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Two dsRNA segments, the replicative forms of two ssRNA viruses of SsHV2/SX247 (Sclerotinia sclerotiorum hypovirus 2) and SsDRV/SX247 (Sclerotinia sclerotiorum debilitation-associated RNA virus), were isolated from the hypovirulent strain SX247 of Sclerotinia sclerotiorum. SsDRV/SX247 has the highest similarities (81% aa identity) with the previously reported virus SsDRV/Ep-1PN. The genome of SsHV2/SX247 is 15,219bp in length with a poly-A tail, and it has only one large putative open reading frame (ORF) that encodes a polyprotein containing RNA-dependent RNA polymerase (RdRp) and viral RNA helicase domains. The RdRp domain shares amino acid similarity with that of CHV1 (23%). However, the genome organization of SsHV2/SX247 is significantly different from that of CHV1 on genomic size and ORFs. We conclude that SsDRV/SX247 is a novel strain in species SsDRV of genus Sclerodarnavirus, whereas SsHV2/SX247 is a representative member of new proposed lineage Gammahypovirus in the family Hypoviridae and confers hypovirulence in its host.

Non-self recognition is a common phenomenon among organisms; it often leads to innate immunity to prevent the invasion of parasites and maintain the genetic polymorphism of organisms. Fungal vegetative incompatibility is a type of non-self recognition which often induces programmed cell death (PCD) and restricts the spread of molecular parasites. It is not clearly known whether virus infection could attenuate non-self recognition among host individuals to facilitate its spread. Here, we report that a hypovirulence-associated mycoreovirus, named Sclerotinia sclerotiorum mycoreovirus 4 (SsMYRV4), could suppress host non-self recognition and facilitate horizontal transmission of heterologous viruses. We found that cell death in intermingled colony regions between SsMYRV4-infected Sclerotinia sclerotiorum strain and other tested vegetatively incompatible strains was markedly reduced and inhibition barrage lines were not clearly observed. Vegetative incompatibility, which involves Heterotrimeric guanine nucleotide-binding proteins (G proteins) signaling pathway, is controlled by specific loci termed het (heterokaryon incompatibility) loci. Reactive oxygen species (ROS) plays a key role in vegetative incompatibility-mediated PCD. The expression of G protein subunit genes, het genes, and ROS-related genes were significantly down-regulated, and cellular production of ROS was suppressed in the presence of SsMYRV4. Furthermore, SsMYRV4-infected strain could easily accept other viruses through hyphal contact and these viruses could be efficiently transmitted from SsMYRV4-infected strain to other vegetatively incompatible individuals. Thus, we concluded that SsMYRV4 is capable of suppressing host non-self recognition and facilitating heterologous viruses transmission among host individuals. These findings may enhance our understanding of virus ecology, and provide a potential strategy to utilize hypovirulence-associated mycoviruses to control fungal diseases.

Background and Aims The study objective was to compare the effectiveness of microwave ablation (MWA) and laparoscopic liver resection (LLR) on solitary 3–5‐cm HCC over time. Approach and Results From 2008 to 2019, 1289 patients from 12 hospitals were enrolled in this retrospective study. Diagnosis of all lesions were based on histopathology. Propensity score matching was used to balance all baseline variables between the two groups in 2008–2019 (n = 335 in each group) and 2014–2019 (n = 257 in each group) cohorts, respectively. For cohort 2008–2019, during a median follow‐up of 35.8 months, there were no differences in overall survival (OS) between MWA and LLR (HR: 0.88, 95% CI 0.65–1.19, p = 0.420), and MWA was inferior to LLR regarding disease‐free survival (DFS) (HR 1.36, 95% CI 1.05–1.75, p = 0.017). For cohort 2014–2019, there was comparable OS (HR 0.85, 95% CI 0.56–1.30, p = 0.460) and approached statistical significance for DFS (HR 1.33, 95% CI 0.98–1.82, p = 0.071) between MWA and LLR. Subgroup analyses showed comparable OS in 3.1–4.0‐cm HCCs (HR 0.88, 95% CI 0.53–1.47, p = 0.630) and 4.1–5.0‐cm HCCs (HR 0.77, 95% CI 0.37–1.60, p = 0.483) between two modalities. For both cohorts, MWA shared comparable major complications (both p > 0.05), shorter hospitalization, and lower cost to LLR (all p < 0.001). Conclusions MWA might be a first‐line alternative to LLR for solitary 3–5‐cm HCC in selected patients with technical advances, especially for patients unsuitable for LLR.

Various mycoviruses have been isolated from Sclerotinia sclerotiorum. Here, we identified a viral RNA sequence contig, representing a novel virus, Sclerotinia sclerotiorum deltaflexivirus 2 (SsDFV2), from an RNA_Seq database. We found that SsDFV2 was harbored in the hypovirulent strain, 228, which grew slowly on potato dextrose agar, produced a few sclerotia, and could not induce typical lesions on detached rapeseed (Brassica napus) leaves. Strain 228 was also infected by Botrytis porri RNA Virus 1 (BpRV1), a virus originally isolated from Botrytis porri. The genome of SsDFV2 comprised 6711 nucleotides, excluding the poly (A) tail, and contained a single large predicted open reading frame encoding a putative viral RNA replicase. Phylogenetic analysis demonstrated that SsDFV2 is closely related to viruses in the family Deltaflexiviridae; however, it also differs significantly from members of this family, suggesting that it may represent a new species. Further we determined that SsDFV2 could be efficiently transmitted to host vegetative incompatible individuals by dual culture. To our best knowledge, this is the first report that a (+) ssRNA mycovirus can overcome the transmission limitations of the vegetative incompatibility system, a phenomenon that may facilitate the potential use of mycoviruses for the control of crop fungal diseases.

Objectives We aimed to compare the therapeutic outcomes of radiofrequency ablation (RFA) and microwave ablation (MWA) as first-line therapies in patients with small single perivascular hepatocellular carcinoma (HCC). Methods A total of 144 eligible patients with small (≤ 3 cm) single perivascular (proximity to hepatic and portal veins) HCC who underwent RFA (N = 70) or MWA (N = 74) as first-line treatment were included. The overall survival (OS), disease-free survival (DFS), and local tumor progression (LTP) rates between the two ablation modalities were compared. The inverse probability of treatment weighting (IPTW) method was used to reduce selection bias. Subgroup analysis was performed according to the type of hepatic vessels. Results After a median follow-up time of 38.2 months, there were no significant differences in OS (5-year OS: RFA 77.7% vs. MWA 74.6%; p = 0.600) and DFS (5-year DFS: RFA 24.7% vs. MWA 40.4%; p = 0.570). However, a significantly higher LTP rate was observed in the RFA group than the MWA group (5-year LTP: RFA 24.3% vs. MWA 8.4%; p = 0.030). IPTW-adjusted analyses revealed similar results. The treatment modality (RFA vs. MWA: HR 7.861, 95% CI 1.642–37.635, p = 0.010) was an independent prognostic factor for LTP. We observed a significant interaction effect of ablation modality and type of peritumoral vessel on LTP (p = 0.034). For patients with periportal HCC, the LTP rate was significantly higher in the RFA group than in the MWA group (p = 0.045). However, this difference was not observed in patients with perivenous HCC (p = 0.116). Conclusions In patients with a small single periportal HCC, MWA exhibited better tumor control than RFA. Key Points • Microwave ablation exhibited better local tumor control than radiofrequency ablation for small single periportal hepatocellular carcinoma. • There was a significant interaction between the treatment effect of ablation modality and type of peritumoral vessel on local tumor progression. • The type of peritumoral vessel is vital in choosing ablation modalities for hepatocellular carcinoma.

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The effective nanoparticles could play a valuable role in enhancing the thermo-sensitizing effect of MWA for achieving better therapeutic efficacy.