Assessment of the Effect of Environmental Factors on the Antagonism of <i>Bacillus amyloliquefaciens</i>and <i>Trichoderma harzianum</i>to <i>Colletotrichum acutatum</i>

The effect of temperature (18°C - 30°C), water activity (0.85 - 1) and pH (4 - 9) was studied by dual culture technique on the antagonism of Bacillus amyloliquefaciens and Trichoderma harzianum to Colletotrichum acutatum, responsible of strawberry (Fragaria x ananassa (Weston) Duchesne ex Rozier) anthracnose. The antagonistic bacteria’s strains behave significantly and differently according to the parameters studied. These results reveal useful information about the applicability of their biocontrol in agricultural culture with the change of environmental factors.

Effect of Synergism and Antagonism between Metals on Toxicity in Soils

Synergism and antagonism of cadmium (Cd), copper (Cu) and selenium (Se) to biological toxicities in red soil, yellow brown soil and black soil were evaluated by MICROTOX method. The relation between forms of the tested metals in soil and the synergism or antagonism between them was also studied.Results showed that owing to the difference of soil chemical properties, toxicity of these metals in soils was different. In red soil with acid reaction and low in cation exchange capacity, antagonism occurred significantly between metals when they coexisted at high concentrations, while synergism occurred only under low concentrations. It is indicated that in red soil, toxicity of metals affected by synergism or antagonism depends on concentration of the metals present. For yellow brown soil and black soil with larger cation exchange capacity and lower exchangeable aluminium (A1), no toxicity of metals was observed even if metals were added to soil in high concentrations. Synergism and antagonism between Cd, Cu and Se were controlled by the forms of metals present. The amount of water-soluble metals was the most important factor in determining synergism and antagonism.In this paper, comparisons of synergism and antagonism between metals in soils and in water solutions were made. There occurred the synergism of metal toxicity in water solutions when the concentration of coexisting metals was high. This is just opposite to the case in soils.

Identification of A Strain HN-1 against Banana Wilt Disease and Determination of Its Antagonism

[Objective] The paper was to identify strain HN-1 against banana wilt disease and to determine its antagonism. [Method] The strain HN-1 was ob- tained from the soil in fields heavily infected by Fusarium oxysporum f. sp. cubense （FOC）. Antagonism of the strain against F. oxysporum was tested via dual-cul- ture and inhibition test on spore germination. [Result] HN-1 effectively inhibited mycelial growth and spore germination of F. oxysporum, Strain HN-1 was identi- fied as BrevibaciUus brevis according to its characteristics in morphology, physiology and biochemistry and its 16S rDNA sequence. The strain showed high inhibition effect on 15 species of fungal pathogens in the dual-culture trials with fungal pathogens. [ Conclusion] The study provides theoretical basis for application of strain HN-1 in agricultural fields.

Growth and Antagonism of <i>Trichoderma</i>spp. and Conifer Pathogen <i>Heterobasidion annosum</i>s.l. <i>in Vitro</i>at Different Temperatures

Variations in the radial growth rate of 24 isolates belonging to ten species of Trichoderma, three isolates of conifer pathogen Heterobasidion annosum s.s. and four isolates of H. parviporum were evaluated by incubation on a solid malt extract medium at a temperature of 4℃, 15℃ and 21℃. Trichoderma antagonism against Heterobasidion was investigated in dual culture in vitro. The slowest rate of growth was referable to all seven strains of Heterobasidion spp. All Heterobasidion spp. strains were overgrown by 63% of Trichoderma spp. strains after two weeks at 21℃ and by 33% of strains at 15℃. 21% of Trichoderma strains did not grow and only four strains belonging to T. koningii, T. viride and T. viridescens demonstrated the ability to completely overgrow Heterobasidion spp. after two weeks incubation at 4℃. According to the antagonistic efficiency, Trichoderma strains were divided into five groups with an Euclidean distance of 25. The groups contained isolates from different species. It was suggested that selected psychrotrophic fast growing T. viride, T. koningii and T. viridescens strains could be examined in different substrate conditions as suitable antagonist agents for the control of H. annosum and H. parviporum.

WORLD MILITARY SITUATION 2016: ANTAGONISM INTENSIFIES BUT CRISES REMAIN CONTROLLABLE

The world military situation in 2016was complex,military strategies of major countries undergoing profound readjustment,contest in emerging fields increasing and a new round of populism cropping up worldwide which resulted in'Black swan events'happening one after another,major-country contest and geopolitical conflicts piling up and local

Isolation,identification,and antagonism protein analysis of B34 against Thanatephorus cuc-umeris

A strain B34 against Thanatephorus cucumeris was screened from rice plants. Lab and field experiments showed that the control effects of this fungal strain were better than that of Jinggangmycin on PDA plate. Based on the chemical components of cell wall and physiological and biochemical characters of B34, the fungal was named as Pseudomonas aureofaciens. It was a new antagonistic strain against Thanatephorus cucumeris.

Mutual antagonism of mouse-adaptation mutations in HA and PA proteins on H9N2 virus replication

Avian H9N2 viruses have wide host range among the influenza A viruses.However,knowledge of H9N2 mammalian adaptation is limited.To explore the molecular basis of the adaptation to mammals,we performed serial lung passaging of the H9N2 strain A/chicken/Hunan/8.27 YYGK3W3-OC/2018(3W3)in mice and identified six mutations in the hemagglutinin(HA)and polymerase acidic(PA)proteins.Mutations L226Q,T511I,and A528V of HA were responsible for enhanced pathogenicity and viral replication in mice;notably,HA-L226Q was the key determinant.Mutations T97I,I545V,and S594G of PA contributed to enhanced polymerase activity in mammalian cells and increased viral replication levels in vitro and in vivo.PA-T97I increased viral polymerase activity by accelerating the viral polymerase complex assembly.Our findings revealed that the viral replication was affected by the presence of PA-97I and/or PA-545V in combination with a triple-point HA mutation.Furthermore,the double-and triple-point PA mutations demonstrated antagonistic effect on viral replication when combined with HA-226Q.Notably,any combination of PA mutations,along with double-point HA mutations,resulted in antagonistic effect on viral replication.We also observed antagonism in viral replication between PA-545V and PA-97I,as well as between HA-528V and PA-545V.Our findings demonstrated that several antagonistic mutations in HA and PA proteins affect viral replication,which may contribute to the H9N2 virus adaptation to mice and mammalian cells.These findings can potentially contribute to the monitoring of H9N2 field strains for assessing their potential risk in mammals.

Infection against infection: parasite antagonism against parasites, viruses and bacteria

Background:Infectious diseases encompass a large spectrum of diseases that threaten human health,and coinfection is of particular importance because pathogen species can interact within the host.Currently,the antagonistic relationship between different pathogens during concurrent coinfections is defined as one in which one pathogen either manages to inhibit the invasion,development and reproduction of the other pathogen or biologically modulates the vector density.In this review,we provide an overview of the phenomenon and mechanisms of antagonism of coinfecting pathogens involving parasites.Main body:This review summarizes the antagonistic interaaion between parasites and parasites,parasites and viruses,and parasites and bacteria.At present,relatively clear mechanisms explaining polyparasitism include apparent competition,exploitation competition,interference competition,biological control of intermediate hosts or vectors and suppressive effect on transmission.In particular,immunomodulation,including the suppression of dendritic cell(DC)responses,activation of basophils and mononuclear macrophages and adjuvant effeas of the complement system,is described in detail.Conclusions:In this review,we summarize antagonistic concurrent infections involving parasites and provide a funaional framework for in-depth studies of the underlying mechanisms of coinfeaion with different microorganisms,which will hasten the development of promising antimicrobial alternatives,such as novel antibaaerial vaccines or biological methods of controlling infeaious diseases,thus relieving the overwhelming burden of ever-increasing antimicrobial resistance.

‘Friendship Always,Antagonism Never’The launch of the Year of Russia marks a new chapter in a growing partnership between China and Russia

Most Chinese are at ease when talking about Russia. After all, past generations of Chinese were heavily influenced by things Russian-be it the language, folk songs, literature or food. This is easy to understand. China is Russia's largest neighbor and vice versa. The two countries are also important strategic partners. Joint efforts over the years have led to an unprecedented level of part-

Application of Silicon and Selenium in Rice for Reducing Cadmium Stress

Rice is an essential part of the human diet in most parts of the world;On the other hand,the industrialization of societies has led to pollution of the environment,including heavy metal contamination of soil and water,which negatively affects rice production and quality.Therefore,finding ways to increase the yield and quality of this strategic crop seems essential.Several studies have been conducted in recent decades to find effective and inexpensive solutions to reduce the adverse effects of heavy metals in rice fields.Due to the negative effect of cadmium pollution on rice quality and yield,the current study aimed to investigate cadmium absorption and transfer mechanisms in rice(from absorption by roots to loading in grains),and its effects on rice morphology,physiology,and biochemistry(such as biomass,nutrient absorption,antioxidant defenses).Also,rice’s natural mechanisms for detoxifying cadmium were discussed.This study also intended to identify the absorption and transfer pathways of silicon and selenium in rice,their roles in improving rice structures,and their antagonistic effects on reducing cadmium stress(absorption,transport,and toxicity of cadmium).

Isolation of Endophyte and Screening for Antagonistic Bacteria in Solanaceae

[ Objective] The aim of this study was to isolate the endophyte of three solanaceae fruits and vegetables such as tomato, pepper and eggplant, to screen and identify the bacterial wilt antagonistic bacteria. [ Methodl According to the lapping liquid culture method, the endophyte of three plants was isolated by the selective medium and purified by the plate streaking method, so the purified enclophyte was screened by the hyphal pieces confront culture method. Furthermore, the screened antagonistic and endophyteic bacteria was identified and classified through culture characteristics of isolates and morphological features of thallus, Gram stain as well as physiological and biochemical reactions. [ Result] Fifty-three endophytic bacteria, fifty-three endophytic fungi and forty-four endophytic actinomycetes were separated from the endophyte of three plants. The screened fourteen endophytic bacteria with strong antagonistic effect on the bacterial wilt were classified to Bacillus, Escherichia, Klebsiella, Agromonas, Erwinia and Curto Bacterium respectively. Especially, Bacillus was the dominant species, which had the strongest antagonistic effect on the bacterial wilt. [ Conclusion] This study provides an effective way for biological control of the bacterial wilt in solanaceae.

Screening for Siderophore-producing Endophytic Bacteria against Fusarium oxysporum

[Objective] With a strain of endophytic antagonistic bacteria with good disease control efficacy in pot as trial material,the paper was to explore the antagonistic mechanism of siderophore against Fusarium oxysporum.[Method] Whether the strain produced siderophore and its fluorescent property was judged by MSA（Modified Sugar-Aspartic acid） plate.The siderophore activity of strains in liquid MSA medium was determined through the absorbance values at particular wavelength.The inhibition effects of it siderophore against F.oxysporum under different concentrations of Fe3＋ were compared.Then the strain was preliminarily identified based on morphological,physiological and biochemical characteristics [Result] The fluorescent siderophore produced by the endophytic bacteria in MSA medium had a strong inhibition effect against F.oxysporum.With the increasing concentration of Fe3＋,the inhibition effect against the pathogen weakened.The preliminary analysis showed these strains belonged to Bacillus.[Conclusion] Bacillus could compete the absorption of Fe3＋ by secreting siderophore to inhibit the growth of F.oxysporum.

Research Application Progress on the Bacillus sp. in Plant Pathogenic Fungi Biocontrol

For about half a century, chemical control has played a major role in plant disease control. However, the long-term irrational use of chemical pesticide produces many problems. In nature, there exit extensive antagonistic microorganisms which are tightly concerned with plant pathogenic microbes, and biological pesticides can be researched to control related pathogenic microbes from its metabolites. It＇s an important research direction of new pesticide development. The Bacillus is the ideal and frequently studied object of bio-control bacteria, and it can produce some entospores with following characteristics such as heat-resistant, drought tolerance, antiultraviolet and organic solvent. In this article, the bio-control mechanism, problems and application prospects of the Bacillus were reviewed to promote the application in new biological pesticide.

Inhibition Effect of Antagonistic Fungal Strain BOS-013 against the Pathogen of Rice Blast (Pyricularia oryzae)

[ ObjeeUve ] To search for the beneficial microorganisms and their metabolic products with control effect against rice Mast, the paper studied the inhibi- tion effect of the fermentation broth of actinomycetes BOS-013 strain against the pathogen of rice blast （Pyricularia oryzae）. [ Method ] With P. oryzae as the target indicator fungus, the inhibition effect of the fermentation broth of BOS-013 strain and its extracts from different solvents against the pathogen were determined using cylinder plate method and filter paper method. [ Result] The results showed that the inhibition rate of the fermentation broth of BOS-013 strain with fungus amount of 4×10^8 cfu/ml against P. oryzae was 92.0% ±0.5% ; the fermentation broth still had inhibition effect against P. oryaae after inactivation under high temperature and high pressure, and the inhibition rate was 60.0%±0.5%. After absorbed by non-polar CAD-45 type macroperous adsorption resin and eluted by 60% etha- nol, the antifungal activity of the fermentation broth was still high, and the diameter of inhibition zone reached 33.0 mm. [ Conclusion] The fermentation broth of BOS-O13 strain had significant inhibition effect against P. oryzae. The results would provide foundation for further clarification of inhibition mechanism of BOS-013 strain fermentation broth against P. oryzae and its practical application.

Comparison of the Evolvement Structure of Chenopodium album L.under the Stress of Different Saline Environments

[Objective] The aim of this study was to reveal the evolvement structures,especially the crystal characteristics of Chenopodium album L.under saline stress,so as to providing the first-hand data for utilizing biological techniques to control saline environment.[Method] Employing high definition display method of plant crystal structure and paraffin-section method,we performed a comparative study on the evolvement structures of C.album growing in high salinity areas in the coast of Egyptian Red Sea and common salinity areas in the grasslands in Changling County of Jilin Province.[Result] The regionally distributed crystal and the developed assimilating tissue of C.album are the key structural characteristics to antagonize the saline stress during the evolving process.Stem cortex of C.album growing in both the high salinity areas in coast of Egyptian Red Sea and common salinity areas in the grasslands in Changling County of Jilin Province has similar discontinuous crystal rings.Assimilating tissue in C.album growing in high salinity areas is highly developed than that in common salinity environment.Comparative analysis indicates that the developed stratum corneum and marrow is also the key structural characteristics to antagonize the saline stress.[Conclusion] Our results provide a valuable approach to study the salt-tolerance mechanism of plant using structural botanical techniques,i.e.,crystal may become the identification characteristics of salt tolerant plant.

Isolation of High-virulence Strains and Antagonistic Bacteria of the Pathogen of Ginger Blast (Ralstonia solanacearum)

[ Objective] The paper was to screen Bacillus with strong antagonistic effect. [ Method] The diseased ginger and the surrounding soils were collected from Laiwu of Shandong Province, and the high-virulence strains of the pathogen of ginger blast （Ralstonia solanacearum） were isolated, Bacillus was used to carry out antagonistic test. [Result] Three strains LW-4, LW-7 and LW-32 had strong antagonistic effect against R. solanacearum, the area of their inhibition zone was larger than other strains. [ Conclusion] The study provided theoretical basis for the control of ginger blast.

Bio-control trials of Chaetomium spirale ND35 against apple canker

A new endophytic antagonistic fungus, Chaetomium spirale ND35 from Populus tomentosa, was reported. The bio-control trials of C. spirale ND35 against the Valsa Canker of apple were preliminarily investigated. The results of dual culture on PDA plate showed that C. spirale ND35 was capable of strong antagonism against Valsa ceratosperma, and for inhibiting the mycelial growth of V. ceratosperma,.the crude extract of liquid culture of corn steep powder broth was more effective than that one of malt extract broth (MEB). The results of bio-control in greenhouse and field indicated that the disease incidence of apple tree treated with C. spirale ND35 was lower significantly than that treated by other methods. The re-isolation experiment suggested that C. spirale ND35 could colonize in stems and branches of apple trees successfully, and the ND35 colonization rate of the treatment with solid wheat bran culture was higher than that of corn steep powder broth, but the field experiment result the control effect of liquid culture of C. spirale ND35 was better than that of solid culture.

Synergistic and antagonistic interactions between potassium and magnesium in higher plants

Magnesium(Mg)affects various critical physiological and biochemical processes in higher plants,and its deficiency impedes plant growth and development.Although potassium(K)-induced Mg deficiency in agricultural production is widespread,the specific relationship of K with Mg and especially its competitive nature is poorly understood.This review summarizes current knowledge on the interactions between K and Mg with respect to their root uptake,root-to-shoot translocation and distribution in plants.Their synergistic effects on certain physiological functions are also described.The antagonistic effect of K on Mg is stronger than that of Mg on K in root absorption and transport within plants,indicating that the balanced use of K and Mg fertilizers is necessary for sustaining high plant-available Mg and alleviating K-induced Mg deficiency,especially in plant species with high K demand or in highavailable-K soil.The relationship between Mg and K in plant tissues may be antagonistic or synergistic depending on plant species,cell type,leaf age,source-and sink organs.There are synergistic effects of K and Mg on photosynthesis,carbohydrate transport and allocation,nitrogen metabolism,and turgor regulation.Definition of optimal K/Mg ratios for soils and plant tissues is desirable for maintaining proper nutritional status in plants,leading to a physiological state supporting crop production.Future research should concentrate on identifying the physiological and molecular mechanisms underlying the interactions between K and Mg in a given physiological function.

Superior growth performance in broiler chicks fed chelated compared to inorganic zinc in presence of elevated dietary copper

Background： The goal of this study was to compare the antagonism of elevated dietary Cu （250 mg/kg） from CuS04 on three different Zn sources （ZnS04. H20; [Zn bis（-2-hydroxy-4-（methylthio）butanoic acid）], Zn（HMTBa）2 a chelated Zn methionine hydroxy analogue; and Zn-Methionine）, as measured using multiple indices of animal performance in ROSS 308 broilers. Methods： Three experiments were conducted in broiler chicks fed a semi-purified diet. All birds were fed a Zn-deficient diet （8.5 mg/kg diet） for 1 wk, and then provided with the experimental diets for 2 wks. Results： Experiment 1 was a 2 x 2 factorial design with two levels of Cu （8 vs. 250 mg/kg diet from CuSO4） and two Zn sources at 30 mg/kg [ZnSO4. H20 vs. Zn（HMTBa）2]. Elevated Cu impaired growth performance only in birds fed ZnSO4. Compared to ZnSO4. H20, Zn（HMTBa）2 improved feed intake （12 %; P 〈 0.001） and weight gain （12 %, P 〈 0.001） and the benefits were more pronounced in the presence of 250 mg/kg diet Cu. Experiment 2 was a dose titration of ZnSO4- H20 and Zn（HMTBa）2 at 30, 4,5, 60, and 75 mg/kg diet in the presence of 250 mg/kg CuSO4. Feed：gain was decreased and tibia Zn was increased with increasing Zn levels from 30 to 75 mg/kg. Birds fed Zn（HMTBa）2 consumed more food and gained more weight compared to birds fed ZnSO4, especially at lower supplementation levels （30 and 45 mg/kg; interaction P 〈 0,05）. Experiment 3 compared two organic Zn sources （Zn（HMTBa）2 vs. Zn-Methionine） at 30 mg/kg with or without 250 mg/kg CuSO4. No interactions were observed between Zn sources and Cu levels on performance or tissue mineral concentrations. High dietary Cu decreased weight gain （P 〈 0.01）. Tibia Cu and liver Cu were significantly increased with 250 mg/kg dietary Cu supplementation （P 〈 0.01）. No difference was observed between the two Zn sources. Conclusions： Dietary 250 mg/kg Cu significantly impaired feed intake and weight gain in birds fed ZnSO4. H20, but had less impact in birds fed Zn（HMTBa）2. No difference was observed between the two organic zinc sources These results are consistent with the hypothesis that chelated organic Zn is better utilized than inorganic zinc in the presence of elevated Cu.

Interactions of cadmium and aluminum toxicity in their effect on growth and physiological parameters in soybean

The effect of Al and Cd on the growth, photosynthesis, and accumulation of Al, Cd and plant nutrients in two soybean genotypes were determined using hydroponic culture. There were six treatments: pH 6.5; pH 4.0; pH 6.5+1.0 μmol/L Cd; pH 4.0+1.0 μmol/L Cd; pH 4.0+150 μmol/L Al; pH 4.0+1.0 μmol/L Cd+150 μmol/L Al. The low pH (4.0) and Al treatments caused marked reduction in root length, shoot height, dry weight, chlorophyll content (SPAD value) and photosynthetic rate. Al-sensitive cv. Zhechun 2 accumulated comparatively more Al and Cd in plants than Al-tolerant cv. Liao 1. Compared with pH 6.5, pH 4.0 resulted in significant increase in Cd and Al concentration in plants. Combined application of Cd and Al enhanced their accu-mulation in roots, but caused a reduction in shoots. The concentrations of all 10 nutrients (P, K, Ca, Mg, Fe, Mn, Cu, Zn and B), except Mo were also increased when plants were exposed to pH lower than pH 6.5. Al addition caused a reduction in the con-centration of most nutrients in plant roots and shoots; but K, Mn and Zn in roots were increased. Treatments with Cd alone or together with Al reduced the concentrations of all the plant nutrients in plants. Al-sensitive genotype Zhechun 2 has lower nutrient concentration than Al-tolerant genotype Liao 1. The current findings imply that Al and Cd are synergistic in their effect on plant growth, physiological traits and nutrient uptake.