A Distinct Arabidopsis Latent Virus 1 Isolate Was Found in Wild Plants and Bees, Suggesting the Potential Involvement of Pollinators in Virus Spread.

During our search for aphid-pathogenic viruses, a comovirus was isolated from wild asymptomatic (white mustard) plants harboring a dense population of aphids. The transmission-electron-microscopy visualization of purified virions revealed icosahedral particles. The virus was mechanically transmitted to plants belonging to , , and families, showing unique ringspot symptoms only on var.

Rapid defense mechanism suppression during viral- oomycete disease complex formation.

Combined infection of the host plant with pathogens involving different parasitic lifestyles may result in synergistic effects that intensify disease symptoms. Understanding the molecular dynamics during concurrent infection provides essential insight into the host response. The transcriptomic pattern of cucumber plants infected with a necrotrophic pathogen, , and a biotrophic pathogen, Cucumber green mottle mosaic virus (CGMMV) was studied at different time points, under regimes of single and co-infection.

Genomic characterization of viruses associated with the parasitoid (Hymenoptera: Encyrtidae).

Knowledge on symbiotic microorganisms of insects has increased dramatically in recent years, yet relatively little data are available regarding non-pathogenic viruses. Here we studied the virome of the parasitoid wasp Triapitsyn (Hymenoptera: Encyrtidae), a biocontrol agent of mealybugs. By high-throughput sequencing of viral nucleic acids, we revealed three novel viruses, belonging to the families [provisionally termed AnvRV (Anagyrus vladimiri reovirus)], (AnvIFV) and (AnvDV).

Pepper Plants Harboring Resistance Alleles Showed Tolerance toward Manifestations of Tomato Brown Rugose Fruit Virus Disease.

The tobamovirus tomato brown rugose fruit virus (ToBRFV) infects tomato plants harboring the resistance allele, which corresponds with tobamoviruses' avirulence () gene encoding the movement protein to activate a resistance-associated hypersensitive response (HR). ToBRFV has caused severe damage to tomato crops worldwide. Unlike tomato plants, pepper plants harboring the resistance alleles, which correspond with the tobamovirus gene encoding the coat protein, have shown HR manifestations upon ToBRFV infection.

Platform for Active Vaccine Formulation Using a Two-Mode Enhancement Mechanism of Epitope Presentation by Pickering Emulsion.

The efficiency of epitope-based vaccination (subunit vaccines) is tightly correlated with heterogeneity and the high density of epitope presentation, which maximizes the potential antigenic determinants. Here, we developed a two-mode platform for intensifying the epitope presentation of subunit vaccines. The two-mode epitope presentation enhancement includes a covalent attachment of high concentrations of SARS-CoV-2-S1 peptide epitope to the surface of virus-like-particles (VLPs) and the subsequent assembly of VLP/epitope conjugates on the oil droplet surface at an oil/water interface of an emulsion as Pickering stabilizers.

New early phenotypic markers for cucumber green mottle mosaic virus disease in cucumbers exposed to fluctuating extreme temperatures.

Studies of early stages of cucumber green mottle mosaic virus (CGMMV) disease have been recently focused on plant molecular responses. However, extreme diurnal environmental temperatures, characteristic of global climate changes, could affect plant susceptibility and disease phenotype progression. Our studies of CGMMV disease progression, under simulated extreme temperature waves, have revealed two new disease initiation phenotypes that developed gradually, preceding severe symptom manifestations of post-recovery CGMMV systemic infections.

Nanodissection of Selected Viral Particles by Scanning Transmission Electron Microscopy/Focused Ion Beam for Genetic Identification.

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).

Tomato Brown Rugose Fruit Virus Contributes to Enhanced Pepino Mosaic Virus Titers in Tomato Plants.

The tobamovirus tomato brown rugose fruit virus (ToBRFV), a major threat to tomato production worldwide, has recently been documented in mixed infections with the potexvirus pepino mosaic virus (PepMV) CH2 strain in traded tomatoes in Israel. A study of greenhouse tomato plants in Israel revealed severe new viral disease symptoms including open unripe fruits and yellow patched leaves. PepMV was only detected in mixed infections with ToBRFV in all 104 tested sites, using serological and molecular analyses.

Isolation and characterization of a novel cripavirus, the first Dicistroviridae family member infecting the cotton mealybug Phenacoccus solenopsis.

A new virus belonging to the family Dicistroviridae was identified in the hibiscus-infesting cotton mealybug Phenacoccus solenopsis. Using high-throughput sequencing (HTS) on an Illumina HiSeq platform, a single contig of the complete genome sequence was assembled. The authenticity of the sequence obtained by HTS was validated by RT-PCR and Sanger sequencing of the amplicons, which was also employed for the 3' untranslated region (UTR).

The Potential Risk of Plant-Virus Disease Initiation by Infected Tomatoes.

During 2019, tomato fruits showing viral-like symptoms of marbled yellow spots were abundant in Israel. The new symptoms were distinctive from those typical of tomato brown rugose fruit virus (ToBRFV) infection but resembled symptoms of pepino mosaic virus (PepMV) infection. RT-PCR analysis and the serological tests (enzyme linked immunosorbent assay, western blot and in situ immunofluorescence) revealed and confirmed the presence of both the tobamovirus ToBRFV and the potexvirus PepMV in the symptomatic fruits.

Lettuce Chlorosis Virus Disease: A New Threat to Cannabis Production.

In a survey conducted in L. (cannabis) authorized farms in Israel, plants showed disease symptoms characteristic of nutrition deprivation. Interveinal chlorosis, brittleness, and occasional necrosis were observed in older leaves.

Transmission of a New Polerovirus Infecting Pepper by the Whitefly .

Many animal and plant viruses depend on arthropods for their transmission. Virus-vector interactions are highly specific, and only one vector or one of a group of vectors from the same family is able to transmit a given virus. Poleroviruses () are phloem-restricted RNA plant viruses that are exclusively transmitted by aphids.

Insights into the maternal pathway for Cucumber green mottle mosaic virus infection of cucurbit seeds.

Cucumber green mottle mosaic virus (CGMMV), genus Tobamovirus, is a major pathogen of cucurbits that primarily affects cucumber, melon, and watermelon crops. The aim of this study was to reveal the contribution of CGMMV-infected female flowers to disease spread. Using a fluorescent in situ hybridization (FISH) technique, we show that ovaries and ovules of CGMMV-infected cucumber and melon plants showed a CGMMV-specific fluorescence signal prior to and following anthesis.

The bumblebee Bombus terrestris carries a primary inoculum of Tomato brown rugose fruit virus contributing to disease spread in tomatoes.

The bumblebee Bombus terrestris is a beneficial pollinator extensively used in tomato production. Our hypothesis was that bumblebee hives collected from a Tomato brown rugose fruit virus (ToBRFV) infected tomato greenhouse, preserve an infectious primary inoculum. Placing a bumblebee hive collected from a ToBRFV contaminated greenhouse, in a glass-/net-house containing only uninfected healthy tomato plants, spread ToBRFV disease.

A local strain of Paprika mild mottle virus breaks L resistance in peppers and is accelerated in Tomato brown rugose fruit virus-infected Tm-2-resistant tomatoes.

During October 2014, unfamiliar mild mosaic and mottling symptoms were identified on leaves of pepper (Capsicum chinense cv. Habanero) seedlings grown in the Arava valley in Israel 2-3 weeks post planting. Symptomatic plants were tested positive by ELISA using laboratory-produced antisera for tobamovirus species.

Differential gene expression in tomato fruit and Colletotrichum gloeosporioides during colonization of the RNAi-SlPH tomato line with reduced fruit acidity and higher pH.

Background: The destructive phytopathogen Colletotrichum gloeosporioides causes anthracnose disease in fruit. During host colonization, it secretes ammonia, which modulates environmental pH and regulates gene expression, contributing to pathogenicity. However, the effect of host pH environment on pathogen colonization has never been evaluated.

A New Israeli Tobamovirus Isolate Infects Tomato Plants Harboring Tm-22 Resistance Genes.

An outbreak of a new disease infecting tomatoes occurred in October-November 2014 at the Ohad village in Southern Israel. Symptomatic plants showed a mosaic pattern on leaves accompanied occasionally by narrowing of leaves and yellow spotted fruit. The disease spread mechanically and rapidly reminiscent of tobamovirus infection.

Cation-Stress-Responsive Transcription Factors SltA and CrzA Regulate Morphogenetic Processes and Pathogenicity of Colletotrichum gloeosporioides.

Growth of Colletotrichum gloeosporioides in the presence of cation salts NaCl and KCl inhibited fungal growth and anthracnose symptom of colonization. Previous reports indicate that adaptation of Aspergillus nidulans to salt- and osmotic-stress conditions revealed the role of zinc-finger transcription factors SltA and CrzA in cation homeostasis. Homologs of A.

Mutation of AREA affects growth, sporulation, nitrogen regulation, and pathogenicity in Colletotrichum gloeosporioides.

The GATA transcription factor AreA is a global nitrogen regulator that restricts the utilization of complex and poor nitrogen sources in the presence of good nitrogen sources in microorganisms. In this study, we report the biological function of an AreA homolog (the CgareA gene) in the fruit postharvest pathogen Colletotrichum gloeosporioides. Targeted gene deletion mutants of areA exhibited significant reductions in vegetative growth, increases in conidia production, and slight decreases in conidial germination rates.

Genome Sequence of a Potential New Benyvirus Isolated from Mango RNA-seq Data.

We report here the sequence of a new benyvirus found through mango cultivar Shelly RNA-seq analysis in Israel. This is the first virus strain reported in mango trees.

Watermelon Fruit Rot Disease in Israel is Caused by a Distinct Squash vein yellowing virus (SqVYV) Strain.

In spring 2014, unfamiliar watermelon disease symptoms were observed on 1,000 ha of watermelon plants (Citrullus lanatus Thunb.) growing in open fields in Jordan and Beit-She'an Valleys, Israel. These represented systemic wilt and yellowing of leaves with necrosis on leaves and stems, in some cases leading to plant dieback, fruit exocarp deterioration, and rotting of the fleshy mesocarp, leading to unmarketable fruit.

Extended phylogenetic analysis of a new Israeli isolate of Brevicoryne brassicae virus (BrBV-IL) suggests taxonomic revision of the genus Iflavirus.

Background: Brevicoryne brassicae virus (BrBV) is a positive-strand genomic RNA virus which is unassigned tentative member of the genus Iflavirus. BrBv was first identified and characterized in the late 90's in the cabbage aphid in the United Kingdom (UK) (J Gen Virol 88:2590-2595, 2007) and was fully sequenced, using random amplification of encapsidated RNA. No other reports have been published demonstrating detection of this virus outside the UK.

Carbon regulation of environmental pH by secreted small molecules that modulate pathogenicity in phytopathogenic fungi.

Fruit pathogens can contribute to the acidification or alkalinization of the host environment. This capability has been used to divide fungal pathogens into acidifying and/or alkalinizing classes. Here, we show that diverse classes of fungal pathogens-Colletotrichum gloeosporioides, Penicillium expansum, Aspergillus nidulans and Fusarium oxysporum-secrete small pH-affecting molecules.

Adenine methylation may contribute to endosymbiont selection in a clonal aphid population.

Background: The pea aphid Acyrthosiphon pisum has two modes of reproduction: parthenogenetic during the spring and summer and sexual in autumn. This ability to alternate between reproductive modes and the emergence of clonal populations under favorable conditions make this organism an interesting model for genetic and epigenetic studies. The pea aphid hosts different types of endosymbiotic bacteria within bacteriocytes which help the aphids survive and adapt to new environmental conditions and habitats.