Viral Resistance Research Articles

Enhancing ‘Mirlo Rojo’ Apricot (Prunus armeniaca L.) Quality Through Regulated Deficit Irrigation: Effects on Antioxidant Activity, Fatty Acid Profile, and Volatile Compounds

Water scarcity is a significant global risk affecting health, food security, economic development, social stability, environmental sustainability, and climate change adaptation. Implementing deficit irrigation strategies can improve water efficiency and agricultural resilience. Spain, particularly the Region of Murcia, has pioneered apricot cultivation, with the ‘Mirlo Rojo’ variety known for its high productivity, Sharka virus resistance, and exceptional organoleptic qualities. This study evaluates the effects of regulated deficit irrigation (RDI) on the quality, antioxidant activity, fatty acid profile, and volatile compounds of ‘Mirlo Rojo’ apricots. Four irrigation treatments (100% ETc, 60% ETc, 33% ETc, and 0% ETc) were tested during the final growth stages in May 2023. Results showed no adverse effects on the evaluated parameters. RDI treatments increased total soluble solids, glucose, and fructose content, improving maturity and sweetness indices. RDI also enhanced phenolic content and antioxidant activity, optimizing water use without compromising fruit quality and bioactive compounds.

Metagenome-Assembled Genomes of Pig Fecal Samples in Nine European Countries: Insights into Antibiotic Resistance Genes and Viruses

Gut microbiota plays a crucial role in the health and productivity of pigs. However, the spread of antibiotic resistance genes (ARGs) and viruses within the pig intestinal microbiota poses significant threats to animal and public health. This study utilized 181 pig samples from nine European countries and employed metagenomic assembly methods to investigate the dynamics and distribution of ARGs and viruses within the pig intestinal microbiota, aiming to observing their associations with potential bacterial hosts. We identified 4605 metagenome-assembled genomes (MAGs), corresponding to 19 bacterial phyla, 97 families, 309 genera, and a total of 449 species. Additionally, 44 MAGs were classified as archaea. Analysis of ARGs revealed 276 ARG types across 21 ARG classes, with Glycopeptide being the most abundant ARG class, followed by the class of Multidrug. Treponema D sp016293915 was identified as a primary potential bacterial host for Glycopeptide. Aligning nucleotide sequences with a viral database, we identified 1044 viruses. Among the viral genome families, Peduoviridae and Intestiviridae were the most prevalent, with CAG-914 sp000437895 being the most common potential host species for both. These findings highlight the importance of MAGs in enhancing our understanding of the gut microbiome, revealing microbial diversity, antibiotic resistance, and virus–bacteria interactions. The data analysis for the article was based on the public dataset PRJEB22062 in the European Nucleotide Archive.

Highly Conjugated Ergosterols with Anti-Influenza Virus Activity from the Marine-Derived Fungus Eutypella sp. F0219.

one rare 15-nor-cadinane sesquiterpenoid (1), one new chromene amide derivative (2), and one new highly conjugated ergosterol steroid(3), along with three known compounds (4-6) were isolated from the marine-derived fungus Eutypella sp. F0219. Their chemical structures including absolute configurations were established by HR-ESIMS, extensive 1D and 2D NMR investigations, and electronic circular dichroism (ECD) calculations. All compounds were evaluated for their anti-influenza A virus and anti-influenza B virus activities against the A/PR/8/34 (H1N1), ZX1109 (H1N1, oseltamivir resistant virus), HK68 (H3N2), and B/Florida/78/2015 strains. Compounds 3 and 4 showed significant antiviral activities against those four virus strains with EC50 values ranging from 2.07 to 11.3 μM. Most notably, compound 3 exhibited potent anti-influenza B virus activity against B/Florida/78/2015 strain with EC50 value of 2.27±1.76 μM, versus the postive control (oseltamivir, EC50 = 7.14±1.94 μM).

Emerging Strategies and Therapeutic Advances in Influenza Treatment: A Comprehensive Review

Influenza remains a significant global health challenge, causing annual epidemics and occasional pandemics that impact millions worldwide. While current antiviral drugs and seasonal vaccines offer some protection, their limitations—such as drug resistance, variable efficacy, and evolving viral strains—highlight the urgent need for new therapeutic approaches. This review explores recent advancements in influenza treatment, including novel antiviral drugs, combination therapies, host-targeted treatments, monoclonal antibodies, and innovative delivery methods using nanotechnology. Emerging experimental therapies, such as RNA-based treatments and universal vaccines, offer promising avenues for enhanced, broad-spectrum protection. Additionally, the review discusses mechanisms of viral resistance to current treatments and potential solutions to overcome these barriers. These advancements could significantly improve clinical outcomes and inform future strategies for managing influenza. By addressing gaps in current treatments and advancing the development of innovative approaches, this review emphasizes the importance of a multifaceted approach to influenza management.

The pilot study of the features of HIV-1 resistant variants spread using molecular clusters

Introduction. As a result of routine testing of HIV-1 drug resistance (DR), a significant amount of viral nucleotide sequences and epidemiological data of HIV-infected individuals have been collected. Combined with the increasing use of bioinformatics methods in practice, it has become possible to study the features of HIV-1 resistant variants spread using molecular clustering analysis. The aim of the study was to validate the molecular clustering analysis in a pilot region of Russia using a significant number of nucleotide sequences to study the features of the spread of HIV-1 resistant variants. Materials and methods. HIV-1 nucleotide sequences were obtained from 899 HIV-infected patients who were registered at the Oryol AIDS Center in 2016–2021. HIV-1 genetic variants were determined using the Stanford University database, REGA and HIV BLAST. Resistance mutations and prognostic HIV-1 DR were determined using the Stanford University database. Phylogenetic analysis was carried out using the MEGA program. HIV-1 molecular clusters were identified using Cluster Picker software. Results. In the pilot region, sub-subtype A6 dominated (85.7%); an increase in the share of CRF63_02A6 was noted. HIV-1 resistance was found in 13.6% of patients without antiretroviral therapy (ART) experience and in 52.0% with ART experience. Molecular clusters were more often formed by HIV-1 nucleotide sequences from ART-naïve patients. HIV-1 DR variants were less likely to fall into molecular clusters. The sources of transmitted mutations were more often patients with ART experience. The most actively and efficiently transmitted mutations were K103N, V179E/T, Y181C and G190S, associated with virus resistance to efavirenz and nevirapine.

Designing a recombinant coat protein to reduce tobacco mosaic virus infection in plants

The Tobacco Mosaic Virus (TMV) is a critical plant virus that can cause a significant drop in crop yield. To understand how recombinant coat-protein impacts the affinity and assembly of TMV’s subunits, research is being conducted to assess the effect of recombinant protein on virus resistance. To develop a recombinant coat-protein that can lower TMV infection rates in plants, a design strategy was employed that involves creating defective viral subunits leading to incorrect assembly. This method is similar to using defective puzzle pieces that form incorrect connections resulting in disrupted viral assembly, ultimately affecting the production of mature virus particles. The study investigated the effect of mutations on one side of the Tobacco mosaic virus coat-protein using molecular modeling and dynamics simulation techniques. The simulation showed that the recombinant subunit had lower flexibility (between 0.15 to 0.20 nm) compared to the other subunits (between 0.45 to 0.75 nm), which was attributed to the smaller loop area. The study suggests an effective recombinant coat-protein with the potential to prevent virus infection by disrupting the coat-protein assembly process. This approach can be used to design a plant vaccine against viruses. Developing a recombinant protein can also provide benefits to plants such as protection from pests and enhancement of growth and productivity.

Disseminated vaccine-strain varicella-zoster virus reactivation in an adolescent with secondary immunodeficiency: a case report and literature review

BackgroundRoutine childhood immunization against varicella-zoster virus has led to a dramatic reduction in the incidence of primary varicella. However, there are rare, yet significant cases reported of reactivated Oka-strain varicella, primarily in immunocompromised hosts.Case presentationA 16-year-old female with Hodgkin’s lymphoma developed a vesicular rash shortly after completing all chemotherapy treatment. Swabs obtained from the vesicles were positive for varicella-zoster virus. By the time of hospitalization, the patient developed a disseminated rash involving multiple dermatomes. Subsequent polymerase chain reaction confirmed Oka vaccine-strain varicella-zoster virus. The patient had previously received a primary series of immunizations against varicella in 2008 and 2012, with her 2nd dose given 11 years prior to her development of vaccine-strain herpes zoster and 10 years prior to her diagnosis of Hodgkin’s lymphoma, respectively. The patient was treated with parenteral acyclovir upon hospitalization and monitored clinically for cutaneous disease progression as well as sequelae. After 8 days of inpatient treatment, her rash had stopped spreading with no new lesions. All earlier lesions had crusted over. No serious sequelae of disease such as pneumonitis, hepatitis, encephalitis, or meningitis occurred, and she made a complete recovery.ConclusionsThere are individual and community-wide benefits to childhood immunization against varicella. This case highlights an unusual presentation of disseminated vaccine-strain herpes zoster in an adolescent with secondary immunodeficiency 11 years after completing primary immunization. In addition, this case informs pediatricians of complications that can arise in immunized subjects if they become immunosuppressed years later. The only way to distinguish between wild-type and vaccine-strain herpes zoster was by viral genotyping. Providers should be cognizant of potential vaccine virus reactivation in their differential. Considerations for work-up and management should include infection control and viral resistance in refractory cases.

SARS-CoV-2 main protease (M-pro) mutational profiling: An insight into mutation coldspots

SARS-CoV-2 and the COVID-19 pandemic have marked a milestone in the history of scientific research worldwide. To ensure that treatments are successful in the mid-long term, it is crucial to characterize SARS-CoV-2 mutations, as they might lead to viral resistance. Data from >5,700,000 SARS-CoV-2 genomes available at GISAID was used to report SARS-CoV-2 mutations. Given the pivotal role of its main protease (M-pro) in virus replication, a detailed analysis of SARS-CoV-2 M-pro mutations was conducted, with particular attention to mutation-resistant residues or mutation coldspots, defined as those residues that have mutated in five or fewer genomes. 32 mutation coldspots were identified, most of which mediate interprotomer interactions or funneling interaction networks from the substrate-binding site towards the dimerization surface and vice versa. Besides, mutation coldspots were virtually conserved in all main proteases from other CoVs. Our results provide valuable information about key residues to M-pro structure that could be useful in rational target-directed drug design and establish a solid groundwork based on mutation analyses for the inhibition of M-pro dimerization, with a potential applicability to future coronavirus outbreaks.

Single-nucleus RNA sequencing reveals midgut cellular heterogeneity and transcriptional profiles in Bombyx mori cytoplasmic polyhedrosis virus infection.

The gut is not only used by insects as an organ for the digestion of food and absorption of nutrients but also as an important barrier against the invasion and proliferation of pathogenic microorganisms. Bombyx mori cytoplasmic polyhedrosis virus (BmCPV), an insect-specific virus, predominantly colonizes the midgut epithelial cells of the silkworm, thereby jeopardizing its normal growth. However, there is limited knowledge of the cellular immune responses to viral infection and whether the infection is promoted or inhibited by different types of cells in the silkworm midgut. In this study, we used single-nucleus RNA sequencing to identify representative enteroendocrine cells, enterocytes, and muscle cell types in the silkworm midgut. In addition, by analyzing the transcriptional profiles of various subpopulations in the infected and uninfected groups, we found that BmCPV infection suppresses the response of the antiviral pathways and induces the expression of BmHSP70, which plays a role in promoting BmCPV replication. However, certain immune genes in the midgut of the silkworm, such as BmLebocin3, were induced upon viral infection, and downregulation of BmLEB3 using RNA interference promoted BmCPV replication in the midgut of B. mori. These results suggest that viral immune evasion and active host resistance coexist in BmCPV-infected silkworms. We reveal the richness of cellular diversity in the midgut of B. mori larvae by single-nucleus RNA sequencing analysis and provide new insights into the complex interactions between the host and the virus at the single-cell level.

Mutations in human cytymegalovirus (Orthoherpesviridae: Herpesvirales: Cytomegalovirus: Cytomegalovirus humanbeta 5) UL97 gene lead to increase in viremia duration and poor antiviral response in recipients of allogeneic hematopoietic stem cells.

Human cytomegalovirus (Orthoherpesviridae: Herpesvirales: Cytomegalovirus: Cytomegalovirus humanbeta 5) (HCMV) is one of the most commonly detected viruses in recipients of allogeneic hematopoietic stem cell (allo-HSCT) transplants. However, the emergence of resistance to antiviral drugs such as ganciclovir (GCV) poses a challenge in managing these patients. This study aims to investigate the prevalence and impact of mutations in the HCMV UL97 gene associated with resistance to GCV on the course of infection among allo-HSCT patients. The study examined the association between UL97 mutations and the clinical course of HCMV infection in allo-HSCT patients. Genetic sequencing was performed to identify mutations, and their impact on viral replication and resistance to GCV was assessed. Six mutations were identified (D490A, T502A, C592G, C592F, E596G, C603W). C592G, C592F, E596G, and C603W are associated with resistance to antiviral drugs, while D490A and T502A described for the first time. When comparing patients with wild-type and those carrying the mutant variant, several parameters of peripheral blood were significantly lower in the former group. The median time to peak viral load following allo-HSCT, duration of viremia, and rate of virological response to high-dose therapy also differed significantly between the two groups. It was shown that approximately one third (4 out of 14) of allogeneic stem cell transplant recipients had mutations associated with resistance to GCV. Patients carrying the mutant variant of HCMV had longer viremia and took longer to achieve a negative virological test result after starting high-dose therapy. Performing genotyping may help make more evidence-based therapeutic decisions.

Targeting protein homeostasis with small molecules as a strategy for the development of pan-coronavirus antiviral therapies

The COVID-19 pandemic has created a global health crisis, with challenges arising from the ongoing evolution of the SARS-CoV-2 virus, the emergence of new strains, and the long-term effects of COVID-19. Aiming to overcome the development of viral resistance, our study here focused on developing broad-spectrum pan-coronavirus antiviral therapies by targeting host protein quality control mechanisms essential for viral replication. Screening an in-house compound library led to the discovery of three candidate compounds targeting cellular proteostasis. The three compounds are (1) the nucleotide analog cordycepin, (2) a benzothiozole analog, and (3) an acyldepsipeptide analog initially developed as part of a campaign to target the mitochondrial ClpP protease. These compounds demonstrated dose-dependent efficacy against multiple coronaviruses, including SARS-CoV-2, effectively inhibiting viral replication in vitro as well as in lung organoids. Notably, the compounds also showed efficacy against SARS-CoV-2 delta and omicron strains. As part of this work, we developed a BSL2-level cell-integrated SARS-CoV-2 replicon, which could serve as a valuable tool for high-throughput screening and studying intracellular viral replication. Our study should aid in the advancement of antiviral drug development efforts.

Prickly Ash Seeds Improve the Ruminal Epithelial Development and Growth Performance of Hu Sheep by Modulating the Rumen Microbiota and Metabolome.

It is known that the addition of feed rich in bioactive components to animal diets will affect rumen fermentation parameters and flora structure. However, research on the regulatory effects of prickly ash seeds (PASs) during rumen development or on the rumen microbiome and its metabolites in sheep is limited. The current study was designed to explore the effects of PASs on sheep rumen development and growth performance using metagenomics and metabolomics. Eighteen 3-month-old Hu lambs were randomly allotted to three different dietary treatment groups: 0% (basal diet, CK), 3% (CK with 3% PAS, low-dose PAS, LPS), and 6% (CK with 6% PAS, high-dose PAS, HPS) PASs. The lambs were slaughtered to evaluate production performance. Our results showed that dietary PAS addition improved the average daily gain and reduced the F/G ratio of the experimental animals. Additionally, the height and width of the rumen papilla in the treatment groups were significantly higher than those in the CK group. The fermentation parameters showed that the levels of acetate and butyrate were significantly higher in the LPS group than in the CK and HPS groups. The propionate levels in the HPS group were significantly higher than those in the CK and LPS groups. Metagenomics analysis revealed that PAS dietary supplementation improved the abundance of Clostridiales and Bacteroidales and reduced the abundance of Prevotella, Butyrivibrio, and Methanococcus. Metabolomic analyses revealed that increased metabolite levels, such as those of serotonin, L-isoleucine, and L-valine, were closely related to growth-related metabolic pathways. The correlations analyzed showed that papilla height and muscular thickness were positively and negatively correlated with serotonin and L-valine, respectively. Average daily gain (ADG) was positively and negatively correlated with L-valine and several Prevotella, respectively. In addition, muscular thickness was positively correlated with Sodaliphilus pleomorphus, four Prevotella strains, Sarcina_sp_DSM_11001, and Methanobrevibacter_thaueri. Overall, PAS addition improved sheep growth performance by regulating beneficial microorganism and metabolite abundances, facilitating bacterial and viral invasion resistance.

Evaluation of F2 Segregating Population of Chilli (Capsicum annuum L.) for Yield and Leaf Curl Virus Resistance

Chilli (Capsicum annuum L.) is an important vegetable crop, cultivated worldwide for its fruits which are valued for pungency, flavor, and nutritional benefits. However, chilli production is significantly restricted by various biotic stresses, especially the Chilli leaf curl virus (CLCV). The present study was conducted at the Department of Vegetable Science, College of Agriculture, Vellayani, Kerala Agricultural University during 2020-2021 to evaluate the F2 segregating population of chilli crosses viz., CHIVAR-6 x Sel-4 and CHIVAR-10 x Sel-3 for yield and leaf curl virus resistance. Evaluation of vegetative and yield related traits was conducted on these populations under the field conditions. Significant variability was observed for various traits such as plant height, fruits per plant, fruit length, yield per plant and resistance to leaf curl virus. The scoring for chilli leaf curl virus was done and based on the scoring the segregants were categorized into highly resistant, resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible. Among the F2 population of the first cross, fruits per plant, plant height, fruit weight and fruit girth showed high and positive correlation with yield per plant. The segregants of the second cross recorded significant positive correlation for fruits per plant, plant height and fruit length with yield. The results of the study provide valuable insights into breeding for both high yield and leaf curl virus resistance, crucial for enhancing chilli production under the challenging situations.

Genetic characterization of influenza B virus and oseltamivir resistance in pediatric patients with acute respiratory infections: a cross-sectional study.

Influenza virus neuraminidase inhibitors (NAIs) drug usage can result in NAI resistance, especially in children and individuals with weakened immune systems. The aim of the present study was to identify NAI-resistant variants of IBV and to introduce probable novel mutations, phylogenetic study, and its epitope mapping based on NA gene in patients from Shiraz, Iran. A cross-sectional study was conducted between 2017 and 2018 on symptomatic children. A real-time PCR was run for IBV screening. Then, making use of direct sequencing, amplified 1401 bases of NA gene and phylogenetic tree reconstructed. Epitopes were predicted using ABCpred server. From among a total of 235 specimens, 9.7% were identified with IBV infection. Of them, sequence of NA gene for 17 isolates were analyzed. Phylogenetic analysis showed that 15 isolates belonged to Yamagata clade 3 Wisconsin/01-like subclade and 2 were related to Victoria clade 1 Brisbane/60-like subclade (Vic-1A-2). NA gene sequence analysis showed a total of 52 substitutions in which 27 were for BVic and 37 were for BYam isolates and 19 were novel substitutions. Only one substitution (S198N) was found in NA active site and T49M, I120V, N198S, N219K, S295R, D320K N340D, E358K, D384G, and D463N were found as probable resistance variants to NAIs. Epitope mapping showed some major differences in our isolates NA gene. Present study was one of the rare comprehensive studies conducted in Shiraz/Iran on IBV resistant associated variants to NAIs. We reported 11.7% mutation in NA active site and some probable NAIs resistant mutations. Epitope mapping confirmed major changes in NA gene which needs broader studies to confirm.

Single Amino Acid Substitution Within the Helicase of Varicella Zoster Virus Makes It Resistant to Amenamevir.

A helicase-primase inhibitor, amenamevir (ASP2151), is the active pharmaceutical ingredient of a drug for the herpes zoster that is caused by reactivation of varicella-zoster virus (VZV). Here we report a new amenamevir-resistant VZV isolated under the selection pressure of amenamevir. The resistant virus has a nonsynonymous mutation K350N in the helicase gene ORF55. A recombinant virus artificially constructed harboring the ORF55 K350N also acquired amenamevir resistance, and thus the single amino-acid substitution in helicase is revealed to be responsible for the resistance. We observed that the drug-resistant virus and the ORF55 K350N recombinant virus have high resistance to amenamevir, as the EC50 values in a plaque reduction assay were > 100 μM, while the two viruses remained susceptible to the nucleoside analog drug acyclovir. No defect in viral growth was observed for these resistant viruses in a plaque size assay in human malignant melanoma cells. However, defect in plaque formation was observed from resistant virus in human fetal lung fibroblast cells, showing that the growth of the resistant virus is dependent on the cell type. We observed that the single amino-acid substitution in the helicase induces amenamevir resistance, confirming the importance of the helicase in amenamevir's inhibition of virus growth. Our findings highlight the importance of regulating the clinical use of amenamevir to minimize the risk of the emergence of helicase K350N mutation, especially in the long-term use of amenamevir by immunosuppressed patients.

Comprehensive analysis of biochemical compounds, chemical elements and metabolites modifications in maize plants infected with maize rayado fino virus (MRFV)

Maize cultivation is crucial worldwide, especially in Latin America. However, diseases related to corn stunt complex have significantly impacted crops, reducing grain productivity and quality. Maize rayado fino virus (MRFV) is part of this complex, and its symptom is characterized by chlorotic dots along veins and, depending on maize genotype, there will be stunting and an impact on the corn cob development, which can lead to productivity losses. However, this intricate plant-pathogen relationship is yet not well understood. Here, we investigated the effects of MRFV transmitted by the corn leafhopper Dalbulus maidis in infected plants in their early stage of development. To show the impact of the viral infection in the maize plant, we performed biochemical and chemical analysis and nuclear magnetic resonance (NMR). The total set of analyses showed that changes in chemical and biochemical compounds, as well as in metabolites composition and activities, can be perceived in MRFV-infected maize plants when compared to healthy plants. An increase in the activity of superoxide dismutase, catalase, peroxidase, and β-glucanase was detected, whereas small changes have been identified in antioxidant activity and phenolic compounds. For chemical components, unique changes were observed, mainly the increase in the presence of some elements such as calcium (Ca), phosphorus (P), sodium (Na), and iron (Fe). We identified 20 metabolites of the amino acids, organic compounds, and carbohydrates classes in maize plants which are regulated during MRFV infection. Maize plants reacted to D. maidis herbivory by modulating both enzymatic and non-enzymatic activities, as well as chemical compounds. This research offers insights into the responses of maize against MRFV and sheds light on parameters to be used on the search of rayado fino viral disease resistance for a sustainable production.

Identification of novel SARS-CoV-2 3CLpro inhibitors by molecular docking, in vitro assays, molecular dynamics simulations and DFT analyses.

SARS-CoV-2 pandemic has presented a significant threat to global health and the economy, necessitating urgent efforts to develop effective antiviral drugs. The main protease (3CLpro) of SARS-CoV-2 is a critical target for antiviral therapy due to its essential role in viral replication. In order to find new structural types of 3CLpro inhibitors to facilitate the solution to the problem of new virus resistance. Six potential pharmacologically bioactive compounds were identified by utilizing structure-based virtual screening and in vitro assays from the Topscience database containing 10 million compounds. Among these, compounds 34 and 36 exhibited potent inhibitory activity with IC50 values of 6.12 ± 0.42μM and 4.47 ± 0.39μM, respectively. To elucidate their binding mechanisms with 3CLpro, all-atom molecular dynamics (MD) simulations were conducted. Principal component analysis (PCA), free energy landscapes (FEL) and dynamic cross-correlation maps (DCCM) revealed that the binding of compounds 34 and 36 to 3CLpro significantly enhanced the structural stability of 3CLpro, reducing conformational flexibility and internal motions. The results of protein-ligand interaction showed that compounds 34 and 36 formed strong and stable interactions to key residues at active site of 3CLpro with different binding modes from S-217622. And HOMO-LUMO gap and molecular electrostatic potential distribution revealed the quantum chemical properties of compounds 34 and 36. These findings suggested that compounds 34 and 36 can be as novel SARS-CoV-2 3CLpro inhibitors and promising lead-like drug candidates for developing COVID-19 treatments.

Begomovirus disease of pumpkin crop in India and its management strategies possibility: a review

Pumpkin is an important commercial crop grown worldwide in tropical and subtropical regions. The whitefly-transmitted Pumpkin yellow vein mosaic disease seriously threatens pumpkin cultivation worldwide. The advent of transgenic technology in the 1980s revolutionized the possibilities for introducing virus resistance into agriculturally important plant species. It offered a powerful tool to enhance crop protection and provided a pathway to potentially unlimited sources of resistance against viral diseases. The ongoing research and development in this field continue to explore and refine conventional and non-conventional approaches for effective virus management in agriculture crops. This review focuses on developing transgenic resistance against begomoviruses and discusses possible management strategies to address these challenges.

Phaleria macrocarpa Fruit Protein Aqueous Extract Affects Viral Entry, Virucidal Activity, and Progeny Release

Presence of acyclovir (ACV) resistant virus posed a major problem in treating virus infection. Alternative treatment with the ability to encounter infection of acyclovir-resistant virus is thus needed and possibly with a different mode of action from ACV. Hence, this study evaluates the antiviral effect of Phaleria macrocarpa (Scheff.) Boerl fruit protein aqueous extract (PMFPAE) against three different strains of human herpesvirus type-1 (HHV-1) including a clinical strain, a less pathogenic strain (KOS-1), and acyclovir (ACV) resistant mutant (UKM-1). PMFPAE displayed antiviral activity towards all the HHV-1 strains when post-treated with high selective indices (SIs) of 80.6, 50, and 35, respectively. Plaque reduction percentages were reduced in attachment and penetration assays following treatment with PMFPAE indicating the ability to deactivate the early phases of the HHV-1 replication cycle. The virucidal activity was also noted following treatment of the virus with PMFPAE and this is supported by damages to the virus envelope as observed by transmission electron microscopy (TEM). Incubation of virus-treated cells with PMFPAE for 24 hr, reduced progeny release in a dose-dependent manner. The study confirms the antiviral mode of action of P. macrocarpa fruit against HHV-1 strains and the ACV-mutant strain includes inhibition during virus entry represented as the early stages of viral replication, virucidal activity, and interfering with progeny release. PMFPAE mode of action is hence different from ACV and worthy for the development of future antiviral drugs.

Plum pox virus (sharka) resistance in peach by grafting ‘Garrigues’ almond as interstock

Sources of resistance to sharka (Plum pox virus, PPV) have not been identified among peach [Prunus persica (L) Batsch] cultivars to date. However, several studies have shown the possibility of inducing resistance to PPV by grafting with the ‘Garrigues’ almond [P. dulcis (Mill) D. A. Webb] cultivar. The so-called “Garrigues effect” progressively reduces the symptoms of the disease and the accumulation of the virus in ‘GF305’ peach plants highly infected with PPV Dideron after grafting ‘Garrigues’. In addition, grafting 'Garrigues' onto ‘GF305’ before inoculation completely prevents infection by the virus. In this work, the ‘Garrigues’ cultivar has been used as an interstock to prevent PPV infection in peach. We have evaluated a collection of peach cultivars representing red and yellow skin, white and yellow flesh, and free and cling stones, in addition to platycarpa peaches (‘Maya’, ‘Transvalia’, ‘Romea’, ‘Catherine’, ‘Astoria’, ‘Tirrenia’, ‘Maruja M13’, ‘Levante 30′, ‘Alisio 15′ and ‘Carioca’). The cultivars were grafted onto ‘Garrigues’ that was already growing on ‘GF305’, ‘GF677’ and ‘Garnem’ rootstocks. Once the assayed plants were ready and fully developed [rootstock + interstock (‘Garrigues’) + peach cultivars], we graft inoculated the rootstocks and the growing peach plants with PPV at least three times. We were not able to obtain symptoms or detect the virus by RT-PCR in any of the cases, despite the proven susceptibility of these cultivars. In view of the results, we can affirm that using the ‘Garrigues’ graft as interstock could act as a kind of "vaccine" against PPV-Dideron in peach that is ready to be used commercially.