No abstract

The development of new green fungicides is an effective way to solve the resistance of agricultural pathogens and plays an important role in promoting high-quality and sustainable development of modern agriculture. In this project, a series of aryloxy-, arylthio-, and arylamino-containing acethydrazide derivatives were designed, synthesized, and characterized by 1 H nuclear magnetic resonance (NMR), 13 C NMR, and high-resolution mass spectrometry (HRMS). The fungicidal bioassays indicated that some compounds showed excellent and broad-spectrum fungicidal activity, and the structure−activity relationship was discussed. The in vivo fungicidal activity demonstrated that compounds C4 and D8 exhibited good preventative effects against Fusarium graminearum infecting wheat leaves, of which the preventative activity of compound D8 was almost equal to that of the positive agents. Transmission electron microscopy (TEM) observation revealed that the plasma membrane in the C4-treated F. graminearum hyphal cells was severely contracted and separated with the cell wall, coupling with the visible lysosomes and the disappeared cytoplasm and organelles, which may be the reasons for the shriveled and even ruptured hyphae observed by scanning electron microscopy (SEM). Subsequently, transcriptomics and metabolomics were performed to further elucidate the fungicidal mechanism. The regulatory networks of differential genes and metabolites in plasma membrane-related sphingolipid metabolism, linoleic acid metabolism, α-linoleic acid metabolism, and arachidonic acid metabolism were constructed and elaborated. Additionally, preliminary investigation of seeding growth suggested that compounds C4 and D8 may have different degrees of influence on the growth indicators of wheat seedlings; however, this effect may be negligible as the plant grows.

Structural optimization based on natural products has become an effective way to develop new green fungicides, which provide important guiding signi cance for practicing the new development concept and promoting the green development of pesticides. In this project, combined with the fungicidal amide lead compound X-I-4 discovered in our previous work and fungicidal piperazine derivatives reported in literatures, the target compounds containing 4-quinolone and piperazine substructures based on waltherione F were designed, synthesized and screened for their biological activity. The bioassay results indicated that compounds I-3, I-5, II-3, II-7, II-10, II-11 and II-13 displayed higher inhibition rates against Rhizoctonia solani than other tested compounds. The in vitro cellular cytotoxicity assay revealed the compounds II-6 and II-11 exhibited higher cytotoxicity against HepG2 than other tested compounds. The uorescence characteristics investigation showed that the absolute uorescence QY value of the methanol solution of the compound I-6 was higher than those of I-2, I-3, I-7 and I-8, which was further elucidated by TD-DFT.

Conventionally, one can constrain the dark matter (DM) interaction with DM mass heavier than GeV by searching for DM induced synchrotron emission in the radio frequency band. However, an MeV DM can also generate detectable radio emission if electrons and positrons produced by DM annihilation or decay undergoes inverse Compton scattering (ICS) with the cosmic microwave background. The upcoming radio telescope Square Kilometre Array (SKA) is designed to operate with extremely high sensitivity. We investigate the capability of the SKA to detect DM particles in a board mass range from MeV to TeV, for both annihilation and decay scenarios. In this paper, we consider the sensitivities of the future SKA first and second phase (SKA1 and SKA2). As a comprehensive study, we systematically study the impacts on the DM-induced signal computation from the magnetic field strengths and particle diffusion coefficients. We compare the detection potential of four very different sources: two dwarf spheroidal galaxies (Draco and Segue 1), one radio-poor cluster (A2199), and one DM-rich ultra-diffuse galaxy (Dragonfly 44). We project the SKA1 and SKA2 sensitivities with the exposure of 100 hours on the annihilation cross section and decay time for DM mass from MeV to TeV by considering two different leptonic final states e + e − and µ + µ − .