Novel 1,3,4-Thiadiazole Derivatives: Synthesis, Antiviral Bioassay and Regulation the Photosynthetic Pathway of Tobacco against TMV Infection

Abstract

Tobacco mosaic virus (TMV) is a systemic virus that poses a serious threat to crops worldwide. In the present study, a series of novel 1-phenyl-4-(1,3,4-thiadiazole-5-thioether)-1H-pyrazole-5-amine derivatives was designed and synthesized. In vivo antiviral bioassay results indicated that some of these compounds exhibited excellent protective activity against TMV. Among the compounds, E2 (EC50 = 203.5 μg/mL) was superior to the commercial agent ningnanmycin (EC50 = 261.4 μg/mL). Observation of tobacco leaves infected with TMV-GFP revealed that E2 could effectively inhibit the spread of TMV in the host. Further plant tissue morphological observation indicated that E2 could induce the tight arrangement and alignment of the spongy mesophyll and palisade cells while causing stomatal closure to form a defensive barrier to prevent viral infection in the leaves. In addition, the chlorophyll content of tobacco leaves was significantly increased after treatment with E2, and the net photosynthesis (Pn) value was also increased, which demonstrated that the active compound could improve the photosynthetic efficiency of TMV-infected tobacco leaves by maintaining stable chlorophyll content in the leaves, thereby protecting host plants from viral infection. The results of MDA and H2O2 content determination revealed that E2 could effectively reduce the content of peroxides in the infected plants, reducing the damage to the plants caused by oxidation. This work provides an important support for the research and development of antiviral agents in crop protection.

Repairing Host Damage Caused by Tobacco Mosaic Virus Stress: Design, Synthesis, and Mechanism Study of Novel Oxadiazole and Arylhydrazone Derivatives

“…The half-leaf spot method was used to evaluate the antiviral activities (inactivation, protective, and curative effects) of the title compounds ( T 1 – T 18 and P 1 – P 18 ) at a concentration of 500 μg/mL. The commercialized antiviral agent NNM was used as a positive control.…”

“…After tobacco plants are infected with TMV, changes in gene expression and enzyme activity can produce certain physiological reactions, resulting in disease symptoms. First, the blade structure changes significantly; the mesophyll cell sequence is disordered; and the leaf epidermis is freed . Second, TMV destroys the chloroplast structure and function, reduces overall photosynthetic activity, reduces auxin and gibberellin contents, − increases abscisic acid and ethylene contents, and delays plant growth and development.…”

Flavonol Derivatives Containing a Quinazolinone Moiety: Design, Synthesis, and Antiviral Activity

“…This result was consistent with the chemical structure of K17 and indicated that the compound contains flavonol and quinazolinone structures. The crystallographic data show that K17 is a triclinic crystal and the total number of reflection points is 1396 at a diffraction temperature of 273 K. The space group was P-1, a = 9.791 (2) Å, b = 10.373 (2) Å, c = 14.980(3) Å; α = 77.954 (7)°, β = 83.658 (7)°, γ = 68.457 (5)°, V = 1383.1 (5) Å 3 , μ = 1.492 mm À 1 , Z = 2, Dx = 1.394 g/cm 3 , F(000) = 604.0. The crystal structure and data of K17 (CCDC: 2292276) could be accessed through the Cambridge crystal database.…”

“…[1] The current commercial agent used to manage plant virus diseases is mainly NNM, but the control effect is poor. [2][3] In addition, the low degradability and high toxicity of traditional active ingredients have resulted in some adverse environmental impacts. [4][5] Therefore, new, broad-spectrum, and highly effective anti-TMV agents need to be developed.…”