Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice, employs the transcription activator-like effectors (TALEs) to induce the expression of the OsSWEET family of putative sugar transporter genes, which function in conferring disease susceptibility (S) in rice plants. To engineer broadspectrum bacterial blight resistance, we used CRISPR/Cas9-mediated gene editing to disrupt the TALEbinding elements (EBEs) of two S genes, OsSWEET11 and OsSWEET14, in rice cv. Kitaake, which harbors the recessive resistance allele of Xa25/OsSWEET13. The engineered rice line MS14K exhibited broadspectrum resistance to most Xoo strains with a few exceptions, suggesting that the compatible strains may contain new TALEs. We identified two PthXo2-like TALEs, Tal5 LN18 and Tal7 PXO61 , as major virulence factors in the compatible Xoo strains LN18 and PXO61, respectively, and found that Xoo encodes at least five types of PthXo2-like effectors. Given that PthXo2/PthXo2.1 target OsSWEET13 for transcriptional activation, the genomes of 3000 rice varieties were analyzed for EBE variationsin the OsSWEET13 promoter, and 10 Xa25-like haplotypes were identified. We found that Tal5 LN18 and Tal7 PXO61 bind slightly different EBE sequences in the OsSWEET13 promoter to activate its expression. CRISPR/Cas9 technology was then used to generate InDels in the EBE of the OsSWEET13 promoter in MS14K to creat a new germplasm with three edited OsSWEET EBEs and broad-spectrum resistance against all Xoo strains tested. Collectively, our findings illustrate how to disarm TALE-S co-evolved loci to generate broad-spectrum resistance through the loss of effector-triggered susceptibility in plants.
Single-crystalline, hexagonal covellite (CuS) nanoplatelets were successfully synthesized through a facile, inexpensive, reproducible, and improved solvothermal process in toluene at 120 degrees C for 24 h with hexadecylamine as a capping agent and copper acetate and carbon disulfide as precursors. These nanoplatelets are about 26+/-1.5 nm in diameter and 8+/-1.2 nm thick, and have a tendency to self-assemble into pillarlike nanostructures with face-to-face stacks, raftlike nanostructures with side-by-side arrays, and stratiform nanostructures with layer-by-layer self-assembly. The crystal shape, morphology, and crystallographic orientation of the covellite obtained were investigated by means of XRD, TEM, and high-resolution TEM, and a potential self-assembly mechanism was proposed.
Molybdates such as CaMoO4 and SrMoO4 have received much attention recently because of their interesting luminescence and structural properties. Herein, we report a microemulsion-mediated method as a novel technique to synthesize CaMoO4 and SrMoO4 mesocrystals with high hierarchy and with hollow structure. The “arms” of the flowerlike 3D mesocrystals are radial and are about 2−3 μm in length. They are constructed from nanoparticles with regular morphology and a size of about 150−300 nm. Study on the formation mechanism of the superstructures reveals that the oriented aggregation mechanism is responsible for the self-assembly. The mesocrystals of CaMoO4 and SrMoO4 are shown to be in a thermodynamically metastable state, which can be destroyed by further reaction time or temperature change.
Single crystalline ZnO nanorods with a diameter of about 5 nm were synthesized without the presence of any surfactants in ethanol solvent at room temperature. Nanodots and nanorods with different size and shape could be observed by TEM via simply altering NaOH concentration and reaction time. The polar ZnO nanorod growth mechanism was discussed by the 'Ostwald ripening' mechanism. Optical absorption and photoluminescence properties of ZnO nanorods have been characterized. The UV absorption spectrum revealed a clear blue-shift with a single absorption peak centred at 350 nm.
Diabetic retinopathy (DR) is the leading cause of blindness in working-age adults across the world. The pathogenesis of DR is multifactorial and the molecular mechanisms are still not fully understood. Accumulating evidence has demonstrated that noncoding RNAs (ncRNAs) may be aberrantly expressed and may play vital roles in the development of DR. Amongst ncRNAs, miRNAs and long ncRNAs (lncRNAs) are known for their regulatory functions. Here, we summarize the functions and mechanisms of known aberrantly expressed miRNAs and lncRNAs in DR. Additionally, a novel lncRNA–mRNA–miRNA network is included in this review. We highlight original studies that provide detailed data about the mechanisms of miRNAs and lncRNAs, their applications as diagnostic or prognostic biomarkers, and their potential therapeutic targets. In conclusion, this review will help us gain a better understanding of the molecular mechanisms by which miRNAs and lncRNAs perform their functions in DR, and provide general strategies and directions for future research.
Hierarchically structured carbon coated SnO2 nanoparticles well-anchored on the surface of a CNT (C-SnO2/CNT) material were synthesized by a facile hydrothermal process and subsequent carbonization. The as-obtained C-SnO2/CNT hybrid, when applied as an anode material for lithium ion batteries (LIBs), showed a high reversible capacity up to 1572 mA h g(-1) at 200 mA g(-1) with a superior rate capability (685 mA h g(-1) at 4000 mA g(-1)). Even after 100 charge/discharge cycles at 1000 mA g(-1), a specific capacity of 1100 mA h g(-1) can still be maintained. Such impressive electrochemical performance can be mainly attributed to the hierarchical sandwiched structure and strong synergistic effects of the ultrafine SnO2 nanoparticles and the carbon coating, and thus presents this material a promising anode material for LIBs.
Colloidal, monodisperse, single-crystalline pyramidal CuInS2 and rectangular AgInS2 nanocrystals were successfully synthesized through a convenient and improved solvothermal process that uses hexadecylamine as a capping reagent. The crystal phase, morphology, crystal lattice, and chemical composition of the as-prepared products were characterized by using X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, and energy dispersive X-ray spectroscopy. Results revealed that the as-synthesized CuInS2 colloid is in the tetragonal phase (size: 13-17 nm) and the AgInS2 in the orthorhombic structure (size: 17+/-0.5 nm). A possible shape evolution and crystal growth mechanism has been suggested for the formation of pyramidal CuInS2 and rectangular AgInS2 colloids. Control experiments indicated that the morphology- and/or phase-change of CuInS2 and orthorhombic AgInS2 colloids are temperature- and/or time-dependent. CuInS2 colloids absorb well in the range of visible light at room-temperature, indicating its potential application as a solar absorber. Two photoluminescence (PL) subbands at 1.938 and 2.384 eV in the PL spectra of CuInS2 colloids revealed that the recombination of the closest and the second closest donor-acceptor pairs within the CuInS2 lattice, in which the donor defect (Cui) occupies an interstitial position and the acceptor defect (VIn) resides at an adjacent cation site. In addition, the synthesis strategy developed in this study is convenient and inexpensive, and could also be used as a general process for the synthesis of other pure or doped ternary chalcogenides that require a controlled size (or shape). This process could be extended to the synthesis of other functional nanomaterials.
The use of CRISPR/LbCpf1 and CRISPR/xCas9 systems in wheat have not yet been reported. In this study, we compared the efficiencies of three CRISPR editing systems (SpCas9, LbCpf1, and xCas9), and three different promoters (OsU6a, TaU3, and TaU6) that drive single-guide (sg)RNA, which were introduced into wheat via Agrobacterium-mediated transformation. The results indicated that TaU3 was a better choice than OsU6a or TaU6. The editing efficiency was higher using two sgRNAs than one sgRNA, and mutants with a large fragment deletion between the two sgRNAs were produced. The LbCpf1 and xCas9 systems could both be used successfully. Two endogenous genes, TaWaxy and TaMTL, were edited with high efficiency by the optimized SpCas9 system, with the highest efficiency (80.5%) being achieved when using TaU3 and two sgRNAs to target TaWaxy. Rates of seed set in the TaMTL-edited T0 transgenic plants were much lower than that of the wild-type. A haploid induction rate of 18.9% was found in the TaMTL-edited T1 plants using the CRISPR/SpCas9 system. Mutants with reverse insertion of the deleted sequences of TaMTL and TaWaxy between the two sgRNAs were identified in the edited T0 plants. In addition, wheat grains lacking embryos or endosperms were observed in the TaMTL-edited T1 generation.
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