Search Results (265)

Diseases like downy mildew (DM) and powdery mildew (PM) are characterized by whitish symptoms on leaves of many plant species. Hyperspectral imaging (HSI) has been successfully used for the detection and identification of various diseases associated with different symptoms. Proximal HSI (400–1000 nm) was tested under controlled conditions for its potential to differentiate among whitish disease symptoms on leaves of apple and grapevine due to DM, PM, and a non-melanized mutant of apple scab at the leaf and tissue (microscopic) level. Spectral traits were analyzed by using difference spectra and spectral ratios, spectral vegetation indices like NDVI, and average brightness and half NIR increase introduced here and were confirmed by supervised spectral angle mapper classification. Although similar, spectral signatures of whitish symptoms were significantly different and could be used for spectral separation of diseases; differences were greater on the tissue level than on the leaf level. However, disease detection and differentiation were affected by spectral differences between plant species, leaf sides, the variability of symptoms in space and time, and the integrity of superficial pathogen structures. In the case of similar disease symptoms, additional spectral information on the effects of pathogens on plant metabolism, e.g., leaf water patterns, supports spectral differentiation of leaf diseases. Full article

Climate warming puts new selective pressures on natural populations, but there are few quantitative measurements of selection in natural populations over protracted time periods. Observations made at the beginning and end ofa 47-year cumulative increase of 2.7 °C in the mean September temperature in Northern Minnesota, USA, permit quantitative estimation of selection against a suite of alleles at a single locus determining the expressionof dark color forms in populations of the meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Cercopoidea: Aphrophoridae). Alternative methods of estimation of the selection coefficient s, a measure of the intensity of selection, produce values of s = 0.0125 and 0.0218, respectively, corresponding to a disadvantage of about one to two percent per year or, since P. spumarius is univoltine, per round of selection. The existence of a locus under selection presents an opportunity for molecular localization and characterization of the genetic locus determining color form. Philaenus spumarius is of particular interest in Europe, as it is the major local vector of the bacterial plant pathogen Xylella fastidiosa. Full article

Eisenia fetida is one of the soil invertebrates most used in ecotoxicological and ecopathological studies. To date, the potential contribution of naturally occurring parasites to the variability of ecotoxicological endpoints has been poorly investigated. In this study, we provide a detailed histological description of the male reproductive system of E. fetida and report the occurrence and histological alterations associated with Monocystis sp. infection in laboratory-reared individuals. Uninfected individuals exhibited complete spermatogenesis, with all developmental stages from spermatogonia to mature spermatozoa and normal sperm storage within the spermathecae. Meanwhile, infected earthworms displayed marked reproductive alterations, including reduced sperm production and diminished sperm retention within spermathecae. Multilayered encapsulations, inflammatory nodules and melanization were detected within the seminal vesicles, in contrast with the immunological evasion observed in Lumbricus terrestris. These findings suggest species-specific differences in immune response and indicate that Monocystis sp. infection can induce reproductive impairment and activate energy-consuming immune responses. Because these parasite-induced changes closely resemble pollutant-driven ecotoxicological effects, Monocystis infections may act as a potential bias in ecotoxicological studies. We therefore recommend implementing parasitological screening of laboratory cultures to ensure the reliability of studies employing E. fetida as a bioindicator. Full article

Background/Objectives: Galleria mellonella (G. mellonella) larvae have emerged as a valuable in vivo model for antifungal drug screening. This study aimed to determine the optimal inoculum concentrations of Candida albicans (C. albicans) in G. mellonella, as well as the appropriate fluconazole concentrations, in order to standardize a preliminary screening method for compounds with antifungal activity. Methods: Larvae were infected with four C. albicans strains, including two reference strains (ATCC^® 10231 and ATCC^® 90028) and two oral isolates (A1 and A2). Fluconazole toxicity was evaluated at doses of 20, 40, and 80 mg/kg over a 72 h period. In the treatment assays, larvae were infected via the left pro-leg and treated with fluconazole, administered as a single or two doses, one hour after infection. Larval viability was monitored over five days based on movement, cocoon formation, and melanization, and survival data were analyzed using Kaplan–Meier curves and the log-rank test. Results: Fluconazole showed no toxicity at the tested concentrations. Infection with up to 2 × 10⁷ cells/mL was non-lethal for most strains, except for A2, which exhibited 50% mortality within 48 h but it was effectively controlled with a single 20 mg/kg dose of fluconazole. Infection with 2 × 10⁸ cells/mL resulted in complete mortality within 48 h; however, a single 80 mg/kg dose significantly improved survival. Conclusions: The G. mellonella model proved to be a suitable and reproducible in vivo system for the preliminary screening of antifungal compounds. The standardized experimental conditions established in this study support its applicability for evaluating antifungal activity in early research stages. Future studies should expand this approach to different fungal species and antifungal agents, as well as explore its applicability in combination therapies. Full article

Modifications in leaf architecture disrupt optical properties and internal light-scattering dynamics. Accurate modeling of leaf-scale light scattering is therefore essential not only for understanding how disease affects the availability of light for chlorophyll absorption, but also for evaluating its potential as an early optical marker for plant disease detection prior to visible symptom development. Conventional ray-tracing and radiative-transfer models rely on high-frequency approximations and thus fail to capture diffraction and coherent multiple-scattering effects when internal leaf structures are comparable to optical wavelengths. To overcome these limitations, we present a GPU-accelerated finite-difference time-domain (FDTD) framework for full-wave simulation of light propagation within plant leaves, using anatomically realistic dicot and monocot leaf cross-section geometries. Microscopic images acquired from publicly available sources were segmented into distinct tissue regions and assigned wavelength-dependent complex refractive indices to construct realistic electromagnetic models. The proposed FDTD framework successfully reproduced characteristic reflectance and transmittance spectra of healthy leaves across the visible and near-infrared (NIR) ranges. Quantitative agreement between the FDTD-computed spectral reflectance and transmittance and those predicted by the reference PROSPECT leaf optical model was evaluated using Lin’s concordance correlation coefficient. Higher concordance was observed for dicot leaves ($C_b=0.90$) than for monocot leaves ($C_b=0.79$), indicating a stronger agreement for anatomically complex dicot structures. Furthermore, simulations mimicking an early-stage fungal infection in a dicot leaf—modeled by the geometric introduction of melanized hyphae penetrating the cuticle and upper epidermis—revealed a pronounced reduction in visible green reflectance and a strong suppression of the NIR reflectance plateau. These trends are consistent with experimental observations reported in previous studies. Overall, this proof-of-concept study represents the first full-wave FDTD-based optical modeling of internal light scattering in plant leaves. The proposed framework enables direct electromagnetic analysis of pre- and post-penetration light-scattering dynamics during early fungal infection and establishes a foundation for exploiting leaf-scale light scattering as a next-generation, pre-symptomatic diagnostic indicator for plant fungal diseases. Full article

Chitinases are crucial in the molting process of insects and represent potential targets for the development of RNA interference (RNAi)-based insecticidal strategies. In this study, we identified and characterized 11 chitinase genes (TaChts) in T. absoluta, each harboring at least one GH18 catalytic domain. Phylogenetic analysis placed these proteins into 11 established groups (I-X and h), revealing conserved lineage-specific patterns. Spatiotemporal expression profiling showed that most TaChts peak during key developmental transitions. TaCht1, TaCht2, TaCht3, TaCht5, TaCht6, TaCht7, TaCht10, TaCht-h, and TaIDGF were predominantly expressed in the integument, whereas TaCht8 and TaCht11 showed gut-enriched expression, indicating functional specialization. Stage-tailored RNAi assays demonstrated that silencing TaCht5, TaCht7, TaCht10, and TaIDGF caused pronounced mortality in both larvae and pupae. In larvae, delivery of dsRNA using carbon quantum dots (CQDs) disrupted molting: knockdown of TaCht7, TaCht10, and TaIDGF prevented shedding of the old cuticle, whereas TaCht5 silencing produced severe cuticular shrinkage and blackening. Hematoxylin and eosin staining revealed detachment of epidermal cells from the cuticle, providing cytological evidence of disrupted cuticle–epidermis remodeling. In pupae, microinjection of dsRNA induced cuticular collapse, melanization, and eclosion failure due to persistent adhesion of the pupal case, accompanied by marked reductions in chitinase activity. Together, our findings highlight the critical roles of four key chitinases in endocuticular turnover and metamorphic progression in T. absoluta, offering mechanistic insight into chitin-mediated developmental processes. The identified genes represent strong candidates for RNAi-based, species-specific pest management strategies against this globally significant insect. Full article

The Spt-Ada-Gcn5 acetyltransferase (SAGA) complex is a conserved transcriptional coactivator that coordinates histone modifications and transcriptional regulation in eukaryotes. In Cryptococcus neoformans, SAGA governs key virulence traits, yet the roles of several core scaffold subunits remain undefined. Here, we characterize the functional roles of Spt7, a core SAGA component, in C. neoformans. Comparative genomics revealed that C. neoformans Spt7 retains conserved histone fold and bromodomain motifs. Deletion of SPT7 produced pleiotropic phenotypes, including defective melanization and capsule formation, impaired titan cell development, and heightened sensitivity to thermal, metal, antifungal, and cell wall stresses. The spt7Δ mutant exhibited strong sensitivity to the echinocandin micafungin, implicating Spt7 in maintaining cell wall integrity. The spt7Δ mutant was avirulent in a murine inhalation model. At the chromatin level, SPT7 deletion disrupted SAGA-dependent histone post-translational modifications, increasing H2B ubiquitination while reducing H3K14ac and H3K18ac levels. Proteomic profiling revealed reduced abundance of ribosomal, mitochondrial, and translational proteins and upregulation of lipid metabolic and secretory pathway components. Collectively, our findings establish Spt7 as a central integrator of SAGA-mediated chromatin regulation, proteomic balance, and virulence in C. neoformans and highlight the SAGA core as a potential antifungal target. Full article

Calonectria ilicicola (anamorph: Cylindrocladium parasiticum) is a globally important soil-borne fungal pathogen, causing Cylindrocladium black rot (CBR) in peanuts (Arachis hypogaea) and red crown rot (RCR) in soybeans (Glycine max), two legume crops central to global food security. Under favorable conditions, these diseases can cause yield losses of 15–50%, with severe epidemics causing substantial economic damage. A defining feature of C. ilicicola is its production of melanized microsclerotia that persist in soil for up to seven years, complicating long-term disease management across major production regions worldwide. The recent spread of RCR into the U.S. Midwest highlights the adaptive potential of the pathogen and underscores the urgency of updated, integrated control strategies. This review synthesizes current knowledge on disease symptoms, pathogen biology, the life cycle, isolation techniques, and molecular diagnostics, with particular emphasis on recent genomic and multiomics advances. These approaches have identified key virulence-associated genes and core pathogenicity factors, providing new insights into host–pathogen interactions and enabling more targeted resistance breeding through marker-assisted selection and the use of wild germplasm. We critically evaluate integrated disease management strategies, including host resistance, chemical and biological control, cultural practices, and physical interventions, highlighting their complementarities and limitations. By integrating classical pathology with emerging molecular and ecological innovations, this review provides a comprehensive background for developing more effective and sustainable management approaches for CBR and RCR. Full article

Light is a fundamental ecological cue for insects, influencing physiological rhythms and behavior. We investigated how varying light intensities affect locomotion and foraging in H. axyridis color morphs, and examined the role of visual opsins. Three adult female morphs were assayed under white light at 1000, 5000, and 10,000 lx. Higher light intensity significantly elevated body temperature and locomotor activity across morphs, with the inherently dark f. conspicua morph exhibiting the greatest increases. Predation rates on pea aphids trended upward with intensity but differed significantly by morph: f. conspicua beetles consistently consumed more prey than f. succinea. RNAi knockdown of the UV-sensitive opsin HaUVSop-2 significantly reduced the crawling distance of satiated beetles under 5000 lux white light. Correspondingly, supplementation of white light with blue light (short wave) enhanced movement, whereas red supplementation increased aphid consumption. These results suggest that Short-wavelength light has the potential to stimulate the dispersal of ladybirds, whereas long-wavelength light may enhance predation on prey by increasing microenvironment temperature or improving prey recognition. We conclude that light intensity and spectrum jointly modulate H. axyridis behavior in a morph-dependent manner, mediated in part by visual opsins. Melanic morphs leverage thermal melanism to gain higher activity under bright light, implying an evolved trade-off between dispersal and stress tolerance. Our findings have practical implications: tailored lighting (e.g., blue-enhanced illumination to stimulate predation and dispersal of H. axyridis) could improve biological control efficacy in agroecosystems. Full article

Biological control using beneficial microbes offers a sustainable alternative to chemical fungicides for managing postharvest diseases. This study reports the isolation and characterization of Bacillus amyloliquefaciens AsL-1 from the latex of Alstonia scholaris (L.) R. Br., unconventional ecological niche. The cell-free supernatant (CFS) of AsL-1 showed strong antifungal activity, inhibiting the growth of Colletotrichum musae (48.89 ± 0.57%), Glomerella cingulata (52.22 ± 0.00%), Fusarium graminearum (47.78 ± 0.57%), and Colletotrichum gloeosporioides (47.78 ± 0.00%) in vitro. Microscopy revealed that the CFS disrupted fungal development by blocking conidial germination and appressorium formation, and in C. gloeosporioides caused melanization defects linked to reduced virulence. In vivo tests on mango fruit confirmed that AsL-1 significantly decreased anthracnose lesion size and disease incidence. Protein analyses (SDS-PAGE, gel overlay, and LC-MS/MS) identified two antifungal proteins (24 and 16 kDa), corresponding to β-1,3-1,4-glucanase and flagellin. The detected β-1,3-1,4-glucanase activity indicates its role in degrading fungal cell walls and interfering with melanin biosynthesis pathways essential for pathogenicity. Overall, these findings highlight B. amyloliquefaciens AsL-1 as a promising protein-based biocontrol agent and show that latex-associated microbes may serve as valuable sources of new antifungal strategies. Full article

Uterine angiomyolipoma (AML) is an exceptionally rare mesenchymal tumor of the perivascular epithelioid cell tumor (PEComa) family. Most cases are benign and exhibit a triphasic histologic pattern. Although extragenital PEComas typically show strong, diffuse HMB-45 reactivity, uterine AMLs/PEComas often exhibit weak or negative staining, thereby introducing diagnostic uncertainty. We describe a rare case of uterine AML with diffuse nuclear atypia in a postmenopausal woman, which mimicked a degenerative leiomyoma or leiomyosarcoma. A 49-year-old postmenopausal woman presented with the rapid enlargement of a uterine mass that had been followed for four years as a presumed leiomyoma. Imaging revealed a well-circumscribed uterine mass with heterogeneous enhancement, cystic degeneration, and restricted diffusion on MRI. A total hysterectomy was performed. Grossly, the tumor measured 8 cm. Microscopically, it consisted of pleomorphic epithelioid cells (70%), mature adipose tissue (20%), and thick-walled vessels. Immunohistochemistry revealed diffuse smooth muscle actin (SMA) positivity, while Human Melanoma Black (HMB)-45 and Melan-A were negative. Only one mitosis per 50 HPF was identified, with no atypical mitoses or necrosis, and the Ki-67 index was low (<5%). The patient has remained disease-free for 56 months post-surgery. This case represents the first documented HMB-45-negative uterine angiomyolipoma with diffuse nuclear atypia, characterized by a low mitotic index, low Ki-67 proliferation rate, and a benign 56-month follow-up. It broadens the morphologic spectrum of uterine AML, demonstrating that diffuse nuclear atypia can occur in HMB-45-negative tumors with benign behavior, and that atypia alone should not be interpreted as evidence of malignancy. Recognition of this rare variant is essential to avoid misdiagnosing it as leiomyosarcoma. Full article

Cutaneous melanoma remains one of the most aggressive tumors, yet the role innate immunity plays in its progression remains poorly understood. Effector elements with high regulatory potential, capable of both promoting and inhibiting tumor growth—mast cells (MCs), are of particular interest. This includes quantitatively characterizing the interactions between tryptase-positive mast cells (MCs) with atypical Melanin—A⁺ cells and describing their spatial phenotype, in relation to the stage of cutaneous melanoma. A retrospective analysis was carried out on samples retrieved from 128 patients with cutaneous melanoma (AJCC 8th edition: IA–IIID). Histological analysis, histochemistry (toluidine blue, Giemsa), and diplex /multiplex IHC for tryptase and Melan-A were performed; as well as Fluorescence imaging, 3D reconstructions and quantitative mapping in QuPath v 0.6.0. Proximity was assessed by the nucleus-to-nucleus distance: <10 μm (contact), 10–20 μm (paracrine zone), >20 μm (out of interaction). The relative amount of MCs in the intratumoral zone was lower than in the intact dermis, with a simultaneous increase in their absolute density per mm² in the melanoma microenvironment, maximum in the peritumoral area and most pronounced at stage II. Three types of interactions were identified: (i) juxtaposition without secretion, (ii) degranulation of MCs directed to tumor cells, (iii) melanosecretion of Melanin—A⁺ cells directed towards MCs, followed by phagocytosis of melanocores. An inverse intratumoral connection between the number of MCs and the number of Melanin—A⁺ cells was noted; MCs with elongated forms, extensive contacts and polarized tryptase secretion, including granule localization near/at the nuclei of adjacent cells, were frequently observed. The obtained data indicate stage-region-dependent bidirectional cross-talk between melanin and MCs, forming tissue spatial signals, potentially useful as biomarkers and targets for personalized therapy. Full article

Hemocytes (insect blood cells) consist of several morphological types and perform a variety of physiological processes, including immune responses. However, we do not know how many cell types are functionally differentiated in hemocytes or how they perform independent physiological processes. To address this fundamental question, we analyzed hemocyte transcripts with a single-cell RNA-sequencing (scRNA-Seq) technique. The hemocytes were collected from larvae of a lepidopteran insect, Spodoptera exigua, in which four different hemocyte types were morphologically recognized. scRNA-Seq discriminated 24 hemocyte clusters based on the transcripts of each cell. The clusters were separated into seven functional groups predicted from the top three highly expressed and annotated genes in each cluster: active protein synthesis (12 clusters), apoptosis (5 clusters), melanization (2 clusters), modulating cell shape (6 clusters), antimicrobial peptide production (9 clusters), calcium homeostasis (8 clusters), and cell repairing (1 cluster). Signal components of Toll/IMD immune pathways were variably expressed among the clusters. Biosynthetic genes associated with oxylipin immune mediators were specifically expressed among the clusters. Immune effectors such as melanization and apoptosis were expressed in specific hemocyte clusters. Specifically expressed genes that discriminate hemocyte types were used to develop fluorescence in situ hybridization (FISH) markers. In addition, five new hemocyte groups, which were not among the four known hemocyte types in the transcript profile, were identified and discriminated with their specific FISH markers. The hemocyte clusters underwent dynamic changes upon immune challenge. A trajectory analysis using the transcriptome suggests at least three different hemocyte differentiation pathways. These results indicate that the hemocytes of S. exigua are functionally highly differentiated and exhibit a dynamic transition in response to environmental changes. Full article

Sclerotinia sclerotiorum (Lib.) de Bary, the causal agent of Sclerotinia stem rot (SSR) or white mold, is a soil-borne hemibiotrophic fungus that causes substantial soybean yield losses worldwide. This pathogen infects over 400 plant species and persists in soil for extended periods through melanized sclerotia, which can survive under extreme environmental conditions. The wide host range, environmental adaptability, and longevity of sclerotia make SSR a persistent challenge in soybean production. No single management tactic provides reliable control, which underscores the importance of integrated pest management (IPM). Cultural practices such as crop rotation with non-hosts, optimized row spacing, adjusted seeding rates, and targeted irrigation are fundamental to reducing inoculum and modifying canopy microclimates to slow infection. Although genetic resistance remains partial, the deployment of cultivars with stable performance across environments contributes to disease suppression, particularly when combined with fungicide applications. However, fungicide efficacy is inconsistent and limited due to environmental concerns and potential resistance. Advances in disease modeling have improved the timing and precision of chemical control, while biological control agents and RNA interference approaches offer promising future options. This review synthesizes current IPM strategies for SSR and explores emerging alternatives to support sustainable soybean production. Full article

Starry flounder (Platichthys stellatus) is extensively farmed in Korea, and the importance of aquaculture technology in the economic and industrial sectors continues to grow. However, pigmentation anomalies, such as skin discoloration during farming, have resulted in significant economic losses. Despite continuous research to uncover the underlying causes, genomic research in this area remains insufficient. This study utilized RNA-seq with de novo assembly analysis to establish candidate genes in brain tissue related to pigmentation variation in P. stellatus. Genes associated with albinism and melanism were identified, with 1053 genes linked to albinism and 642 genes associated with melanism. Functional analysis of these genes was also conducted using gene ontology analysis, categorizing the genes according to biological processes, cellular components, and molecular functions. KEGG pathway analysis revealed significant associations with five pathways for albinism and two pathways for melanism in brain tissue. The large-scale gene expression profiles identified in this study provide valuable genomic resources for future studies of aquaculture species, including P. stellatus. While the findings provide valuable genomic insights, the study was limited to brain tissue analysis and requires further gene-level validation. Full article