Helicoverpa zea is a major target pest of pyramided transgenic crops expressing Cry1, Cry2 and/or Vip3Aa proteins from Bacillus thuringiensis (Bt) in the United States.  Laboratory-selected Cry1Ac/Cry2Ab cross resistance and field-evolved practical dual resistance of H. zea to these two toxins have been widely reported.  Whether the widespread Cry1Ac/Cy2Ab dual resistance of H. zea has resulted from the selection of one shared or two independent resistance mechanisms by pyramided Bt crops remains unclear.  Cadherin is a well-confirmed receptor of Cry1Ac and a suggested receptor of Cry2Ab in at least three Lepidopteran species.  To test whether cadherin may serve as one shared mechanism for the cross and dual resistance of H. zea to Cry1Ac and Cry2Ab, we cloned H. zea cadherin (HzCadherin) cDNA and studied its functional roles in the mode of action of Cry1Ac and Cry2Ab by gain- and loss-of-function analyses.  Heterologous expression of HzCadherin in H. zea midgut, H. zea fat body and Sf9 cells made all three of these cell lines more susceptible to activated Cry1Ac but not activated Cry2Ab, whereas silencing HzCadherin of H. zea midgut and fat body cells significantly reduced the susceptibility to Cry1Ac but not Cry2Ab.  Likewise, suppressing HzCadherin with siRNA made H. zea larvae resistant to Cry1Ac.  These results clearly demonstrate that HzCadherin is not a receptor for Cry2Ab, and thus it is unlikely to serve as one shared mechanism for the cross and dual resistance of H. zea to Cry1Ac and Cry2Ab.

To understand the CH₄ flux variations and their climatic drivers in the rice–wheat agroecosystem in the Huai River Basin of China, the CH₄ flux was observed by using open-path eddy covariance at a typical rice–wheat rotation system in Anhui Province, China from November 2019 to October 2021.  The variations and their drivers were then analyzed with the Akaike information criterion method.  CH₄ flux showed distinct diurnal variations with single peaks during 9:00–13:00 local time.  The highest peak was 2.15 µg m^–2 s^–1 which occurred at 11:00 in the vegetative growth stage in the rice growing season (RGS).  CH₄ flux also showed significant seasonal variations.  The average CH₄ flux in the vegetative growth stage in the RGS (193.8±74.2 mg m^–2 d^–1) was the highest among all growth stages.  The annual total CH₄ flux in the non-rice growing season (3.2 g m^–2) was relatively small compared to that in the RGS (23.9 g m^–2).  CH₄ flux increased significantly with increase in air temperature, soil temperature, and soil water content in both the RGS and the non-RGS, while it decreased significantly with increase in vapor pressure deficit in the RGS.  This study provided a comprehensive understanding of the CH₄ flux and its drivers in the rice–wheat rotation agroecosystem in the Huai River Basin of China.  In addition, our findings will be helpful for the validation and adjustment of the CH₄ models in this region.

Soil aggregates profoundly impact soil sustainability and crop productivity, and they are influenced by complex interactions between minerals and organics. This study aimed to elucidate the alterations in mineralogy and soil organic carbon (SOC) following long-term green manure incorporation and the effect on soil aggregates. Based on 5- and 36-year field experiments, surface soil samples (0-20 cm) were collected from Alfisol and Ferrisol soils subjected to rice-rice-winter fallow (CK) and rice-rice-Chinese milk vetch (MV) treatments to investigate aggregate stability, mineralogy, SOC composition, and soil microstructural characteristics. The results showed that high clay-content Ferrisol exhibited greater aggregate stability than low clay-content Alfisol. The phyllosilicates in Alfisol primarily comprised illite and vermiculite, whereas those in Ferrisol with high-content free-form Fe oxides (Fed) were dominated by kaolinite. Additionally, the clay fraction in Ferrisol contained more aromatic-C than the clay fraction in Alfisol. The 36-year MV incorporation significantly increased the Ferrisol macroaggregate stability (9.57-13.37%), and it also facilitated the transformation of vermiculite into kaolinite and significantly increased the clay, Fed, and aromatic-C contents in Ferrisol. Backscattered electron (BSE)-scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) revealed a compact aggregate structure in Ferrisol with co-localization of Fe oxides and kaolinite. Moreover, the partial least path model (PLS-PM) revealed that clay content directly improved macroaggregate stability, and that kaolinite and Fed positively and directly affected clay or indirectly modulated clay formation by increasing the aromatic-C levels. Overall, long-term MV incorporation promotes clay aggregation by affecting mineral transformation to produce more kaolinite and Fe oxides and retain aromatic-C, and it ultimately improves aggregate stability. 

Maize is a cornerstone of global food security, but it faces increasing challenges from corn aphids, particularly with the widespread adoption of genetically modified Bt maize. This trend suggests a growing need for sustainable pest control strategies. Methyl salicylate has been proposed as a volatile compound with the potential for managing aphids. In this study, Y-tube olfactometer and Petri dish dispersal assays showed that methyl salicylate can repel wingless and winged aphids at 0.1 to 1,000 ng μL^-1. Moreover, at concentrations of 100 and 1,000 ng μL^-1, it was found to attract beneficial insects such as adults and larvae of Harmonia axyridis. Exposing maize plants to methyl salicylate resulted in a prominent reduction in the number of aphids compared to the control. In addition, clip cage experiment assays showed that the nymphal development duration was increased, while the adult duration and generation time were reduced, and the reproductive duration and total number of aphid offspring in plants treated with methyl salicylate were dramatically lower than in the control. Over two years of field trials, methyl salicylate-impregnated alginate beads provided significant reductions in the populations of key aphid species, including Rhopalosiphum padi, Rhopalosiphum maidis, and Aphis gossypii. Concurrently, there were marked increases in the presence of natural predators such as H. axyridis, Propylaea japonica, Syrphus corollae, and Chrysoperla sinica. These compelling results underscore the potential of methyl salicylate as a key component in integrated pest management strategies for maize, offering a green alternative to traditional chemical control.