Estimation of wheat protein content and wet gluten content based on fusion of hyperspectral and RGB sensors using machine learning algorithms.

The protein content (PC) and wet gluten content (WGC) are crucial indicators determining the quality of wheat, playing a pivotal role in evaluating processing and baking performance. Original reflectance (OR), wavelet feature (WF), and color index (CI) were extracted from hyperspectral and RGB sensors. Combining Pearson-competitive adaptive reweighted sampling (CARs)-variance inflation factor (VIF) with four machine learning (ML) algorithms were used to model accuracy of PC and WGC. As a result, three CIs, six ORs, and twelve WFs were selected for PC and WGC datasets. For single-modal data, the back-propagation neural network exhibited superior accuracy, with estimation accuracies (WF > OR > CI). For multi-modal data, the random forest regression paired with OR + WF + CI showed the highest validation accuracy. Utilizing the Gini impurity, WF outweighed OR and CI in the PC and WGC models. The amalgamation of MLs with multimodal data harnessed the synergies among various remote sensing sources, substantially augmenting model precision and stability.

Mutagenesis-Derived Resistance to Black Point in Wheat.

Black point, a severe global wheat disease, necessitates deploying resistant cultivars for effective control. However, susceptibility remains prevalent among most wheat cultivars. Identifying new sources of resistance and understanding their mechanisms are crucial for breeding resistant cultivars. This study pinpointed black point resistance in an ethyl methane sulfonate (EMS)-mutagenized wheat population of Wanyuanbai 1 (WYB) and analyzed resistant mutants using RNA-Seq. The findings revealed the following: (i) wyb-18, among 10,008 EMS-mutagenized lines, exhibited robust resistance with significantly lower black point incidence under artificial Bipolaris sorokiniana inoculation in 2020 and 2021 (average incidence of 5.2% over 2 years), markedly reduced compared with WYB (50.9%). (ii) wyb-18 kernels displayed black point symptoms at 12 days after inoculation (dai), 3 days later than WYB. At 15 dai, wyb-18 kernels had isolated black spots, unlike WYB kernels, where the entire embryo turned black. (iii) wyb-18 showed heightened antioxidant enzyme activity, including peroxidase, catalase, and superoxide dismutase. (iv) Analysis of 543 differentially expressed genes between wyb-18 and WYB at 9 dai identified enrichment in the MAPK signaling pathway through KEGG analysis. Ten genes in this pathway exhibited upregulated expression, while one was downregulated in wyb-18. Among these genes, PR1, WRKY11, SAPK5, and TraesCS1A02G326800 (chitin recognition protein) consistently showed upregulation in wyb-18, making them potential candidates for black point resistance. These results offer valuable germplasm resources for breeding and novel insights into the mechanisms of black point resistance.

Screening and Resistance Locus Identification of the Mutant fcrZ22 Resistant to Crown Rot Caused by Fusarium pseudograminearum.

Crown rot caused by Fusarium pseudograminearum is a devastating wheat disease worldwide. In addition to yield losses, the fungi causing Fusarium crown rot (FCR) also deteriorate the quality and safety of food because of the production of mycotoxins. Planting resistant cultivars is an effective way to control FCR. However, most wheat cultivars are susceptible to FCR. Therefore, development of new sources and detection of loci for FCR resistance are necessary. In the present study, a resistant mutant, fcrZ22, was identified from an ethyl methane sulfonate (EMS)-mutagenized population of the cultivar Zhoumai 22, and then fcrZ22 was crossed with the wild type to produce an F2 population. Genetic analysis of the F2 population was carried out by the mixed inheritance model of major genes plus polygenes, and 20 resistant and 20 susceptible plants were selected to assemble mixed pools. Combining 660K SNP arrays, the resistance loci were detected by bulked segregant analysis. The resistance to FCR caused by F. pseudograminearum in the F2 population was in accordance with the "mixed model with two major genes of additive-epistasis effect + additive-dominant polygenes," and the heritability of the major gene was 0.92. Twenty-one loci were detected, which were located on 10 chromosomes, namely, 1B (1), 1D (1), 2A (3), 1B (1), 3A (3), 3B (3), 4A (2), 5A (2), 7A (3), and 7B (2). Among the 21 loci, eight were new loci for FCR resistance. This is the first report of detecting loci for FCR resistance from a mutant. The results of the present study provided excellent germplasm resources for breeding wheat cultivars with FCR resistance and laid the foundation for fine mapping of FCR resistance loci.

Wheat gibberellin oxidase genes and their functions in regulating tillering.

Multiple genetic factors control tillering, a key agronomy trait for wheat (Triticum aestivum L.) yield. Previously, we reported a dwarf-monoculm mutant (dmc) derived from wheat cultivar Guomai 301, and found that the contents of gibberellic acid 3 (GA3) in the tiller primordia of dmc were significantly higher. Transcriptome analysis indicated that some wheat gibberellin oxidase (TaGAox) genes TaGA20ox-A2, TaGA20ox-B2, TaGA3ox-A2, TaGA20ox-A4, TaGA2ox-A10 and TaGA2ox-B10 were differentially expressed in dmc. Therefore, this study systematically analyzed the roles of gibberellin oxidase genes during wheat tillering. A total of 63 TaGAox genes were identified by whole genome analysis. The TaGAoxs were clustered to four subfamilies, GA20oxs, GA2oxs, GA3oxs and GA7oxs, including seven subgroups based on their protein structures. The promoter regions of TaGAox genes contain a large number of cis-acting elements closely related to hormone, plant growth and development, light, and abiotic stress responses. Segmental duplication events played a major role in TaGAoxs expansion. Compared to Arabidopsis, the gene collinearity degrees of the GAoxs were significantly higher among wheat, rice and maize. TaGAox genes showed tissue-specific expression patterns. The expressions of TaGAox genes (TaGA20ox-B2, TaGA7ox-A1, TaGA2ox10 and TaGA3ox-A2) were significantly affected by exogenous GA3 applications, which also significantly promoted tillering of Guomai 301, but didn't promote dmc. TaGA7ox-A1 overexpression transgenic wheat lines were obtained by Agrobacterium mediated transformation. Genomic PCR and first-generation sequencing demonstrated that the gene was integrated into the wheat genome. Association analysis of TaGA7ox-A1 expression level and tiller number per plant demonstrated that the tillering capacities of some TaGA7ox-A1 transgenic lines were increased. These data demonstrated that some TaGAoxs as well as GA signaling were involved in regulating wheat tillering, but the GA signaling pathway was disturbed in dmc. This study provided valuable clues for functional characterization of GAox genes in wheat.

Quantitative trait loci for resistance to black point caused by Bipolaris sorokiniana in bread wheat.

Black point disease is a serious concern in wheat production worldwide. In this study, we aimed to identify the major quantitative trait loci (QTL) for resistance to black point caused by Bipolaris sorokiniana and develop molecular markers for marker-assisted selection (MAS). A recombinant inbred line (RIL) population derived from a cross between PZSCL6 (highly susceptible) and Yuyou1 (moderately resistant) was evaluated for black point resistance at four locations under artificial inoculation with B. sorokiniana. Thirty resistant and 30 susceptible RILs were selected to form resistant and susceptible bulks, respectively, which were genotyped by the wheat 660 K SNP array. Two hundred and four single-nucleotide polymorphisms (SNPs) were identified, among which 41(20.7%), 34 (17.2%), 22 (11.1%), and 22 (11.1%) were located on chromosomes 5A, 5B, 4B, and 5D, respectively. The genetic linkage map for the RIL population was constructed using 150 polymorphic SSR and dCAPS markers. Finally, five QTL were detected on chromosomes 5A, 5B, and 5D, designated QBB.hau-5A, QBB.hau-5B.1, QBB.hau-5B.2, QBB.hau-5D.1, and QBB.hau-5D.2, respectively. All resistance alleles were contributed by the resistant parent Yuyou1. QBB.hau-5D.1 is likely to be a new locus for black point resistance. The markers Xwmc654 and Xgwm174 linked to QBB.hau-5A and QBB.hau-5D.1, respectively, have potential utility in MAS-based breeding. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-023-01356-6.

Role of bran particles in the formation of dark spots on fresh wet noodle sheets: what are the dark spots?

BACKGROUND: Dark spots may affect the appearance of fresh noodles during storage, even when made from flour with low ash content. The effect of flour bran content on the degree of dark spot formation in fresh wet noodle sheets (FWNS) is investigated to explain this phenomenon. RESULTS: Confocal laser scanning microscopy (CLSM) observation revealed that the wheat bran particles were responsible for the formation of dark spots on FWNS, with each bran particle core generating a single dark spot. In wheat flours with low ash content, the number of wheat bran particles causing dark spot formation on FWNS was limited, and these particles were not visible to the naked eye until their size exceeded approximately 50 µm. Tropolone, a polyphenol oxidase inhibitor (PubChem CID: 24900578) and dry heating treatment, which inactivates polyphenol oxidase, was found to inhibit or reduce the formation of dark spots. CONCLUSION: Based on these findings, it can be concluded that bran particles, rich in polyphenol oxidase, play a key role in dark spot formation. © 2023 Society of Chemical Industry.

Dynamic Metabolomics and Transcriptomics Analyses for Characterization of Phenolic Compounds and Their Biosynthetic Characteristics in Wheat Grain.

Phenolic compounds are important bioactive phytochemicals with potential health benefits. In this study, integrated metabolomics and transcriptomics analysis was used to analyze the metabolites and differentially expressed genes in grains of two wheat cultivars (HPm512 with high antioxidant activity, and ZM22 with low antioxidant activity) during grain development. A total of 188 differentially expressed phenolic components, including 82 phenolic acids, 81 flavonoids, 10 lignans, and 15 other phenolics, were identified in the developing wheat grains, of which apigenin glycosides were identified as the primary flavonoid component. The relative abundance of identified phenolics showed a decreasing trend with grain development. Additionally, 51 differentially expressed phenolic components were identified between HPm512 and ZM22, of which 41 components, including 23 flavonoids, were up-regulated in HPm512. In developing grain, most of the identified differentially expressed genes involved in phenolic accumulation followed a similar trend. Integrated metabolomics and transcriptomics analysis revealed that certain genes encoding structural proteins, glycosyltransferase, and transcription factors were closely related to metabolite accumulation. The relatively higher accumulation of phenolics in HPm512 could be due to up-regulated structural and regulatory genes. A sketch map was drawn to depict the synthetic pathway of identified phenolics and their corresponding genes. This study enhanced the current understanding of the accumulation of phenolics in wheat grains. Besides, active components and their related genes were also identified, providing crucial information for the improvement of wheat's nutritional quality.

Comparative Transcriptome Analysis of Male Sterile Anthers Induced by High Temperature in Wheat (Triticum aestivum L.).

Global warming will have a negative effect on agricultural production as high temperature (HT) stress can seriously threaten plant growth and reproduction. Male sterility caused by HT may be exploited by the creation of a male-sterile line, which has great potential for application in crop heterosis. Therefore, it is important to understand the molecular mechanisms of anther abortion induced by HT in wheat, which remain unclear at present. In this study, we performed phenotype improve language in the abstract and comparative transcriptome analysis of the male sterile anthers induced by HT in wheat. Compared with Normal anthers, the cytological analysis indicated that HT-induced male sterile anthers were smaller and had no starch accumulation in pollen grains, which is consistent with the results observed by scanning electron microscopy (SEM). The 9601 differentially expressed genes (DEGs) identified by transcriptome sequencing compared with the Normal anthers were noticeably involved in the following pathways: starch and sucrose metabolism, phosphatidylinositol (PI) signaling system, peroxidase activity and response to oxidative stress, and heme binding. In addition, TUNEL assays were performed and the results further confirmed the excessive accumulation of reactive oxygen species (ROS) in sterile anthers. Moreover, a total of 38 hub genes were obtained from the protein-protein interaction network analysis of these pathways, including genes, for example, heat shock protein 90 (HSP90), thioredoxin-like protein 1, peroxidase (POD), calreticulin, UDP glucose pyrophosphorylase (UGPase), sucrose synthase, phosphatidylinositol-4-phosphate 5-Kinase (PIP5K), cytochrome c, and Cystathionine beta-synthase X6-like (CBSX6-like). These findings provide insights for predicting the functions of the candidate genes, and the comprehensive analysis of our results is helpful for studying the abortive interaction mechanism induced by HT in wheat.

The Sugar Transporter family in wheat (Triticum aestivum. L): genome-wide identification, classification, and expression profiling during stress in seedlings.

The sugar transporter protein (STP) plays a crucial role in regulating plant growth and stress tolerance. We performed genome-wide identification and expression analysis of the STP gene family to investigate the STPSs' potential roles in the growth of wheat seedlings under stress. Here, a total of 81 TaSTP genes containing the Sugar_tr conserved motif were identified within the wheat genome. Bioinformatic studies including phylogenetic tree, chromosome position, and tandem repeat were performed to analyze the identified genes. The 81 TaSTP genes can be classified into five main groups according to their structural and phylogenetic features, with several subgroups, which were located separately on chromosomes A, B, and D. Moreover, six gene clusters were formed with more than three genes each. The results of three comparative syntenic maps of wheat associated with three representative species suggested that STP genes have strong relationships in monocots. qRT-PCR analysis confirmed that most TaSTP genes displayed different expression profiles after seedlings were subjected to six days of different stress (10% PEG6000, 150 mM NaCl, and their combination, respectively), suggesting that these genes may be involved in regulating plant growth and stress tolerance. In conclusion, 81 TaSTP genes were identified and their expressions changed under stress, indicating TaSTP's potential roles in wheat growth monosaccharide distribution is regulated.

Transcriptome-based analysis of resistance mechanism to black point caused by Bipolaris sorokiniana in wheat.

Black point is a cereal disease caused by complex pathogens, of which the pathogenicity of Bipolaris sorokiniana is the most serious in wheat. Resistance to black point is quantitative in nature, and thus the mechanism is poorly understood. We conducted a comparative transcriptome analysis to identify differentially expressed genes (DEGs) in black point-slightly susceptible and -highly susceptible wheat lines at different timepoints following B. sorokiniana inoculation. DEGs associated with photosynthesis were upregulated in black point-slightly susceptible lines. The top Gene Ontology enrichment terms for biological processes were oxidation-reduction, response to cold, salt stress, oxidative stress, and cadmium ion; terms for cellular component genes were mainly involved in plasma membrane and cytoplasmic membrane-bounded vesicle, whereas those for molecular function were heme binding and peroxidase activity. Moreover, activities of antioxidant enzymes superoxide dismutase, catalase, and peroxidase were higher in slightly susceptible lines than those in highly susceptible lines (except peroxidase 12-24 days post-inoculation). Thus, resistance to B. sorokiniana-caused black point in wheat was mainly related to counteracting oxidative stress, although the specific metabolic pathways require further study. This study presents new insights for understanding resistance mechanisms of selected wheat lines to black point.

Wheat heat tolerance is impaired by heightened deletions in the distal end of 4AL chromosomal arm.

Heat stress (HS) causes substantial damages to worldwide crop production. As a cool season crop, wheat (Triticum aestivum) is sensitive to HS-induced damages. To support the genetic improvement of wheat HS tolerance (HST), we conducted fine mapping of TaHST1, a locus required for maintaining wheat vegetative and reproductive growth under elevated temperatures. TaHST1 was mapped to the distal terminus of 4AL chromosome arm using genetic populations derived from two BC6 F6 breeding lines showing tolerance (E6015-4T) or sensitivity (E6015-3S) to HS. The 4AL region carrying TaHST1 locus was approximately 0.949 Mbp and contained the last 19 high confidence genes of 4AL according to wheat reference genome sequence. Resequencing of E6015-3S and E6015-4T and haplotype analysis of 3087 worldwide wheat accessions revealed heightened deletion polymorphisms in the distal 0.949 Mbp region of 4AL, which was confirmed by the finding of frequent gene losses in this region in eight genome-sequenced hexaploid wheat cultivars. The great majority (86.36%) of the 3087 lines displayed different degrees of nucleotide sequence deletions, with only 13.64% of them resembling E6015-4T in this region. These deletions can impair the presence and/or function of TaHST1 and surrounding genes, thus rendering global wheat germplasm vulnerable to HS or other environmental adversities. Therefore, conscientious and urgent efforts are needed in global wheat breeding programmes to optimize the structure and function of 4AL distal terminus by ensuring the presence of TaHST1 and surrounding genes. The new information reported here will help to accelerate the ongoing global efforts in improving wheat HST.

Genome-Wide Linkage Mapping Reveals QTLs for Seed Vigor-Related Traits Under Artificial Aging in Common Wheat (Triticum aestivum).

Long-term storage of seeds leads to lose seed vigor with slow and non-uniform germination. Time, rate, homogeneity, and synchrony are important aspects during the dynamic germination process to assess seed viability after storage. The aim of this study is to identify quantitative trait loci (QTLs) using a high-density genetic linkage map of common wheat (Triticum aestivum) for seed vigor-related traits under artificial aging. Two hundred and forty-six recombinant inbred lines derived from the cross between Zhou 8425B and Chinese Spring were evaluated for seed storability. Ninety-six QTLs were detected on all wheat chromosomes except 2B, 4D, 6D, and 7D, explaining 2.9-19.4% of the phenotypic variance. These QTLs were clustered into 17 QTL-rich regions on chromosomes 1AL, 2DS, 3AS (3), 3BS, 3BL (2), 3DL, 4AS, 4AL (3), 5AS, 5DS, 6BL, and 7AL, exhibiting pleiotropic effects. Moreover, 10 stable QTLs were identified on chromosomes 2D, 3D, 4A, and 6B (QaMGT.cas-2DS.2, QaMGR.cas-2DS.2, QaFCGR.cas-2DS.2, QaGI.cas-3DL, QaGR.cas-3DL, QaFCGR.cas-3DL, QaMGT.cas-4AS, QaMGR.cas-4AS, QaZ.cas-4AS, and QaGR.cas-6BL.2). Our results indicate that one of the stable QTL-rich regions on chromosome 2D flanked by IWB21991 and IWB11197 in the position from 46 to 51 cM, presenting as a pleiotropic locus strongly impacting seed vigor-related traits under artificial aging. These new QTLs and tightly linked SNP markers may provide new valuable information and could serve as targets for fine mapping or markers assisted breeding.

Mapping and validation of a new QTL for adult-plant resistance to powdery mildew in Chinese elite bread wheat line Zhou8425B.

KEY MESSAGE: Four QTLs for adult-plant resistance to powdery mildew were mapped in the Zhou8425B/Chinese Spring population, and a new QTL on chromosome 3B was validated in 103 wheat cultivars derived from Zhou8425B. Zhou8425B is an elite wheat (Triticum aestivum L.) line widely used as a parent in Chinese wheat breeding programs. Identification of genes for adult-plant resistance (APR) to powdery mildew in Zhou8425B is of high importance for continued controlling the disease. In the current study, the high-density Illumina iSelect 90K single-nucleotide polymorphism (SNP) array was used to map quantitative trait loci (QTL) for APR to powdery mildew in 244 recombinant inbred lines derived from the cross Zhou8425B/Chinese Spring. Inclusive composite interval mapping identified QTL on chromosomes 1B, 3B, 4B, and 7D, designated as QPm.caas-1BL.1, QPm.caas-3BS, QPm.caas-4BL.2, and QPm.caas-7DS, respectively. Resistance alleles at the QPm.caas-1BL.1, QPm.caas-3BS, and QPm.caas-4BL.2 loci were contributed by Zhou8425B, whereas that at QPm.caas-7DS was from Chinese Spring. QPm.caas-3BS, likely to be a new APR gene for powdery mildew resistance, was detected in all four environments. One SNP marker closely linked to QPm.caas-3BS was transferred into a semi-thermal asymmetric reverse PCR (STARP) marker and tested on 103 commercial wheat cultivars derived from Zhou8425B. Cultivars with the resistance allele at the QPm.caas-3BS locus had averaged maximum disease severity reduced by 5.3%. This STARP marker can be used for marker-assisted selection in improvement of the level of powdery mildew resistance in wheat breeding.

Mapping stripe rust resistance gene YrZH22 in Chinese wheat cultivar Zhoumai 22 by bulked segregant RNA-Seq (BSR-Seq) and comparative genomics analyses.

KEY MESSAGE: A stripe rust resistance gene YrZH22 was mapped by combined BSR-Seq and comparative genomics analyses to a 5.92 centimorgan (cM) genetic interval spanning a 4 Mb physical genomic region on wheat chromosome 4BL1. Stripe rust, caused by Puccinia striiformis f. sp. tritici (PST), is one of the most destructive diseases of wheat and severely threatens wheat production worldwide. The widely grown Chinese wheat cultivar Zhoumai 22 is highly resistant to the current prevailing PST race CYR34 (V26). Genetic analysis of F5:6 and F6:7 recombinant inbred line (RIL) populations indicated that adult-plant stripe rust resistance in Zhoumai 22 is controlled by a single gene, temporarily designated YrZH22. By applying bulked segregant RNA-Seq (BSR-Seq), 7 SNP markers were developed and SNP mapping showed that YrZH22 is located between markers WGGB105 and WGGB112 on chromosome arm 4BL. The corresponding genomic regions of the Chinese Spring 4BL genome assembly and physical map of Aegilops tauschii 4DL were selected for comparative genomics analyses to develop nine new polymorphic markers that were used to construct a high-resolution genetic linkage map of YrZH22. YrZH22 was delimited in a 5.92 cM genetic interval between markers WGGB133 and WGGB146, corresponding to 4.1 Mb genomic interval in Chinese Spring 4BL and a 2.2 Mb orthologous genomic region in Ae. tauschii 4DL. The genetic linkage map of YrZH22 will be valuable for fine mapping and positional cloning of YrZH22, and can be used for marker-assisted selection in wheat breeding.

QTL Mapping of Adult-Plant Resistance to Leaf Rust in the Wheat Cross Zhou 8425B/Chinese Spring Using High-Density SNP Markers.

Wheat leaf rust is an important disease worldwide. Growing resistant cultivars is an effective means to control the disease. In the present study, 244 recombinant inbred lines from Zhou 8425B/Chinese Spring cross were phenotyped for leaf rust severities during the 2011-2012, 2012-2013, 2013-2014, and 2014-2015 cropping seasons at Baoding, Hebei province, and 2012-2013 and 2013-2014 cropping seasons in Zhoukou, Henan province. The population was genotyped using the high-density Illumina iSelect 90K SNP assay and SSR markers. Inclusive composite interval mapping identified eight QTL, designated as QLr.hebau-2AL, QLr.hebau-2BS, QLr.hebau-3A, QLr.hebau-3BS, QLr.hebau-4AL, QLr.hebau-4B, QLr.hebau-5BL, and QLr.hebau-7DS, respectively. QLr.hebau-2BS, QLr.hebau-3A, QLr.hebau-3BS, and QLr.hebau-5BL were derived from Zhou 8425B, whereas the other four were from Chinese Spring. Three stable QTL on chromosomes 2BS, 4B and 7DS explained 7.5-10.6%, 5.5-24.4%, and 11.2-20.9% of the phenotypic variance, respectively. QLr.hebau-2BS in Zhou 8425B might be the same as LrZH22 in Zhoumai 22; QLr.hebau-4B might be the residual resistance of Lr12, and QLr.hebau-7DS is Lr34. QLr.hebau-2AL, QLr.hebau-3BS, QLr.hebau-4AL, and QLr.hebau-5BL are likely to be novel QTL for leaf rust. These QTL and their closely linked SNP and SSR markers can be used for fine mapping, candidate gene discovery, and marker-assisted selection in wheat breeding.

Combined Small RNA and Degradome Sequencing Reveals Novel MiRNAs and Their Targets in the High-Yield Mutant Wheat Strain Yunong 3114.

Wheat is one of the main food sources worldwide; large amount studies have been conducted to improve wheat production. MicroRNAs (miRNAs) with about 20-30 nucleotide are a class of regulatory small RNAs (sRNAs), which could regulate gene expression through sequence-specific base pairing with target mRNAs, playing important roles in plant growth. An ideal plant architecture (IPA) is crucial to enhance yield in bread wheat. In this study, the high-yield wheat strain Yunong 3114 was EMS-mutagenesis from the wild-type strain Yunong 201, exhibiting a preferable plant structure compared with the wild-type strain. We constructed small RNA and degradome libraries from Yunong 201 and Yunong 3114, and performed small RNA sequencing of these libraries in order identify miRNAs and their targets related to IPA in wheat. Totally, we identified 488 known and 837 novel miRNAs from Yunong 3114 and 391 known and 533 novel miRNAs from Yunong 201. The number of miRNAs in the mutant increased. A total of 37 known and 432 putative novel miRNAs were specifically expressed in the mutant strain; furthermore, 23 known and 159 putative novel miRNAs were specifically expressed in the wild-type strain. A total of 150 known and 100 novel miRNAs were differentially expressed between mutant and wild-type strains. Among these differentially expressed novel miRNAs, 4 and 8 predict novel miRNAs were evidenced by degradome sequencing and showed up-regulated and down-regulated expressions in the mutant strain Yunong 3114, respectively. Targeted gene annotation and previous results indicated that this set of miRNAs is related to plant structure. Our results further suggested that miRNAs may be necessary to obtain an optimal wheat structure.

Genome-Wide Linkage Mapping of QTL for Yield Components, Plant Height and Yield-Related Physiological Traits in the Chinese Wheat Cross Zhou 8425B/Chinese Spring.

Identification of genes for yield components, plant height (PH), and yield-related physiological traits and tightly linked molecular markers is of great importance in marker-assisted selection (MAS) in wheat breeding. In the present study, 246 F8 RILs derived from the cross of Zhou 8425B/Chinese Spring were genotyped using the high-density Illumina iSelect 90K single nucleotide polymorphism (SNP) assay. Field trials were conducted at Zhengzhou and Zhoukou of Henan Province, during the 2012-2013 and 2013-2014 cropping season under irrigated conditions, providing data for four environments. Analysis of variance (ANOVA) of agronomic and physiological traits revealed significant differences (P < 0.01) among RILs, environments, and RILs × environments interactions. Broad-sense heritabilities of all traits including thousand kernel weight (TKW), PH, spike length (SL), kernel number per spike (KNS), spike number/m(2) (SN), normalized difference in vegetation index at anthesis (NDVI-A) and at 10 days post-anthesis (NDVI-10), SPAD value of chlorophyll content at anthesis (Chl-A) and at 10 days post-anthesis (Chl-10) ranged between 0.65 and 0.94. A linkage map spanning 3609.4 cM was constructed using 5636 polymorphic SNP markers, with an average chromosome length of 171.9 cM and marker density of 0.64 cM/marker. A total of 866 SNP markers were newly mapped to the hexaploid wheat linkage map. Eighty-six QTL for yield components, PH, and yield-related physiological traits were detected on 18 chromosomes except 1D, 5D, and 6D, explaining 2.3-33.2% of the phenotypic variance. Ten stable QTL were identified across four environments, viz. QTKW.caas-6A.1, QTKW.caas-7AL, QKNS.caas-4AL, QSN.caas-1AL.1, QPH.caas-4BS.2, QPH.caas-4DS.1, QSL.caas-4AS, QSL.caas-4AL.1, QChl-A.caas-5AL, and QChl-10.caas-5BL. Meanwhile, 10 QTL-rich regions were found on chromosome 1BS, 2AL (2), 3AL, 4AL (2), 4BS, 4DS, 5BL, and 7AL exhibiting pleiotropic effects. These QTL or QTL clusters are tightly linked to SNP markers, with genetic distances to the closest SNPs ranging from 0 to 1.5 cM, and could serve as target regions for fine mapping, candidate gene discovery, and MAS in wheat breeding.

[Molecular identification on Waxy genes in wheat using multiple-PCR].

Multiple-PCR was conducted to establish a stable PCR system for identifying the three Wx genes in wheat. Two pairs of primers were employed to amplify Wx-A1, Wx-B1, and Wx-D1 genes of wheat, with the target sequences of 230 bp/265 bp, 854 bp, and 204 bp, respectively. The results showed that Wx-A1, Wx-B1, and Wx-D1 can be detected simultaneously in a single reaction. This method proved to be repeatable and low cost for evaluation of wheat quality properties in breeding program. This multiple-PCR technique can be efficiently used in marker-assisted selection for Wx genes, which will improve selection procedure for waxy wheat.