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Damage and loss of crops and plants caused by pathogens are global problems that have major effects on the food supply of many countries. Environmentally friendly viricide approaches are gaining in popularity to combat these problems. This study proposes the use of environmentally friendly hydrogen peroxide (HP) as a pesticide entrapped in a poly(vinyl alcohol) (PVA)/polyvinylpyrrolidone (PVP) hydrogel for controlled release in agricultural applications. The hydrogel was prepared as a matrix of PVA and PVP containing HP. Freeze–thaw cycles of the PVA/PVP/HP hydrogel improve the mechanical properties and thereby decrease the HP release rate. The hydrogel chemical composition, morphology, and HP release rate through direct and indirect (gas phase) contact were investigated. Viricide capabilities were tested, indicating a high efficiency against ToBRFV on tobacco and tomato plants. Additionally, low to zero phytotoxicity was found for HP release. These results demonstrate the future potential of hydrogen peroxide-loaded hydrogels as effective viricide agrogels.

This study presents the development of a new correlative workflow to bridge the gap between electron microscopy imaging and genetic analysis of viruses. The workflow enables the assignment of genetic information to a specific biological entity by harnessing the nanodissection capability of focused ion beam (FIB). This correlative workflow is based on scanning transmission electron microscopy (STEM) and FIB followed by a polymerase chain reaction (PCR). For this purpose, we studied the tomato brown rugose fruit virus (ToBRFV) and the adenovirus that have significant impacts on plant integrity and human health, respectively. STEM imaging was used for the identification and localization of virus particles on a transmission electron microscopy (TEM) grid followed by FIB milling of the desired region of interest. The final-milled product was subjected to genetic analysis by the PCR. The results prove that the FIB-milling process maintains the integrity of the genetic material as confirmed by the PCR. We demonstrate the identification of RNA and DNA viruses extracted from a few micrometers of an FIB-milled TEM grid. This workflow enables the genetic analysis of specifically imaged viral particles directly from heterogeneous clinical samples. In addition to viral diagnostics, the ability to isolate and to genetically identify specific submicrometer structures may prove valuable in additional fields, including subcellular organelle and granule research.

Abstract: Pepper (Capsicum annuum) is an important crop worldwide. In Israel, approximately 2,500 ha are grown all year round for the local and export markets. Herein, we report the identification of a viral pathogen causing a new devastating disease in pepper crops. The disease syndrome includes shortening of stem internodes, interveinal yellowing, and upward rolling of the leaf blade, accompanied by fruit discoloration and size reduction. Virus purification from infected plants yielded isometric particles, 25 nm in diameter. The causal agent of the disease was tentatively named Pepper yellow leaf curl virus (PYLCV). The virus cross-reacted in DAS ELISA with antisera against Cucurbit aphid-borne yellows virus and Potato leafroll virus, members of the Polerovirus genus. The partial nucleotide sequence obtained from the cloned viral coat protein and movement protein genes indicated 92% identity at the amino acid level with Tobacco vein distortion virus (TVDV), another member of the Polerovirus genus. However, the host range of PYLCV is significantly different from the host range described for TVDV. Based on our findings, the taxonomic status of PYLCV is discussed.

Abstract: Eggplant (Solanum melongena), which is grown worldwide, is cultivated all year round in Israel. We report on the outbreak of a new viral disease infecting eggplants in Israel, which causes significant damage due to plant stunting, leaf mottling and narrowing, accompanied by fruit malformation. Virus purification from the infected plants yielded isometric particles, 37–40 nm in diameter. Biological and molecular characterization of the viral agent indicates that it is a new strain of the Eggplant mottled crinkle virus (EMCV-Is) that has been assigned to the Tombusvirus genus. Phylogenetic analysis indicated a close relationship of EMCV with Pear latent virus (PeLV) and Lisianthus necrosis virus (LNV), which can be considered strains of EMCV rather than distinct viruses.

N-halamines are a commonly applied class of antimicrobial agents used for a variety of applications relating to human health. Here, we present the modulation of the common polymers polyurea and polyguanidine with the N-halamine technology. The N–H bonds in either polymer were converted to N–Cl or N–Br bonds capable of releasing Cl+or Br+cations to aqueous media as antiviral agents. Controlled release of the oxidizing agents was monitored for a period of 4 weeks. Antiviral activity was evaluated against the T4 bacteriophage as well as against the highly stable plant virus belonging to the Tobamovirusgenus, tomato brown rugose fruit virus. The incorporation of the N-halamine technology on commonly used polymers has effectively introduced antiviral functionality for a wide variety of potential applications.

Preventing microbial contamination of aquatic environments is crucial for the proper supply of drinking water. Hence, understanding the interactions that govern bacterial and virus adsorption to surfaces is crucial to prevent infection transmittance. Here, we describe a new approach for studying the organization and interactions of various microorganisms, namely, Escherichia coli(E. coli) bacteria, E. coli-specific bacteriophage T4, and plant cucumber green mottle mosaic viruses (CGMMV), at the air/water interface using the Langmuir–Blodgett (LB) technique. CGMMV were found as applicable candidates for further studying their interactions with Langmuir lipid monolayers. The zwitterionic, positively, and negatively charged LB lipid monolayers with adsorbed viruses were deposited onto solid supports and characterized by atomic force microscopy. Using polymerase chain reaction, we indicated that the adsorption of CGMMV onto the LB monolayer is a result of electrostatic interactions. These insights are useful in engineering membrane filters that prevent biofouling for efficient purification systems.