The impact of rural e-commerce participation on farmers' entrepreneurial behavior: Evidence based on CFPS data in China.

The "Three Rural Issues", encompass challenges related to agriculture, farmer, and rural area, which hold significant importance in driving comprehensive rural revitalization efforts in China. Farmer entrepreneurship, as a crucial means to enhance productivity, create job opportunities, and increase residents' income, has gradually become a key driving force in promoting rural revitalization in the new stage of development in China. With the rapid development of rural e-commerce, farmer entrepreneurship has encountered new opportunities. This study utilizes the 2020 China Family Panel Studies (CFPS) data and employs a structural equation model (SEM) to analyze the direct impact of rural e-commerce participation on farmer entrepreneurial behavior, considering factors such as human capital, social capital, and network infrastructure. This study further explores the indirect effects and mechanisms of e-commerce participation as a mediating variable and analyzes the impact and mechanisms on agricultural entrepreneurship behavior. The findings are as follows: (1) E-commerce participation significantly promotes farmer entrepreneurial behavior; (2) E-commerce participation as a mediating variable has a positive indirect effect on the relationship between social trust, network infrastructure, human capital, and farmer entrepreneurial behavior; (3) E-commerce participation has a significant positive influence on farmer entrepreneurship in the agricultural sector, and farmers with higher levels of network infrastructure and human capital have a higher probability of choosing agricultural entrepreneurship under the influence of e-commerce participation. Finally, this study provides policy recommendations in terms of infrastructure construction, entrepreneurial policy environment, and education level, aiming to optimize the situation of farmer entrepreneurship and contribute to the comprehensive promotion of rural revitalization.Overall, the research in this paper effectively combines theory and empirical evidence to outline the direct and indirect impact mechanisms of rural e-commerce participation on farmers' entrepreneurial behavior and agriculture-related entrepreneurial behavior and to test the effects of their impacts. First, most of the existing literature deals with farmers in individual sample areas, while the sample selected in this paper is farmers in the whole country, which is relatively more generalizable; second, most of the previous studies explore the level of e-commerce in the inter-provincial or county areas, while this paper expands the empirical study of rural e-commerce on the entrepreneurial behavior of farmers and the micro-period of agricultural entrepreneurial behavior, and focuses on the impacts of the e-commerce activities of farmers on their entrepreneurial behavior.

Selective Capture and Manipulation of DNA through Double Charged Nanopores.

In the past few decades, nanometer-scale pores have been employed as powerful tools for sensing biological molecules. Owing to its unique structure and properties, solid-state nanopores provide interesting opportunities for the development of DNA sequencing technology. Controlling DNA translocation in nanopores is an important means of improving the accuracy of sequencing. Here we present a proof of principle study of accelerating DNA captured across targeted graphene nanopores using surface charge density and find the intrinsic mechanism of the combination of electroosmotic flow induced by charges of nanopore and electrostatic attraction/repulsion between the nanopore and ssDNA. The theoretical study performed here provides a new means for controlling DNA transport dynamics and makes better and cheaper application of graphene in molecular sequencing.

Actuation mechanism of a nanoscale drilling rig based on nested carbon nanotubes.

With the increasing emphasis on health and the continuous improvement of medical standards, more and more micro/nano devices are being used in the medical field. However, the existing micro/nano devices cannot effectively solve various problems encountered in medical processes and achieve specific therapeutic effects. Based on this, this article designs a new type of nanoscale drilling rig. The nanoscale drilling rig is composed of double-layer nested carbon nanotubes with multiple electrodes, and is powered by an external power source, making it easy to perform long-term surgery in the human body. Through coding strategies, we can adjust the surface charge density and distribution of the nanoscale drilling rig, thereby controlling its periodical rotation and achieving precise medical treatment. In addition, in order to control the length of the nanoscale drill bit, meet the treatment needs of different parts of the human body, and reduce damage to the human body, we have designed a structure of ion electric double layers so that the drill bit can be fixed in different positions, reducing the risk of treatment to a certain extent. This drilling rig enriches the functions of micro/nano devices, which is beneficial for the development of the medical industry.

An overview of current advances in perinatal alcohol exposure and pathogenesis of fetal alcohol spectrum disorders.

The adverse use of alcohol is a serious global public health problem. Maternal alcohol consumption during pregnancy usually causes prenatal alcohol exposure (PAE) in the developing fetus, leading to a spectrum of disorders known as fetal alcohol spectrum disorders (FASD) and even fetal alcohol syndrome (FAS) throughout the lifelong sufferers. The prevalence of FASD is approximately 7.7 per 1,000 worldwide, and is even higher in developed regions. Generally, Ethanol in alcoholic beverages can impair embryonic neurological development through multiple pathways leading to FASD. Among them, the leading mechanism of FASDs is attributed to ethanol-induced neuroinflammatory damage to the central nervous system (CNS). Although the underlying molecular mechanisms remain unclear, the remaining multiple pathological mechanisms is likely due to the neurotoxic damage of ethanol and the resultant neuronal loss. Regardless of the molecular pathway, the ultimate outcome of the developing CNS exposed to ethanol is almost always the destruction and apoptosis of neurons, which leads to the reduction of neurons and further the development of FASD. In this review, we systematically summarize the current research progress on the pathogenesis of FASD, which hopefully provides new insights into differential early diagnosis, treatment and prevention for patents with FASD.

Rare-Earth Metal Complexes Supported by A Tridentate Amidinate Ligand: Synthesis, Characterization, and Catalytic Comparison in Isoprene Polymerization.

To systematically investigate the dependence of the initiating group and metal size on polymerization performance, a family of rare-earth metal bis(alkyl)/bis(benzyl)/bis(amide) complexes supported by a monoanionic tridentate amidinate ligand [(2,6-iPr2C6H3)NC(Ph)N(C6H4-2-OMe]- (HL) were synthesized and well-characterized. Treatment of rare-earth metal tris(alkyl)/tris(benzyl)/tris(amide) complexes Y(CH2C6H4NMe2-o)3 or Y(CH2SiMe3)3(THF)2 or Ln[N(SiHMe2)2]3(THF)x (Ln = Sc, x = 1; Ln = Y, La, Sm, Lu, x = 2) with 1 equiv of HL gave the corresponding mono(amidinate) rare-earth metal bis(alkyl)/bis(benzyl)/bis(amide) complexes [(2,6-iPr2C6H4)NC(Ph)N(C6H4-2-OMe)]Y(CH2C6H4NMe2-o)2 (1), [(2,6-iPr2C6H4)NC(Ph)N(C6H4-2-OMe)]Y(CH2SiMe3)2(THF) (2), and [(2,6-iPr2C6H4)NC(Ph)N(C6H4-2-OMe)]Ln[N(SiHMe2)2]2(THF)n (Ln = Y, n = 1 (3); Ln = La, n = 1 (4); Ln = Sc, n = 0 (5); Ln = Lu, n = 0 (6); Ln = Sm, n = 0 (7)) in good isolated yields. These complexes were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction. In the presence of excess AlMe3 and on treatment with 1 equiv of [Ph3C][B(C6F5)4], these complexes could serve as precatalysts for cationic polymerization of isoprene, in which the dependence of the polymerization activity and regioselectivity on the initiating group and metal size was observed.

Gate-Tunable Quantum Acoustoelectric Transport in Graphene.

Transport probes the motion of quasi-particles in response to external excitations. Apart from the well-known electric and thermoelectric transport, acoustoelectric transport induced by traveling acoustic waves has rarely been explored. Here, by adopting hybrid nanodevices integrated with piezoelectric substrates, we establish a simple design of acoustoelectric transport with gate tunability. We fabricate dual-gated acoustoelectric devices based on hBN-encapsulated graphene on LiNbO3. Longitudinal and transverse acoustoelectric voltages are generated by launching a pulsed surface acoustic wave. The gate dependence of zero-field longitudinal acoustoelectric signal presents strikingly similar profiles to that of Hall resistivity, providing a valid approach for extracting carrier density without magnetic field. In magnetic fields, acoustoelectric quantum oscillations appear due to Landau quantization, which are more robust and pronounced than Shubnikov-de Haas oscillations. Our work demonstrates a feasible acoustoelectric setup with gate tunability, which can be extended to the broad scope of various van der Waals materials.

Atomic-Level Matching Metal-Ion Organic Hybrid Interface to Enhance Energy Storage of Polymer-Based Composite Dielectrics.

In this work, a distinctive "metal-ion organic hybrid interface" (MOHI) between polyimide (PI) and calcium niobate (CNO) nanosheets is designed. The metal ions in the MOHI can achieve atomic-level matching not only with the inorganic CNO, but also with the PI chains, forming uniform and strong chemical bonds. These results are demonstrated by experiment and theory calculations. Significantly, the MOHI reduces the free volume and introduces deep traps across the filler-matrix interfacial area, thus suppressing the electric field distortion in PI-based composite dielectrics. Consequently, PI-based dielectric containing the MOHI exhibits excellent energy storage performance. The energy storage densities (Ue) of the composite dielectric reach 9.42 J cm-3 and 4.75 J cm-3 with energy storage efficiency (η) of 90% at 25 °C and 150 °C respectively, which are 2.6 and 11.6 times higher than those of pure PI. This study provides new ideas for polymer-based composite dielectrics in high energy storage.

Biotransformation of HBCDs by the microbial communities enriched from mangrove sediments.

1,2,5,6,9,10-Hexabromocyclododecanes (HBCDs) are a sort of persistent organic pollutants (POPs). This research investigated 12 microbial communities enriched from sediments of four mangroves in China to transform HBCDs. Six microbial communities gained high transformation rates (27.5-97.7%) after 12 generations of serial transfer. Bacteria were the main contributors to transform HBCDs rather than fungi. Analyses on the bacterial compositions and binning genomes showed that Alcanivorax (55.246-84.942%) harboring haloalkane dehalogenase genes dadAH and dadBH dominated the microbial communities with high transformation rates. Moreover, expressions of dadAH and dadBH in the microbial communities and Alcanivorax isolate could be induced by HBCDs. Further, it was found that purified proteins DadAH and DadBH showed high conversion rates on HBCDs in 36 h (91.9 ± 7.4 and 101.0 ± 1.8%, respectively). The engineered Escherichia coli BL21 strains harbored two genes could convert 5.7 ± 0.4 and 35.1 ± 0.1% HBCDs, respectively, lower than their cell-free crude extracts (61.2 ± 5.2 and 56.5 ± 8.7%, respectively). The diastereoisomer-specific transforming trend by both microbial communities and enzymes were γ- > α- > ß-HBCD, differed from α- > ß- > Î³-HBCD by the Alcanivorax isolate. The identified transformation products indicated that HBCDs were dehalogenated via HBr elimination (dehydrobromination), hydrolytic and reductive debromination pathways in the enriched cultures. Two enzymes converted HBCDs via hydrolytic debromination. The present research provided theoretical bases for the biotransformation of HBCDs by microbial community and the bioremediation of HBCDs contamination in the environment.

An Isolable One-Coordinate Lead(I) Radical with Strong g-Factor Anisotropy.

Lead-based radicals in the oxidation state of +1 are elusive species and are highly challenging to isolate in the condensed phase. In this study, we present the synthesis and characterization of the first isolable free plumbylyne radical 2 bearing a one-coordinate Pb(I) atom. It reacts with an N-heterocyclic carbene (NHC) to afford a two-coordinate NHC-ligated Pb(I) radical 3. 2 and 3 represent the first isolable Pb(I)-based radicals. Theoretical calculations and electron paramagnetic resonance analysis revealed that the unpaired electron mainly resides at the Pb 6p orbital in both radicals. Owing to the unique one-coordinate nature of the Pb atom in 2, it possesses two-fold orbital pseudo-degeneracy and substantial unquenched orbital angular momentum, and exhibits hitherto strongest g-factor anisotropy (gx,y,z=1.496, 1.166, 0.683) amongst main group radicals. Preliminary investigations into the reactivity of 2 unveiled its Pb-centered radical nature, and plumbylenes were isolated as products.

Predictive value of delta radiomics in xerostomia after chemoradiotherapy in patients with stage III-IV nasopharyngeal carcinoma.

BACKGROUND: Xerostomia is one of the most common side effects in nasopharyngeal carcinoma (NPC) patients after chemoradiotherapy. To establish a Delta radiomics model for predicting xerostomia secondary to chemoradiotherapy for NPC based on magnetic resonance T1-weighted imaging (T1WI) sequence and evaluate its diagnostic efficacy. METHODS: Clinical data and Magnetic resonance imaging (MRI) data before treatment and after induction chemotherapy (IC) of 255 NPC patients with stage III-IV were collected retrospectively. Within one week after CCRT, the patients were divided into mild (92 cases) and severe (163 cases) according to the grade of xerostomia. Parotid glands in T1WI sequence images before and after IC were delineated as regions of interest for radiomics feature extraction, and Delta radiomics feature values were calculated. Univariate logistic analysis, correlation, and Gradient Boosting Decision Tree (GBDT) methods were applied to reduce the dimension, select the best radiomics features, and establish pretreatment, post-IC, and Delta radiomics xerostomia grading predictive models. The receiver operating characteristic (ROC) curve and decision curve were drawn to evaluate the predictive efficacy of different models. RESULTS: Finally, 15, 10, and 12 optimal features were selected from pretreatment, post-IC, and Delta radiomics features, respectively, and a xerostomia prediction model was constructed with AUC values of 0.738, 0.751, and 0.843 in the training set, respectively. Only age was statistically significant in the clinical data of both groups (P < 0.05). CONCLUSION: Delta radiomics can predict the degree of xerostomia after chemoradiotherapy for NPC patients and it has certain guiding significance for clinical early intervention measures.

Pharmacological profiling of a berbamine derivative for lymphoma treatment.

ABSTRACT: Ca2+/calmodulin-dependent protein kinase II γ (CAMKIIγ) has been identified as a potential target for treating cancer. Based on our previous study of berbamine (BBM) as a CAMKIIγ inhibitor, we have synthesized a new BBM derivative termed PA4. Compared with BBM, PA4 showed improved potency and specificity and was more cytotoxic against lymphoma and leukemia than against other types of cancer. In addition to indirectly targeting c-Myc protein stability, we demonstrated that its cytotoxic effects were also mediated via increased reactive oxygen species production in lymphoma cells. PA4 significantly impeded tumor growth in vivo in a xenograft T-cell lymphoma mouse model. Pharmacokinetics studies demonstrated quick absorption into plasma after oral administration, with a maximum concentration of 1680 ± 479 ng/mL at 5.33 ± 2.31 hours. The calculated oral absolute bioavailability was 34.1%. Toxicity assessment of PA4 showed that the therapeutic window used in our experiments was safe for future development. Given its efficacy, safety, and favorable pharmacokinetic profile, PA4 is a potential lead candidate for treating lymphoma.

Synthesis and Reactivity of N-Heterocyclic Carbene Coordinated Formal Germanimidoyl-Phosphinidenes.

Treatment of N-heterocyclic carbene (NHC) ligated germylidenylphosphinidene MsFluidtBu-GeP(NHCiPr) (where MsFluidtBu is a bulky hydrindacene substituent, and NHCiPr is 1,3-diisopropyl-4,5-dimethyl-imidazolin-2-ylidene) with mesityl azide and 4-tertbutylphenyl azide afforded NHC coordinated formal germanimidoyl-phosphinidenes, which represent the first compounds bearing both Ge═N double bond and phosphinidene functionalities. Studies of the chemical properties revealed that the reactions preferred to occur at the Ge═N double bond, which underwent [2 + 2] cycloadditions with CO2 and ethyl isocyanate, and coordinated with coinage metals through the nitrogen atom.

Boosting the Plasmon-Mediated Electrochemical Oxidation of p-Aminothiophenol with p-Hydroxythiophenol as Molecular Cocatalyst.

Plasmon-mediated electrochemistry is an emerging area of interest in which the electrochemical reactions are enhanced by employing metal nanostructures possessing localized surface plasmon resonance (LSPR). However, the reaction efficacy is still far below its theoretical limit due to the ultrafast relaxation of LSPR-generated hot carriers. Herein, we introduce p-hydroxythiophenol (PHTP) as a molecular cocatalyst to significantly improve the reaction efficacy in plasmon-mediated electrochemical oxidation of p-aminothiophenol (PATP) on gold nanoparticles. Using electrochemical techniques, in situ Raman spectroscopy, and theoretical calculations, we elucidate that the presence of PHTP improves the hot hole-mediated electrochemical oxidation of PATP by 2-fold through the trapping of plasmon-mediated hot electrons. In addition, the selectivity of PATP oxidation could also be modulated by the introduction of PHTP cocatalyst. This tactic of employing molecular cocatalyst can be drawn out to endorse various plasmonic electrochemical reactions because of its simple protocol, high efficiency, and high selectivity.

Transmission infrared micro-spectroscopic study of individual human hair.

Significance: Understanding the optical transmission property of human hair, especially in the infrared regime, is vital in physical, clinical, and biomedical research. However, the majority of infrared spectroscopy on human hair is performed in the reflection mode, which only probes the absorptance of the surface layer. Aim: The direct transmission spectrum of individual hair without horizontal cut offers a rapid and non-destructive test of the hair cortex but is less investigated experimentally due to the small size and strong absorption of the hair. Approach: In this work, we conduct a transmission infrared micro-spectroscopic study on individual human hair with the help of Fourier-transform infrared microscope experimentally. Its high spatial resolution of infrared micro-spectroscopy further allows the comparison among different regions of hair. The geometry effect of the internal hair structure is also quantified using the finite-element simulation, which supports the experimental results. Results: By utilizing direct measurements of the transmission spectrum using a Fourier-transform infrared microscope, the human hair is found to display prominent band filtering behavior. In a case study of adult-onset Still's disease, the corresponding infrared transmission exhibits systematic variations of spectral weight as the disease evolves. Conclusions: Our work implies that the variation of spectral weight may relate to the disordered microscopic structure variation of the hair cortex during an inflammatory attack. Our work reveals the potential of hair infrared transmission spectrum in tracing the variation of hair cortex retrospectively.

MC-YOLOv5: A Multi-Class Small Object Detection Algorithm.

The detection of multi-class small objects poses a significant challenge in the field of computer vision. While the original YOLOv5 algorithm is more suited for detecting full-scale objects, it may not perform optimally for this specific task. To address this issue, we proposed MC-YOLOv5, an algorithm specifically designed for multi-class small object detection. Our approach incorporates three key innovations: (1) the application of an improved CB module during feature extraction to capture edge information that may be less apparent in small objects, thereby enhancing detection precision; (2) the introduction of a new shallow network optimization strategy (SNO) to expand the receptive field of convolutional layers and reduce missed detections in dense small object scenarios; and (3) the utilization of an anchor frame-based decoupled head to expedite training and improve overall efficiency. Extensive evaluations on VisDrone2019, Tinyperson, and RSOD datasets demonstrate the feasibility of MC-YOLOv5 in detecting multi-class small objects. Taking VisDrone2019 dataset as an example, our algorithm outperforms the original YOLOv5L with improvements observed across various metrics: mAP50 increased by 8.2%, mAP50-95 improved by 5.3%, F1 score increased by 7%, inference time accelerated by 1.8 ms, and computational requirements reduced by 35.3%. Similar performance gains were also achieved on other datasets. Overall, our findings validate MC-YOLOv5 as a viable solution for accurate multi-class small object detection.

Effects of acupuncture on the brain in primary insomnia: a coordinate-based meta-analysis of fMRI studies.

Importance: Primary insomnia (PI) has a high global incidence, and effective treatments with fewer side effects are needed. Acupuncture, a treatment used in traditional Chinese medicine, has become increasingly established as a treatment method for PI and is recognized by many physicians and patients. Some evidence has suggested that acupuncture was associated with improvements in objective sleep parameters and might induce changes in some brain regions. Individual studies with limited sample size and low detection thresholds may lead to false positives, and no systematic review of the effects of acupuncture has been conducted in PI. Objective: The aim of this systematic review and coordinate-based meta-analysis was to summarize the literature on fMRI evaluation of patients with PI treated with acupuncture. Design: We performed a methodical and comprehensive search of multiple publication databases (from inception to December 2022): Web of Science, PubMed, ScienceDirect, Embase, Wan Fang, China National Knowledge Infrastructure, and Chinese Scientific Journal Database. Bias and quality of studies were evaluated by three researchers. Furthermore, a seed-based D-mapping meta-analysis with permutation of subject images (SDM-PSI) was applied to investigate the central mechanisms behind acupuncture treatment at PI. The International Prospective Registry of Systematic Reviews received the protocol for this study. (PROSPERO: CRD42023400086). Results: The analysis included 305 patients with PI and 116 healthy controls from 11 studies. SDM-PSI analysis showed that patients with PI exhibited increased amplitudes of regional homogeneity and low-frequency fluctuations in the left superior frontal gyrus (1352 voxels, p = 0.0028), right angular gyrus (14 voxels, p = 0.0457), and cerebellum (12 voxels, p = 0.0446). Acupuncture improved the function of right superior frontal gyrus (1, 404 voxels, p = 0.0123), left inferior frontal gyrus (1068 voxels, p = 0.0088), left inferior temporal gyrus (903 voxels, p = 0.0074), left supramarginal gyrus (888 voxels, p = 0.0113), left precuneus (457 voxels, p = 0.0247), right precuneus (302 voxels, p = 0.0191), left supplementary motor area (82 voxels, p = 0.0354), and right parahippocampal gyrus (28 voxels, p = 0.0379). The brain regions affected by non-acupoint acupuncture were all located in the frontal lobe. The Cochrane risk-of bias tool and MINORS5 were used for quality assessment and the included articles had high performance bias and attrition bias. Conclusion: This coordinate-based meta-analysis found that acupuncture in patients with PI had significant effects on the default mode network, particularly on the frontal lobe and precuneus, and that non-acupoint acupuncture may provide some benefit to frontal brain region function. Systematic review registration: PROSPERO: CRD42023400086.

Advances in PD-1 signaling inhibition-based nano-delivery systems for tumor therapy.

In recent years, cancer immunotherapy has emerged as an exciting cancer treatment. Immune checkpoint blockade brings new opportunities for more researchers and clinicians. Programmed cell death receptor-1 (PD-1) is a widely studied immune checkpoint, and PD-1 blockade therapy has shown promising results in a variety of tumors, including melanoma, non-small cell lung cancer and renal cell carcinoma, which greatly improves patient overall survival and becomes a promising tool for the eradication of metastatic or inoperable tumors. However, low responsiveness and immune-related adverse effects currently limit its clinical application. Overcoming these difficulties is a major challenge to improve PD-1 blockade therapies. Nanomaterials have unique properties that enable targeted drug delivery, combination therapy through multidrug co-delivery strategies, and controlled drug release through sensitive bonds construction. In recent years, combining nanomaterials with PD-1 blockade therapy to construct novel single-drug-based or combination therapy-based nano-delivery systems has become an effective mean to address the limitations of PD-1 blockade therapy. In this study, the application of nanomaterial carriers in individual delivery of PD-1 inhibitors, combined delivery of PD-1 inhibitors and other immunomodulators, chemotherapeutic drugs, photothermal reagents were reviewed, which provides effective references for designing new PD-1 blockade therapeutic strategies.

A new detection algorithm for alien intrusion on highway.

In recent years, highway accidents occur frequently, the main reason is that there is always foreign body invasion on the highway, which makes people unable to respond to emergencies in time. In order to reduce the occurrence of highway incidents, an object detection algorithm for highway intrusion was proposed in this paper. Firstly, a new feature extraction module was proposed to better preserve the main information. Secondly, a new feature fusion method was proposed to improve the accuracy of object detection. Finally, a lightweight method was proposed to reduce the computational complexity. We compare the algorithm in this paper with existing algorithms, the experimental results showed that: On the Visdrone dataset (small size targets), (a) the CS-YOLO was 3.6% more accurate than the YOLO v8. (b) The CS-YOLO was 1.2% more accurate than the YOLO v8 on the Tinypersons dataset (minimal size targets). (c) CS-YOLO was 1.4% more accurate than YOLO v8 on VOC2007 data set (normal size).

Recent advances in iron-catalysed coupling reactions for the construction of the C(sp2)-C(sp2) bond.

The advancement of transition-metal-catalyzed coupling reactions has been demonstrated as a highly effective strategy for the formation of carbon-carbon bonds, which serve as the fundamental basis for organic synthetic chemistry. Given that iron represents one of the most economical and ecologically sustainable metallic elements available, the exploration and enhancement of iron-catalysed coupling reactions have garnered increasing interest within the scientific community. In recent years, numerous iron-catalysed reactions have been reported, showcasing their efficacy in establishing C-C bonds. In this minireview, we present a systematic analysis of C(sp2)-C(sp2) bond formation via iron-catalysed coupling reactions as documented in the extant literature.

Genome-wide association study reveals novel SNPs and genes in Gossypium hirsutum underlying Aphis gossypii resistance.

KEY MESSAGE: A. gossypii resistance showed great variability in G. hirsutum varieties. One hundred and seventy-six SNPs associated with A. gossypii resistance were identified using GWAS. Four candidate resistance genes were functionally validated. Aphis gossypii is an economically important sap-feeding pest and is widely distributed in the world's cotton-producing regions. Identification of cotton genotypes and developing cultivars with improved A. gossypii resistance (AGR) is essential and desirable for sustainable agriculture. In the present study, A. gossypii was offered no choice but to propagate on 200 Gossypium hirsutum accessions. A relative aphid reproduction index (RARI) was used to evaluate the AGR, which showed large variability in cotton accessions and was classified into 6 grades. A significantly positive correlation was found between AGR and Verticillium wilt resistance. A total of 176 SNPs significantly associated with the RARI were identified using GWAS. Of these, 21 SNPs could be repeatedly detected in three replicates. Cleaved amplified polymorphic sequence, a restriction digestion-based genotyping assay, was developed using SNP1 with the highest observed -log10(P-value). Four genes within the 650 kb region of SNP1 were further identified, including GhRem (remorin-like), GhLAF1 (long after far-red light 1), GhCFIm25 (pre-mRNA cleavage factor Im 25 kDa subunit) and GhPMEI (plant invertase/pectin methylesterase inhibitor superfamily protein). The aphid infection could induce their expression and showed a significant difference between resistant and susceptible cotton varieties. Silencing of GhRem, GhLAF1 or GhCFIm25 could significantly increase aphid reproduction on cotton seedlings. Silencing of GhRem significantly reduced callose deposition, which is reasonably believed to be the cause for the higher AGR. Our results provide insights into understanding the genetic regulation of AGR in cotton and suggest candidate germplasms, SNPs and genes for developing cultivars with improved AGR.