Search Results (274)

Detection of brown spot needle blight (BSNB) disease caused by the fungal pathogen Lecanosticta acicola (Thum.) Syd. has increased significantly at commercial loblolly pine (Pinus taeda L.) plantations across the southeastern United States in recent years. Historically, it has been a serious problem in longleaf pine (Pinus palustris Mill) during the grass stage of seedlings, when the environment is more conducive to fungal infection. However, since 2016, confirmed cases of the disease on loblolly pines have increased in several states, including AL, AR, FL, GA, LA, MS, SC, TN, and TX. We investigated the distribution pattern of confirmed cases of BSNB on loblolly pine between 2016 and 2023, identified site-specific factors, and evaluated the historical standardized precipitation index (SPI) value record over the past four decades. Our results showed that extended periods of above-normal SPI values are associated with BSNB spatial distribution patterns, particularly where the disease has been widely reported in AL, AR, LA, and MS. We observed significant reduction in tree height and dbh in severely infected versus healthy trees at the six study sites evaluated in 2023. Excessive rainfall and prolonged water saturation associated with historical 5-Year SPI values suggest that vulnerable loblolly pine seedlings (depending on genetic family) are more likely to be predisposed to L. acicola infection due to persistent stress from reduced soil nutrient flux and other physiological processes of the host. Understanding the effect of precipitation patterns on cases of BSNB is an important step toward preventing or minimizing the future impact of the disease on commercial plantations in the Southeast. Full article

Cryptocaryon irritans Brown, 1951, a ciliated protozoan, is the pathogen of cryptocaryoniasis (white spot disease) in marine fish, causing substantial morbidity and mortality, particularly in tropical and subtropical regions. This is the first study to investigate the antiparasitic activity of baohuoside I, a natural flavonoid isolated from Epimedium brevicornu Maxim., against C. irritans. In vitro exposure to baohuoside I suppressed theront viability and tomont hatching in a dose- and time-dependent manner, inducing an apoptosis-like death in both stages, characterized by ciliary detachment, mitochondrial disruption, nuclear condensation, and extensive vacuolization, as evidenced by transmission electron microscopy and Annexin V-FITC/PI staining. Further studies demonstrated that baohuoside I elevated the intracellular Ca²⁺ and reactive oxygen species levels in tomonts, indicating Ca²⁺ overload and oxidative stress. Transcriptomic analysis of infected Larimichthys crocea skin revealed that baohuoside I upregulated immune-related genes while downregulating pro-inflammatory genes, concurrently enhancing host serum acid phosphatase activity and mitigating oxidative stress in enzyme activity assays. In vivo trials showed that oral administration of baohuoside I reduced trophont attachment and improved fish survival. It did not exhibit hemolytic activity at concentrations effective against the parasites. Collectively, these findings elucidate a multi-target mechanism of baohuoside I, highlighting its potential as an eco-friendly therapeutic agent for cryptocaryoniasis control in marine aquaculture. Full article

The increasing interest in valorizing agricultural by-products has positioned grape pomace as a rich source of bioactive compounds. This study developed an effect-directed extraction (EDE) approach guided by bioactivity quantification on thin layer chromatography (TLC). Twelve grape pomaces were screened based on antioxidant and tyrosinase inhibitory properties. Using hydroalcoholic solvent (ethanol:water, 1:1), the two most promising sources (Malbec from San Rafael) were subjected to response surface methodology (RSM) to optimize extraction of anti-browning and antioxidant compounds visualized as TLC spots. Temperature and time were optimized (76 °C, 45 min), and samples were analyzed using TLC coupled with DPPH and laccase inhibition bioautography. Antioxidant compounds showed retention factor values on TLC plates of 0.37 and 0.75 (DPPH/ABTS-active), while laccase inhibition occurred at Rf 0.35, coinciding with the primary tyrosinase inhibition zone. However, subsequent bioassay-guided HPLC fractionation and HRMS/MS analysis revealed that tyrosinase and laccase inhibitions are mediated by distinct compounds within this bioactive zone, highlighting a synergistic multi-target effect in the optimized extract that is retained throughout the process. The primary tyrosinase inhibitor at Rf ~0.35 was tentatively elucidated as an acylated anthocyanin, consistent with malvidin-3-O-(p-coumaroyl)glucoside. Optimized extracts were evaluated on Pink Lady apple slices at different timepoints. The browning index was reduced by 25% versus the control at 15 h, confirmed by significantly lower ΔE values (p < 0.05). The process requires only food-grade solvents and conventional equipment, facilitating scale-up for grape pomace generated worldwide. Validating the EDE strategy, this TLC-guided approach successfully tracked and preserved the primary anti-tyrosinase activity from the crude waste matrix down to the tentatively identified molecule, contributing to circular economy objectives in the wine industry. Full article

Viral diseases pose a major threat to tomato cultivation, mainly due to the lack of effective antiviral control methods. Plant growth-promoting microorganisms (PGPMs) represent a promising and sustainable strategy for virus disease management, as, in addition to plant growth, they can promote resistance to pathogens. In this study, we examined the antiviral potential of selected PGPMs against three economically important and genetically distinct tomato viruses, tomato spotted wilt virus (TSWV, Orthotospovirus tomatomaculae), cucumber mosaic virus (CMV, Cucumovirus CMV), and tomato brown rugose fruit virus (ToBRFV, Tobamovirus fructirugosum) under controlled greenhouse conditions. The efficacy of each PGPM was assessed by monitoring disease development via visual scoring and DAS-ELISA. Our results indicate a significant TSWV symptom attenuation upon the application of Paraburkholderia eburnea EP3 and the yeast isolate SRL248, though, without a respective reduction in virus accumulation. However, no antiviral effect was observed by any PGPM tested against CMV or ToBRFV. A targeted gene expression analysis revealed a PGPM-specific induction of salicylic acid-dependent defense and RNA silencing markers, indicating priming of host immune responses. Overall, this work increases our knowledge on the antiviral potential of PGPMs showing a strain- and virus-specific effect primarily associated with enhanced symptom tolerance. Full article

Essential oils (EOs) have gained attention as biodegradable biopesticides for sustainable crop protection. This study investigated the chemical composition, antifungal activity and antioxidant potential of EOs from Mentha pulegium (EO-MP) and Cymbopogon citratus (EO-CC) against Bipolaris oryzae, the causal agent of rice brown spot, including the first quantitative determination of IC₅₀ values through standardized dose–response modeling and temporal evaluation of antifungal efficacy. Volatile profiles of both EOs were characterized by gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography–mass spectrometry (GC-MS). Antifungal activity was evaluated in vitro by a poisoned food assay at six concentrations ranging from 9.375 to 300 µL per plate (0.469–15.000 µL/mL PDA medium). Mycelial growth inhibition was assessed after 7 and 14 days of incubation. Antioxidant potential was determined by ferric reducing antioxidant power (FRAP) assay while protection against lipid oxidative damage was evaluated through inhibition of lipid peroxidation by the thiobarbituric acid reactive substances (TBARS) method. Both EO-MP and EO-CC exhibited strong, dose-dependent antifungal effects and achieved complete inhibition of mycelial growth at ≥37.50 µL per plate (1.875 µL/mL PDA) and ≥18.75 µL per plate (0.938 µL/mL PDA), respectively. EO-MP showed high reducing capacity (its FRAP value was 1.45 Trolox equivalent antioxidant capacity—TEAC) and high inhibition of lipid peroxidation (89.09%). Similarly, EO-CC exhibited a FRAP value of 1.55 TEAC and lipid peroxidation inhibition of 87.66%. These findings highlight the biofungicidal activity and multifunctional antioxidant-related properties of EOs from M. pulegium and C. citratus, supporting their potential application as eco-friendly tools for sustainable rice brown spot management. Full article

Brown spot, caused by the fungus Bipolaris oryzae, has led to significant yield losses in rice production worldwide. This study hypothesized that azelaic acid (AzA) could reduce brown spot symptoms in rice leaves by potentiating biochemical defense reactions. A 2 × 2 factorial experiment was arranged in a completely randomized design with five replications per sampling time. The factors studied were plants sprayed with water (control) or AzA (10 mM; 7.5 mL per plant), either non-inoculated or inoculated with B. oryzae. In the in vitro assay, conidia exposed to AzA solutions at rates of 2.5, 5, 7.5, and 10 mM and to the fungicide solution did not form germ tubes compared to those in the control (water) treatment. The area of fungal colonies on oat–agar medium was reduced for the fungicide and AzA (rates increasing from 2.5 to 10 mM) treatments compared to the control (water) treatment. The EC₅₀ value was 3.8 mM AzA. Brown spot severity significantly decreased by 57, 48, 52, and 58% at 36, 60, 84, and 108 h after inoculation (hai) for AzA-sprayed plants compared to water-sprayed ones. The area under brown spot progress curve significantly decreased by 53% for AzA-sprayed plants compared to water-sprayed ones. Greatest activities of defense-related enzymes (chitinase at 108 hai, β-1,3-glucanase at 60 hai, phenylalanine ammonia-lyase at 60 and 108 hai, and lipoxygenase at 84 and 108 hai), a higher concentration of lignin at 84 and 108 hai, and a more robust antioxidative metabolism (higher activities of ascorbate peroxidase at 36 hai, catalase at 84 and 108 hai, and superoxide dismutase at 84 hai) were obtained for AzA-sprayed infected plants. The higher concentration of the superoxide anion radical in AzA-sprayed infected leaves helped to intensify the cell defense reactions against fungal infection and had a fungistatic effect against its hyphae and conidia germination. The findings of this study provide valuable insights into using AzA to potentiate foliar defense reactions in rice plants to hamper the infection by B. oryzae. Full article

Ultrapure water (UPW) distribution loops must deliver stable hydraulics while limiting contamination from polymer piping. This study integrates computational fluid dynamics (CFD) with systematic pipe autopsy to examine contaminant behavior in a pilot-scale UPW loop constructed using chlorinated polyvinyl chloride (CPVC) and polyvinylidene fluoride (PVDF) and operated under identical conditions. CFD predicted nearly identical loop-scale velocity, pressure, and temperature fields for both materials, and identified low-shear recirculation at elbows and downstream tees as zones of elevated particle residence. Lagrangian particle tracking (0.05 μm, no-sticking) showed rapid breakthrough and complete flushing within 13 min, providing a hydraulic susceptibility map for transient retention. After eight months of operation, 17 sections were inspected endoscopically and leached at 60 °C. CPVC exhibited yellow–brown discoloration and highly heterogeneous total organic carbon (TOC) release with hot spots of 16–18 mg·L⁻¹, whereas PVDF showed low, spatially uniform TOC (0.4–2.3 mg·L⁻¹) and minimal fouling; inorganic ions remained at sub-mg·L⁻¹ levels for both materials. Overall, geometry governs where contamination can accumulate, while material properties control its magnitude and persistence, with PVDF providing greater resistance to long-term organic contamination than CPVC. Full article

Brown spot, caused by the seedborne fungus Bipolaris oryzae, remains a major constraint in rice production. Here, we used in vitro and in vivo assays to evaluate the biocontrol potential of three Bacillus strains (Ba. cereus OQ725688.1, Ba. velezensis OP938696.1, and Ba. subtilis OP937353.1) against Bi. oryzae in two rice cultivars (“Rubelita” and “Predileta”). Ba. cereus showed the highest in vitro mycelial inhibition (≈95%), whereas Ba. velezensis was the most effective under greenhouse conditions, reducing disease severity by up to 60% and increasing seedling vigor by 51% compared with infected controls. “Predileta” showed the strongest response to bacterial treatment, maintaining severity scores below 2 even under high inoculum pressure. Functional assays confirmed that all strains displayed amylolytic, catalase, and phosphate-solubilizing activities, with Ba. velezensis uniquely expressing strong cellulase and protease activities. Genome analysis of Ba. velezensis OP938696.1 revealed multiple biosynthetic gene clusters for antifungal polyketides and lipopeptides. These integrated biochemical and genomic traits demonstrate the novelty and potential of this Neotropical strain as a multifunctional agent capable of suppressing Bi. oryzae while enhancing rice seedling performance. Incorporating such a native strain into seed and soil management offers a sustainable strategy for rice protection in Neotropical systems. Full article

Diseases caused by Bipolaris sorokiniana, expressed as leaf spot blotch (SB) and common root rot (CRR), continue to limit spring wheat production, particularly in dry regions where yield losses may reach 35–40%. This study evaluated resistance to SB and CRR in fifty spring wheat genotypes at both seedling and adult plant stages and identified genetic sources of resistance using molecular markers linked to the Sb1 and Sb2 genes. Field trials were conducted in 2023 and 2024 in the Aktobe region under natural infection, artificial inoculation, and a fungicide-treated background. Based on leaf spot blotch severity quantified as the area under the disease progress curve (leaf AUDPC) under natural infection, nine genotypes displayed stable resistance across both years, while fungicide-treated plots revealed twenty-three resistant genotypes in 2023 and eighteen in 2024. Artificial inoculation identified five resistant lines in 2023 and one in 2024. Resistance to common root rot (CRR) was assessed independently based on subcrown internode (SCI) browning at the adult plant stage. Seedling assays confirmed consistent resistance in six genotypes, all of which carried Sb1, Sb2, or their combination. In total, Sb genes were detected in thirty-six of the fifty accessions, including genotypes from Kazakhstan, Russia, and several other countries. The presence of Sb1 or Sb2 was associated with reduced disease severity, particularly at the seedling stage. These findings identify valuable germplasm for breeding wheat with improved resistance to B. sorokiniana in Kazakhstan. Full article

Blood and meat spots are key internal egg quality indicators, and clarifying their genetic characteristics in late laying periods is critical for quality improvement via selective breeding. This study collected 392 eggs from 421 96-week-old Rhode Island Red hens across 69 families, analyzing 10 traits including blood/meat spots and standard egg quality traits. Heritability, genetic and phenotypic correlations were estimated using the DMU package. The incidences of blood and meat spots were 15.8% and 64.8%, respectively. Blood spots were yolk-localized, single and <1 mm in diameter, while meat spots mostly occurred on chalazae (83.5%) and thick albumen (33.1%), mostly multiple (56.1% with 2–5 spots) and 1.80 ± 1.53 mm in diameter (30% >2 mm). Blood spots had low heritability (0.05), meat spots moderate heritability (0.20). The two traits showed high positive genetic correlation (r_G = 0.93), and strong negative genetic correlations with albumen height and eggshell strength. In conclusion, blood and meat spots in late-laying hens differ in distribution, size and number, and meat spots are amenable to genetic selection for internal egg quality enhancement. Full article

Plum (Prunus salicina Lindl.), belonging to the genus Prunus in the Rosaceae family, is one of the most widely cultivated deciduous fruit trees globally. Plums are renowned for their round, sweet fruits, which are rich in a variety of bioactive compounds and are deeply loved by consumers. However, in 2021, alarming reddish-brown–dark brown sunken lesions appeared on the fruits of Qingcui plums in Wanzhou, Chongqing, China. The pathogens were identified as Colletotrichum nymphaeae, Fusarium sulawesiense, and Fusarium pernambucanum. The present study further describes the growth patterns and pathogenic differences of these strains in different environments, elucidating their infection mechanisms and pathogenic characteristics; these findings provide a theoretical basis for the efficient management of plum brown spot disease. Additionally, we determined that fluazinam is the most effective control agent against the plum brown rot caused by these pathogens. Notably, this study is the first to document plum brown spot disease induced by C. nymphaeae in China. These findings are intended to provide a vital theoretical framework for the scientific management and control of plum brown spot; furthermore, they underscore the necessity of proactive prevention strategies in agricultural settings. Full article

European plum (Prunus domestica) orchards in the Kashi region, Xinjiang, China, suffer from fruit brown spot disease. The disease typically appears as red spots on the fruit surface that expand into brown necrotic lesions; affected fruit flesh can shrink, and fruits can harden and drop. We isolate and identify pathogens associated with this disease in this plum from five Kashi counties. Of 210 fungal isolates obtained through standard tissue isolation, Alternaria accounted for 84.8%, with the remainder comprising species of Aspergillus (9.5%), Diplodia (3.3%), and Neoscytalidium (2.4%). Using PCR amplification and sequencing of five loci, pathogens were identified using multi-gene phylogenetic analyses, combined with observations of colony and spore morphology. Multi-locus sequences of Alternaria isolates were highly homologous to those of the Alternaria alternata type strain, and we refer them to an A. alternata species complex. Pathogenicity tests confirm that Alternaria isolates reproduce brown spot symptoms on European plum fruits. By demonstrating that Alternaria is the primary pathogen causing brown spot disease in European plum in Xinjiang, we clarify both the fungal species composition and taxonomic placement of the dominant pathogen associated with this disease. Full article

The paper describes a predatory Gram-negative bacterium from the genus Bdellovibrio, which was isolated from water of the Lyubozhikha River. As revealed by electron microscopy, the bacterium is an intracellular predator of Gram-negative microorganisms. Its prey range includes Pseudomonas tolaasii, the phytopathogen responsible for brown spot disease in the cultivated button mushroom (Agaricus bisporus). Based on the results of a 16S rRNA gene sequence analysis, the bacterium was identified as Bdellovibrio bacteriovorus strain LR3. We characterized the predator–prey dynamics between B. bacteriovorus LR3 and P. tolaasii, determining the optimal temperature and pH conditions for this interaction. Our results demonstrate the potential of B. bacteriovorus LR3 as a biocontrol agent against P. tolaasii in mushroom cultivation. The possibility of using B. bacteriovorus LR3 against clinical cases Salmonella and Escherichia infections is also addressed. Full article

European plum (Prunus domestica L.) is widely cultivated worldwide, with China producing 6.8 million t annually (55% of the global total output). However, the Kashgar region of Xinjiang, China’s primary production area, has experienced outbreaks of brown spot disease caused by Alternaria alternata (Fr.) Keissl. Outbreaks of this disease severely hinder both domestic and global development of the European plum industry. Because this pathogen has a strong latent infection capability during the early stages of disease development, its early detection is important. We develop two detection methods targeting the ITS sequence of A. alternata: LAMP-Cresol Red chromogenic visible endpoint detection and LAMP-SYBR Green I real-time fluorescent detection. Both methods demonstrate high specificity for A. alternata, enabling stable detection of the pathogen in various plant samples; detection limits reach the femtogram (fg) level, significantly surpassing conventional PCR detection capabilities. Development of these highly efficient and precise early detection methods provides a solid foundation for sustainable development of China as a global hub of the European plum industry, and contributes significantly to global disease prevention, control, and industrial stability for this crop. Full article

Citrus bacterial canker (CBC), caused by Xanthomonas citri subsp. citri (Xcc), threatens citrus production worldwide. Long-term dependence on copper-based bactericides not only poses environmental risks but also accelerates the emergence of copper-resistant Xcc strains. To develop safe and efficient alternative control strategies, 72 bacterial strains were isolated from the phyllosphere of citrus plants naturally infected by CBC and identified by 16S rRNA sequencing. Using an Xcc-GFP-based screening method, we systematically screened a highly effective strain, which was identified as Bacillus velezensis RF2 (Bv-RF2). Both inhibition zone assays and bioactivity tests of the crude methanolic extract of Bv-RF2 demonstrated stable antibacterial activity under UV irradiation, protease treatment, high temperature, and across a wide pH range. Whole-genome sequencing and antiSMASH analysis revealed multiple predicted NRPS/PKS-type biosynthetic gene clusters (BGCs). Together with metabolomic profiling, these data provide hypotheses for candidate metabolites that may contribute to antagonism. Bv-RF2 was associated with the induction of PR gene expression in immune-related pathways implicated in CBC responses. In sweet orange leaves, Bv-RF2 infiltration was associated with transient induction of defense-related (PR) genes, consistent with an ISR-like, priming-related response. In addition, Bv-RF2 inhibited the growth of fungal pathogens associated with citrus anthracnose and brown spot in vitro, indicating broad inhibitory potential under the tested conditions. Collectively, Bv-RF2 represents a promising candidate for developing environmentally friendly strategies against CBC and other citrus diseases. Full article