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P0 protein of some polerovirus members can target ARGONAUTE1 (AGO1) to suppress RNA silencing. Although P0 harbors an F-box-like motif reported to be essential for interaction with S phase kinase-associated protein 1 (SKP1) and RNA silencing suppression, it is the autophagy pathway that was shown to contribute to AGO1 degradation. Therefore, the role of P0-SKP1 interaction in silencing suppression remains unclear. We conducted global mutagenesis and comparative functional analysis of P0 encoded by Brassica yellows virus (BrYV) (P0Br ). We found that several residues within P0Br are required for local and systemic silencing suppression activities. Remarkably, the F-box-like motif mutant of P0Br , which failed to interact with SKP1, is destabilized in vivo. Both the 26S proteasome system and autophagy pathway play a role in destabilization of the mutant protein. Furthermore, silencing of a Nicotiana benthamiana SKP1 ortholog leads to the destabilization of P0Br . Genetic analyses indicated that the P0Br -SKP1 interaction is not directly required for silencing suppression activity of P0Br , but it facilitates stability of P0Br to ensure efficient RNA silencing suppression. Consistent with these findings, efficient systemic infection of BrYV requires P0Br . Our results reveal a novel strategy used by BrYV for facilitating viral suppressors of RNA silencing stability against degradation by plant cells.

Ethernet circuit based on IEEE 802.3 has been widely used in the field of rail transit. Open systems interconnection (OSI) model divides Ethernet into seven layers, of which the physical layer (PHY) belongs to the first layer, which is mainly responsible for converting Ethernet signals into specific electrical signals and transmitting them to Ethernet cables, and plays a very important role in the interconnection between different network interfaces. In order to improve the reliability of train network system based on Ethernet and improve the quality of train communication, this paper designs and studies the physical layer circuit of train Ethernet, including PHY chip filtering and impedance matching, the application of different xMII (medium independent interface) interfaces, EMC protection, factors in the consistency test of network interface and PCB layout and wiring rules, and designs an Ethernet physical layer circuit according to the research results. The application results show that the designed circuit is suitable for the field of train Ethernet communication, and has strong EMC protection ability and high reliability.

Based on the requirements of resin‐based plugging agents on initial viscosity, gel time and cost, the urea‐formaldehyde resin Poly‐UF was synthesized via aqueous solution polymerization. Subsequently, the Poly‐UF was further modified by using melamine, polyvinyl alcohol (PVA), and oxidized starch to enhance its application performances, which were marked by Poly‐UF‐M, Poly‐UF‐PVA and Poly‐UF‐OS, respectively. Simultaneously, the relationship between the preparation process, structural, and performance characteristics of the different resin types was investigated using a single‐factor experimental approach, specifically, the solid content, viscosity, and free formaldehyde content were evaluated to gauge its application performance. In this study, the chemical structure, thermal stability and microscopic morphology of Poly‐UF‐M, Poly‐UF‐PVA and Poly‐UF‐OS were studied by using FTIR, TG‐DTG and SEM. As a result, it was confirmed that the Poly‐UF was successfully modified, and the thermal stability was obviously improved, and the microstructure was further enhanced by melamine, PVA and oxidized starch. The outcomes revealed a notable reduction in free formaldehyde content and a significant increase in solid content for Poly‐UF‐M, Poly‐UF‐PVA, and Poly‐UF‐OS, specifically, the free formaldehyde content decreased by 47.15%, 36.59%, and 32.52%, respectively, while the solid content increased by 3.47%, 1.62%, and 1.39%, respectively. Moreover, the acid and alkali solubility, mechanical strength of cured Poly‐UF‐M, Poly‐UF‐PVA and Poly‐UF‐OS were improved attribute to excellent membrane‐forming performance. The innovation of this study is that the systematic investigation and optimization of urea‐formaldehyde resin are presented, providing technical insights on its utilization as a plugging agent in fractured and caved oil and gas reservoirs. [ABSTRACT FROM AUTHOR]

Dicer-mediated processing of virus-specific dsRNA into short interfering RNAs (siRNAs) in plants and animals initiates a specific antiviral defense by RNA interference (RNAi). In this study, we developed a forward genetic screen for the identification of host factors required for antiviral RNAi in Arabidopsis thaliana Using whole-genome sequencing and a computational pipeline, we identified aminophospholipid transporting ATPase 2 (ALA2) and the related ALA1 in the type IV subfamily of P-type ATPases as key components of antiviral RNAi. ALA1 and ALA2 are flippases, which are transmembrane lipid transporter proteins that transport phospholipids across cellular membranes. We found that the ala1/ala2 single- and double-mutant plants exhibited enhanced disease susceptibility to cucumber mosaic virus when the virus-encoded function to suppress RNAi was disrupted. Notably, the antiviral activity of both ALA1 and ALA2 was abolished by a single amino acid substitution known to inactivate the flippase activity. Genetic analysis revealed that ALA1 and ALA2 acted to enhance the amplification of the viral siRNAs by RNA-dependent RNA polymerase (RdRP) 1 (RDR1) and RDR6 and of the endogenous virus-activated siRNAs by RDR1. RNA virus replication by plant viral RdRPs occurs inside vesicle-like membrane invaginations induced by the recruitment of the viral RdRP and host factors to subcellular membrane microdomains enriched with specific phospholipids. Our results suggest that the phospholipid transporter activity of ALA1/ALA2 may be necessary for the formation of similar invaginations for the synthesis of dsRNA precursors of highly abundant viral and host siRNAs by the cellular RdRPs.

The barley stripe mosaic virus (BSMV) triple gene block 1 (TGB1) protein is required for virus cell-to-cell movement. However, little information is available about how these activities are regulated by post-translational modifications. In this study, we showed that the BSMV Xinjiang strain TGB1 (XJTGB1) is phosphorylated in vivo and in vitro by protein kinase CK2 from barley and Nicotiana benthamiana. Liquid chromatography tandem mass spectrometry analysis and in vitro phosphorylation assays demonstrated that Thr-401 is the major phosphorylation site of the XJTGB1 protein, and suggested that a Thr-395 kinase docking site supports Thr-401 phosphorylation. Substitution of Thr-395 with alanine (T395A) only moderately impaired virus cell-to-cell movement and systemic infection. In contrast, the Thr-401 alanine (T401A) virus mutant was unable to systemically infect N. benthamiana but had only minor effects in monocot hosts. Substitution of Thr-395 or Thr-401 with aspartic acid interfered with monocot and dicot cell-to-cell movement and the plants failed to develop systemic infections. However, virus derivatives with single glutamic acid substitutions at Thr-395 and Thr-401 developed nearly normal systemic infections in the monocot hosts but were unable to infect N. benthamiana systemically, and none of the double mutants was able to infect dicot and monocot hosts. The mutant XJTGB1T395A/T401A weakened in vitro interactions between XJTGB1 and XJTGB3 proteins but had little effect on XJTGB1 RNA-binding ability. Taken together, our results support a critical role of CK2 phosphorylation in the movement of BSMV in monocots and dicots, and provide new insights into the roles of phosphorylation in TGB protein functions.

Antiviral immunity controlled by RNA interference (RNAi) in plants and animals is thought to specifically target only viral RNAs by the virus-derived small interfering RNAs (siRNAs). Here we show that activation of antiviral RNAi in Arabidopsis plants is accompanied by the production of an abundant class of endogenous siRNAs mapped to the exon regions of more than 1,000 host genes and rRNA. These virus-activated siRNAs (vasiRNAs) are predominantly 21 nucleotides long with an approximately equal ratio of sense and antisense strands. Genetically, vasiRNAs are distinct from the known plant endogenous siRNAs characterized to date and instead resemble viral siRNAs by requiring Dicer-like 4 and RNA-dependent RNA polymerase 1 (RDR1) for biogenesis. However, loss of exoribonuclease4/thylene-insensitive5 enhances vasiRNA biogenesis and virus resistance without altering the biogenesis of viral siRNAs. We show that vasiRNAs are active in directing widespread silencing of the target host genes and that Argonaute-2 binds to and is essential for the silencing activity of vasiRNAs. Production of vasiRNAs is readily detectable in Arabidopsis after infection by viruses from two distinct supergroups of plant RNA virus families and is targeted for inhibition by the silencing suppressor protein 2b of Cucumber mosaic virus. These findings reveal RDR1 production of Arabidopsis endogenous siRNAs and identify production of vasiRNAs to direct widespread silencing of host genes as a conserved response of plants to infection by diverse viruses. A possible function for vasiRNAs to confer broad-spectrum antiviral activity distinct to the virus-specific antiviral RNAi by viral siRNAs is discussed.

Plant viruses are a group of intracellular pathogens that persistently threaten global food security. Significant advances in plant virology have been achieved by Chinese scientists over the last 20 years, including basic research and technologies for preventing and controlling plant viral diseases. Here, we review these milestones and advances, including the identification of new crop‐infecting viruses, dissection of pathogenic mechanisms of multiple viruses, examination of multilayered interactions among viruses, their host plants, and virus‐transmitting arthropod vectors, and in‐depth interrogation of plant‐encoded resistance and susceptibility determinants. Notably, various plant virus‐based vectors have also been successfully developed for gene function studies and target gene expression in plants. We also recommend future plant virology studies in China. [ABSTRACT FROM AUTHOR]

The Swin‐Transformer is a variant of the Vision Transformer, which constructs a hierarchical Transformer that computes representations with shifted windows and window multi‐head self‐attention. This method can handle the scale invariance problem and performs well in many computer vision tasks. In image retrieval, high‐quality feature descriptors are necessary to improve retrieval accuracy. This paper proposes a self‐ensemble Swin‐Transformer network structure to fuse the features of different layers of the Swin‐Transformer network, eliminating noise points present in a single layer, and improving the retrieval effect. Two experiments were conducted, one on the In‐shop Clothes Retrieval dataset and another on the Stanford Online Product dataset. The experiments showed that the proposed method significantly increased the retrieval effect of features extracted using Vision Transformer, surpassing previous state‐of‐the‐art image retrieval methods. In the second experiment, the feature map of the trained model was visualized, revealing that the improved network significantly reduces focus on some noise points and enhances focus on image features compared to the original network. [ABSTRACT FROM AUTHOR]

In order to improve the cuttings transport ability and well hole purification effect of horizontal shale gas wells in the Sichuan and Chongqing area, a new type of aluminum alloy drill pipe is put forward, and the floatability is validated by theoretical analysis and actual parameter calculation. According to the cuttings migration mechanism, the cuttings cleaning simulation model of the new aluminum alloy drill pipe and the traditional steel drill pipe was established by Fluent, and the hexahedral mesh is used to divide the model. Thus, the mesh independence and convergence of the two models are verified. Then, the simulation model is verified by comparing the calculation results of the two simulation models with the experimental data of the indoor cuttings migration device. Finally, the rock-cleaning ability of the two drill pipes is analyzed under the conditions of changing the cuttings particle size, well inclination angle, displacement, and mechanical speed. Compared with the traditional steel drill pipe, the new aluminum alloy drill pipe can improve the borehole purification capacity by 13% on average. This research result is of great significance in reducing the quality of cuttings in the annulus and improving the borehole purification effect. [ABSTRACT FROM AUTHOR]