Grain yield improvement by genome editing of TaARF12 that decoupled peduncle and rachis development trajectories via differential regulation of gibberellin signalling in wheat.

Plant breeding is constrained by trade-offs among different agronomic traits by the pleiotropic nature of many genes. Genes that contribute to two or more favourable traits with no penalty on yield are rarely reported, especially in wheat. Here, we describe the editing of a wheat auxin response factor TaARF12 by using CRISPR/Cas9 that rendered shorter plant height with larger spikes. Changes in plant architecture enhanced grain number per spike up to 14.7% with significantly higher thousand-grain weight and up to 11.1% of yield increase under field trials. Weighted Gene Co-Expression Network Analysis (WGCNA) of spatial-temporal transcriptome profiles revealed two hub genes: RhtL1, a DELLA domain-free Rht-1 paralog, which was up-regulated in peduncle, and TaNGR5, an organ size regulator that was up-regulated in rachis, in taarf12 plants. The up-regulation of RhtL1 in peduncle suggested the repression of GA signalling, whereas up-regulation of TaNGR5 in spike may promote GA response, a working model supported by differential expression patterns of GA biogenesis genes in the two tissues. Thus, TaARF12 complemented plant height reduction with larger spikes that gave higher grain yield. Manipulation of TaARF12 may represent a new strategy in trait pyramiding for yield improvement in wheat.

TaIAA21 represses TaARF25-mediated expression of TaERFs required for grain size and weight development in wheat.

Auxin signaling is essential for the development of grain size and grain weight, two important components for crop yield. However, no auxin/indole acetic acid repressor (Aux/IAA) has been functionally characterized to be involved in the development of wheat (Triticum aestivum L.) grains to date. Here, we identified a wheat Aux/IAA gene, TaIAA21, and studied its regulatory pathway. We found that TaIAA21 mutation significantly increased grain length, grain width, and grain weight. Cross-sections of mutant grains revealed elongated outer pericarp cells compared to those of the wild type, where the expression of TaIAA21 was detected by in situ hybridization. Screening of auxin response factor (ARF) genes highly expressed in early developing grains revealed that TaARF25 interacts with TaIAA21. In contrast, mutation of the tetraploid wheat (Triticum turgidum) ARF25 gene significantly reduced grain size and weight. RNA sequencing analysis revealed upregulation of several ethylene response factor genes (ERFs) in taiaa21 mutants which carried auxin response cis-elements in their promoter. One of them, ERF3, was upregulated in the taiaa21 mutant and downregulated in the ttarf25 mutant. Transactivation assays showed that ARF25 promotes ERF3 transcription, while mutation of TtERF3 resulted in reduced grain size and weight. Analysis of natural variations identified three TaIAA21-A haplotypes with increased allele frequencies in cultivars relative to landraces, a signature of breeding selection. Our work demonstrates that TaIAA21 works as a negative regulator of grain size and weight development via the ARF25-ERFs module and is useful for yield improvement in wheat.

Matrilineal empowers wheat pollen with haploid induction potency by triggering postmitosis reactive oxygen species activity.

Reactive oxygen species (ROS) play important roles during anther and pollen development. DNA damage may cause chromosome fragmentation that is considered to underlie chromosome elimination for haploid induction by matrilineal pollen, a key step in MATRILINEAL-based double haploid breeding technology. But when and how DNA damage occurs is unknown. We performed comparative studies of wheat pollens from the wild-type and the CRISPR/Cas9 edited matrilineal mutant (mMTL). Chemical assays detected a second wave of ROS in mMTL pollen at the three-nuclei-stage and subsequently, along with reduced antioxidant enzyme activities. RNA-seq analysis revealed disturbed expression of genes for fatty acid biosynthesis and ROS homoeostasis. Gas chromatography-mass spectrometry measurement identified abnormal fatty acid metabolism that may contribute to defective mMTL pollen walls as observed using electron microscopy, consistent with the function of MTL as a phospholipase. Moreover, DNA damage was identified using TdT-mediated dUTP nick-end labelling and quantified using comet assays. Velocity patterns showed that ROS increments preceded that of DNA damage over the course of pollen maturation. Our work hypothesises that mMTL-triggered later-stage-specific ROS causes DNA damage that may contribute to chromosome fragmentation and hence chromosome elimination during haploid induction. These findings may provide more ways to accelerate double haploid-based plant breeding.

InDels Identification and Association Analysis with Spike and Awn Length in Chinese Wheat Mini-Core Collection.

Diversity surveys of germplasm are important for gaining insight into the genomic basis for crop improvement; especially InDels, which are poorly understood in hexaploid common wheat. Here, we describe a map of 89,923 InDels from exome sequencing of 262 accessions of a Chinese wheat mini-core collection. Population structure analysis, principal component analysis and selective sweep analysis between landraces and cultivars were performed. Further genome-wide association study (GWAS) identified five QTL (Quantitative Trait Loci) that were associated with spike length, two of them, on chromosomes 2B and 6A, were detected in 10 phenotypic data sets. Assisted with RNA-seq data, we identified 14 and 21 genes, respectively that expressed in spike and rachis within the two QTL regions that can be further investigated for candidate genes discovery. Moreover, InDels were found to be associated with awn length on chromosomes 5A, 6B and 4A, which overlapped with previously reported genetic loci B1 (Tipped 1), B2 (Tipped 2) and Hd (Hooded). One of the genes TaAGL6 that was previously shown to affect floral organ development was found at the B2 locus to affect awn length development. Our study shows that trait-associated InDels may contribute to wheat improvement and may be valuable molecular markers for future wheat breeding.

Cleavage of PrePL by Lon promotes growth and pathogenesis in Magnaporthe oryzae.

ATP-dependent Lon proteases function in bacterial pathogenesis by regulating the expression of the Type III secretion system; however, little is known about how Lon proteases regulate fungal pathogenesis. We previously investigated Lon-binding proteins involved in fungal pathogenesis that interact with PrePL, the smallest Magnaporthe oryzae Lon-binding protein. Here, we show that Lon cleaves PrePL and produces Pc, an extracellular 11-kDa isoform with catalase and peroxidase activity. The ΔPrePL loss-of-function strain showed stronger sporulation and accelerated disease development, suggesting a temporally specific negative regulatory mechanism controlled by PrePL in disease progression. Neither the truncated Pc, nor the full-length PrePL missing the Lon cleavage site complemented the ΔPrePL phenotype, suggesting that full-length PrePL and Pc both function in fungal development. PrePL targeted to the mitochondria undergoes hydrolysis by Lon to produce Pc, which accumulates in the fungal apoplast. Importantly, recombinant Pc induced plant defence responses and cell death after being infiltrated into selected plant leaves, indicating that it functions as an avirulence factor. This work thus reveals a novel pathogenic factor in the fungal Lon-mediated pathway. Additionally, our results provide new insight into the functions of a full-length protein and its cleaved isoform in fungal pathogenesis.

The C3HC type zinc-finger protein (ZFC3) interacting with Lon/MAP1 is important for mitochondrial gene regulation, infection hypha development and longevity of Magnaporthe oryzae.

BACKGROUND: The rice blast is a typical fungal disease caused by Magnaporthe oryzae, and the mitochondrial ATP-dependent Lon protease (MAP1) has been proven to be involved in blast development. We previously screened a C3HC type Zinc-finger domain protein (ZFC3), which is interacted with MAP1. The purpose of this research was to study the biological function of ZFC3 protein in M. oryzae. RESULTS: We first confirmed that the ZFC3-RFP fusion protein is localized within the mitochondria. The deleted mutant strains of ZFC3 (∆ZFC3) showed the enhanced expression level of mtATP6, particularly mtATP8, and almost unchanged nATP9. ΔZFC3 produces more conidia and more tolerance to multiple stressors. The knock-out strain shows more melanin accumulation suggests the susceptibility to aging. ΔZFC3 displays faster early-stage hypha infiltration involved in MAP1-mediated pathogenicity in host rice. CONCLUSION: These results support the view that ZFC3 is a key regulator involved in gene regulation, stress response, cell wall integrity, longevity, conidiation, infection hypha development and MAP1-mediated pathogenicity in M. oryzae.

Effects of supplemented culture media from solid-state fermented Isaria cicadae on performance, serum biochemical parameters, serum immune indexes, antioxidant capacity and meat quality of broiler chickens.

OBJECTIVE: The objective of this study was to investigate effects of supplementation of culture media from solid-state fermented Isaria cicadae (I. cicadae) on performance, serum biochemical parameters, serum immune indexes, antioxidant capacity and meat quality of broiler chickens. METHODS: A total of 648 Arbor Acres male broiler chickens(1 d; average body weight, 42.93± 0.47 g) were randomly assigned to 6 treatments, each with six replicates and 18 broiler chickens per replicate. Broiler chickens were fed phase I (d 1 to 21) and phase II (d 22 to 42) diets. The phase I diets were corn and soybean-meal based diets supplemented with 0%, 2%, 4%, 6%, 8%, or 10% culture media from solid-state fermented I. cicadae respectively. The phase II diets were corn and soybean-meal based diets supplemented with 0%, 1.33%, 2.67%, 4.00%, 5.32%, or 6.67% culture media from solid-state fermented I. cicadae respectively. RESULTS: In phase I, the broiler chickens with the supplementation of culture media had increased body weight gain and feed intake (linear and quadratic, p<0.05) with increasing inclusion of culture media. The levels of serum total antioxidant capacity (T-AOC), glutathione (GSH) and superoxide dismutase (SOD) increased linearly (p<0.05). In phase II, levels of serum T-AOC and interleukin-1ß increased linearly (p<0.05), and GSH increased (p<0.05). In the kidney, GSH and glutathione peroxidase (GSH-Px) concentrations increased (linear and quadratic, p<0.05) and SOD concentration increased linearly (p<0.05). Compared to the control, shear force and drip loss of breast muscle decreased (linear and quadratic, p<0.05). Drip loss of leg muscle decreased linearly and quadratically (p<0.05). CONCLUSION: Dietary supplementation of culture media from solid-state fermented I.cicadae which was enriched in both wheat and residual bioactive components of I. cicadae enhanced the growth performance of broiler chickens. It also improved body anti-oxidative status and contributed to improve broiler meat quality.

Clinical characteristics and prognosis of heart failure with mid-range ejection fraction: insights from a multi-centre registry study in China.

BACKGROUND: Heart failure (HF) with mid-range ejection fraction (EF) (HFmrEF) has attracted increasing attention in recent years. However, the understanding of HFmrEF remains limited, especially among Asian patients. Therefore, analysis of a Chinese HF registry was undertaken to explore the clinical characteristics and prognosis of HFmrEF. METHODS: A total of 755 HF patients from a multi-centre registry were classified into three groups based on EF measured by echocardiogram at recruitment: HF with reduced EF (HFrEF) (n = 211), HFmrEF (n = 201), and HF with preserved EF (HFpEF) (n = 343). Clinical data were carefully collected and analyzed at baseline. The primary endpoint was all-cause mortality and cardiovascular mortality while the secondary endpoints included hospitalization due to HF and major adverse cardiac events (MACE) during 1-year follow-up. Cox regression and Logistic regression were performed to identify the association between the three EF strata and 1-year outcomes. RESULTS: The prevalence of HFmrEF was 26.6% in the observed HF patients. Most of the clinical characteristics of HFmrEF were intermediate between HFrEF and HFpEF. But a significantly higher ratio of prior myocardial infarction (p = 0.002), ischemic heart disease etiology (p = 0.004), antiplatelet drug use (p = 0.009), angioplasty or stent implantation (p = 0.003) were observed in patients with HFmrEF patients than those with HFpEF and HFrEF. Multivariate analysis showed that the HFmrEF group presented a better prognosis than HFrEF in all-cause mortality [p = 0.022, HR (95%CI): 0.473(0.215-0.887)], cardiovascular mortality [p = 0.005, HR (95%CI): 0.270(0.108-0.672)] and MACE [p = 0.034, OR (95%CI): 0.450(0.215-0.941)] at 1 year. However, no significant differences in 1-year outcomes were observed between HFmrEF and HFpEF. CONCLUSION: HFmrEF is a distinctive subgroup of HF. The strikingly prevalence of ischemic history among patients with HFmrEF might indicate a key to profound understanding of HFmrEF. Patients in HFmrEF group presented better 1-year outcomes than HFrEF group. The long-term prognosis and optimal medications for HFmrEF require further investigations.

ß-xylosidase and ß-mannosidase in combination improved growth performance and altered microbial profiles in weanling pigs fed a corn-soybean meal-based diet.

OBJECTIVE: In this study, two glycosidases (XMosidases), ß-xylosidase and -mannosidase, were investigated on their in vitro hydrolysis activities of feed and on the improvement of growth performance in vivo in weanling pigs. METHODS: Enzyme activities of XMosidases in vitro were evaluated in test tubes and simulation of gastric and small intestinal digestion, respectively, in the presence of NSPase. In vivo study was performed in 108 weaned piglets in a 28-d treatment. Pigs were allotted to one of three dietary treatments with six replicate pens in each treatment. The three treatment groups were as follows: i) Control (basal diet). ii) CE (basal diets + CE); iii) CE-Xmosidases (basal diets +CE + ß-xylosidase at 800U/kg and ß-mannosidase at 40U/kg). CE was complex enzymes (amylase, protease, xylanase and mannanase). RESULTS: In vitro XMosidases displayed significant activities on hydrolysis of corn and soybean meal in the presence of non-starch polysaccharide degrading enzymes (xylanase and ß-mannanase). In vitro simulation of gastric and small intestinal digestion by XMosidases showed XMosidases achieved 67.89±0.22% of dry matter digestibility and 63.12±0.21% of energy digestibility at 40 °C for 5 hrs. In weanling pigs, additional XMosidases to CE in feed improved ADG, F:G (p&lt; 0.05) and ATTD of crude protein (p= 0.01) and dry matter (p=0.02). XMosidases also altered the gut bacterial diversity and composition by increasing the proportion of beneficial bacteria. CONCLUSION: Addition of a complex enzyme supplementation (contained xylanase, ß-mannanase, protease and amylase), XMosidases (ß-xylosidase and ß-mannosidase) can further improve the growth performance and nutrient digestion of young pigs.

Radiation tolerance of La-doped nanocrystalline steel under heavy-ion irradiation at different temperatures.

Nanostructured materials have great potential for use as structural materials in advanced nuclear reactors due to the high density of grain boundaries that can serve as sinks to absorb irradiation-induced defects. In the present study, the irradiation tolerance of a La-doped nanocrystalline 304 austenitic stainless steel (NC-La) with a grain size of about 40 nm was investigated under an irradiation of 6 MeV Au ions to 1.5 × 1016 ions cm-2 at 600 °C and room temperature. Compared to its coarse-grained counterpart, in La-doped nanocrystalline steel no visible voids were observed at high-temperature irradiation, and no significant difference in extended defects, such as irradiation-induced dislocation loops or clusters, were found between irradiated and unirradiated areas at room temperature irradiation. Furthermore, the nano grain remains stable under irradiation, and no significant grain growth occurs at both irradiation temperatures. The excellent irradiation tolerance of the La-doped nanocrystalline alloys is attributed to the abundant grain boundaries and enhanced stability of nano grains induced by the Zener pinning effect and La segregation on grain boundaries. This study therefore demonstrates the superior irradiation tolerance of the La-doped nanocrystalline steel.

Effects of xylanase supplementation to wheat-based diets on growth performance, nutrient digestibility and gut microbes in weanling pigs.

OBJECTIVE: This study was designed to investigate the effects of an Aspergillus sulphureus xylanase expressed in Pichia pastoris on the growth performance, nutrient digestibility and gut microbes in weanling pigs. METHODS: A total of 180 weanling pigs (initial body weights were 8.47±1.40 kg) were assigned randomly to 5 dietary treatments. Each treatment had 6 replicates with 6 pigs per replicate. The experimental diets were wheat based with supplementation of 0, 500, 1,000, 2,000, and 4,000 U xylanase/kg. The experiment lasted 28 days (early phase, d 0 to 14; late phase, d 15 to 28). RESULTS: In the early phase, compared to the control, average daily gain (ADG) was higher for pigs fed diets supplemented with xylanase and there was a quadratic response in ADG (p<0.05). In the entire phase, ADG was higher for the pigs fed 1,000 or 2,000 U/kg xylanase compared to the control (p<0.05). The gain to feed ratio was higher for pigs fed diets supplemented with 1,000 or 2,000 U/kg xylanase compared to the control (p<0.05). Increasing the amount of xylanase improved the apparent total tract digestibility of dry matter, crude protein, neutral detergent fiber, calcium, and phosphorus during both periods (p<0.05). Xylanase supplementation (2,000 U/kg) decreased the proportion of Lachnospiraceae (by 50%) in Firmicutes, but increased Prevotellaceae (by 175%) in Bacteroidetes and almost diminished Enterobacteriaceae (Escherichia-Shigella) in Proteobacteria. CONCLUSION: Xylanase supplementation increased growth performance and nutrient digestibility up to 2,000 U/kg. Supplementation of xylanase (2,000 U/kg) decreased the richness of gut bacteria but diminished the growth of harmful pathogenic bacteria, such as Escherichia-Shigella, in the colon.

Cardiac arrest and cardiogenic shock complicating ST-segment elevation myocardial infarction in China: A retrospective multicenter study.

Background: Data on the effect of cardiac arrest (CA), cardiogenic shock (CS), and their combination on the prognosis of Chinese patients with ST-segment elevation myocardial infarction (STEMI) are limited. The present study sought to evaluate the clinical outcomes of STEMI complicated by CA and CS, and to identify the risk factors for CA or CS. Methods: This study included 7468 consecutive patients with STEMI in China. The patients were divided into 4 groups (CA + CS, CA only, CS only, and No CA or CS). The endpoints were 30-day all-cause death and major adverse cardiovascular events. A Cox proportional hazards regression analysis was performed. Results: CA, CS, and their combination were noted in 332 (4.4 %), 377 (5.0 %), and 117 (1.6 %) among all patients. During the 30-day follow-up, 817 (10.9 %) all-cause deaths and 964 (12.9 %) major adverse cardiovascular events occurred, and the incidence of all-cause mortality (3.6 %, 62.3 %, 74.1 %, 83.3 %) and major adverse cardiovascular events (5.4 %, 67.1 %, 75.0 %, and 87.2 %) significantly increased in the No CA or CS, CS only, CA only, and CA + CS groups, respectively. In the multivariate Cox regression models, compared with the No CA or CS group, the CA + CS, CA, and CS-only groups were associated with an increased risk of all-cause death and major adverse cardiovascular events. Patients with CA + CS had the highest risk of all-cause death (hazard ratio [HR], 25.259 [95 % confidence interval (CI) 19.221-33.195]) and major adverse cardiovascular events (HR 19.098, 95%CI 14.797-24.648). Conclusions: CA, CS, and their combination were observed in approximately 11 % of Chinese patients with STEMI, and were associated with increased risk for 30-day mortality and major adverse cardiovascular events in Chinese patients with STEMI.

Regulating Grind-Induced Lattice Distortion for Nickel-Rich Cathodes by Annealing.

The commercialization of high-performance nickel-rich cathodes always awaits a cost-effective, environmentally friendly, and large-scale preparation method. Despite a grinding process normally adopted in the synthesis of the nickel-rich cathodes, lattice distortion, rough surface, and sharp edge transformation inevitably occurr in the resultant samples. In this work, an additional annealing process is proposed that aims at regulating lattice distortion as well as achieving round and smoother morphologies without any structural or elemental modifications. Such a structural enhancement is favored for improved lithium diffusion and electrochemical stability during cycling. Consequently, the annealed cathodes demonstrate a considerable enhancement in capacity retention, escalating from 68.7% to 91.9% after 100 cycles at 1 C. Additionally, the specific capacity is significantly increased from 64 to 142 mAh g-1 at 5 C when compared to the unannealed cathodes. This work offers a straightforward and effective approach for reinforcing the electrochemical properties of nickel-rich cathodes.

Ni/Mg Dual Concentration-Gradient Surface Modification to Enhance Structural Stability and Electrochemical Performance of Li-Rich Layered Oxides.

Li-rich layered oxides (LRLOs), with the advantages of high specific capacity and low cost, are considered as candidates for the next-generation cathode of lithium-ion batteries (LIBs). Unfortunately, sluggish kinetics and interfacial degradation lead to capacity loss and voltage decay of the material during cycling. To address these issues, we propose a Ni/Mg dual concentration-gradient modification strategy for LRLOs. From the center to the surface of the modified materials, the contents of Ni and Mg are gradually increased while the content of Mn is decreased. The high Ni content on the surface increases the proportion of cationic redox, elevating the operating voltage and accelerating reaction kinetics. Moreover, the doped Mg on the surface of the material acting as a stabilizing pillar suppresses the migration of transition metals, stabilizing the layered structure. Therefore, the material with the Ni/Mg dual concentration-gradients delivers a superior electrochemical performance, exhibiting a suppressed voltage decay of 2.8 mV per cycle during 200 cycles (1 C, 2-4.8 V) and an excellent rate capability of 94.84 mAh/g at 7C. This study demonstrates a synergic design to construct high-performance LRLO cathode materials for LIBs.

Genome-editing of a circadian clock gene TaPRR95 facilitates wheat peduncle growth and heading date.

Plant height and heading date are important agronomic traits in wheat (Triticum aestivum L.) that affect final grain yield. In wheat, knowledge of pseudo-response regulator (PRR) genes on agronomic traits is limited. Here, we identify a wheat TaPRR95 gene by genome-wide association studies to be associated with plant height. Triple allele mutant plants produced by CRISPR/Cas9 show increased plant height, particularly the peduncle, with an earlier heading date. The longer peduncle is mainly caused by the increased cell elongation at its upper section, whilst the early heading date is accompanied by elevated expression of flowering genes, such as TaFT and TaCO1. A peduncle-specific transcriptome analysis reveals up-regulated photosynthesis genes and down-regulated IAA/Aux genes for auxin signaling in prr95aabbdd plants that may act as a regulatory mechanism to promote robust plant growth. A haplotype analysis identifies a TaPRR95-B haplotype (Hap2) to be closely associated with reduced plant height and increased thousand-grain weight. Moreover, the Hap2 frequency is higher in cultivars than that in landraces, suggesting the artificial selection on the allele during wheat breeding. These findings suggest that TaPRR95 is a regulator for plant height and heading date, thereby providing an important target for wheat yield improvement.

Comprehensive Comparative Analysis of the JAZ Gene Family in Common Wheat (Triticum aestivum) and Its D-Subgenome Donor Aegilops tauschii.

JASMONATE-ZIM DOMAIN (JAZ) repressor proteins work as co-receptors in the jasmonic acid (JA) signalling pathway and are essential for plant development and environmental adaptation. Despite wheat being one of the main staple food crops, until recently, comprehensive analysis of its JAZ gene family has been limited due to the lack of complete and high-quality reference genomes. Here, using the latest reference genome, we identified 17 JAZ genes in the wheat D-genome donor Aegilops tauschii. Then, 54 TaJAZs were identified in common wheat. A systematic examination of the gene structures, conserved protein domains, and phylogenetic relationships of this gene family was performed. Five new JAZ genes were identified as being derived from tandem duplication after wheat divergence from other species. We integrated RNA-seq data and yield QTL information and found that tandemly duplicated TaJAZ genes were prone to association with spike-related traits. Moreover, 12 TaJAZ genes were located within breeding selection sweeps, including 9 tandemly duplicated ones. Haplotype variation analysis of selected JAZ genes showed significant association of TaJAZ7A and TaJAZ13A with thousand-grain weight. Our work provides a clearer picture of wheat JAZ gene evolution and puts forward the possibility of using these genes for wheat yield improvement.

An Approach to Intelligent Fault Diagnosis of Cryocooler Using Time-Frequency Image and CNN.

Cryocooler plays an essential role in the field of infrared remote sensing. Linear compressor, as the power component of the cryocooler, will directly affect the normal operation and performance of the detector if there is a fault. Therefore, the intelligent fault diagnosis of the linear compressor is of great significance. An intelligent fault diagnosis method based on time-frequency image and convolutional neural network is proposed to solve the problems of piston and cylinder friction, mass imbalance, and plate spring distortion in the linear compressor. Firstly, the wavelet transform time-frequency analysis method is used to generate the corresponding time-frequency image. Convolutional neural network (CNN) is used to automatically extract features of time-frequency images, so as to realize the classification of various fault modes. The results of simulation experiments show that the method can identify several fault modes of the linear compressor with 95% accuracy.

Transcriptome Analysis of Developing Wheat Grains at Rapid Expanding Phase Reveals Dynamic Gene Expression Patterns.

Grain development, as a vital process in the crop's life cycle, is crucial for determining crop quality and yield. The wheat grain expanding phase is the early process involving the rapid morphological changes and initiation of grain filling. However, little is known about the molecular basis of grain development at this stage. Here, we provide a time-series transcriptome profile of developing wheat grain at 0, 2, 4, 6, 8, and 10 days after pollination of the wheat landrace Chinese Spring. A total of 26,892 differentially expressed genes, including 1468 transcription factors, were found between adjacent time points. Co-expression cluster analysis and Gene Ontology enrichment revealed dynamic expressions of cell division and starch biosynthesis related structural genes and transcription factors. Moreover, diverse, differential and drastically varied expression trends of the key genes related to hormone metabolism were identified. Furthermore, ~30% of triads showed unbalanced expression patterns enriching for genes in multiple pivotal metabolic pathways. Hormone metabolism related genes, such as YUC10 (YUCCA flavin-containing monooxygenase 10), AOS2 (allene oxide synthase 2), CYP90D2 (cytochrome P450 90D2), and CKX1 (cytokinin dehydrogenase 1), were dominantly contributed by A or D homoeologs of the triads. Our study provided a systematic picture of transcriptional regulation of wheat grains at the early grain expanding phase which should deepen our understanding of wheat grain development and help in wheat yield improvement.

A Multi-Omics Approach for Rapid Identification of Large Genomic Lesions at the Wheat Dense Spike (wds) Locus.

Optimal spike architecture provides a favorable structure for grain development and yield improvement. However, the number of genes cloned to underlie wheat spike architecture is extremely limited. Here, we obtained a wheat dense spike mutant (wds) induced by 60Co treatment of a common wheat landrace Huangfangzhu that exhibited significantly reduced spike and grain lengths. The shortened spike length was caused by longitudinal reduction in number and length of rachis cells. We adopted a multi-omics approach to identify the genomic locus underlying the wds mutant. We performed Exome Capture Sequencing (ECS) and identified two large deletion segments, named 6BL.1 at 334.8∼424.3 Mb and 6BL.2, 579.4∼717.8 Mb in the wds mutant. RNA-seq analysis confirmed that genes located in these regions lost their RNA expression. We then found that the 6BL.2 locus was overlapping with a known spike length QTL, qSL6B.2. Totally, 499 genes were located within the deleted region and two of them were found to be positively correlated with long spike accessions but not the ones with short spike. One of them, TraesCS6B01G334600, a well-matched homolog of the rice OsBUL1 gene that works in the Brassinosteroids (BR) pathway, was identified to be involved in cell size and number regulation. Further transcriptome analysis of young spikes showed that hormone-related genes were enriched among differentially expressed genes, supporting TraesCS6B01G334600 as a candidate gene. Our work provides a strategy to rapid locate genetic loci with large genomic lesions in wheat and useful resources for future wheat study.

RNAi technology for plant protection and its application in wheat.

The RNAi technology takes advantage of the intrinsic RNA interference (RNAi) mechanism that exists in nearly all eukaryotes in which target mRNAs are degraded or functionally suppressed. Significant progress has been made in recent years where RNAi technology is applied to several crops and economic plants for protection against diseases like fungi, pests, and nematode. RNAi technology is also applied in controlling pathogen damages in wheat, one of the most important crops in the world. In this review, we first give a brief introduction of the RNAi technology and the underneath mechanism. We then review the recent progress of its utilization in crops, particular wheat. Finally, we discuss the existing challenges and prospect future development of this technology in crop protection.