Spores Research Articles

In Vitro Evaluation of Selenium Against Some Plant Pathogenic Fungi

Objective: Selenium (Se) is garnering interest as a promising environmentally friendly element for controlling fungal pathogens in agricultural production. This study evaluated the impact of Se treatments, comprising sodium selenite (selenite) and sodium selenate (selenate) forms, on the growth of 10 plant pathogenic fungi. Materials and Methods: The impact of Se treatments on the mycelial growth and sporulation of fungi was assessed in in vitro conditions. Probit analysis was used to determine the concentrations of salts that induced a 50% reduction (EC50) in both mycelial growth and sporulation of fungi. Results: At the highest concentration (120 ppm), selenite demonstrated inhibitory effects on mycelial growth across various species, with a reduction in growth ranging from 6.82% to 62.46%. In contrast, selenate exhibited a broader spectrum of inhibition, affecting mycelial growth from 0% to 87.14%. Across different concentrations, Fusarium pseudograminearum displayed the highest sensitivity to selenite (EC50

First Report of Fruit Rot Disease on melon (Cucumis melo L.) Caused by Fusarium ipomoeae in China.

Fusarium rot on melon fruit has become an important postharvest disease for producers worldwide, typically involving multiple Fusarium pathogens (Khuna et al. 2022; Medeiros Araújo et al. 2021). In 2022, Fusarium fruit rot of muskmelon (Cucumis melo var. conomon) occurred sporadically in a field at Huainan Academy of Agricultural Sciences (32.658193º N, 117.064922º E) with an incidence of about 10%. Among these diseased muskmelons, a fruit exhibiting a white to yellowish colony athe intersection of the diseased and healthy tissues was collected and labeled TGGF22-17. The streak plate method was employed to isolate fungal spores on Bengal Red PDA (potato dextrose agar), which were then incubated at 25℃ in darkness. Following isolation and purification, a single-spore strain, TGGF22-17, was obtained and analyzed using morphological characters on PDA, synthetic nutrient agar (SNA) and carnation leaf agar (CLA) (Leslie and Summerell 2006), along with molecular identification. Colours were rated according to the color charts of Kornerup and Wanscher (1978). Based on the colony morphology on PDA, the isolate displayed a rosy buff or buff color with a white to buff margin. The colony margin was undulate, with the reverse transitioning from amber-yellow to honey-yellow. Aerial macroconidia on SNA were thin-walled, hyaline, mostly 3-5 septate, falcate, and measured 18.5-46.4 (x̄=34.2) × 2.9-4.8 (x̄ =3.9) μm in size (n =50). Sporodochial macroconidia on CLA were mostly five-septate with long apical and basal cells, exhibiting dorsiventral curvature. They were hyaline, with the apical cell hooked to tapering and the basal cell foot-shaped, measuring 46.5-89.6 (x̄ =72.3) × 3.5-5.0 (x̄ =4.3) μm in size (n = 100). Portions of three loci (TEF-1α, RPB1 and RPB2) were amplified and sequenced as described by Wang et al. (2019). Sequences were deposited in GenBank with accession number PP196583 to PP196585. The three gene sequences (TEF-1α, RPB1 and RPB2) of strain TGGF2022-17 shared 99.5% (629/632bp), 97.9% (1508/1540 bp) and 99.9% (1608/1609 bp) identity to the ex-type strain F. ipomoeae LC12165 respectively by pairwise DNA alignments on the FUSARIOID-ID database (https://www.fusarium.org). Phylogenetic analysis of the partial TEF-1α and RPB2 sequences with PhyloSuite (Zhang et al. 2020) showed the isolated fungus clustered with F. ipomoeae. Based on the morphological and phylogenetic analyses, TGGF22-17 was identified as F. ipomoeae. Pathogenicity tests were performed on healthy melons, which were surface-sterilized with 75% alcohol and wounded using a sterilized inoculation needle. A 4-mm diameter plug from a 7-day-old SNA culture of TGGF22-17 was aseptically inserted in the middle of the wound, sealed with plastic bag after absorbent cotton was included to maintain moisture. Five melons were each inoculated at three points. Noncolonized PDA agar plugs served as the negative control. The inoculated and uninoculated plugs were removed approximately 48 hours after inoculation. The melon inoculated with TGGF22-17 exhibited water-soaked black lesions 48h post-inoculation, resulting in a 100% infection rate (15/15). After 7 days, mycelium was obseved on the inoculated melons. No disease symptoms were observed on the uninoculated melons. To fulfill Koch's postulates, fungi were isolated from the inoculated fruit and confirmed as F. ipomoeae by morphological observation. Fusarium ipomoeae has been reported to cause fruit rot on winter squash (Cucurbita maxima) in Japan (Kitabayashi et al. 2023). To our knowledge, this is the first report of fruit rot on muskmelon caused by F. ipomoeae in China and this report will be valuable for monitoring and management of fruit rot disease on muskmelons.

Clearing the Air, Breathe Easy: Intensive Care Unit Remodeling Unveils Insights into Aspergillosis Prevention

Background: Invasive aspergillosis (IA) poses a substantial threat to morbidity and mortality, particularly among immunocompromised individuals. In 2023, a New York City Intensive Care Unit (ICU) experienced an aspergillus outbreak following a structural water leak, resulting in two patients diagnosed with Invasive Aspergillus niger in their bronchial cultures. Immediate interventions, including patient relocation and ICU reconstruction were implemented to mitigate further impacts. This study aims to assess the impact of timely relocation of patients and renovation of the ICU, on the incidence of invasive aspergillosis. Method: A quasi-experimental study design of ICU patients over a nine month period included surveillance by the Infection Prevention department from March 1 to December 1, 2023. Surveillance included review of microbiology reports, environmental cultures, and patient chart reviews. The Pre-intervention spanned March 1 to May 1, and the post-intervention from May 4 to December 1. Indoor mold assessments of pre- and post-intervention involved testing wall surfaces for moisture, air sample collection for fungal spores, and surface swabs for direct fungal analysis. The intervention included relocating all seventeen patients from the impacted ICU and comprehensive reconstruction. Reconstruction involved the removal and replacement of all sheetrock within the unit extending four feet from the floor with moisture-resistant sheetrock. Additionally, moisture resistant single sheet welded vinyl flooring and cove-bases were installed. All heating, ventilation, and air-conditioning (HVAC) systems were inspected and cleaned. Construction activities strictly adhered to Infection Control Risk Assessment (ICRA) guidelines, with emphasis on maintaining negative pressure, to ensure a safe environment. Result: Environmental swab samples from 50% of ICU rooms indicated growth of Aspergillus/Penicillium, Chaetomium, and Stachybotrys/Memnoniella type spores during the pre-intervention phase. Environmental microbiology results strongly suggest the indoor environment as the fungal spore source, with the presence of fruiting structures indicating surface mold growth. Indoor air samples, when compared to outdoor samples collected during pre-intervention, showed rare (2-6 raw count) growth of Aspergillus in 55% of the sampled rooms and subequently no growth post-intervention. Prospective surveillance revealed no further aspergillus growth in the ICU population and environment. Conclusion: Our findings highlight a potential correlation between environmental modifications and reduced IA incidence. Swift mitigation and structural interventions are crucial in averting potentially fatal outcomes, marking a significant advancement of prevention strategies for inner-city hospital settings. Although promising, study limitations include the inability to speciate environmental aspergillus for comparison to patient bronchial cultures and the absence of baseline bronchial cultures for affected patients on admission.

Phylogeny, biogeography, and host range of gall midges (Diptera: Cecidomyiidae) feeding on spores of rust fungi (Basidiomycota: Pucciniales).

Rust fungi (Pucciniales) are plant pathogens that can cause devastating yield losses to economically important crops and threaten native plants with extinction. Rusts are usually controlled with fungicides when rust-resistant plant varieties are unavailable. However, natural enemies may offer an alternative to chemicals by acting as biological controls. The larvae of Mycodiplosis Rübsaamen (49 spp.) feed on the spores of rusts and powdery mildew fungi and have been suggested as a potential biocontrol candidate for disease-causing rusts. However, little is known about the phylogenetic relationships, biogeography, and host range of this genus. We screened 5,665 rust specimens from fungarium specimens and field collections and recovered a total of 363 larvae on 315 rust specimens from 17 countries. Three mitochondrial and 2 nuclear loci were amplified and sequenced for the phylogenetic reconstruction of 129 individuals. We recovered 12 clades, of which 12 and 10 were supported with maximum likelihood and Bayesian inference, respectively. Of the 12 clades, 7 comprised species from multiple continents and climatic regions, and 5 comprised species from a single region. Individuals forming clades were collected from 2 to 18 rust species, suggesting that Mycodiplosis species have a broad host range. In total, Mycodiplosis larvae were identified on 44 different rust species collected from 18 plant families. Future studies should focus on expanding field sampling efforts, including data from additional gene regions, and incorporating morphological data to further elucidate species diversity and distribution patterns.

Effect of glyphosate on the sporulation of aquatic fungi: an in-vitro experience

Effect of glyphosate on the sporulation of aquatic fungi: an in-vitro experience

PENGARUH PEMBENAH TANAH HAYATI TERHADAP SIFAT KIMIA ENTISOL TERGENANG DAN TIDAK TERGENANG

Farmers began to implement organic systems when the quality of rice fields decreased. Indonesia has several active volcanoes so that the agricultural land was formed by generally Entisols. Several natural and synthetic soil conditioners were starting to be used to decompose the litter and increase the availability of Entisol nutrients. The research aimed to study the effect of providing biological soil amendments on the chemical properties of Entisols. The demonstration plots scale research were used a completely randomized design with a combination of treatments: (P1) Flooded dolomite control, (P2) Non-flooded dolomite control, (P3) Flooded bio soil-neutralizer, and (P4) Non-flooded bio soil-neutralizer. Parameters of soil chemical properties observed were pH, C-organic (%), N-total (%), P2O5-total (%), K2O-total (%), CEC (c mol + kg-1), total bacteria (CFU mL-1), and total fungi (spores g-1). The chemical properties of Entisols before treatment showed slightly acidic pH, low C-organic, low N-total, low K-total, low P-total, and very high CEC. After applying the soil neutralizer, there were an increase in chemical properties including pH becoming alkaline and neutral, medium C-organic, standards to moderat NPK-total, and high CEC. Flooding treatment did not increase the chemical properties of the Entisols.

Biodegradation of Difenoconazole Using Fungal-Bacterial Consortia

Abstract Pesticides are used all over the world in agricultural operations to reduce the damage of pests and to improve the productivity of agricultural crops. The excessive use of these chemical compounds has led to the deterioration of soil and increase the level of pollution of water and air resources. Moreover, the continuous use and non-target toxicity of pesticides has become a major concern to the agricultural ecosystem that directly hinders the productivity of agricultural products. Therefore, this study aimed to isolate and identify fungal and bacterial species with the ability to biodegrade fungicide via conducting preliminary tests to find out which of them have the ability to grow in a treated medium with a fungicide Difenoconazole, which belongs to the group of the pesticides Triazoles. The fungi and bacteria that succeeded in growing were as follow Aspergillus flavus, Aspergillus ochraceus, Bacillus cereus S1 and Bacillus cereus S2 were identified by extracting their genomic DNA and applying the primers ITS and 16s rRNA for both examined fungi and bacteria, respectively. The fungi were laboratory adapted to multiple concentrations reaching the highest concentration of 550 mgL-1, while bacteria reached 1200 mgL-1 laboratory to break down the pesticide. The results of the combinations tested as the B. cereus S1 and B. cereus S2 were the fastest growing in the liquid medium PDB at the concentration of 325 mgL-1. While the combination A. flavus and B. cereus S1 had the highest biodegrading ability at the same concentration, which led to the disappearance of the pesticide Difenoconazole turbidity in the liquid medium as a result of its consumption by fungal and bacterial isolates. As for the treatment of the pesticide in the solid PDA medium to know its effect on the growth of fungi and the formation of spores, the results revealed that fungal isolates increase their vegetative growth when the concentration increases, the production of fungal spores decreases, and indicates the ability of the fungi to use the pesticide as an energy source.

WITHDRAWN: Reconstructing the environmental impact of mining on mountain lakes

Mountain lakes are particularly fragile ecosystems undergoing important transformations associated with ongoing global change. However, the history of anthropogenic impacts on mountain lakes and their catchments is much longer, in many cases featuring millennia of summer pastoral farming. More recently, the growing demand for raw materials and energy linked to industrialization, particularly accelerated since the 19th century CE, meant a further increase in human impact on mountain areas. The Cantabrian Range (northern Spain) constitutes a paradigmatic case of southern European mountain range experiencing intense human impact during the past few millennia and particularly the past two centuries. Here, we have reconstructed the environmental dynamics of this area during the last millennium, with a particular focus on the impact of mining, based on the multidisciplinary analysis (sedimentology, biogeochemistry, magnetic susceptibility, diatoms, pollen, charcoal and dung fungal spores) of sediment cores from Lago de La Cueva (43°03′N, 6°06′W, 1550 m a.s.l.). Changing land use and climate have driven lake dynamics during the last centuries. A major fire-caused deforestation event dated to the late 15th century CE increased erosion and the frequency of intense runoff episodes, in the context of the wetter and colder Little Ice Age. The onset of iron mining activities in the catchment ca. 200 years ago had a strong impact on the lake. Sedimentation rates notably raised and mining waste containing hematite and potentially toxic elements (e.g. Fe, Co, As) was washed into the lake. Additionally, diatom assemblages showed that lake regulation since the early 20th century CE severely altered the natural hydrological regime introducing rapid seasonal lake-level oscillations and increased lakeshore erosion, water turbidity and nutrient loads. The recent environmental restoration, finished in 2006, has involved the re-deposition of large volumes of mine tailing. Although some mining wastewater still arrives into the lake because mine drainage is still active, restoration works have succeeded in reducing erosion rates and nutrient loads. Lower land-use intensity has also contributed to natural vegetation recovery, further diminishing erosion. This study illustrates the complex interactions between human activities (grazing, mining, hydropower) and climate change in defining mountain landscape shifts through time. Moreover, our results highlight the usefulness of paleolimnological research to quantitatively assess the effectiveness of lake restoration programs.

Non-thermal Atmospheric Plasma for the Treatment of Onychomycosis: in vitro and ex vivo Ultrastructural Study

Background: Nonthermal atmospheric plasma (NTAP) has been studied as a new treatment option for various medical conditions. Onychomycosis is a common nail disorder caused by a fungus that is difficult to treat and often recurs. One reason for treatment difficulty is the growing resistance to current antifungal medications. Given the medical concerns related to antifungal drugs, there is a need for newly developed treatment options. Objective: This study sought to determine if NTAP was effective as an antifungal treatment for onychomycosis. To explore this innovative treatment option, we conducted in vitro and ex vivo experiments using microbial methods and microscopy. Methods: For the in vitro experiments, Trichophyton (T.) rubrum was inoculated into Sabouraud dextrose agar plates. For the ex vivo experiments, nail specimens diagnosed with onychomycosis resulting from T. rubrum were used. NTAP using argon gas was utilized in this study. Scanning electron and reflectance confocal microscopy were used to analyze the nail specimens. Results: The growth of T. rubrum colonies exposed to NTAP was markedly suppressed compared to untreated colonies in vitro. T. rubrum ultra-structures noticeably transformed from smooth to rough or ruptured after exposure. Conclusion: NTAP can inhibit the growth of T. rubrum and cause damage to fungal spores. This finding could potentially lead to the development of new and effective treatments for onychomycosis.

Recognition of Davidsoniella virescens on Fagus sylvatica Wood in Poland and Assessment of Its Pathogenicity.

Davidsoniella virescens is so far only known in North America. However, recently in southern Poland, blackish growth consisting of fungal mycelia and sporulation structures was found on the wood of Fagus sylvatica. As a result of isolation, 17 cultures of this fungus were obtained. All cultures produced an intense sweet odor. This fungus, both in situ and in vitro, abundantly produced perithecia with long necks and asexual stage. Particularly characteristic was the production of variable endoconidia in two types of phialophores differing mainly in the width of the collarette. The nucleotide sequences for five gene fragments of representative cultures were used in phylogenetic analyses: 18S; the internal transcribed spacer regions ITS1 and ITS2, including the 5.8S gene (ITS); 28S region of the ribosomal RNA (rRNA), β-tubulin 2 (TUB2) and translation elongation factor 1-α (TEF1). Based on morphological and phylogenetic analyses, the fungus on European beech in Poland was identified as Davidsoniella virescens. The optimal temperature for radial colony growth was 20 °C. However, the differences between colony diameter at 25 °C compared to that at the optimal temperature were not statistically significant. Six D. virescens isolates were used for pathogenicity assay. They were inoculated into wounds on stems of two-year-old seedlings of Fagus sylvatica and Acer saccharum (36 seedlings of each tree species). Final evaluation was performed 4 months after inoculation. No external symptoms were observed in any A. saccharum seedling, neither in the crown nor on the stem. However, 13.9% of F. sylvatica seedlings showed wilting symptoms throughout the entire crown within 3-6 weeks after inoculation. Moreover, after 4 months on the stems of 30.6% beech seedlings, necrotic lesions with a length of 1.3 to 7.2 cm were formed, without any symptoms of wilting. The most noticeable internal symptom was the discoloration of the wood, which was observed in all inoculated seedlings of both tree species. All D. virescens isolates caused greater wood discoloration in F. sylvatica than in A. saccharum. Most of the differences found in the extent of discoloration between host plants were statistically significant. The discoloration caused by all D. virescens isolates in F. sylvatica was significantly greater than in the control. However, none of the isolates tested on A. saccharum caused significantly greater wood discoloration compared to the control. Pathogenicity tests showed that the D. virescens isolates identified in southern Poland may pose a greater threat to native European beech than to foreign sugar maple.

A review of the status of air quality monitoring in the Permian Basin, USA, and its implications for effective long-term monitoring of industrial operations

The Permian Basin is the largest petroleum producing region in the United States. Few studies have investigated impact the Petroleum Industry had on the air quality of the Permian Basin. Industry operations in the Basin has two primary impacts on air quality, (a) it significantly contributes carbon dioxide (CO2) and methane (CH4) to the atmosphere during extraction, transport and use of fossil fuels, (b) industry operations influence public health especially when populations are in proximity to all categories of oil and gas facilities. The advent of Covid-19 in late 2019 and a severe drought that began prior to 2019 in West Texas have created unusual circumstances regarding air quality and public health in the Permian Basin. This study has monitored airborne pollen, spores, fungal spores, and other organically derived particles, and inorganic particulate matter (1, 2.5, 10-micron particulate matter (PM) and total suspended particles (TSP)), volatile organic compounds (VOCs), and sulfur dioxide (SO2). The pandemic caused a historic reduction in oil and gas production slowing operations in the Permian Basin to near zero during the study period, reducing environmental effects on air quality and concomitantly an increase in flaring of natural gas. Although there were increases in the release of VOCs fixed base monitors detected no notable increase. However, an increase in the concentration of airborne pollutants (VOCs and SO2) shows a close correlation with proximity to oil and gas facilities and the intensity of industry operations. This phenomenon is attributed to the highly local nature of flaring and CH4 plume emissions from leaking oil and gas facilities. Air quality improved in the Permian Basin due to reduction in production activity because of the Covid-19 pandemic, and the reduction of particulate matter due to the ongoing drought during the study period.

Anthropogenic forest degradation and its impact on soil erosion in the mountainous region of northern China

Soil erosion has significant negative effects on the eco-environment, and it also threatens the sustainability of agricultural production. However, studies on soil erosion in northern China during the historical period, and its relationship with climate change and human activities, are rare. Here we present a 2900-year pollen and geochemical record from a sediment core from Lingganhai Lake, an alpine freshwater lake on the Chinese Loess Plateau in northern China. We observed an abrupt increase in the influx of detrital elements at ∼ 750 CE, accompanied by decreased tree pollen and increased cereal pollen percentages, which suggest severe soil erosion induced by intensified human activities. Coeval pollen and fungal spore records from other sites in the vicinity of Lingganhai Lake also indicate reduced forest cover, intensified agricultural and grazing activity, and increased dust storm frequency. During 1250–1380 CE, decreased soil erosion at Lingganhai Lake was accompanied by forest recovery and a reduction in the intensity of human activities. However, after ∼ 1380 CE, intensive soil erosion was renewed, likely caused by enhanced human activity, which partially overlapped with intensified dust activity in northern China during the Little Ice Age. Overall, our results demonstrate the close link between vegetation cover and soil erosion, and they highlight the importance of the maintenance of montane forest in northern China for soil preservation.

Role of Hydrogen Peroxide (H2O2) and Trichoderma koningii in Reducing Root Rot Disease of Tomato Causing by Fusarium solani

Two isolates of the pathogenic fungus Fusarium solani the causative of tomato root rot disease named Fs1 and Fs2 were isolated from tomato plants infected with root rot disease. Results showed that both examined isolates had significant effects on the percentage of seed germination of tomato and damping-off disease. Thus, isolate Fs1 was more effective than isolate Fs2, as it recorded a percentage of germination and damping-off 56.6 and 71.6% respectively, compared to the control treatment, which recorded 100 and 0% respectively. It was found that the use of hydrogen peroxide (H2O2) at concentrations of 50, 100 and 200 ppm had a significant effect on the fungal radial growth, dry weight (DW) and sporulation of F. solani. Antifungal activity of H2O2 appeared even at the lowest concentration (50 ppm), which inhibited radial growth to 49.33%, and decreased the dry weight to 498 mg, and the sporulation to 3.75×106 spores. Additionally, the results indicated significant inhibitory effects of hydrogen peroxide (H2O2) and the bioagent Trichoderma koningii on F. solani growth. It was noticed that H2O2 has compatible effects with T. koningii, where the antagonistic ability of T. koningii against F. solani increased when the concentration of H2O2 had increased. The results revealed that the treatment F. solani + H2O2 (200 ppm) + T. koningii significantly reduced the percentage of damping-off and plant survival to 9.40 and 5.39% respectively, in comparison with the control treatment and F. solani alone treatment, which reached 20.22, 14.48, 34.32 and 67.41% respectively.

Amphiphilic polysiloxane graft guanidine salts with a combination of low environmental toxicity and high antifungal activity

Banana Fusarium wilt is one of the most serious diseases that restricts the banana industry. How to achieve efficient, low toxicity, and long-term inhibition of pathogenic fungal spores (Fusarium oxysporum f. sp. cubense, race 4, Foc4) that grow in soil has become a challenge in the field of chemical control of plant diseases in recent years. Based on the special antimicrobial mechanism of guanidine salts, which can effectively inhibit microbes by forming transmembrane stomata on the plasma membrane, we were inspired to introduce hydrophilic guanidine salts to hydrophobic PDMS chains to potentially balance high antimicrobial activity and low environmental toxicity. In this work, a series of novel amphiphilic polysiloxane graft guanidine salts (PDMS-g-GH) were synthesized based on our previous works, i.e., polysiloxane graft primary amine salts (PDMS-g-AH), in which the primary amine salt groups were converted to guanidine salt groups. The molecular weight of the polymer, the grafting density of guanidine salts, the distribution of guanidine salt units on the main chain (random or block), the in vitro antifungal activities and the anti-Foc4 activities in soil, the adsorption characteristics in soil, and the environmental toxicity after soil adsorption were systematically studied. The results confirmed that compared with PDMS-g-AH, PDMS-g-GH showed stronger antifungal activity against Foc4 and long-term antifungal activity against Foc4 in soil, but its environmental toxicity was significantly reduced. These results support the potential application of PDMS-g-GH for the prevention and control of banana Fusarium wilt and other soil-borne fungal diseases.

Drought and mycorrhizal inoculation affect growth and morphology of Australian stormwater biofilter plants

This study evaluated the effect of mycorrhizal inoculation on six common Australian biofilter plant species using a pot experiment. We divided 120 pots planted with six common biofilter species into four treatments: control water-deficit, inoculated water-deficit, control well-watered, and inoculated well-watered. Inoculated treatments were inoculated with a commercially available blend of arbuscular mycorrhizal fungi spores. While well-watered pots were watered to pot capacity daily, water-deficit pots were subjected to a simulated drought that lasted six weeks until harvesting. All plants inoculated with arbuscular mycorrhizal fungi developed greater total root surface area, plant biomass, and plant relative growth rate. Which are associated with better stormwater nutrient removal. Mycorrhizal inoculation also increased the average root diameter, total length, and surface area of thick roots (diameter > 1 mm) of six species, which are essential to maintain the infiltration rates and hydraulic functions of biofilter systems. Moreover, an increase in shoot biomass following inoculation was also observed across six species, potentially contributing to higher water loss and stormwater volume reduction. Although the water-deficit condition greatly limited the effects of mycorrhizal inoculation on other morphological traits, we still observed the benefits of inoculation on total root length and surface area in well-watered J. pallidus and C. appressa. As drought stress imposes limitations on the effects of inoculation, we recommend inoculation should be carried out in advantageous times, such as during wet periods before the drought season for the optimal colonization and plant biomass and morphological responses. Additionally, selecting mycorrhizae-responsive species like C. appressa, J. pallidus, and G. sieberiana can result in favorable outcomes.

Utilizing zinc oxide nanoparticles as an environmentally safe biosystem to mitigate mycotoxicity and suppress Fusarium graminearium colonization in wheat

The biosynthesis of zinc oxide nanoparticles (ZnONPs) offers great potential for plant disease management due to their potent antimicrobial properties and environmental safety. However, the precise mechanisms underlying their antifungal mode of action and role in suppressing mycotoxins remain unclear. This study aims to elucidate the mechanisms by which ZnONPs suppress the pathogenic fungus Fusarium graminearium, known to cause Fusarium head blight in wheat. Additionally, it investigates how ZnONPs mitigate the production of mycotoxins, which pose risks to humans and ruminants. The study demonstrates that ZnONPs, bioproduced by Pseudomonas poae (P. poae), inhibit not only fungal growth, colony formation, and spore germination, but also significantly reduce mycotoxin production of F. graminearium by inhibiting the synthesis of deoxynivalenol (DON), downregulating the FgTRI gene, and causing morphological alterations of the toxisomes. The results also highlight that ZnONPs exert significant effects on fungi through multiple mechanisms, including cell wall damage and the generation of reactive oxygen species (ROS). Moreover, ZnONPs effectively inhibit F. graminearium in wheat leaves and coleoptiles. Fluorescence microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy all show that ZnONPs stop F. graminearium from getting into wheat plants and colonising them. Overall, the findings of this study provide evidence that ZnONPs are highly effective in reducing F. graminearium colonization in wheat plants and effectively decreasing mycotoxin production through multiple pathways.

Potential antifungal applications of heterometallic silica nanohybrids: A synergistic activity

An estimated 1.7 million fatalities and 150 million cases worldwide are attributed to fungal infections annually, that are in rise due to immunocompromised patient population. The challenges posed by traditional treatments can be addressed with the help of nanotechnology advancements. In this study, Co, Cu, and Ag—were doped into silica nanoparticles. Then the synthesized monometallic silica nanohybrids were combined to formulate heterometallic silica nanohybrids, characterized structurally and morphologically, compared, and evaluated for antifungal activity based on their individual and synergistic activity. The antifungal assays were conducted by using ATCC cultures of Candida albicans and QC samples of Trichophyton rubrum, Microsporum gypseum, and Aspergillus niger. The MIC (ranging from 49.00 to 1560.00 μg/mL), MFC (ranging from 197.00 to 3125.00 μg/mL), IC50 values (ranging from 31.10 to 400.80 μg/mL), and FICI of nanohybrids were determined and compared. Moreover, well diffusion assay was performed. ABTS assay and DPPH assay were conducted to investigate the radical scavenging activity (RSA) of nanohybrids. SEM analysis clearly evidenced the structural deformations of each fungal cells and spores due to the treatment with trimetallic nanohybrid. According to the results, the trimetallic silica nanohybrids exhibited the most powerful synergistic RSA and the most effective antifungal activity, compared to the bimetallic silica nanohybrids.

PRODUCTION OF Pinus durangensis Mart. UNDER DIFFERENT SUBSTRATE AND MYCORRHIZAL INOCULATION CONDITIONS IN NURSERY

Substrate and mycorrhization are important aspects when producing plants. The objective of the study was to determine the effect of three substrates inoculated with ectomycorrhizal fungal spores on the morphological characteristics of nursery-grown Pinus durangensis as well as the inherent costs of the substrate. A randomized block experimental design with a 3 x 3 factorial arrangement was used. The substrates evaluated were: 1) peat, vermiculite, and perlite (50:25:25) [PVP]; 2) peat, composted bark, and raw sawdust (50:25:25) [PBS]; and 3) peat and bark (50:50) [PB]. The mycorrhizal inoculants were: 1) Pisolithus tinctorius; 2) Laccaria laccata; and 3) control. The plant was produced in black polyethylene tubes (160 mL) and evaluated at 13 months. The substrate factor presented statistical differences (p ≤ 0.05) in the variables evaluated, with higher values in PVP, followed by PBS and PB, the latter being similar to each other. The mycorrhizal inoculation factor showed differences (p ≤ 0.05) in root and total biomass, Dickson’s quality index, and mycorrhizal colonization, obtaining higher values when P. tinctorius was inoculated, except in the last variable, where the application of L. laccata stood out. In the substrate-mycorrhizal inoculation interaction, the most favorable combination was PVP and P. tinctorius. The PVP substrate was 28.4 and 34.6 % more expensive than PB and PBS, respectively. The combined effect of PVP and P. tinctorius produced the best growth, although the substrate was more expensive.

Leaf-cutting ant species (Hymenoptera: Formicidae, Myrmicinae) in three agrosystems and the attractiveness of a natural bait to Atta laevigata’s biocontrol

Leaf-cutting ant species with economic importance are those of the genera: Atta and Acromyrmex. Natural baits with spores of these entomopathogenic fungi can be used in the biological control of pest species. Therefore, the aims of this research, were: 1) inventory the species of leaf-cutting ants in three agroecosystems; 2) evaluate the attractiveness of the natural bait based on orange peel albedo impregnated with a bioinsecticide; 3) compare the amount of baits carried between the different concentrations of the bioinsecticide, and 4) evaluate the difference in the times spent for the first meeting of the bait and beginning of the loading in the direction of the nest by Atta laevigata, in relation to the concentrations of conidia of the bioinsecticide. Active searches were carried out in the anthills to collect adults (“soldiers”) and identify the species. The evaluations of the natural baits occurred in four adult nests of A. laevigata, being offered 2g of baits per repetition. The position of the treatments was changed at each repetition. We found four species: Atta sexdens, Atta laevigata, Acromyrmex rugosus and Acromyrmex balsani. There was a significant difference between the total amount of loaded and unloaded baits, indicating that leaf-cutter ants were attracted by the baits and ignored the presence of Beauveria bassiana conidia. The time for first contact and start of loading, did not differ significantly between treatments, nor between loaded amounts of different treatments. The bait containing the bioinsecticide is attractive to Atta laevigata workers, regardless of the concentration of conidia.

A Simulation Study to Reveal the Epidemiology and Aerosol Transmission Characteristics of Botrytis cinerea in Grape Greenhouses.

Most previously studies had considered that plant fungal disease spread widely and quickly by airborne fungi spore. However, little is known about the release dynamics, aerodynamic diameter, and pathogenicity threshold of fungi spore in air of the greenhouse environment. Grape gray mold is caused by Botrytis cinerea; the disease spreads in greenhouses by spores in the air and the spore attaches to the leaf and infects plant through the orifice. In this study, 120 μmol/L propidium monoazide (PMA) were suitable for treatment and quantitation viable spore by quantitative real-time PCR, with a limit detection of 8 spores/mL in spore suspension. In total, 93 strains of B. cinerea with high pathogenicity were isolated and identified from the air samples of grapevines greenhouses by a portable sampler. The particle size of B. cinerea aerosol ranged predominately from 0.65-3.3 μm, accounting for 71.77% of the total amount. The B. cinerea spore aerosols were infective to healthy grape plants, with the lowest concentration that could cause disease being 42 spores/m3. Botrytis cinerea spores collected form six greenhouse in Shandong Province were quantified by PMA-qPCR, with a higher concentration (1182.89 spores/m3) in May and June and a lower concentration in July and August (6.30 spores/m3). This study suggested that spore dispersal in aerosol is an important route for the epidemiology of plant fungal disease, and these data will contribute to the development of new strategies for the effective alleviation and control of plant diseases.