCR (STARP) markers for wheat quality, tolerance to biotic and abiotic stresses, grain yield, and adaptation-related traits. The STARP assays were validated by (1) comparison of the assays with corresponding diagnostic STS/CAPS markers on 40 diverse wheat cultivars and (2) characterization of allelic effects based on the phenotypic and genotypic data of three segregating populations and 305 diverse wheat accessions from China and 13 other countries. The STARP assays showed the advantages of high-throughput, accuracy, flexibility, simple assay design, low operational costs, and platform compatibility. The state-of-the-art assays of this study provide a robust and reliable molecular marker toolkit for wheat breeding programs.

This study characterized and evaluated a set of wheat-Aegilops comosa introgression lines, including six additions and one substitution. A total of 47 PLUG markers and a set of cytogenetic markers specific for Ae. comosa chromosomes were established after screening 526 PLUG primer pairs and performing FISH using oligonucleotides as probes. Marker analysis confirmed that these lines were wheat-Ae. comosa 2M–7M addition lines and a 6M(6A) substitution line. The molecular and cytogenetic markers developed herein could be used to trace Ae. comosa chromatin in wheat background. In order to evaluate the breeding value of the material, disease resistance tests and agronomical trait investigations were carried out on these alien chromosome introgression lines. Disease resistance tests showed that chromosomes 2M and 7M of Ae. comosa might harbor new stripe rust and powdery mildew resistance genes, respectively, therefore, they could be used as resistance sources for wheat breeding. Investigations into agronomical traits showed that all chromosomes 2M to 7M had detrimental effects on the agronomic performance of wheat, therefore, the selection of plants with relatively negative effects should be avoided when inducing wheat-A. comosa chromosome translocations using chromosome engineering procedures.

Carotenoid content of wheat is an important criterion for prediction of the commercial and nutritional value of products made from bread wheat (Triticum aestivum) cultivars. The objective of this study was to determine the major components of carotenoids in Chinese wheat using ultra performance liquid chromatography (UPLC) including lutein, zeaxanthin, α-carotene and β-carotene. Grain carotenoid content was investigated in 217 cultivars from three major Chinese wheat regions and from seven other countries grown in two environments. Genotype contributed to the majority of variation in carotenoid components. Lutein, zeaxanthin and β-carotene concentrations varied from 18.3 to 100.1, 4.9 to 12.0 and 0.9 to 48.7 μg per 100 g in wheat flour with an average of 40.2, 7.2 and 18.2 μg per 100 g, respectively. Lutein (61.3%) was the main carotenoid component, followed by β-carotene (27.7%) and zeaxanthin (11.0%). No α-carotene was detected. Total carotenoids, lutein, zeaxanthin and β-carotene were all higher in cultivars with the 1BL.1RS translocation compared to those without the translocation. This is the first report on assay of lutein, zeaxanthin and β-carotene concentrations for a large number of wheat cultivars. These data will be useful for genetic improve- ment of wheat carotenoid content and for understanding of the carotenoid biosynthetic pathway in wheat.

Wheat flour dough can be regarded as a complicated mixture in which gluten forms a continuous three-dimensional network filled with starch particles. Previous studies have concentrated on the influences of either gluten or starch alone on the rheological properties of wheat dough and found the components of gluten and starch responsible for the dough behavior, including use of parameters, such as the content of protein, wet gluten and amylose, for the evaluation of wheat quality. Earlier, in our study of six wheat materials, significant differences were observed in size distribution of starch granules affecting the dough mixing behavior. However, to our knowledge little research has been undertaken on the association of starch granules and protein networks on dough formation. In this study, the six wheat lines were further explored for the effect of gluten-starch interactions on dough properties. In order to achieve this, the wheat flour samples were quantified for gluten secondary structures, percentage of unextractable polymeric protein, high- to low-molecular-weight glutenin ratio, gluten micro-structure, number distribution of starch granules and moisture distribution in dough samples. A/Lacunarity (A-type starch granule content divided by lacunarity of gluten network) and B/A/Lacunarity (B- to A-type starch granule ratio divided by lacunarity) were proposed to characterize the level of interactions of differently sized starch granules to gluten protein networks in the dough. Results showed that dough stability time increased with the increase of B/A/Lacunarity, as closely packed dough, due to close interaction between starch granules and gluten, exhibited greater dough stability. Application of A/Lacunarity and B/A/Lacunarity as novel indicators is proposed to further elucidate precise influences between starch and gluten for better evaluation of dough properties.

The 14-3-3 gene family members play key roles in various cellular processes. However, little is known about the numbers and roles of 14-3-3 genes in wheat. The aims of this study were to identify TaGF14 numbers in wheat by searching its whole genome through blast, to study the phylogenetic relationships with other plant species and to discuss the functions of TaGF14s. The results showed that common wheat harbored 20 TaGF14 genes, located on wheat chromosome groups 2, 3, 4, and 7. Out of them, eighteen TaGF14s are non-ε proteins, and two wheat TaGF14 genes, TaGF14i and TaGF14f, are ε proteins. Phylogenetic analysis indicated that these genes were divided into six clusters: cluster 1 (TaGF14d, TaGF14g, TaGF14j, TaGF14h, TaGF14c, and TaGF14n); cluster 2 (TaGF14k); cluster 3 (TaGF14b, TaGF14l, TaGF14m, and TaGF14s); cluster 4 (TaGF14a, TaGF14e, and TaGF14r); cluster 5 (TaGF14i and TaGF14f); and cluster 6 (TaGF14o, TaGF14p, TaGF14q, and TaGF14t). Tissue-specific gene expressions suggested that all TaGF14s were likely constitutively expressed, except two genes, i.e., TaGF14p and TaGF14f. And the highest amount of TaGF14 transcripts were observed in developing grains at 20 days post anthesis (DPA), especially for TaGF14j and TaGF14l. After drought stress, five genes, i.e., TaGF14c, TaGF14d, TaGF14g, TaGF14h, and TaGF14j, were up-regulated expression under drought stress for both 1 and 6 h, suggesting these genes played vital role in combating against drought stress. However, all the TaGF14s were down-regulated expression under heat stress for both 1 and 6 h, indicating TaGF14s may be negatively associated with heat stress by reducing the expression to combat heat stress or through other pathways. These results suggested that cluster 1, e.g., TaGF14j, may participate in the whole wheat developing stages, e.g., grain-filling (starch biosynthesis) and may also participate in combating against drought stress. Subsequently, a homolog of TaGF14j, TaGF14-JM22, were cloned by RACE and used to validate its function. Immunoblotting results showed that TaGF14-JM22 protein, closely related to TaGF14d, TaGF14g, and TaGF14j, can interact with AGP-L, SSI, SSII, SBEIIa, and SBEIIb in developing grains, suggesting that TaGF14s located on group 4 may be involved in starch biosynthesis. Therefore, it is possible to develop starch-rich wheat cultivars by modifying TaGF14s.

Background Phytoene synthase 1 (PSY1) is the most important regulatory enzyme in carotenoid biosynthesis, whereas its function is hardly known in common wheat. The aims of the present study were to investigate Psy1 function and genetic regulation using reverse genetics approaches. Results Transcript levels of Psy1 in RNAi transgenic lines were decreased by 54–76 % and yellow pigment content (YPC) was reduced by 26–35 % compared with controls, confirming the impact of Psy1 on carotenoid accumulation. A series of candidate genes involved in secondary metabolic pathways and core metabolic processes responded to Psy1 down-regulation. The aspartate rich domain (DXXXD) was important for PSY1 function, and conserved nucleotides adjacent to the domain influenced YPC by regulating gene expression, enzyme activity or alternative splicing. Compensatory responses analysis indicated that three Psy1 homoeologs may be coordinately regulated under normal conditions, but separately regulated under stress. The period 14 days post anthesis (DPA) was found to be a key regulation node during grain development. Conclusion The findings define key aspects of flour color regulation in wheat and facilitate the genetic improvement of wheat quality targeting color/nutritional specifications required for specific end products. Electronic supplementary material The online version of this article (doi:10.1186/s12870-016-0916-z) contains supplementary material, which is available to authorized users.

We developed and validated a robust marker toolkit for high-throughput and cost-effective screening of a large number of functional genes in wheat. Functional markers (FMs) are the most valuable markers for crop breeding programs, and high-throughput genotyping for FMs could provide an excellent opportunity to effectively practice marker-assisted selection while breeding cultivars. Here we developed and validated kompetitive allele-specific PCR (KASP) assays for genes that underpin economically important traits in bread wheat including adaptability, grain yield, quality, and biotic and abiotic stress resistances. In total, 70 KASP assays either developed in this study or obtained from public databases were validated for reliability in application. The validation of KASP assays were conducted by (a) comparing the assays with available gel-based PCR markers on 23 diverse wheat accessions, (b) validation of the derived allelic information using phenotypes of a panel comprised of 300 diverse cultivars from China and 13 other countries, and (c) additional testing, where possible, of the assays in four segregating populations. All KASP assays being reported were significantly associated with the relevant phenotypes in the cultivars panel and bi-parental populations, thus revealing potential application in wheat breeding programs. The results revealed 45 times superiority of the KASP assays in speed than gel-based PCR markers. KASP has recently emerged as single-plex high-throughput genotyping technology; this is the first report on high-throughput screening of a large number of functional genes in a major crop. Such assays could greatly accelerate the characterization of crossing parents and advanced lines for marker-assisted selection and can complement the inflexible, high-density SNP arrays. Our results offer a robust and reliable molecular marker toolkit that can contribute towards maximizing genetic gains in wheat breeding programs.

Primers developed for qRT-PCR analysis. (DOCX 17.5Â kb)

Primers used for the RNAi vector construction and positive transgenic line detection. (DOCX 16.7Â kb)

Transcriptome details for three transgenic lines with the most significantly reduced YPC and non-transformed controls. (DOCX 18Â kb)

Primers designed for the detection of alternative splicing. (DOCX 16.6Â kb)

Culture media used in this study for callus induction and differentiation. (DOCX 16.7Â kb)

Homoeolog-specific primers developed for mutation detection by TILLING. (DOCX 17.9Â kb)

Fifty-six QTL for flour color-related traits and polyphenol oxidase activity were identified using a genome-wide linkage mapping of data from a RIL population derived from a Gaocheng 8901/Zhoumai 16 cross. Flour color-related traits, including L*, a*, b*, yellow pigment content (YPC), and polyphenol oxidase (PPO) activity are important parameters influencing the quality of wheat end-use products. Mapping quantitative trait loci (QTL) for these traits and characterization of candidate genes are important for improving wheat quality. The aims of this study were to identify QTL for flour color-related traits and PPO activity and to characterize candidate genes using a high-density genetic linkage map in a common wheat recombinant inbred line (RIL) population derived from a cross between Gaocheng 8901 and Zhoumai 16. A linkage map was constructed by genotyping the RILs with the wheat 90 K iSelect array. Fifty-six QTL were mapped on 35 chromosome regions on homoeologous groups 1, 2, 5 and 7 chromosomes, and chromosomes 3B, 4A, 4B and 6B. Four QTL were for PPO activity, and the others were for flour color-related traits. Compared with previous studies, five QTL for a*, two for b*, one for L*, one for YPC and one for PPO activity were new. The new QTL on chromosome 2DL was involved in both a* and YPC, and another on chromosome 7DS affected both a* and L*. The scan for SNP sequences tightly linked to QTL for flour color-related traits against the wheat and/or related cereals genomes identified six candidate genes significantly related to these traits, and five of them were associated with the terpenoid backbone biosynthesis pathway. The high-density genetic linkage map of Gaocheng 8901/Zhoumai 16 represents a useful tool to identify QTL for important quality traits and candidate genes.

A novel synthetic procedure is described for the fabrication of macroporous titanium dioxide (TiO2) films with an ordered, uniform pore framework comprised of nanocrystalline anatase mainly. The synthetic approach involved several processes. First, polymethyl methacrylate (PMMA) microspheres (87 nm) were synthesized by using a dispersion polymerization technique in the presence of Fenton reagent (FeSO4/H2O2) as a novel initiator, which has advantages such as simple and fast polymerization process without deoxygenation. Next, the templates of PMMA microspheres were assembled on clean substrates by dip-drawing technique. Finally, the macroporous TiO2 films with the average size of pores about 87 nm were obtained by sol-dipping template method and calcination to remove the templates at 550 °C. The test results of X-ray diffraction indicate that the nanocrystalline of anatase formed after calcination. The mechanisms of PMMA polymerization and template formation were proposed. Furthermore, both structures and morphologies of the composite films were investigated with field emission scanning electron microscope, and the processes of the thermal decomposition of PMMA and TiO2 gel were also discussed with thermo gravimetric analysis. This ordered and uniform pore framework could be used as the promising ultrafilter membranes showing active photocatalysis without intensive fouling.