This data article reports the bacterial profile associated with the pear lace bug (Stephanitis pyri) collected from organic orchards in Catalonia, Spain, and reared under laboratory conditions. Total DNA from four composite samples, each comprising 30 individuals, along with an extraction control, was subjected to high-throughput amplicon sequencing targeting the V3-V4 region of the 16S rRNA gene on an Illumina NextSeq platform using a 2 × 300 bp paired-end configuration. The sequencing reads were processed with QIIME2 v2025.7, using a pre-trained SILVA classifier (2024-5) for the taxonomic assignment of amplicon sequence variants. Due to the fact that endosymbionts and other associated microorganisms can shape pest adaptation to new environments, this dataset is intended to serve as a valuable resource for evaluating changes in the microbiota of S. pyri in response to different conditions, thereby improving our understanding of its ecology and ultimately aiding the development of integrated management strategies.

The pyripyropenes A-X represent a family of 24 alkaloids isolated from fungi, mainly Aspergillus and Penicillium species, over the past 30 years. Numerous analogues have been isolated from fungi or (hemi)synthesized to investigate structure-activity relationships. The leader product in the series remains the first identified natural product pyripyropene A (Pyri-A), known as a highly potent and selective inhibitor of acyl CoA:cholesterol acyltransferase 2 (ACAT2). The present review retraces the products history, from their discovery to the characterization of the target engagement, the cellular mechanism of action and bioactivities. In parallel to the identification of naturally occurring pyripyropenes and the synthesis of derivatives, studies have progressed in three directions. First, the development of agricultural insecticides from Pyri-A led to discovery and worldwide commercialization of afidopyropen (Inscalis®) to protect crops against sucking insects. Second, the highly potent and selective targeting of ACAT2, largely expressed in human liver cells notably, drove the design of analogues aimed at regulating cholesterol metabolism for the treatment of metabolic and cardiovascular diseases. Third, the emerging roles of ACAT2 as a regulator of tumor cell proliferation and anticancer immune response call for the development of the pyripyropenes in oncology. A few tumor-active pyripyropene derivatives targeting ACAT2 have been identified recently. The review underlines the evolution of research in this domain, from the fungal production to the insecticidal action, and from the treatment of atherosclerosis to cancers. The pyripyropene saga is alive and well.

Apple Valsa canker (AVC), a destructive fungal disease caused primarily by Valsa mali (= Cytospora mali), poses a major threat to apple production. Its close relative, V. pyri, also infects apples but exhibits substantially weaker virulence than V. mali, and the molecular basis underlying this difference remains unclear. Here, we identified a V. mali-specific effector, Vm00799, as a key determinant of enhanced virulence on apple. Vm00799 targets the apple transcription factor MdTCP7 to enhance its binding to the MdERF1B promoter, thereby activating the MdTCP7-MdERF1B module and suppressing ethylene-mediated defense responses. Consistently, MdTCP7 and MdERF1B negatively regulate apple resistance, whereas ethylene signaling positively contributes to immunity against V. mali. Importantly, ectopic expression of Vm00799 significantly increased the virulence of V. pyri on apple in an MdTCP7-dependent manner. Collectively, our findings reveal that Vm00799 promotes V. mali infection by hijacking host transcriptional regulation to suppress ethylene-dependent immunity. This study uncovers the molecular basis of virulence divergence among closely related Valsa species and identifies potential target for AVC control.

Plants release volatile organic compounds (VOCs) as part of their defense mechanisms when attacked by phytopathogens and herbivores. These specific volatile emissions can help plants avoid damage. In this study, we investigated the effects of the brown marmorated stink bug (BMSB), Halyomorpha halys, and the phytopathogens "Candidatus phytoplasma mali", causing apple proliferation (AP) or "Ca. P. pyri", causing pear decline (PD) on the volatile emissions from apple (Malus domestica) or pear (Pyrus communis) trees. We analyzed VOCs emitted by uninfected and infected trees exposed to male and female BMSB. Using random forest analysis, the profiles of uninfected trees and those singly infected with PD- or AP-phytoplasma were clearly distinguishable from those infested with BMSB and double-infections with both phytoplasma and BMSB. BMSB-infested apple and pear trees emitted higher levels of linalool and 4,8-dimethyl-1(E)-3,7-nonatriene (DMNT) compared to uninfested trees. In addition, dual infections with phytoplasma and BMSB showed an induction in the content of these VOCs. Phytoplasma-infected apple trees significantly increased emissions of methyl salicylate (MeSA), whereas MeSA content was significantly increased in pear trees exposed to BMSB and also dual infections with phytoplasma and BMSB. In apple trees, α-farnesene was emitted at a higher amount only from phytoplasma-infected trees exposed to BMSB males, whereas in pear trees this VOC was significantly induced in response to female BMSB and dual infections with phytoplasma and female BMSB. Furthermore, we found three acids in healthy pear trees, n-hexadecanoic acid, octadecanoic acid, and oleic acid, which were not detected in phytoplasma-infected or BMSB-infested trees. It was demonstrated that this information can help to identify specific chemical signatures and specific VOCs, which may be used as biomarkers for detecting and monitoring these pests.

Valsa canker, caused by Valsa pyri, threatens the pear industry significantly and hampers molecular breeding for disease resistance due to the scarce knowledge of resistance genes. The NAC (NAM, ATAF1/2, CUC2) transcription factor family plays a crucial role in plant responses to biotic stresses, yet its involvement in pear Valsa canker resistance remains largely underexplored. In this study, we performed a genome-wide identification and bioinformatics analysis of the NAC gene family across the plant kingdom. Our analysis covered 19 diverse species, identified 2501 NAC genes, and classified them into 10 distinct subfamilies. A high member size and expansion rate were discovered in subfamilies E and H, respectively. The subfamily- and species-specific expansion of NAC genes is primarily driven by whole-genome duplication (WGD). Using Weighted Gene Co-expression Network Analysis (WGCNA) combined with experimental functional validation, we identified two NAC genes, PbeNAC32 and PbeNAC105, as crucial positive regulators of Valsa canker resistance. These genes conferred enhanced resistance when overexpressed in both pear and apple fruits, as well as in suspension cells of 'Duli-G03' (Pyrus betulifolia). Overexpression of PbeNAC32 activated multiple immune pathways. Through transcriptome analysis of samples collected at 1 h (T1), 3 h (T2), and 6 h (T3) after Valsa pyri metabolites (VpM) treatment, 3198 shared differentially expressed genes (DEGs) were enriched in multiple immune-related processes. Based on the binding motif, 38 genes were identified, mainly resistance genes related to the PR10 family, as potential targets for PbeNAC32. These findings provide novel insights into the molecular mechanisms of disease resistance in P. betulifolia and offer valuable genetic resources for breeding apple and pear varieties with improved resistance to V. pyri.

The pear psyllid (Cacopsylla pyri), the main vector of 'Candidatus Phytoplasma pyri', relies on substrate-borne vibrational signals for mate recognition and duet coordination. As pathogens can alter insect communication, we examined whether phytoplasma infection alters key parameters of male and female mating signals. We used laser vibrometry on a standardised artificial substrate, as well as playbacks, to examine this. We detected sex-specific differences in individual signal parameters. In males, infection significantly reduced the amplitude of chirps, whereas uninfected males showed a markedly higher number of interruptions within their trill units. Infected females produced longer inter-chirp intervals and showed higher dominant spectral components than uninfected females. However, fundamental frequency remained stable across treatments, suggesting that differences in dominant frequency reflect shifts in spectral energy among harmonics rather than changes in the primary oscillation frequency. These infection-induced changes may reflect physiological constraints affecting vibrational mechanics. These findings suggest that infection-related differences in dominant frequency reflect changes in the distribution of spectral energy among harmonics rather than a change in the fundamental frequency. Despite these differences at the individual level, the preliminary results of duet communication between males and females did not differ significantly across the various infection treatments. This suggests that the basic coordination in the duet may not be significantly impaired under laboratory conditions; this should be investigated more closely in a specially designed experiment.

The occurrence of pear Valsa canker caused by Cytospora pyri poses a serious threat to the healthy and sustainable development of the Korla fragrant pear industry. To effectively control the disease, endophytic strains were isolated from the bark of Korla fragrant pear trees and screened for strong antagonistic activity against the pathogen. The selected strain was identified based on morphological characteristics and 16S rRNA phylogenetic analysis. Its biocontrol potential and functional traits were further evaluated, along with its growth-promoting ability assessed through in vitro tests and preliminary tomato pot experiments. Results showed that a total of 264 endophytic isolates were obtained from 200 pear tissue samples using dilution plating and tissue separation methods. Among them, strain FB-4 exhibited significant inhibition against C. pyri. Morphological observations and phylogenetic analysis identified the strain as Bacillus velezensis, named FB-4. The cell-free supernatant inhibited conidial germination and mycelial growth of the pathogen by 88.21% and 85.51%, respectively, and showed preventive and curative efficacies of 74.49% and 58.97% against pear Valsa canker. In vitro assays indicated that FB-4 could produce indole-3-acetic acid, protease, amylase, and cellulase, and demonstrated abilities to solubilize inorganic phosphate and synthesize siderophores. Inoculation with FB-4 bacterial suspension promoted the growth of tomato seedlings, with higher concentrations yielding more pronounced effects. In conclusion, strain FB-4 represents a dual-functional biocontrol agent with both antagonistic and plant-growth-promoting properties.

Protonation of pyridinic nitrogen (pyri-N) sites in nitrogen-doped carbon catalysts under acidic conditions converts pyri-N to pyri-NH+, leading to severe catalytic deactivation. Restoring activity requires transforming pyri-NH+ back to pyri-NH, an energetically demanding process that limits oxygen reduction reaction (ORR) efficiency. To overcome this challenge, we developed an N-doped porous carbon catalyst (NpC-7) featuring surface pyri-N active sites and a subsurface graphitic nitrogen (grap-N) layer. The 2D growth of cyanuric acid (CA)-functionalized 2-hydroxyethyl methacrylate (HEMA) polymer within graphene oxide layers ensures uniform N-doping which modulates π-electron and spin states. This engineered architecture delivers ORR activity approaching Pt/C and surpasses conventional nitrogen doped graphene oxide (NrGO) (Eonset = 0.86 V, E1/2 = 0.70 V vs. 0.76 and 0.61 V, respectively). Enhanced performance arises from subsurface grap-N, which donates electron to protonated pyri-NH+, generating an active pyri - NHδ +  state that promotes O2 adsorption. In situ electrochemical Raman spectroscopy and density functional theory (DFT) calculations confirm efficient O2 adsorption and intermediate formation, indicating a (2 + 2)e- ORR pathway. These findings highlight the critical role of subsurface grap-N in overcoming acidic deactivation through electronic modulation, offering a blueprint for designing acid-stable carbon electrocatalysts.

Bacillus atrophaeus has considerable potential for development as a microbial pesticide. Optimization of fermentation conditions and the wettable powder (WP) formulation is critical for its industrialization and application in sustainable agriculture. In this study, the fermentation of B. atrophaeus YL84 was optimized using single-factor experiments and response surface methodology. Based on these results, a WP formulation was developed and further optimized. The optimal carbon, nitrogen, and inorganic salt sources were sucrose (13.9 g·L[-1]), tryptone (11.8 g·L[-1]), and MgSO4 (5.9 g·L[-1]), respectively; optimal fermentation conditions were pH 7.0, 32 °C, and 210 r·min[-1]. After optimization, the inhibition rate and OD600 reached 83.71% and 1.758, respectively. The optimized formulation comprised attapulgite-based powder (79%, as carrier), sodium alkyl naphthalene sulfonate (5.4%) as a wetting agent, PEG-6000 (12.6%), CaCO3 (2%), and vitamin C (1%). The resulting WP exhibited a spore viability of 2.63 × 10[9] CFU·g[-1], and its 50-fold dilution demonstrated antagonistic activity in vitro against Cytospora pyri (Korla pear valsa canker agent) and biocontrol efficacy in vivo on detached-branch assays. These findings demonstrate that the YL84 WP is a promising candidate for the biological control of Korla pear valsa canker.

Pear decline (PD), associated with 'Candidatus Phytoplasma pyri', is one of the most severe diseases affecting pear cultivation in Europe and the United States. Several psyllid species act as vectors of phytoplasmas belonging to the 16SrX group and play a key role in the epidemiology of the disease. This study aimed to characterize the epidemiology of pear decline in Sicily using integrated field, molecular, vector, and remote sensing approaches, four years after the first detection of PD in the region. Visual surveys and molecular analyses were conducted over two years in eight pear orchards. A total of 115 plant samples and 101 Cacopsylla spp. specimens, selected from 1435 collected individuals, were analysed, confirming the presence of 'Ca. P. pyri' in 69% of symptomatic plants and in 4.6% of C. pyri individuals. Genetic characterization revealed a high degree of similarity among the phytoplasma isolates analysed. Remote sensing analyses conducted since 2018, combined with vector population monitoring, confirmed the epidemic nature of PD and indicated the persistence of a risk of further pathogen spread within the region, supporting the use of remote sensing as a complementary tool for large-scale disease monitoring.

Pear decline, associated to 'Candidatus Phytoplasma pyri', has emerged in Chilean pear orchards in recent years. While several Cacopsylla species are potential vectors of 'Ca. P. pyri', the disease's full epidemiological cycle remains uncertain. Cacopsylla bidens, present in Chilean orchards, has recently been reported as a vector. This study conducted year-long surveys in two commercial pear orchards across different Chilean regions, capturing C. bidens in zones with 'Ca. P. pyri'-infected pear trees. All developmental stages were collected, with peak abundances occurring in March and April. Outside the study zones, C. bidens were found in pine trees but not in adjacent cultivated areas. Two seasonal morphotypes, summer and winter forms, were identified. Molecular analysis detected 'Ca. P. pyri' in a high proportion of insects, with maximum infection rates in March and April. These findings advance our understanding of 'Ca. P. pyri' spatial and temporal dynamics and their potential role in 'Ca. P. pyri' spreading under Chilean field conditions.

Valsa canker, a destructive necrotrophic disease caused by Valsa species (V. mali and V. pyri), threatens global apple and pear production. Resistance breeding has gained much attention because of its environmental friendliness and effectiveness, making it extremely critical to obtain key disease resistance genes. In this study, we identified that the expression of PbeSTOP2, a C2H2-type transcription factor in 'Duli-G03' (Pyrus betulifolia, rootstock of pear), was induced in response to signals from Vp and Vp metabolites (VpM). Transient expression in fruits and stable overexpression in suspension cells demonstrated that PbeSTOP2 enhances resistance to Vp. In overexpressing cells, genes associated with jasmonic acid (JA) and pattern-triggered immunity (PTI) signaling were upregulated, and endogenous JA and auxin (IAA) levels increased. These results revealed that JA signaling was involved in the enhanced Valsa canker resistance conferred by PbeSTOP2 overexpression. This finding on host disease resistance should facilitate the breeding efforts for Valsa canker resistance.

The high mutation rates of RNA virus replication generate genetically diverse virus variants in infected hosts. However, the effects of mutations on viral fitness and adaptability remain understudied in fungal-virus pathosystems. In this study, a novel hypovirus (single-stranded positive-sense RNA genome, family Hypoviridae), designated Valsa pyri hypovirus 1-α (VpHV1-α), and two of its shorter, less prevalent variants (VpHV1-β and VpHV1-γ), that contain different internal deletions in the N-terminal coding region of the viral protein, were identified in phytopathogenic Valsa pyri fungal strains. Repeated subculture of a fungal strain infected with VpHV1-α produced VpHV1-β and VpHV1-γ, demonstrating that VpHV1-β and VpHV1-γ were generated by the deletion of the VpHV1-α genome. Compared to VpHV1-α and VpHV1-β, VpHV1-γ, which has a larger deletion, attenuated fungal growth and pathogenicity while accumulating to higher levels. However, it exhibited lower vertical transmission efficiency through spores. Intriguingly, unlike VpHV1-α and VpHV1-β, VpHV1-γ showed restricted horizontal transmission via hyphal anastomosis. This restriction was associated with the induction of programmed cell death and transcriptional activation of vegetative incompatibility-related genes upon VpHV1-γ infection. Additionally, VpHV1-γ infection upregulated key components of RNA silencing (AGO3 and DCL2). Our results reveal a trade-off between viral accumulation and transmission efficiency, influencing the spread and persistence of VpHV1 variants in fungal populations. These findings provide new insights into viral evolution and host adaptation in natural fungal-virus ecosystems.IMPORTANCEStudies on mycoviruses are significant for advancing our understanding of viral evolution and host-pathogen interactions. In this study, we identified and characterized a novel hypovirus (VpHV1) infecting the plant-pathogenic fungus Valsa pyri. VpHV1 exists as three viral variants (α, β, and γ). Notably, the γ variant, the least prevalent and shortest due to an internal genomic deletion, exhibited unique phenotypic traits: enhanced viral accumulation and symptom severity but impaired horizontal and vertical transmission. Intriguingly, infection by the γ variant induces programmed cell death during hyphal anastomosis with an isogenic fungal strain, thereby preventing viral transmission. This vegetative incompatibility-like reaction may represent a previously unknown defense mechanism in filamentous fungi, functioning to restrict viral spread within genetically homogeneous populations. Our findings demonstrate that transmission ability is a critical selective factor in viral evolution and adaptation within host populations.