Grapevine fanleaf virus (GFLV) (genus Nepovirus, family Secoviridae) causes fanleaf degeneration, one of the most damaging viral diseases of grapevines. Despite substantial advances at deciphering GFLV-host interactions, how this virus overcomes the host antiviral pathways of RNA silencing is poorly understood. In this study, we identified viral suppressors of RNA silencing (VSRs) encoded by GFLV, using fluorescence assays, and tested their capacity at modifying host gene expression in transgenic Nicotiana benthamiana expressing the enhanced green fluorescent protein gene ( EGFP). Results revealed that GFLV RNA1-encoded protein 1A, for which a function had yet to be assigned, and protein 1B^Hel, a putative helicase, reverse systemic RNA silencing either individually or as a fused form (1AB^Hel) predicted as an intermediary product of RNA1 polyprotein proteolytic processing. The GFLV VSRs differentially altered the expression of plant host genes involved in RNA silencing, as shown by reverse transcription-quantitative PCR. In a co-infiltration assay with an EGFP hairpin construct, protein 1A upregulated NbDCL2, NbDCL4, and NbRDR6, and proteins 1B^Hel and 1A+1B^Hel upregulated NbDCL2, NbDCL4, NbAGO1, NbAGO2, and NbRDR6, while protein 1AB^Hel upregulated NbAGO1 and NbRDR6. In a reversal of systemic silencing assay, protein 1A upregulated NbDCL2 and NbAGO2 and protein 1AB^Hel upregulated NbDCL2, NbDCL4, and NbAGO1. This is the first report of VSRs encoded by a nepovirus RNA1 and of two VSRs that act either individually or as a predicted fused form to counteract the systemic antiviral host defense, suggesting that GFLV might devise a unique counterdefense strategy to interfere with various steps of the plant antiviral RNA silencing pathways during infection. [ ] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Sesame is an oilseed crop threatened by a phyllody disease associated with the presence of phytoplasmas, which can reduce yields by up to 80%. The molecular identification of these bacteria in crops located in Western Iran was achieved from samples showing symptoms of diverse intensity and types. For biological characterization, the pathogen was also dodder-transmitted to periwinkle plants. After nucleic acid extraction and nested PCR using phytoplasma-specific primer pairs amplifying part of the 16S rRNA gene, it was possible to amplify DNA fragments from both symptomatic sesame samples and dodder-inoculated periwinkle plants. The virtual RFLP pattern from the 16S rRNA gene sequences using iPhyClassifier indicated the presence of phytoplasma strains in 16SrII-D and 16SrIX-C subgroups. The identity percentage values of the obtained amplified sequences corroborated by the phylogenetic analysis identified them as ‘Candidatus Phytoplasma australasiaticum’ and ‘Ca. P. phoenicium’, respectively. The two phytoplasma strains were detected in different sesame samples collected in the same field. The coexistence of two phytoplasmas may influence the observed differences in disease severity and suggests appropriate management strategies, since diverse insect vectors were reported alongside diverse phytoplasmas associated with this disease. Moreover, the widespread disease presence strongly suggests the breeding of resistant varieties.

Background: The mass production, widespread use, and improper disposal of plastic products have led to significant environmental pollution. Over time, larger plastic polymers break down into smaller particles known as microplastics. This study aimed to isolate and identify indigenous beneficial bacteria capable of degrading microplastics in the vicinity of the ...

Background: Tomato brown rugose fruit virus (ToBRFV) is an emerging plant pathogen that has rapidly spread from the Mediterranean to almost all continents, posing a serious threat to sustainable greenhouse crop production. Cold atmospheric plasma (CAP), a low-temperature ionized gas containing electrons, ions, photons, and reactive oxygen and nitrogen species (ROS and RNS), has gained attention for boosting yield and controlling plant diseases such as by virus inactivation. Methods: This study evaluated the efficacy of cold argon plasma-activated water applied for 3, 5, and 10 min in suppressing ToBRFV and the severity of viral symptoms under greenhouse conditions. In addition to assessing disease severity, the effect of cold plasma treatment was also examined on plant vegetative growth parameters, the activity of enzymatic and non-enzymatic antioxidants, and the expression levels of genes related to pathogenesis. Principal component analysis (PCA) was used to simplify multivariate data on plant growth and antioxidant activity across plasma treatments. Results: The results indicated that cold plasma treatments, particularly the 5-minute treatment, differed significantly from the control group and induced a strong positive correlation among tomato growth traits. This correlation appears to have played a key role in both improved growth and enhanced defense against ToBRFV. Moreover, plasma treatments, particularly 5-minute treatments, significantly increased the levels of antioxidant compounds—including phenols, flavonoids, DPPH, CAT, SOD, POD, APX, and proline —and reduced the oxidative stress index (MDA) compared to the control group. Peak antioxidant activity and accumulation of defense compounds were observed 14 days post-inoculation, indicating the apex of the plant’s defense response. PCA further confirmed that the 5-minute treatment induced the greatest differentiation and defense against ToBRFV, underscoring the presence of a coordinated defense mechanism in tomato plants. Also, the significant increase and peak expression of defense genes—PR1 (pathogenesis-related protein-1), PR2 (β-1,3-glucanase), and PR5 (thaumatin-like protein)—observed in plasma treatments, especially at 14 days post-inoculation, suggest that plasma induces systemic defense responses in plants against ToBRFV. Conclusion: The findings of this study suggest that cold plasma is an effective, non-chemical, and environmentally sound technology for eliciting plant defenses. It successfully mitigates ToBRFV severity and enhances plant growth indices, highlighting its high potential as a novel and sustainable strategy for managing the virus in greenhouse cultivation systems.