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Underground coal gasification (UCG) as an alternative coal mining technology is attracting much attention. However, due to the high experimental cost of UCG, the evolution mechanism of coal seam should be deeply explored prior to the implement of experiments. By virtue of the great computational power of computers, the computational fluid dynamics (CFD) is able to simulate the production process of UCG at a relatively lower cost. The in-situ ignition and combustion of deep coal seam heated by 1 000 K flue gas is simulated and the changes of temperature, molar O2 fraction and porosity are analyzed by the CFD software, Fluent, developed by Ansys cor-poration. It is elucidated that pumping 1 000 K flue gas for 500 s is inadequate for coal seam ignition, while 1 000 s heating has been enough for coal seam ignition. On the internal surface of coal seam, the high temperature is accumulated in the 0−0.6 m coal seam near inlet. The maximum temperature before ignition is below inlet temperature of heating flue gas, 1 000 K, while the maximum temperature after ignition exceeds 1 000 K and reaches up to 1 250 K. Almost all O2 is consumed in the high-temperature zone, while less than 2% molar O2 fraction arrives at the internal surface of coal seam in other lower-temperature zones. The porosity rapidly increases in high-temperature zone and at 1000 s the porosity in the part of coal seam reaches up to 0.9. In the interior of coal seam, the thicker the coal seam is, the lower the temperature rises. The maximum temperature on 7 cm line is only 500 K at 1 000 s and 2 000 s, much lower than that on the internal surface of coal seam when it is heated for the same time. During 2 000 s ignition, little O2 penetrates 7 cm and 14 cm coal seam and the porosities of interior coal seam are all below 0.4. The low porosities are attributed to the low temperature and low molar O2 fraction. The simulation on temperature, molar O2 fraction and porosity may provide a reference for how to promote the reaction in the interior of coal seam.

Mounting evidence suggests that insect hormones associated with growth and development also participate in pathogen defense. We have discovered a previously undescribed midgut transcriptional control pathway that modulates the availability of 20-hydroxyecdysone (20E) in a worldwide insect pest (Plutella xylostella), allowing it to defeat the major virulence factor of an insect pathogen Bacillus thuringiensis (Bt). A reduction of the transcriptional inhibitor (PxDfd) increases the expression of a midgut microRNA (miR-8545), which in turn represses the expression of a newly identified ecdysteroid-degrading glucose dehydrogenase (PxGLD). Downregulation of PxGLD reduces 20E degradation to increase 20E titer and concurrently triggers a transcriptional negative feedback loop to mitigate 20E overproduction. The moderately elevated 20E titer in the midgut activates a MAPK signaling pathway to increase Bt tolerance/resistance. These findings deepen our understanding of the functions attributed to these classical insect hormones and help inform potential future strategies that can be employed to control insect pests.

Jasmonic acid is a crucial phytohormone that plays a pivotal role, serving as a regulator to balancing plant development and resistance. However, there are analogous and distinctive characteristics exhibited in JA biosynthesis, perception, and signal transduction pathways in both herbaceous and woody plants. Moreover, the majority of research subjects have predominantly focused on the function of JA in model or herbaceous plants. Consequently, there is a significant paucity of studies investigating JA regulation networks in woody plants, particularly concerning post-transcriptional regulatory events such as alternative splicing (AS). This review article aims to conduct a comprehensive summary of advancements that JA signals regulate plant development across various woody species, comparing the analogous features and regulatory differences to herbaceous counterparts. In addition, we summarized the involvement of AS events including splicing factor (SF) and transcripts in the JA regulatory network, highlighting the effectiveness of high-throughput proteogenomic methods. A better understanding of the JA signaling pathway in woody plants has pivotal implications for forestry production, including optimizing plant management and enhancing secondary metabolite production.

The investigation of iron under high pressure and temperatures is crucial to understand the Earth’s core structure and composition and the generation of magnetic fields. Here, we present new in situ XRD measurements for iron in an off-Hugoniot state by laser-driven ramp compression at pressure of 200–238 GPa. The lattice parameters for the hexagonal (hcp)-Fe phase and the c/a ratios were obtained to compare them with previous static and dynamical data, which provides the direct confirmation of such parameters via the different compression paths and strain rates. This work indicates that laser ramp compression can be utilized to provide crystal structure information and direct key information on the crystal structure of Fe at the ultrahigh pressure–temperature conditions relevant for planetology.

Abstract Polyunsaturated fatty acids (PUFAs) are essential nutrients for all living organisms. PUFA synthesis is mediated by Δ12 desaturases in plants and microorganisms, whereas animals usually obtain PUFAs through their diet. The whitefly Bemisia tabaci is an extremely polyphagous agricultural pest that feeds on phloem sap of many plants that do not always provide them with sufficient PUFAs. Here, a plant‐derived Δ12 desaturase gene family BtFAD2 is characterized in B. tabaci and it shows that the BtFAD2‐9 gene enables the pest to synthesize PUFAs, thereby significantly enhancing its fecundity. The role of BtFAD2‐9 in reproduction is further confirmed by transferring the gene to Drosophila melanogaster, which also increases the fruit fly's reproduction. These findings reveal an extraordinary evolutionary scenario whereby a phytophagous insect acquired a family of plant genes that enables it to synthesize essential nutrients, thereby lessening its nutritional dependency and allowing it to feed and reproduce on many host plants.

Abstract Bioinsecticides and transgenic crops based on the bacterial pathogen Bacillus thuringiensis (Bt) can effectively control diverse agricultural insect pests, nevertheless, the evolution of resistance without obvious fitness costs has seriously eroded the sustainable use of these Bt products. Recently, it has been discovered that an increased titer of juvenile hormone (JH) favors an insect host (Plutella xylostella) to enhance fitness whilst resisting the Bt pathogen, however, the underlying regulatory mechanisms of the increased JH titer are obscure. Here, the involvement of N6‐methyladenosine (m6A) RNA modification in modulating the availability of JH in this process is defined. Specifically, it is found that two m6A methyltransferase subunit genes, PxMettl3 and PxMettl14, repress the expression of a key JH‐degrading enzyme JH esterase (JHE) to induce an increased JH titer, mitigating the fitness costs associated with a robust defense against the Bt pathogen. This study identifies an as‐yet uncharacterized m6A‐mediated epigenetic regulator of insect hormones for maintaining fitness during pathogen defense and unveils an emerging Bt resistance‐related m6A methylation atlas in insects, which further expands the functional landscape of m6A modification and showcases the pivotal role of epigenetic regulation in host‐pathogen interactions.

The bean flower thrip Megalurothrips usitatus (Bagnall) is a severe pest on cowpeas and causes a 20–30% reduction in cowpeas in Hainan, China, with even complete crop failure in severe cases. Spinetoram is currently the most important pesticide against M. usitatus in cowpea production. In the main producing areas of cowpeas in Hainan, however, the efficacy of spinetoram against M. usitatus is not well known. In the present study, we employed the maximum dose bioassay to evaluate the efficacy of the mortality rates of adult thrips at F0 in spinetoram, freshly collected from 212 field populations of M. usitatus collected from 20 villages in the Yazhou District of Hainan. Our results showed that the mortality rates of these thrip populations exposed to spinetoram were from 3.31% to 100%. Among them, the mortality rates of 66.98% (142/212) of the populations exceeded 80%, while that of 33.96% (72/212) of the populations surpassed 90%. Only a small proportion of 0.47% (1/212) the populations exhibited a mortality rate below 10%, and 4.72% (10/212) displayed rates below 50%. Furthermore, significant differences were also observed in the mortality rates of thrips among different villages. Taken together, the maximum dosage bioassay method is a rapid and easily implemented approach providing valuable insights into the field efficacy of insecticides and offers guidance in determining the optimal dosage required in the field. Spinetoram is still effective against M. usitatus in the main producing areas of cowpeas in Hainan, but caution should be exercised in its combined use with other methods to reduce potential resistance.

Tomato Prosystemin (ProSys), the precursor of Systemin, a small peptidic hormone, is produced at very low concentration in unchallenged plants, while its expression greatly increases in response to several different stressors triggering an array of defence responses. The molecular mechanisms that underpin such a wide array of defence barriers are not fully understood and are likely correlated with the intrinsically disordered (ID) structure of the protein. ID proteins interact with different protein partners forming complexes involved in the modulation of different biological mechanisms. Here we describe the ProSys-protein network that shed light on the molecular mechanisms underpinning ProSys associated defence responses. Three different approaches were used. In silico prediction resulted in 98 direct interactors, most clustering in phytohormone biosynthesis, transcription factors and signal transduction gene classes. The network shows the central role of ProSys during defence responses, that reflects its role as central hub. In vitro ProSys interactors, identified by Affinity Purification-Mass Spectrometry (AP-MS), revealed over three hundred protein partners, while Bimolecular Fluorescent Complementation (BiFC) experiments validated in vivo some interactors predicted in silico and in vitro. Our results demonstrate that ProSys interacts with several proteins and reveal new key molecular events in the ProSys-dependent defence response of tomato plant.

Understanding the mechanism of detoxification initiation in arthropods after pesticide exposure is crucial. Although the identity of transcription factors that induce and regulate the expression of detoxification genes in response to pesticides is beginning to emerge, whether transcription factors directly interact with xenobiotics is unclear. The findings of this study revealed that a nuclear hormone receptor, Tetranychus cinnabarinus hormone receptor (HR) TcHR96h, regulates the overexpression of the detoxification gene TcGSTm02, which is involved in cyflumetofen resistance. The nuclear translocation of TcHR96h increased after cyflumetofen exposure, suggesting direct binding with cyflumetofen. The direct binding of TcHR96h and cyflumetofen was supported by several independent proteomic assays that quantify interactions with small molecules. Together, this study proposes a model for the initiation of xenobiotic detoxification in a polyphagous agricultural pest. These insights not only provide a better understanding of the mechanisms of xenobiotic detoxification and metabolism in arthropods, but also are crucial in understanding adaptation in polyphagous herbivores.

Measurement(s) Metabolite profiling of Arabidopsis mutants of enzymes of lower glycolysis Technology Type(s) Gas chromatography–mass spectrometry Factor Type(s) Metabolite profiling of lower glycolysis Sample Characteristic - Organism Arabidopsis mutants of enzymes of lower glycolysis Sample Characteristic - Environment plant grow under 8 h light (22 °C)/16 h dark (18 °C) in growth chamber at a light intensity of 120–150 μmol m-2 s-1 Sample Characteristic - Location 2Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany

Plutella xylostella endures Bt toxins with no performance costs. This study reveals how, depending on the presence of the toxin, this insect modifies MAPK phosphorylation to modulate the transcription factor FTZ-F1 binding, to up- or down- regulate Bt receptors or non-receptor (resistant) paralogs.

Abstract Background Biopesticides and transgenic crops based on Bacillus thuringiensis (Bt) toxins are extensively used to control insect pests, but the rapid evolution of insect resistance seriously threatens their effectiveness. Bt resistance is often polygenic and complex. Mutations that confer resistance occur in midgut proteins that act as cell surface receptors for the toxin, and it is thought they facilitate its assembly as a membrane-damaging pore. However, the mechanistic details of the action of Bt toxins remain controversial. Results We have examined the contribution of two paralogous ABC transporters and two aminopeptidases N to Bt Cry1Ac toxicity in the diamondback moth, Plutella xylostella, using CRISPR/Cas9 to generate a series of homozygous polygenic knockout strains. A double-gene knockout strain, in which the two paralogous ABC transporters ABCC2 and ABCC3 were deleted, exhibited 4482-fold resistance to Cry1A toxin, significantly greater than that previously reported for single-gene knockouts and confirming the mutual functional redundancy of these ABC transporters in acting as toxin receptors in P. xylostella. A double-gene knockout strain in which APN1 and APN3a were deleted exhibited 1425-fold resistance to Cry1Ac toxin, providing the most direct evidence to date for these APN proteins acting as Cry1Ac toxin receptors, while also indicating their functional redundancy. Genetic crosses of the two double-gene knockouts yielded a hybrid strain in which all four receptor genes were deleted and this resulted in a > 34,000-fold resistance, indicating that while both types of receptor need to be present for the toxin to be fully effective, there is a level of functional redundancy between them. The highly resistant quadruple knockout strain was less fit than wild-type moths, but no fitness cost was detected in the double knockout strains. Conclusion Our results provide direct evidence that APN1 and APN3a are important for Cry1Ac toxicity. They support our overarching hypothesis of a versatile mode of action of Bt toxins, which can compensate for the absence of individual receptors, and are consistent with an interplay among diverse midgut receptors in the toxins’ mechanism of action in a super pest.

Potassium-solubilizing bacteria are an important microbial group that play a critical role in releasing mineral potassium from potassium-containing minerals, e.g., potassium feldspar. Their application may reduce eutrophication caused by overused potassium fertilizers and facilitate plants to utilize environmental potassium. In this study, a high-efficiency potassium-solubilizing bacterium, named NK851, was isolated from the Astragalus sinicus rhizosphere soil. This bacterium can grow in the medium with potassium feldspar as the sole potassium source, releasing 157 mg/L and 222 mg/L potassium after 3 days and 5 days of incubation, respectively. 16S rDNA sequencing and cluster analysis showed that this strain belongs to Priestia megaterium. Genome sequencing further revealed that this strain has a genome length of 5,305,142 bp, encoding 5473 genes. Among them, abundant genes are related to potassium decomposition and utilization, e.g., the genes involved in adherence to mineral potassium, potassium release, and intracellular trafficking. Moreover, the strong potassium-releasing capacity of NK851 is not attributed to the acidic pH but is attributed to the extracellular potassium feldspar-binding proteins, such as the elongation factor TU and the enolase that contains potassium feldspar-binding cavities. This study provides new information for exploration of the bacterium-mediated potassium solubilization mechanisms.

The fruitless (fru) gene is a key factor in controlling sexual behavior in insects. The homolog of fru has been identified in most insect species and exhibits conservation in the transcript architecture and regulation of male sexual behavior. However, the structure of fru transcripts in Hemiptera remains unknown. Here, we identified and characterized two fru transcripts in Bemisia tabaci, named fru-a and fru-b. fru-a contained a 1263 bp open reading frame (ORF) encoding for 420 amino acids, while fru-b contained a 1143 bp ORF encoding for 380 amino acids. These two proteins start with the same BTB domain and end with two different zinc finger domains, belonging to ZnA and ZnG, respectively. The expression of fru-a and fru-b differed significantly between females and males, and both were expressed at lower levels in males. We demonstrated the presence of multiple TRA/TRA-2 binding sites and alternative splicing in fru-a and fru-b. Moreover, the RNAi result provided evidence that transformer regulates the expression of fru-a and fru-b. These results promote the study of the sex determination cascade in B. tabaci and lay the foundation for the study of sexual behavior in this insect.

In order to accurately evaluate the strength and fatigue characteristics of the double arc planetary gear transmission system in actual work，the three-dimensional geometric model of the double-arc planetary gear transmission system is established，by using HyperMesh a high-quality hexahedral mesh is obtained，combining with Ansys a finite element model is established and the transient dynamic analysis is carried out，the change curve of equivalent stress and contact pressure during the movement of the transmission system are obtained. At the same time，the fatigue life analysis is carried out based on the finite element model using Fatigue Tool. The results show that the stress of the transmission system is concentrated on the meshing end surface of the planetary gear and the sun gear during the meshing process. The contact stress changes smoothly，and the entire structure has a small impact. Fatigue damage is concentrated on the meshing position of the planetary gear and the sun gear.

Bradysia odoriphaga (Diptera: Sciaridae) is a serious pest of Chinese chives cultivated in China. Chemosensory proteins (CSPs) are important components of insect olfactory systems that capture and bind environmental semiochemicals which are then transported to olfactory receptors. Despite their importance, the mechanism of olfaction and related behavioral processes in B. odoriphaga have not been characterized. Here, we found that BodoCSP4 has an important olfactory function. RT-qPCR indicated that BodoCSP4 expression was highest in the heads (antennae removed) of adult males, followed by the antennae of adult males. Competitive binding assays with 33 ligands indicated that BodoCSP4 binds well with methyl allyl disulfide, diallyl disulfide, and n-heptadecane; the corresponding dissolution constants (Ki) were as high as 5.71, 5.71, and 6.85 μM, respectively. 3D-structural and molecular docking indicated that BodoCSP4 has five α-helices and surrounds the ligand with certain hydrophobic residues including Leu60, Leu63, Leu64, Ala67, Val28, Ile30, Ile33, Leu34, and Val86, suggesting these residues help BodoCSP4 bind to ligands. Silencing of BodoCSP4 significantly decreased the attraction of B. odoriphaga males to diallyl disulfide and n-heptadecane but not to methyl allyl disulfide in Y-tube olfaction assays. These results increase our understanding of how BodoCSP4 contributes to host and female localization by B. odoriphaga males.

BackgroundExtrauterine growth restriction (EUGR) in preterm birth infants could have long-term adverse impacts on health. Less is known about the gut microbiota regarding its establishment in early life and its role in long-term growth in preterm birth infants.MethodsA prospective, longitudinal observational study was conducted with 67 preterm infants in a level III neonatal intensive care unit. Clinical information was obtained from medical records, and fecal samples were collected weekly during hospitalization and processed for 16S rRNA gene sequencing.ResultsThe bacterial profiles from the weekly sampling of preterm infants demonstrated that the early-life gut microbiota was clustered into the following four stages in chronological order: stage 1: 0–4 days, stage 2: 1–2 weeks, stage 3: 3–7 weeks, and stage 4: 8–10 weeks. The development of gut microbiota showed latency at stage 4 in EUGR infants compared with that in non-EUGR infants, which resulted from their consistently high level of facultative anaerobes, including Enterobacteriaceae and Staphylococcus, and lack of obligate anaerobes, including Clostridium and Veillonella. In the 2-year follow-up, infants with a high level of obligate anaerobes-to-facultative anaerobes ratio at stage 4 had a lower risk of long-term growth restriction at the margin of statistical significance.ConclusionThe results of this study indicate that the development of gut microbiota in the early life of EUGR infants is delayed compared with that of non-EUGR infants. The obligate-to-facultative anaerobes ratio could be an indicator of the maturity of gut microbiota development and associated with the risk of long-term growth restriction in preterm infants.

Multi-omics data sets are increasingly being used for the interpretation of cellular processes in response to environmental cues. Especially, the posttranslational modification of proteins by phosphorylation is an important regulatory process affecting protein activity and/or localization, which, in turn, can have effects on metabolic processes and metabolite levels. Despite this importance, relationships between protein phosphorylation status and metabolite abundance remain largely underexplored. Here, we used a phosphoproteomics–metabolomics data set collected at the end of day and night in shoots and roots of Arabidopsis to propose regulatory relationships between protein phosphorylation and accumulation or allocation of metabolites. For this purpose, we introduced a novel, robust co-expression measure suited to the structure of our data sets, and we used this measure to construct metabolite-phosphopeptide networks. These networks were compared between wild type and plants with perturbations in key processes of sugar metabolism, namely, sucrose export (sweet11/12 mutant) and starch synthesis (pgm mutant). The phosphopeptide–metabolite network turned out to be highly sensitive to perturbations in sugar metabolism. Specifically, KING1, the regulatory subunit of SnRK1, was identified as a primary candidate connecting protein phosphorylation status with metabolism. We additionally identified strong changes in the fatty acid network of the sweet11/12 mutant, potentially resulting from a combination of fatty acid signaling and metabolic overflow reactions in response to high internal sucrose concentrations. Our results further suggest novel protein-metabolite relationships as candidates for future targeted research.

The whitefly, Bemisia tabaci MED (Hemiptera: Aleyrodidae), is an omnivorous agricultural pest, which causes huge economic losses to agriculture and is highly resistant to many pesticides. The overexpression of cytochrome P450 may play an important role in host adaptation and insecticide resistance in B. tabaci MED. Therefore, the present study systematically analyzed the cytochrome P450 gene family at the genome-wide level to understand its function in B. tabaci MED. Our analysis identified 58 cytochrome P450 genes in B. tabaci MED, among which 24 were novel. Phylogenetic analysis revealed broad functional and species-specific diversification in B. tabaci MED P450, suggesting the role of multiple P450 genes in detoxifying. Reverse transcription-real time quantitative PCR (RT-qPCR) showed that CYP4CS2, CYP4CS5, CYP4CS6, CYP4CS8, CYP6DW4, CYP6DW5, CYP6DW6, CYP6DZ8, and CYP6EN1 genes increased significantly after two days of exposure to imidacloprid. Interestingly, all nine genes belonged to the CYP4 and CYP6 families. A decrease in the expression of five genes (CYP6DW4, CYP6DW5, CYP6DW6, CYP6DZ8, and CYP4CS6) via RNA interference (RNAi) resulted in a significant increase in the mortalities of whiteflies when exposed to imidacloprid. These results indicate that the overexpression of the P450 genes may play an essential role in imidacloprid tolerance of B. tabaci MED. Thus, the present study provides basic information on P450 genes in B. tabaci MED, which will further help elucidate the insecticide resistance mechanism in the agricultural pest whitefly.

The sweetpotato whitefly, Bemisia tabaci species complex, comprises at least 44 morphologically indistinguishable cryptic species, whose endosymbiont infection patterns often varied at the spatial and temporal dimension. However, the effects of ecological factors (e.g., climatic or geographical factors) on the distribution of whitefly and the infection frequencies of their endosymbionts have not been fully elucidated. We, here, analyzed the associations between ecological factors and the distribution of whitefly and their three facultative endosymbionts (Candidatus Cardinium hertigii, Candidatus Hamiltonella defensa, and Rickettsia sp.) by screening 665 individuals collected from 29 geographical localities across China. The study identified eight B. tabaci species via mitochondrial cytochrome oxidase I (mtCOI) gene sequence alignment: two invasive species, MED (66.9%) and MEAM1 (12.2%), and six native cryptic species (20.9%), which differed in distribution patterns, ecological niches, and high suitability areas. The infection frequencies of the three endosymbionts in different cryptic species were distinct and multiple infections were relatively common in B. tabaci MED populations. Furthermore, the annual mean temperature positively affected Cardinium sp. and Rickettsia sp. infection frequencies in B. tabaci MED but negatively affected the quantitative distribution of B. tabaci MED, which indicates that Cardinium sp. and Rickettsia sp. maybe play a crucial role in the thermotolerance of B. tabaci MED, although the host whitefly per se exhibits no resistance to high temperature. Our findings revealed the complex effects of ecological factors on the expansion of the invasive whitefly.

Insect vectors and insect-borne plant viruses seriously endanger the safety of agricultural production. An insecticide is one of the main methods to prevent insect-borne virus transmission. However, the curious relationship between the resistance of insect vectors and arboviruses has been less studied. In this study, the effect of Tomato chlorosis virus (ToCV) on the insecticide resistance of Bemisia tabaci MED was studied. It was found that the detoxification cytochrome P450, glutathione S-transferase, and carboxylesterase-related genes in ToCV-infected B. tabaci were upregulated. The activity of the three detoxification enzymes all increased at the same time, after 48 h of virus acquisition, with the activity of carboxylesterase being the most pronounced. It was found that cytochrome P450 and glutathione S-transferase activity was the least. ToCV led to the reduced sensitivity of B. tabaci MED to pyrethroids and flupyradifurone. Therefore, it was proven that the insect-borne plant virus ToCV shows the possibility of enhancing insect-borne insecticide resistance.

The benefits of biopesticides and transgenic crops based on the insecticidal Cry-toxins from Bacillus thuringiensis (Bt) are considerably threatened by insect resistance evolution, thus, deciphering the molecular mechanisms underlying insect resistance to Bt products is of great significance to their sustainable utilization. Previously, we have demonstrated that the down-regulation of PxmALP in a strain of Plutella xylostella (L.) highly resistant to the Bt Cry1Ac toxin was due to a hormone-activated MAPK signaling pathway and contributed to the resistance phenotype. However, the underlying transcriptional regulatory mechanism remains enigmatic. Here, we report that the PxGATAd transcription factor (TF) is responsible for the differential expression of PxmALP observed between the Cry1Ac susceptible and resistant strains. We identified that PxGATAd directly activates PxmALP expression via interacting with a non-canonical but specific GATA-like cis-response element (CRE) located in the PxmALP promoter region. A six-nucleotide insertion mutation in this cis-acting element of the PxmALP promoter from the resistant strain resulted in repression of transcriptional activity, affecting the regulatory performance of PxGATAd. Furthermore, silencing of PxGATAd in susceptible larvae reduced the expression of PxmALP and susceptibility to Cry1Ac toxin. Suppressing PxMAP4K4 expression in the resistant larvae transiently recovered both the expression of PxGATAd and PxmALP, indicating that the PxGATAd is a positive responsive factor involved in the activation of PxmALP promoter and negatively regulated by the MAPK signaling pathway. Overall, this study deciphers an intricate regulatory mechanism of PxmALP gene expression and highlights the concurrent involvement of both trans-regulatory factors and cis-acting elements in Cry1Ac resistance development in lepidopteran insects.

Protein-protein interactions are thought to channel substrates between consecutive enzymes during glycolysis. Here the authors show that Arabidopsis phosphoglycerate mutase and enolase can form a substrate-channelling metabolon and also play a moonlighting role in promoting colocalization of chloroplasts and mitochondria.

Wild teas are considered as valuable resource for studying domestication and breeding. Here, Zhang et al. report genome of wild tea DASZ and transcriptome of 217 accessions, which clarify pedigree of Chinese tea cultivars and show tea may not have undergone long-term artificial directional selection on flavor-related metabolites.

Bacillus thuringiensis (Bt) is an important bioinsecticide, but high-level resistance has been rapidly evolving in agricultural pests. Here, Guo et al. show that the MAPK cascade can be activated by enhanced upstream insect hormone signals to counter Bt virulence in the diamondback moth.

Abstract Background While virus-vector-host interactions have been a major focus of both basic and applied ecological research, little is known about how different levels of plant defense interact with prior herbivory to affect these relationships. We used genetically-modified strains of tomato (Solanum lycopersicum) varying in the jasmonic acid (JA) plant defense pathways to explore how plant defense and prior herbivory affects a plant virus (tomato yellow leaf curl virus, ‘TYLCV’), its vector (the whitefly Bemisia tabaci MED), and the host. Results Virus-free MED preferred low-JA over high-JA plants and had lower fitness on high-JA plants. Viruliferous MED preferred low-JA plants but their survival was unaffected by JA levels. While virus-free MED did not lower plant JA levels, viruliferous MED decreased both JA levels and the expression of JA-related genes. Infestation by viruliferous MED reduced plant JA levels. In preference tests, neither virus-free nor viruliferous MED discriminated among JA-varying plants previously exposed to virus-free MED. However, both virus-free and viruliferous MED preferred low-JA plant genotypes when choosing between plants that had both been previously exposed to viruliferous MED. The enhanced preference for low-JA genotypes appears linked to the volatile compound neophytadiene, which was found only in whitefly-infested plants and at concentrations inversely related to plant JA levels. Conclusions Our findings illustrate how plant defense can interact with prior herbivory to affect both a plant virus and its whitefly vector, and confirm the induction of neophytadiene by MED. The apparent attraction of MED to neophytadiene may prove useful in pest detection and management.

Hydrogen-rich superhydrides are promising high-temperature superconductors which have been observed only at pressures above 170 GPa. Here the authors show that CeH9 can be synthesized at 80-100 GPa with laser heating, and is characterized by a clathrate structure with a dense 3-dimensional atomic hydrogen sublattice.

Polycyclic aromatic hydrocarbon (PAH) pollution in the soil of industrial legacy sites is a prominent problem when reusing urban land. To estimate the potential risks of PAHs, this study investigated 16 priority PAHs in the soil at different depths in a typical decommissioned industrial site in Tianjin. PAH concentrations were determined via gas chromatography-(tandem) quadrupole mass spectrometry. Incremental lifetime cancer risk (ILCR) assessment was applied to assess the potential risks to the population after land reconstruction. The total concentrations of PAHs in the soil at different depths ranged from 38.3 ng·g−1 to 1782.5 ng·g−1, which were below the risk control standard for soil contamination of development land (GB 36600-2018). Low-ring (two-three ring) PAHs exhibit a dominant component, and the variations in PAH compositions were closely related to the former production units and soil properties. Compared to silty clay layers, PAHs tended to accumulate in the permeable miscellaneous fill layers. Incremental lifetime cancer risk assessment values associated with different exposure pathways for children, adolescents, and adults were calculated. The results showed potential carcinogenic risks for people of varying ages in this area, but they were still acceptable. In general, this legacy site can meet the demands of sustainable land development.

Host-pathogen interactions are central components of ecological networks where the MAPK signaling pathways act as central hubs of these complex interactions. We have previously shown that an insect hormone modulated MAPK signaling cascade participates as a general switch to trans-regulate differential expression of diverse midgut genes in the diamondback moth, Plutella xylostella (L.) to cope with the insecticidal action of Cry1Ac toxin, produced by the entomopathogenic bacterium Bacillus thuringiensis (Bt). The relationship between topology and functions of this four-tiered phosphorylation signaling cascade, however, is an uncharted territory. Here, we carried out a genome-wide characterization of all the MAPK orthologs in P. xylostella to define their phylogenetic relationships and to confirm their evolutionary conserved modules. Results from quantitative phosphoproteomic analyses, combined with functional validations studies using specific inhibitors and dsRNAs lead us to establish a MAPK "road map", where p38 and ERK MAPK signaling pathways, in large part, mount a resistance response against Bt toxins through regulating the differential expression of multiple Cry toxin receptors and their non-receptor paralogs in P. xylostella midgut. These data not only advance our understanding of host-pathogen interactions in agricultural pests, but also inform the future development of biopesticides that could suppress Cry resistance phenotypes.

The real-time speed estimation of induction motors (IMs) is important for the motors’ state monitoring and control. The utilization of rotor slot harmonics (RSHs) due to the inherent cogging effect is regarded as a promising way to realize the speed estimation of IMs. The key to the RSH-based speed estimation method is how to accurately and quickly identify the frequency of an RSH signal. However, as the RSH signal always consists of two side-frequency components that are adjacent to each other, it is actually improper to directly use the conventional phase-locked loop (PLL) method designed for single-frequency tracking. Furthermore, the form of the two side components in the frequency domain also leads to a significant amplitude fluctuation in the time-domain waveform of RSHs, thus resulting in the obvious frequency tracking errors of the conventional PLL method. In this paper, we proposed an improved PLL through harmonic separation to further improve the performance of the RSH-based speed estimation method of multiphase IMs, so that the dynamic tracking errors of PLL due to the reasons mentioned above can be significantly reduced. Simulations and experiments in a wide speed range were also performed, with their results presented as verifications of the proposed method.

The accurate extraction and analysis of slot harmonics caused by slotting in an induction motor are important for the motor’s performance evaluation and state monitoring. However, the frequency distribution of rotor slot harmonics (RSHs) varies along with the operating states of the motor, such as motor speed and slip ratio, and the voltage and current signals of the motor only contain small-amplitude RSHs compared with other harmonics; both make it difficult to extract and analyze the RSHs accurately online. While offline extraction and filters with constant parameters are mainly utilized in available works, a novel adaptive extraction method for RSHs in a multiphase induction motor is proposed here to realize online RSH extraction under different speed and load conditions. In this paper, the RSHs in the multiphase induction motors are firstly modeled by using the magnetic potential permeability method, and the influence of a skewed rotor on RSHs is analyzed through a multisection method. Then, an adaptive extraction method of RSHs is proposed, which can effectively realize the online processing of RSHs of stator current. Finally, the experimental platform of a nine-phase induction motor has been used to verify the effectiveness of the proposed method under different speeds and load conditions, with a relative error of less than 1% in identifying the RSH frequency distribution.

Fruit flavor is defined as the perception of the food by the olfactory and gustatory systems, and is one of the main determinants of fruit quality. Tomato flavor is largely determined by the balance of sugars, acids and volatile compounds. Several genes controlling the levels of these metabolites in tomato fruit have been cloned, including LIN5, ALMT9, AAT1, CXE1, and LoxC. The aim of this study was to identify any association of these genes with trait variation and to describe the genetic diversity at these loci in the red-fruited tomato clade comprised of the wild ancestor Solanum pimpinellifolium, the semi-domesticated species Solanum lycopersicum cerasiforme and early domesticated Solanum lycopersicum. High genetic diversity was observed at these five loci, including novel haplotypes that could be incorporated into breeding programs to improve fruit quality of modern tomatoes. Using newly available high-quality genome assemblies, we assayed each gene for potential functional causative polymorphisms and resolved a duplication at the LoxC locus found in several wild and semi-domesticated accessions which caused lower accumulation of lipid derived volatiles. In addition, we explored gene expression of the five genes in nine phylogenetically diverse tomato accessions. In general, the expression patterns of these genes increased during fruit ripening but diverged between accessions without clear relationship between expression and metabolite levels.

Photosynthesis in chloroplasts during the day and mitochondrial respiration during the night execute nearly opposing reactions that are coordinated with the internal cellular status and the external conditions. Here, we describe a mechanism by which the Arabidopsis clock component TIMING OF CAB EXPRESSION1 (TOC1) contributes to the diurnal regulation of metabolism. Proper expression of TOC1 is important for sustaining cellular energy and for the diel and circadian oscillations of sugars, amino acids and tricarboxylic acid (TCA) cycle intermediates. TOC1 binds to the promoter of the TCA-related gene FUMARASE 2 to repress its expression at night, which results in decreased fumarate accumulation in TOC1 over-expressing plants and increased in toc1-2 mutant. Genetic interaction studies confirmed that over-expression of FUMARASE 2 in TOC1 over-expressing plants alleviates the molecular and physiological energy-deprivation phenotypes of TOC1 over-expressing plants. Thus, we propose that the tandem TOC1-FUMARASE 2 is one of the mechanisms that contribute to the regulation of plant metabolism during the day and night.

A magnetic metal–organic framework nanocomposite (magnetic MIL-68(Ga)) was synthesized through a “one pot” reaction and used for heavy metal ion removal. The morphology and elemental properties of the nanocomposite were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), as well as zeta potential. Moreover, the factors affecting the adsorption capacity of the nanocomposite, including time, pH, metal ion type and concentration, were studied. It was found that the adsorption capacity of magnetic MIL-68(Ga) for Pb2+ and Cu2+ was 220 and 130 mg/g, respectively. Notably, the magnetic adsorbents could be separated easily using an external magnetic field, regenerated by ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) and reused three times, in favor of practical application. This study provides a reference for the rapid separation and purification of heavy metal ions from wastewater.

Deoxythymidine triphosphate (dTTP) is essential for DNA synthesis and cellular growth in all organisms. Here, genetic capacity analysis of the pyrimidine pathway in insects and their symbionts revealed that dTTP is a kind of metabolic input in several host insect/obligate symbiont symbiosis systems, including Bemisia tabaci MED/Candidatus Portiera aleyrodidarum (hereafter Portiera). As such, the roles of dTTP on both sides of the symbiosis system were investigated in B. tabaci MED/Portiera. Dietary RNA interference (RNAi) showed that suppressing dTTP production significantly reduced the density of Portiera, significantly repressed the expression levels of horizontally transferred essential amino acid (EAA) synthesis-related genes, and significantly decreased the reproduction of B. tabaci MED adults as well as the hatchability of their offspring. Our results revealed the regulatory role of dTTP in B. tabaci MED/Portiera and showed that dTTP synthesis-related genes could be potential targets for controlling B. tabaci as well as other sucking pests.

Metabolons are transient multi-protein complexes of sequential enzymes that mediate substrate channeling. They differ from multi-enzyme complexes in that they are dynamic, rather than permanent, and as such have considerably lower dissociation constants. Despite the fact that a huge number of metabolons have been suggested to exist in plants, most of these claims are erroneous as only a handful of these have been proven to channel metabolites. We believe that physical protein–protein interactions between consecutive enzymes of a pathway should rather be called enzyme–enzyme assemblies. In this review, we describe how metabolons are generally assembled by transient interactions and held together by both structural elements and non-covalent interactions. Experimental evidence for their existence comes from protein–protein interaction studies, which indicate that the enzymes physically interact, and direct substrate channeling measurements, which indicate that they functionally interact. Unfortunately, advances in cell biology and proteomics have far outstripped those in classical enzymology and flux measurements, rendering most reports reliant purely on interactome studies. Recent developments in co-fractionation mass spectrometry will likely further exacerbate this bias. Given this, only dynamic enzyme–enzyme assemblies in which both physical and functional interactions have been demonstrated should be termed metabolons. We discuss the level of evidence for the manifold plant pathways that have been postulated to contain metabolons and then list examples in both primary and secondary metabolism for which strong evidence has been provided to support these claims. In doing so, we pay particular attention to experimental and mathematical approaches to study metabolons as well as complexities that arise in attempting to follow them. Finally, we discuss perspectives for improving our understanding of these fascinating but enigmatic interactions.

The superfamily cytochrome P450s is involved in the evolution of insecticide resistance. However, whether CYP4G68, a differentially expressed gene identified from our transcriptomics analysis, confers resistance to the world’s heavily used insecticide class neonicotinoids is unknown. Hence, we explored the role of CYP4G68 in conferring imidacloprid and thiamethoxam resistance in Bemisia tabaci. The species B. tabaci MED developed low-to-high resistance to imidacloprid and thiamethoxam. Exposure to imidacloprid and thiamethoxam significantly increased the expression of CYP4G68. Moreover, quantitative real-time PCR analysis demonstrated that CYP4G68 was remarkably overexpressed in imidacloprid-resistant and thiamethoxam-resistant strains compared to susceptible strains. Further correlation analysis showed that CYP4G68 expression was significantly positively correlated with the associated resistance level in various strains of B. tabaci. These results suggest that the enhanced expression of CYP4G68 appears to mediate imidacloprid and thiamethoxam resistance in B. tabaci. Additionally, silencing CYP4G68 via RNA interference strongly increased the susceptibility of B. tabaci MED to imidacloprid and thiamethoxam. Collectively, this work revealed that CYP4G68 plays a vital role in imidacloprid and thiamethoxam resistance in B. tabaci MED. These findings will not only advance our understanding of the role of P450s in insecticide resistance but also provide a great potential target for the sustainable control of destructive insect pests such as whiteflies.

The olfactory system serves a vital role in the evolution and survival of insects, being involved in behaviors such as host seeking, foraging, mating, and oviposition. Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are involved in the olfactory recognition process. In this study, BtabCSP11, a CSP11 gene from the whitefly Bemisia tabaci, was cloned and characterized. The open reading frame of BtabCSP11 encodes 136 amino acids, with four highly conserved cysteine residues. The temporal and spatial expression profiles showed that BtabCSP11 was highly expressed in the abdomens of B. tabaci females. Dietary RNA interference (RNAi)-based functional analysis showed substantially reduced fecundity in parthenogenetically reproduced females, suggesting a potential role of BtabCSP11 in B. tabaci reproduction. These combined results expand the function of CSPs beyond chemosensation.

The intersex (ix) gene acts in concert with doublesex (dsx) at the end of the sex determination hierarchy to control somatic sexual differentiation in Drosophila melanogaster. Here, we report the Drosophila ix homolog in Bemisia tabaci (Btix) with differential splicing events. Four isoforms were found in B. tabaci adults, including two sex-specific transcripts (BtixF and BtixM). Knockdown of Btix had no measurable effects on female morphological phenotypes but reduced the expression of the vitellogenin gene and resulted in the production of significantly fewer eggs, a lower eclosion rate, and a shorter body size of female progeny in comparison with control females. These results increase our understanding of the genes underlying sex determination in B. tabaci and reveal a potential target for RNA interference-based pest management.

The three-level (TL) AC/AC converter needs to control the output voltage as well as the voltage of flying capacitor, which makes the control circuit relatively complicated. At the same time, the ranges of the output voltage and load are limited because of the influence of the flying capacitor voltage correction on the duty cycle of the output voltage. For the applications of high-voltage and high-power conversion, a full-duty-cycle-regulated TL AC/AC converter with a self-following flying capacitor was proposed and studied, which adopts a small volume auxiliary transformer. The flying capacitor is directly supplied from the auxiliary transformer, can self-follow half of the input voltage, and does not need to be controlled by other control circuit. The proposed converter only needs to control its output voltage, which makes control strategy simple and easy to be realized. The output voltage can be regulated within the range of full-duty cycle. The capacity of an auxiliary transformer is very small, under ideal condition which only needs to supply the reactive load of the flying capacitor. The circuit operational principle was analyzed in detail, and a prototype was designed. With a simple control circuit, the experimental results were given and the full-duty-cycle regulation of the TL AC/AC converter was realized.

Abstract Background Sweetpotato whitefly, Bemisia tabaci MED/Q and MEAM1/B, are two economically important invasive species that cause considerable damages to agriculture crops through direct feeding and indirect vectoring of plant pathogens. Recently, a draft genome of B. tabaci MED/Q has been assembled. In this study, we focus on the genomic comparison between MED/Q and MEAM1/B, with a special interest in MED/Q’s genomic signatures that may contribute to the highly invasive nature of this emerging insect pest. Results The genomes of both species share similarity in syntenic blocks, but have significant divergence in the gene coding sequence. Expansion of cytochrome P450 monooxygenases and UDP glycosyltransferases in MED/Q and MEAM1/B genome is functionally validated for mediating insecticide resistance in MED/Q using in vivo RNAi. The amino acid biosynthesis pathways in MED/Q genome are partitioned among the host and endosymbiont genomes in a manner distinct from other hemipterans. Evidence of horizontal gene transfer to the host genome may explain their obligate relationship. Putative loss-of-function in the immune deficiency-signaling pathway due to the gene loss is a shared ancestral trait among hemipteran insects. Conclusions The expansion of detoxification genes families, such as P450s, may contribute to the development of insecticide resistance traits and a broad host range in MED/Q and MEAM1/B, and facilitate species’ invasions into intensively managed cropping systems. Numerical and compositional changes in multiple gene families (gene loss and gene gain) in the MED/Q genome sets a foundation for future hypothesis testing that will advance our understanding of adaptation, viral transmission, symbiosis, and plant-insect-pathogen tritrophic interactions.

Increasing evidence has revealed that the enzymes of several biological pathways assemble into larger supramolecular structures called super-complexes. Indeed, those such as association of the mitochondrial respiratory chain complexes play an essential role in respiratory activity and promote metabolic fitness. Dynamically assembled super-complexes are able to alternate between participating in large complexes and existing in a free state. However, the functional significance of the super-complexes is not entirely clear. It has been proposed that the organization of respiratory enzymes into super-complexes could reduce oxidative damage and increase metabolism efficiency. There are several protein complexes that have been revealed in the plant chloroplast, yet little research has been focused on the formation of super-complexes in this organelle. The photosystem I and light-harvesting complex I super-complex’s structure suggests that energy absorbed by light-harvesting complex I could be efficiently transferred to the PSI core by avoiding concentration quenching. Here, we will discuss in detail core complexes of photosystem I and II, the chloroplast ATPase the chloroplast electron transport chain, the Calvin–Benson cycle and a plastid localized purinosome. In addition, we will also describe the methods to identify these complexes.

The physical properties of basic minerals such as magnesium silicates, oxides, and silica at extreme conditions, up to 1000 s of GPa, are crucial to understand the behaviors of magma oceans and melting in Super-Earths discovered to data. Their sound velocity at the conditions relevant to the Super-Earth’s mantle is a key parameter for melting process in determining the physical and chemical evolution of planetary interiors. In this article, we used laser indirectly driven shock compression for quartz to document the sound velocity of quartz at pressures of 270 GPa to 870 GPa during lateral unloadings in a high-power laser facility in China. These measurements demonstrate and improve the technique proposed by Li et al. [PRL 120, 215703 (2018)] to determine the sound velocity. The results compare favorably to the SESAME EoS table and previous data. The Grüneisen parameter at extreme conditions was also calculated from sound velocity data. The data presented in our experiment also provide new information on sound velocity to support the dissociation and metallization for liquid quartz at extreme conditions.

Background/Aims: Radiation therapy is an important treatment for thoracic cancer; however, side effects accompanied with radiotherapy lead to limited tumor control and a decline in patient quality of life. Among these side effects, radiation-induced lung injury (RILI) is the most serious and common. Hence, an effective remedy for RILI is needed. Mesenchymal stromal cells (MSCs) are multipotent adult stem cells that have been demonstrated to be an effective treatment in some disease caused by tissue damage. However, unlike other injuries, RILI received limited therapeutic effects from implanted MSCs due to local hypoxia and extensive reactive oxygen species (ROS) in irradiated lungs. Since the poor survival of MSCs is primarily due to hypoxia and ROS generation, we hypothesize that persistent and adaptive hypoxia treatment induces enhanced resistance to hypoxic stress in implanted MSC. The aim of this study is to investigate whether persistent and adaptive hypoxia treatment of bmMSCs prior to their transplantation in injured mice enhanced survival and improved curative effects in RILI. Methods: Primary bmMSCs were obtained from the marrow of six-week-old male C57BL6/J mice and were cultured either under normoxic conditions (21% O2) or hypoxic conditions (2.5% O2). Mice were injected with normoxia/hypoxia MSCs after thoracic irradiation (20 Gy). The therapeutic effects of MSCs on RILI were assessed by pathological examinations that included H&E staining, Masson staining and α-SMA staining; meanwhile, inflammatory factors were measured using an ELISA. The morphology of MSCs in vitro was recorded using a microscope and identified by flow cytometry, cell viability was measured using the CCK-8 assay, the potential for proliferation was detected by the EdU assay, and ROS levels were measured using a ROS fluorogenic probe. In addition, HIF-1α and several survival pathway proteins (Akt, p-Akt, Caspase-3) were also detected by western blotting. Results: Implanted MSCs alleviated both early radiation-induced pneumonia and late pulmonary fibrosis. However, hypoxia MSCs displayed a more pronounced therapeutic effect compared to normoxia MSCs. Compared to normoxia MSCs, the hypoxia MSCs demonstrated greater cell viability, an enhanced proliferation potential, decreased ROS levels and increased resistance to hypoxia and ROS stress. In addition, hypoxia MSCs achieved higher activation levels of HIF-1α and Akt, and HIF-1α played a critical role in the development of resistance. Conclusion: Hypoxia enhances the therapeutic effect of mesenchymal stromal cells on radiation-induced lung injury by promoting MSC proliferation and improving their antioxidant ability, mediated by HIF-1α.

The belowground pest Bradysia odoriphaga (Diptera: Sciaridae) has a sophisticated and sensitive olfactory system to detect semiochemical signals from the surrounding environment. In particular, odorant-binding proteins (OBPs) are crucial in capturing and transporting these semiochemical signals across the sensilla lymph to the corresponding odorant receptors. In this study, we cloned a full-length cDNA sequence of BodoOBP8 from B. odoriphaga. Real-time PCR (qRT-PCR) analysis revealed that BodoOBP8 has the highest expression levels in males, with more pronounced expression in the male antennae than in other tissues. In this study, the recombinant protein BodoOBP8 was successfully expressed by a bacterial system to explore its function. Competitive binding assays with 33 host plant volatiles and one putative sex pheromone (n-heptadecane) revealed that purified BodoOBP8 strongly bound to two sulfur compounds (methyl allyl disulfide and diallyl disulfide) and to n-heptadecane; the corresponding dissolution constants (Ki) were 4.04, 6.73, and 4.04 μM, respectively. Molecular docking indicated that Ile96, Ile103, Ala107, and Leu111, located in the hydrophobic cavity of BodoOBP8, are the key residues mediating the interaction of BodoOBP8 with two sulfur compounds (methyl allyl disulfide and diallyl disulfide) and n-heptadecane. These results show that BodoOBP8 plays a role in the recognition of plant volatiles and sex pheromones, suggesting its application as a molecular target for the screening of B. odoriphaga attractants and repellents and facilitating a new mechanism of B. odoriphaga control.

The study of protein–protein interactions (PPIs) is fundamental in understanding the unique role of proteins within cells and their contribution to complex biological systems. While the toolkit to study PPIs has grown immensely in mammalian and unicellular eukaryote systems over recent years, application of these techniques in plants remains under-utilized. Affinity purification coupled to mass spectrometry (AP-MS) and proximity labeling coupled to mass spectrometry (PL-MS) are two powerful techniques that have significantly enhanced our understanding of PPIs. Relying on the specific binding properties of a protein to an immobilized ligand, AP is a fast, sensitive and targeted approach used to detect interactions between bait (protein of interest) and prey (interacting partners) under near-physiological conditions. Similarly, PL, which utilizes the close proximity of proteins to identify potential interacting partners, has the ability to detect transient or hydrophobic interactions under native conditions. Combined, these techniques have the potential to reveal an unprecedented spatial and temporal protein interaction network that better understands biological processes relevant to many fields of interest. In this review, we summarize the advantages and disadvantages of two increasingly common PPI determination techniques: AP-MS and PL-MS and discuss their important application to plant systems.

The molecular mechanisms of insect resistance to Cry toxins generated from the bacterium Bacillus thuringiensis (Bt) urgently need to be elucidated to enable the improvement and sustainability of Bt-based products. Although downregulation of the expression of midgut receptor genes is a pivotal mechanism of insect resistance to Bt Cry toxins, the underlying transcriptional regulation of these genes remains elusive. Herein, we unraveled the regulatory mechanism of the downregulation of the ABC transporter gene PxABCG1 (also called Pxwhite), a functional midgut receptor of the Bt Cry1Ac toxin in Plutella xylostella. The PxABCG1 promoters of Cry1Ac-susceptible and Cry1Ac-resistant strains were cloned and analyzed, and they showed clear differences in activity. Subsequently, a dual-luciferase reporter assay, a yeast one-hybrid (Y1H) assay, and RNA interference (RNAi) experiments demonstrated that a cis-mutation in a binding site of the Hox transcription factor Antennapedia (Antp) decreased the promoter activity of the resistant strain and eliminated the binding and regulation of Antp, thereby enhancing the resistance of P. xylostella to the Cry1Ac toxin. These results advance our knowledge of the roles of cis- and trans-regulatory variations in the regulation of midgut Cry receptor genes and the evolution of Bt resistance, contributing to a more complete understanding of the Bt resistance mechanism.

Abstract Background In recent years, two of the crinivirus, Tomato chlorosis virus (ToCV) and Cucurbit chlorotic yellows virus (CCYV) have gained increasing attention due to their rapid spread and devastating impacts on vegetable production worldwide. Both of these viruses are transmitted by the sweet potato whitefly, Bemisia tabaci (Gennadius), in a semi-persistent manner. Up to now, there is still lack of report in Hainan, the south of China. Methods We used observational and experimental methods to explore the prevalence and incidence dynamic of CCYV and ToCV transmitted by whiteflies in Hainan of China. Results In 2016, the chlorosis symptom was observed in the tomato and cucumber plants with a large number of B. tabaci on the infected leaves in Hainan, China, with the incidence rate of 69.8% and 62.6% on tomato and cucumber, respectively. Based on molecular identification, Q biotype was determined with a viruliferous rate of 65.0% and 55.0% on the tomato and cucumber plants, respectively. The weed, Alternanthera philoxeroides near the tomato and cucumber was co-infected by the two viruses. Furthermore, incidence dynamic of ToCV and CCYV showed a close relationship with the weed, Alternanthera philoxeroides, which is widely distributed in Hainan. Conclusion Our results firstly reveal that the weed, A. philoxeroides is infected by both ToCV and CCYV. Besides, whiteflies showed a high viruliferous rate of ToCV and CCYV. Hainan is an extremely important vegetable production and seed breeding center in China. If the whitefly can carry these two viruses concurrently, co-infection in their mutual host plants can lead to devastating losses in the near future.