Tomato Chlorosis Virus Minor Coat Protein as a Novel Target To Screen Antiviral Drugs

Single-cell transcriptome landscape elucidates the cellular and developmental responses to tomato chlorosis virus infection in tomato leaf

Plant viral diseases compromise the growth and yield of the crop globally, and they tend to be more serious under extreme temperatures and drought climate changes. Currently, regulatory dynamics during plant development and in response to virus infection at the plant cell level remain largely unknown. In this study, single-cell RNA sequencing on 23 226 individual cells from healthy and tomato chlorosis virus-infected leaves was established. The specific expression and epigenetic landscape of each cell type during the viral infection stage were depicted. Notably, the mesophyll cells showed a rapid function transition in virus-infected leaves, which is consistent with the pathological changes such as thinner leaves and decreased chloroplast lamella in virus-infected samples. Interestingly, the F-box protein SKIP2 was identified to play a pivotal role in chlorophyll maintenance during virus infection in tomato plants. Knockout of the SlSKIP2 showed a greener leaf state before and after virus infection. Moreover, we further demonstrated that SlSKIP2 was located in the cytomembrane and nucleus and directly regulated by ERF4. In conclusion, with detailed insights into the plant responses to viral infections at the cellular level, our study provides a genetic framework and gene reference in plant-virus interaction and breeding in the future research.

Development and Mechanism Investigation of Novel Thioacetalized Indoles as Antiphytoviral Agents

Potato virus Y (PVY) is a highly destructive pathogen that infects Solanum tuberosumvL., commonly known as potato, a crop that produces one of the most crucial food staples of the world. The PVY viral infection can considerably reduce the yield and quality of potatoes, thereby causing significant economic ramifications. Given the unsatisfactory performance of commercially available antiviral agents against PVY, we synthesized a series of novel indole-derived compounds followed by their bioevaluation and investigation of the mechanisms governing their anti-PVY activity. These indole-based derivatives contain dithioacetal as a key chemical moiety, and most of them exhibit promising anti-PVY activities. In particular, compound B2 displays remarkable in vivo protective and inactivating properties, with half-maximal effective concentration (EC50) values of 209.3 and 113.0 μg/mL, respectively, in stark contrast to commercial agents such as ningnanmycin (EC50 = 281.4 and 136.3 μg/mL, respectively) and ribavirin (EC50 = 744.8 and 655.4 μg/mL, respectively). The mechanism using which B2 enhances plant immune response to protect plants from PVY is elucidated using enzyme activity tests, real-time quantitative polymerase chain reaction (RT-qPCR), and proteomics techniques. This study aims to pave the way for developing candidate pesticides and related molecules using antiphytoviral activity.

Recent Achievements in Antiviral Agent Development for Plant Protection

Plant virus disease is the second most prevalent plant diseases and can cause extensive loss in global agricultural economy. Extensive work has been carried out on the development of novel antiplant virus agents for preventing and treating plant virus diseases. In this review, we summarize the achievements of the research and development of new antiviral agents in the recent five years and provide our own perspective on the future development in this highly active research field.

Plant Viral Coat Proteins as Biochemical Targets for Antiviral Compounds

Coat proteins (CPs) of RNA plant viruses play a pivotal role in virus particle assembly, vector transmission, host identification, RNA replication, and intracellular and intercellular movement. Numerous compounds targeting CPs have been designed, synthesized, and screened for their antiviral activities. This review is intended to fill a knowledge gap where a comprehensive summary is needed for antiviral agent discovery based on plant viral CPs. In this review, major achievements are summarized with emphasis on plant viral CPs as biochemical targets and action mechanisms of antiviral agents. This review hopefully provides new insights and references for the further development of new safe and effective antiviral pesticides.

Recent research progress and outlook in agricultural chemical discovery based on quinazoline scaffold

The discovery of new scaffolds and targets for pesticides is still a huge challenge facing the sustainable development of modern agriculture. In recent years, quinazoline derivatives have achieved great progress in drug discovery and have attracted great attention. Quinazoline is a unique bicyclic scaffold with a variety of biological activities, which increases the possibilities and flexibility of structural modification, showing enormous appeal in the discovery of new pesticides. Therefore, the agricultural biological activities, structure-activity relationships (SAR), and mechanism of action of quinazoline derivatives in the past decade were reviewed systematically, with emphasis on SAR and mechanism. Then, we prospected the application of the quinazoline scaffold as a special structure in agricultural chemical discovery, hoping to provide new ideas for the rational design and mechanism of novel quinazoline agricultural chemicals in the future.

Recent Research Progress: Discovery of Anti-Plant Virus Agents Based on Natural Scaffold

Plant virus diseases, also known as “plant cancers”, cause serious harm to the agriculture of the world and huge economic losses every year. Antiviral agents are one of the most effective ways to control plant virus diseases. Ningnanmycin is currently the most successful anti-plant virus agent, but its field control effect is not ideal due to its instability. In recent years, great progress has been made in the research and development of antiviral agents, the mainstream research direction is to obtain antiviral agents or lead compounds based on structural modification of natural products. However, no antiviral agent has been able to completely inhibit plant viruses. Therefore, the development of highly effective antiviral agents still faces enormous challenges. Therefore, we reviewed the recent research progress of anti-plant virus agents based on natural products in the past decade, and discussed their structure-activity relationship (SAR) and mechanism of action. It is hoped that this review can provide new inspiration for the discovery and mechanism of action of novel antiviral agents.

Effect of Flutriafol Exposure on Residue Characteristics in Pig Muscle and Fat Tissue

This study investigated the effect of exposure to flutriafol based on residues in pigs. Pigs were exposed to different concentrations (0.313, 0.625, 3.125, 6.25, and 12.5 mg/kg bw/d, n=20) for 4 wk in different treatment groups. Serum biochemical analysis, residue levels, and histological analysis were conducted using the VetTest chemistry analyzer, liquid chromatography mass spectrometry, and Masson’s trichrome staining, respectively. The body weight (initial and final) was not significantly different between groups. Parameters such as creatinine, blood urea nitrogen, alanine aminotransferase, and lipase levels were significantly different as compared to the control group. Flutriafol increased the residue limits in individual tissue of the pigs in a dose dependent manner. Flutriafol exposures indicated the presence of fibrosis, as confirmed from Masson’s trichrome staining. These results suggest that flutriafol affects the morphology and serum levels in pigs. The dietary flutriafol levels can provide a basis for maximum residue limits and food safety for pork and related products.

Synthesis, Anti-Tomato Spotted Wilt Virus Activities, and Interaction Mechanisms of Novel Dithioacetal Derivatives Containing a 4(3H)-Quinazolinone Pyrimidine Ring

A series of unreported novel dithioacetal derivatives containing a 4(3H)-quinazolinone pyrimidine ring were synthesized, and their antiviral activities were evaluated against tomato spotted wilt virus (TSWV). A three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis was established, and compound D32 was designed and synthesized according to the analysis results of the CoMFA and CoMSIA models. The bioassay results showed that compound D32 exhibited excellent inactivation activity against TSWV, with EC₅₀ values of 144 μg/mL, which was better than those of ningnanmycin (149 μg/mL) and the lead compound xiangcaoliusuobingmi (525 μg/mL). The binding ability of compound D32 to TSWV CP was tested by microscale thermophoresis (MST), and the binding constant value was 4.4 μM, which was better than those of ningnanmycin (6.2 μM) and xiangcaoliusuobingmi (59.1 μM). Therefore, this study indicates that novel dithioacetal derivatives containing a 4(3H)-quinazolinone pyrimidine ring may be applied as new antiviral agents.

Review on Structures of Pesticide Targets

Molecular targets play important roles in agrochemical discovery. Numerous pesticides target the key proteins in pathogens, insect, or plants. Investigating ligand-binding pockets and/or active sites in the proteins' structures is usually the first step in designing new green pesticides. Thus, molecular target structures are extremely important for the discovery and development of such pesticides. In this manuscript, we present a review of the molecular target structures, including those of antiviral, fungicidal, bactericidal, insecticidal, herbicidal, and plant growth-regulator targets, currently used in agrochemical research. The data will be helpful in pesticide design and the discovery of new green pesticides.