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The rapid evolution of resistance in agricultural pest poses a serious threat to global food security. However, the mechanisms of resistance through metabolic regulation are largely unknown. Here, we found that a GST gene cluster was strongly selected in North China (NTC) population, and it was significantly genetically-linked to lambda-cyhalothrin resistance. Knockout of the GST cluster using CRISPR/Cas9 significantly increased the sensitivity of the knockout strain to lambda-cyhalothrin. Haplotype analysis revealed no non-synonymous mutations or structural variations in the GST cluster, whereas GST_119 and GST_121 were significantly overexpressed in the NTC population. Silencing of GST_119 or co-silencing of GST_119 and GST_121 with RNAi significantly increased larval sensitivity to lambda-cyhalothrin. We also identified additional GATAe transcription factor binding sites in the promoter of NTC_GST_119. Transient expression of GATAe in Hi5 cells activated NTC_GST_119 and Xinjiang (XJ)_GST_119 transcription, but the transcriptional activity of NTC_GST_119 was significantly higher than that of XJ_GST_119. These results demonstrate that variations in the regulatory region result in complex expression changes in the GST cluster, which enhances lambda-cyhalothrin resistance in field-populations. This study deepens our knowledge of the evolutionary mechanism of pest adaptation under environmental stress and provides potential targets for monitoring pest resistance and integrated management. A glutathione S-transferase gene cluster in the cotton bollworm, Helicoverpa armigera, contributes to natural insecticide resistance in this agricultural pest. [ABSTRACT FROM AUTHOR]

Graphene nanosheet and ternary-component nickel cobalt aluminum-layered double hydroxide composite (GNS/NiCoAl-LDH) has been successfully fabricated by a facile assembly method. The NiCoAl-LDH flakes homogeneously distribute on the surfaces of GNS, forming a three-dimensional nanosheets array structure. Electrochemical properties are characterized by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The influence of GNS doped content on the electrochemical behavior of GNS/NiCoAl-LDH composite has been studied. The result indicate that when the GNS content is 3.0 %, the GNS/NiCoAl-LDH composite electrode exhibits a maximum specific capacitance of 1,962 F g at 1 A g and remains at 1,180 F g even at a high current density of 10 A g. After 2,000 cycles, the composite electrode keeps a remarkable specific capacitance of 1,260 F g at 5 A g. The enhanced electrochemical performances of the composite are attributed to the highly electron conductivity and large specific surface area of the graphene nanosheets. This newly designed GNS/NiCoAl-LDH composite may offer a promising electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]

Herein, we report the identification of putative promoters for the non-structural proteins (NS) and capsid structural proteins (VP) of Helicoverpa armigera densovirus (HaDV2) as well as a potential mechanism for how these promoters might be regulated. For the first time, we report that VP is able to transactivate the VP promoter and, to a lesser degree, the NS promoter in densoviruses. In addition to this, another promoter-like sequence designated P2, when co-transfected with the VP gene, enhanced luciferase activity by approximately 35 times compared to a control. This suggests that there are two promoters for VP in HaDV2 and that the VP of parvoviruses might play a more important role in viral transcription than previously appreciated. [ABSTRACT FROM AUTHOR]

Evolution of resistance by pests reduces the benefits of transgenic crops that produce insecticidal proteins from Bacillus thuringiensis (Bt). Here we analyzed resistance to Bt toxin Cry1Ac in a field-derived strain of pink bollworm (Pectinophora gossypiella), a global pest of cotton. We discovered that the r14 allele of the pink bollworm cadherin gene (PgCad1) has a 234-bp insertion in exon 12 encoding a mutant PgCad1 protein that lacks 36 amino acids in cadherin repeat 5 (CR5). A strain homozygous for this allele had 237-fold resistance to Cry1Ac, 1.8-fold cross-resistance to Cry2Ab, and developed from neonate to adult on Bt cotton producing Cry1Ac. Inheritance of resistance to Cry1Ac was recessive and tightly linked with r14. PgCad1 transcript abundance in midgut tissues did not differ between resistant and susceptible larvae. Toxicity of Cry1Ac to transformed insect cells was lower for cells expressing r14 than for cells expressing wild-type PgCad1. Wild-type PgCad1 was transported to the cell membrane, whereas PgCad1 produced by r14 was not. In larval midgut tissue, PgCad1 protein occurred primarily on the brush border membrane only in susceptible larvae. The results imply r14 mediates pink bollworm resistance to Cry1Ac by reduced translation, increased degradation, and/or mislocalization of cadherin. [ABSTRACT FROM AUTHOR]