Summary
The CRISPR/Cas9 system has been demonstrated to efficiently induce targeted gene editing in a variety of organisms including plants. Recent work showed that CRISPR/Cas9‐induced gene mutations ...in Arabidopsis were mostly somatic mutations in the early generation, although some mutations could be stably inherited in later generations. However, it remains unclear whether this system will work similarly in crops such as rice. In this study, we tested in two rice subspecies 11 target genes for their amenability to CRISPR/Cas9‐induced editing and determined the patterns, specificity and heritability of the gene modifications. Analysis of the genotypes and frequency of edited genes in the first generation of transformed plants (T0) showed that the CRISPR/Cas9 system was highly efficient in rice, with target genes edited in nearly half of the transformed embryogenic cells before their first cell division. Homozygotes of edited target genes were readily found in T0 plants. The gene mutations were passed to the next generation (T1) following classic Mendelian law, without any detectable new mutation or reversion. Even with extensive searches including whole genome resequencing, we could not find any evidence of large‐scale off‐targeting in rice for any of the many targets tested in this study. By specifically sequencing the putative off‐target sites of a large number of T0 plants, low‐frequency mutations were found in only one off‐target site where the sequence had 1‐bp difference from the intended target. Overall, the data in this study point to the CRISPR/Cas9 system being a powerful tool in crop genome engineering.
In this paper, a systematic study was conducted to investigate the influence of calcination conditions including grinding time of raw material, temperature, holding time and heating rate on the ...pozzolanic activity of calcined coal gangue (abbreviated as CCG hereinafter). Furthermore, the changes of mineral composition, chemical structure and morphology of coal gangue during calcination were characterized by means of thermogravimetric-differential scanning calorimeter (TG-DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analyses. The results show that heating temperature affects directly the mineralogy and crystallinity of CCG. Kaolinite in coal gangue transforms into metakaolin which is an irregular and amorphous phase as calcined at 600°C–800°C because of the dehydroxylation of Al–(O,OH) octahedrons together with the depolymerization of Si–O tetrahedrons. The amorphous metakaolin is of high pozzolanic activity; however, it will lose its activity due to the recrystallization into mullite when heating temperature is over 1000°C. The pozzolanic activity of CCG is mainly dependent on the non-crystallizing degree of kaolinite after calcination.
•Pozzolanicity of coal gangue calcined under different conditions was studied.•Phase transition temperature of kaolinite was measured by anaerobic TG-DSC.•Crystallinity, structure and morphology of calcined coal gangue were characterized.•Pozzolanicity of calcined coal gangue mainly depends on its amorphization degree.
MicroRNAs are 19- to 22-nucleotide small noncoding RNAs that have been implicated in abiotic stress responses. In this study, we found that knockdown of microRNA166, using the Short Tandem Target ...Mimic (STTM) system, resulted in morphological changes that confer drought resistance in rice (Oryza sativa). From a large-scale screen for miRNA knockdown lines in rice, we identified miR166 knockdown lines (STTM166); these plants exhibit a rolled-leaf phenotype, which is normally displayed by rice plants under drought stress. The leaves of STTM166 rice plants had smaller bulliform cells and abnormal sclerenchymatous cells, likely causing the rolled-leaf phenotype. The STTM166 plants had reduced stomatal conductance and showed decreased transpiration rates. The STTM166 lines also exhibited altered stem xylem and decreased hydraulic conductivity, likely due to the reduced diameter of the xylem vessels. Molecular analyses identified rice HOMEODOMAIN CONTAINING PROTEIN4 (OsHB4), a member of HD-Zip III gene family, as a major target of miR166; moreover, rice plants overexpressing a miR166-resistant form of OsHB4 resembled the STTM166 plants, including leaf rolling and higher drought resistance. The genes downstream of miR166-OsHB4 consisted of polysaccharide synthesis-related genes that may contribute to cell wall formation and vascular development. Our results suggest that drought resistance in rice can be increased by manipulating miRNAs, which leads to developmental changes, such as leaf rolling and reduced diameter of the xylem, that mimic plants' natural responses to water-deficit stress.
Summary
In rice, amylose content (AC) is controlled by a single dominant Waxy gene. We used Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR‐associated 9 (Cas9) to introduce ...a loss‐of‐function mutation into the Waxy gene in two widely cultivated elite japonica varieties. Our results show that mutations in the Waxy gene reduce AC and convert the rice into glutinous ones without affecting other desirable agronomic traits, offering an effective and easy strategy to improve glutinosity in elite varieties. Importantly, we successfully removed the transgenes from the progeny. Our study provides an example of generating improved crops with potential for commercialization, by editing a gene of interest directly in elite crop varieties.
In this study, we reported generation of new glutinous rice with potential for commercialization by editing Waxy gene in elite crop varieties.
The microstructure and mechanical properties of Mg94Zn2.5Y2.5Mn1 (at%) with different Ti contents were investigated. The addition of 0.3 at% Ti yielded the best strength. However, ...Mg93.5Zn2.5Y2.5Mn1Ti0.5 exhibited the lowest yield asymmetry. These changes were attributed to the combined effects of grain refinement, increased LPSO phase, and reduced axial ration (c/a).
Most conventional and modern crop-improvement methods exploit natural or artificially induced genetic variations and require laborious characterization of the progenies of multiple generations ...derived from time-consuming genetic crosses. Genome-editing systems, in contrast, provide the means to rapidly modify genomes in a precise and predictable way, making it possible to introduce improvements directly into elite varieties. Here, we describe the range of applications available to agricultural researchers using existing genome-editing tools. In addition to providing examples of genome-editing applications in crop breeding, we discuss the technical and social challenges faced by breeders using genome-editing tools for crop improvement.
Most conventional and modern crop-improvement methods exploit natural or artificially induced genetic variations and require laborious characterization of the progeny of multiple generations of time-consuming genetic crosses. Genome-editing systems, in contrast, provide the means to rapidly modify genomes in a precise and predictable way, making it possible to introduce improvements directly into elite varieties. Here, we describe the range of applications available to agricultural researchers using existing genome-editing tools. In addition to providing examples of genome-editing applications in crop breeding, we discuss the technical and social challenges faced by breeders using genome-editing tools for crop improvement.
In this work, the high performance as-cast low RE (rare earths) Mg96.5Zn1Y1.5Mn1 alloys with LPSO (long-periodic stacking ordered) phase were fabricated by Ni and Bi microalloying, and the influences ...of Ni and Bi additions on microstructural evolution and mechanical properties in as-cast Mg96.5Zn1Y1.5Mn1 alloy were investigated. Results show that the Ni and Bi co-alloying can greatly refine the microstructure and facilitate the precipitation of 18R-LPSO phase. Meanwhile, in the Mg95.9Zn1Y1.5Mn1Ni0.5Bi0.1 alloy, the nucleation and growth ability of 18R-LPSO phase were higher than those of W phase, and the growth pattern of 18R-LPSO and W phase was optimized from coupled to divorced growth. Besides, the Mg95.9Zn1Y1.5Mn1Ni0.5Bi0.1 alloy exhibited superior mechanical properties with yield strength (YS), ultimate tensile strength (UTS) and elongation (EL) of 167±1 MPa, 239±1.6 MPa and 12±0.45%. Grain refinement, continuous 18R-LPSO phase with optimized growth pattern and the LPSO fibers precipitated in W phase were responsible for the outstanding mechanical properties.
•Effect of Ni/Bi on low RE Mg96.5Zn1Y1.5Mn1 alloy containing LPSO was studied.•The growth pattern transformation of 18R-LPSO and W phase was clarified.•The 18R-LPSO phase exhibited higher nucleation and growth ability than W phase.•The excellent mechanical properties were achieved via Ni and Bi co-microalloying.
Ghrelin is a circulating peptide hormone, which involved in promoting feeding and regulating energy metabolism in human and rodents. Abnormal synovial hyperplasia is the most important pathologic ...hallmark of rheumatoid arthritis (RA), which is characterised by tumor-like expansion. Existing studies indicated that there may exist some relation between the decreased ghrelin and the abnormally proliferating synovial cells in RA. Therefore, the aim of this study is to explore the apoptotic effects of ghrelin on MH7A synovial cells in vitro. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the effects of ghrelin on the viability of MH7A cells. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) and flow cytometry were used to test the apoptotic effects of ghrelin. At last, Western blot and real-time PCR were performed to explore the expression of caspases-8, -9, and -3 after the treatment of ghrelin. MTT experiments showed that ghrelin could inhibit viability of MH7A cells. The results of flow cytometry and TUNEL showed that ghrelin could induce apoptosis of MH7A synovial cells. Western blot showed that expression of cleaved-caspases-8, -9, and -3 were increased in ghrelin stimulation group compared with the control group, while expression of pro-caspases-8, -9, and -3 had no significant difference. In mRNA levels, ghrelin can decrease pro-caspases-8, -9, and -3 mRNA expression, which confirmed the results of protein levels. Then these apoptotic effects were significantly reversed by D-Lys3 GHRP-6 (ghrelin receptor antagonist). This study found that ghrelin can induce apoptosis of MH7A cells through caspase signaling pathways.
Despite the recent discovery of superconductivity in Nd1-xSrxNiO2 thin films,the absence of superconductivity and antiferromagnetism in their bulk materials remains a puzzle.Here we report the 1H NMR ...measurements on powdered Nd0.85Sr0.15NiO2 samples by taking advantage of the enriched proton concentration after hydrogen annealing.We find a large full width at half maximum of the spectrum,which keeps increasing with decreasing the temperature T and exhibits an upturn behavior at low temperatures.The spin-lattice relaxation rate 1T1-1 is strongly enhanced when lowering the temperature,developing a broad peak at about 40 K,then decreases fol-lowing a spin-wave-like behavior 1T1-1 ∝ T2 at lower temperatures.These results evidence a short-range glassy antiferromagnetic ordering of magnetic moments below 40 K and dominant antiferromagnetic fluctuations extend-ing to much higher temperatures.Our findings reveal the strong electron correlations in bulk Nd0.ssSr0.15NiO2,and shed light on the mechanism of superconductivity observed in films of nickelates.
Rex shunt, which was first put in use in 1992, has been considered as an ideal surgical method for the treatment of extra-hepatic portal venous obstruction (EHPVO) due to its reconstruction of the ...hepatopetal portal blood flow. However, despite its long tradition, there are only a few reports about the application and advances in Rex shunt for the treatment of EHPVO in children. In this paper, we summarized the literature related to Rex shunt and discussed the new advances of Rex shunt in the following aspects: surgical method of Rex shunt, the indications of Rex shunt, the strengths of Rex shunt, the effectiveness of Rex shunt, factors affecting the efficacy of Rex shunt, methods that improve the prognosis of Rex shunt, and treatment strategy for recurrence after Rex shunt.
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