Summary
In the present study, we investigated the role of Trichoderma virens (TriV_JSB100) spores or cell‐free culture filtrate in the regulation of growth and activation of the defence responses of ...tomato (Solanum lycopersicum) plants against Fusarium oxysporum f. sp. lycopersici by the development of a biocontrol–plant–pathogen interaction system. Two‐week‐old tomato seedlings primed with TriV_JSB100 spores cultured on barley grains (BGS) or with cell‐free culture filtrate (CF) were inoculated with Fusarium pathogen under glasshouse conditions; this resulted in significantly lower disease incidence in tomato Oogata‐Fukuju plants treated with BGS than in those treated with CF. To dissect the pathways associated with this response, jasmonic acid (JA) and salicylic acid (SA) signalling in BGS‐ and CF‐induced resistance was evaluated using JA‐ and SA‐impaired tomato lines. We observed that JA‐deficient mutant def1 plants were susceptible to Fusarium pathogen when they were treated with BGS. However, wild‐type (WT) BGS‐treated tomato plants showed a higher JA level and significantly lower disease incidence. SA‐deficient mutant NahG plants treated with CF were also found to be susceptible to Fusarium pathogen and displayed low SA levels, whereas WT CF‐treated tomato plants exhibited moderately lower disease levels and substantially higher SA levels. Expression of the JA‐responsive defensin gene PDF1 was induced in WT tomato plants treated with BGS, whereas the SA‐inducible pathogenesis‐related protein 1 acidic (PR1a) gene was up‐regulated in WT tomato plants treated with CF. These results suggest that TriV_JSB100 BGS and CF differentially induce JA and SA signalling cascades for the elicitation of Fusarium oxysporum resistance in tomato.
Solid‐state hydrogen storage materials are safe and lightweight hydrogen carriers. Among the various solid‐state hydrogen carriers, hydrogen boride (HB) sheets possess a high gravimetric hydrogen ...capacity (8.5 wt%). However, heating at high temperatures and/or strong ultraviolet illumination is required to release hydrogen (H2) from HB sheets. In this study, the electrochemical H2 release from HB sheets using a dispersion system in an organic solvent without other proton sources is investigated. H2 molecules are released from the HB sheets under the application of a cathodic potential. The Faradaic efficiency for H2 release from HB sheets reached >90%, and the onset potential for H2 release is −0.445 V versus Ag/Ag+, which is more positive than those from other proton sources, such as water or formic acid, under the same electrochemical conditions. The total electrochemically released H2 in a long‐time experiment reached ≈100% of the hydrogen capacity of HB sheets. The H2 release from HB sheets is driven by a small bias; thus, they can be applied as safe and lightweight hydrogen carriers with economical hydrogen release properties.
Hydrogen boride (HB) sheets possess a high gravimetric hydrogen capacity (8.5 wt%). Gaseous hydrogen molecules are released from HB sheets by an electrochemical bias application in acetonitrile solution. The Faradaic efficiency for hydrogen release reaches 90%, and the onset potential is −0.445 V versus. Ag/Ag+, which is more positive than those from other proton sources, like water or formic acid.
Trichoderma species are applied as biological control agents and biofertilizers to control plant diseases and enhance crop yields. The ability to inhibit pathogens, induce defense responses, and ...promote plant growth can result from the production of volatile organic compounds (VOCs). In this study, we evaluated the effects of VOCs from Trichoderma asperellum T1 on those multifaceted actions in lettuce. The VOCs released by T. asperellum T1 inhibited fungal growth of two leaf spot fungal pathogens, Corynespora cassiicola and Curvularia aeria. Lettuces responded to VOCs by increasing activities of the cell-wall degrading enzymes chitinase and β-1,3-glucanase to 1.26 U mL−1 and 4.45 U mL−1, respectively, above those in the control. Accumulation of cell-wall degrading enzymes in lettuce that had been treated with VOCs resulted in morphological changes to fungal cell-walls. Exposure to the VOCs emitted by T. asperellum T1 significantly increased numbers of leaves and roots, plant biomass and total chlorophyll content in lettuce. Furthermore, GC/MS analysis revealed that T. asperellum T1 emitted 22 volatile compounds, which are involved in antifungal activity, inducing defense responses, and promoting growth in lettuce.
•VOCs of T. asperellum T1 inhibit mycelial growth of leaf spot fungi of lettuce.•VOCs of Trichoderma asperellum T1 enhance cell wall degrading enzyme in lettuce.•Exposure of VOCs emitted by T. asperellum T1 promote plant growth in lettuce.
Frequent fishing activities are causing overfishing, destroying the habitat of marine life, and threatening global marine biodiversity. Understanding the dynamics of fishing activities and their ...drivers is crucial for designing and implementing effective ocean management. The fishing activities in the open sea are reported to be characterized by high spatial variability in local waters; however, it is still unclear whether their high spatial variability is random or regulated by oceanographic variations. Mesoscale eddies are ubiquitous swirling currents that dominate locally biogeochemical processes. Previous case studies presented an ongoing debate regarding how eddies exert impacts on high trophic organisms, which imposes limitations on understanding the dynamics of fishing activities based on the bottom‐top control hypothesis from eddies to fish and fishing activities. By combining global fishing activities from deep learning and oceanic eddy atlases from satellite monitoring, we showed that the spatial variations in fishing activities were closely related to mesoscale eddies in the global midlatitude ocean, confirming that fishing activities primarily targeting tuna, were aggregated in (repelled from) anticyclonic (cyclonic) eddy cores. This eddy‐fishing activity relationship was opposite to satellite‐observed primary production but corresponded well with the temperature and oxygen content in deeper water. By integrating existing evidence, we attribute eddy‐related fishing activities to a reasonable hypothesis that warm and oxygen‐rich deeper water in anticyclonic eddies relieves the thermal and anoxic constraints for diving predation by tuna while the constraints are aggravated in cold and oxygen‐poor cyclonic eddies.
Pyocyanin is a blue green phenazine pigment produced in large quantities by active cultures of Pseudomonas aeruginosa, with advantageous applications in medicine, agriculture and for the environment. ...Hence, in the present study, a potent bacterium was isolated from agricultural soil and was identified morphologically and by 16S rRNA sequencing as P. aeruginosa (isolate KU_BIO2). When the influence of nutrient supplements in both King's A and Nutrient media as amended was investigated, an enhanced pyocyanin production of 2.56 µg ml
was achieved in King's A medium amended with soya bean followed by 1.702 µg ml
of pyocyanin from the nutrient medium amended with sweet potato. Purified pyocyanin was characterized by UV-Vis Spectrophotometer and Fourier-Transform Infrared spectroscopy (FTIR). Furthermore, Liquid Chromatography Mass Spectrum (LCMS) and Nuclear Magnetic Resonance (NMR) confirmed its mass value at 211 and as N-CH
protons resonating at 3.363 ppm as a singlet respectively. The isolated pyocyanin displayed remarkable dye property by inducing color change in cotton cloth from white to pink. Lastly, the antifungal activity of test pyocyanin showed inhibition of growth of rice blast fungus, Magnaporthe grisea and bacterial blight of rice, Xanthomonas oryzae at concentrations of 150 and 200 ppm, respectively. Thus, this investigation provides evidence for diverse actions of pyocyanin which are nutrient dependent and are capable of acting on a large scale, by utilizing microbes existing in agriculture wastes, and thus could be used as an alternative source in the making of natural textile dyes with strong durability and a broad spectrum of ecofriendly agrochemicals.
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•Streptomyces and Trichoderma inhibit Curvularia oryzae growth on PDA.•Streptomyces and Trichoderma enzymes suppress Curvularia oryzae.•Biocontrol effect of Trichoderma V76-12 reduce ...leaf spot of oil palm seedlings.•Application of Trichoderma V76-12 enhance PAL, POD and PPO activities.
Leaf spot disease causes devastating damage to oil palm seedlings and reduces both quality and quantity of the produced seedlings. This study aimed to apply the selected microorganisms Streptomyces hygroscopicus subsp. angustmyceticus NR8-2, Trichoderma harzianum TM2/1, and endophytic Trichoderma V76-12, to the control of leaf spot disease caused by Curvularia oryzae on oil palm leaves, in vitro, in vivo and in field conditions. The isolate V76-12 inhibited the growth of C. oryzae the most at 85.71% inhibition, followed by the isolates TM2/1 (75.71%) and NR8-2 (72.50%) in dual culture tests. Volatile antifungal effects were observed for V76-12 with 68% inhibition, followed by the isolates TM2/1 (45%) and NR8-2 (10%) in a bioassay. Crude metabolites of the isolates inhibited the mycelial growth of C. oryzae in agar diffusion tests. In pot experiments, the V76-12 gave disease severity index (DSI) of about 21%, similar to that with a reference chemical (20%), whereas TM2/1 and NR8-2 gave 66% and 75%, respectively. In naturally infested cases, oil palm seedlings treated with V76-12 showed 35.33% DSI, which is statistically significantly below those obtained with TM2/1, NR8-2 and the chemical (48.67%, 53.33% and 49.33%, respectively). The control treatment without antagonistic microorganisms gave the most severe DSI at 75.33%. The results also show that treatment with the selected isolates enhanced the activities of phenylalanine ammonia-lyase (PAL), peroxidase (POD), and polyphenol oxidase (PPO) enzymes in the oil palm. The V76-12 isolate was the most effective treatment tested in reducing leaf spot disease of oil palm seedlings, due to its ability to inhibit mycelial growth in vitro, to reduce disease symptoms in vivo and in natural fields, as well as to enhance PAL, POD and PPO activities in the oil palm leaves.
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•Strong interaction between Rh and Fe oxide was induced by high-temperature calcination.•The strong interaction greatly promoted the activity of a small amount of rhodium.•After ...low-temperature reduction of the catalyst, the products were selective for hydrogen and acetaldehyde.•After high-temperature reduction showed remarkable hydrogen production in the steam reforming of ethanol.
An Fe-promoted Rh/SiO2 catalyst (Fe + Rh/SiO2) was investigated in terms of the strong metal-oxide interaction (SMOI) between Rh metal and Fe oxide (FeOx) and its application to low-temperature ethanol reforming. Fe + Rh/SiO2 was prepared by a conventional co-impregnation method followed by high-temperature calcination in air at 973 K. For low-temperature ethanol reforming, Fe + Rh/SiO2 was subjected to low-temperature reduction with hydrogen at 573 K, and exhibited enhanced dehydrogenation of ethanol. The generation of carbon monoxide and methane byproducts was suppressed by the SMOI between Rh and FeOx, which inhibited acetaldehyde decomposition. Moreover, high-temperature reduction of Fe + Rh/SiO2 with hydrogen at 773 K (HTR) significantly enhanced steam reforming of ethanol due to interaction between the Fe-Rh alloy and FeOx. These results will lead to efficient utilization of rare and active precious metals by the addition of cheap iron oxide, and promise efficient production of hydrogen and acetaldehyde as basic chemicals from bioethanol.
Leaf spot, caused by Corynespora cassiicola and Curvularia aeria, is a major disease of lettuce that results in the reduction of the quality and the quantity of lettuce production. Primary in vitro ...examination revealed that Trichoderma sp. T1 inhibited the mycelial growth of C. cassiicola and C. aeria by 83.79% and 85.71%, respectively, in dual culture assays. Gel diffusion showed cell-free culture filtrate of Trichoderma sp. T1 inhibited C. cassiicola and C. aeria by 50.38% and 53.97%, respectively. Based on the ITS gene sequence, an effective T1 isolate was identified as Trichoderma asperellum. Treatments of lettuce plants with spore suspension of T. asperellum T1 induced defense-related enzymes such as peroxidase and polyphenol oxidase, and the cell wall degrading enzymes β-1,3-glucanase and chitinase in the plants. The activities of β-1,3-glucanase, chitinase, peroxidase and polyphenol oxidase were higher at 24 and 48 h after treatment with spore suspension of T. asperellum T1 than in the control group. Crude extract from inoculated lettuce caused morphology changes in fungal mycelia. In addition, reduction of disease severity was observed in lettuce pretreated with T. asperellum T1. The obtained results suggest that T. asperellum T1 efficiently controlled leaf spot and induced defense responses in lettuce.
•Endophytic Trichoderma asperellum T1 inhibited mycelial growth of leaf spot fungi.•Defense response was induced in lettuces by inoculation of endophytic Trichoderma.•Application of endophytic Trichoderma suppressed disease severity index in lettuce.
Mesoscale fronts are highly energetic ocean processes that dominate local biogeochemical processes and air-sea interactions and exert significant effects on ocean dynamics, ecology, and climate. An ...automatic front detection algorithm applied to satellite-based observations is a fundamental approach to acquiring frontal occurrence information. Histogram-based algorithms have been widely used in previous studies, and, despite being the most popular front detection algorithm, continuous improvements have been needed to address imperfect detection issues (undetected coastal fronts, discontinuities of fronts and repeated detection of fronts). In this study, a new algorithm is proposed to address the issues by coupling inverse distance weighting and mathematical morphology operators. Using 14,610 images acquired from 1982 to 2021, a series of comparisons between the new and existing algorithms have been implemented to validate the improvements. Statistical results suggest that the number of frontal pixels detected by our algorithm increased by 58.45% in the coastal domain when compared to previous methods. Statistical analysis also shows most of these increased fronts can be supported by a classic gradient-based method which is superior in detecting coastal fronts, which demonstrates the improvement of new algorithm in detecting coastal fronts. Furthermore, visual analyses suggest that our algorithm can better connect discontinuous fronts and reduce repeated detections, and statistical comparisons in the open seas present a 34.50% improvement in the average length of frontal segments. Moreover, based on an automated objective delineation method, an analysis of 40 years of seasonal frontal occurrences (as detected by our algorithm) produced a dataset that shows a detailed map of 59 persistent fronts around the China Seas. This map updates previously hand-delineated frontal positions and identifies some previously unreported persistent fronts. Further analyses show that the frontal occurrence or intensity of a majority of persistent fronts around the China Seas presents significant (P < 0.05) long-term variability over the last 40 years. The improved algorithm, together with its application in identifying persistent fronts around the China Seas, is expected to be extended to other waters to better investigate the response of marine ecosystems to front dynamics and predict the distribution of marine organisms within a changing climate.
•A new algorithm to improve front detection is proposed and validated.•The algorithm is designed to address undetected, discontinuous, and repeated fronts.•A dataset of persistent fronts in the China Seas is produced from 40-year SST images.•It updates hand-painted frontal positions and newly detects some persistent fronts.•Most persistent fronts show significant long-term variations in a changing climate.
Two-dimensional (2D) materials are promising for applications in a wide range of fields because of their unique properties. Hydrogen boride sheets, a new 2D material recently predicted from theory, ...exhibit intriguing electronic and mechanical properties as well as hydrogen storage capacity. Here, we report the experimental realization of 2D hydrogen boride sheets with an empirical formula of H1B1, produced by exfoliation and complete ion-exchange between protons and magnesium cations in magnesium diboride (MgB2) with an average yield of 42.3% at room temperature. The sheets feature an sp2-bonded boron planar structure without any long-range order. A hexagonal boron network with bridge hydrogens is suggested as the possible local structure, where the absence of long-range order was ascribed to the presence of three different anisotropic domains originating from the 2-fold symmetry of the hydrogen positions against the 6-fold symmetry of the boron networks, based on X-ray diffraction, X-ray atomic pair distribution functions, electron diffraction, transmission electron microscopy, photo absorption, core-level binding energy data, infrared absorption, electron energy loss spectroscopy, and density functional theory calculations. The established cation-exchange method for metal diboride opens new avenues for the mass production of several types of boron-based 2D materials by countercation selection and functionalization.
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