Species of the genus Paenibacillus,especially those from extreme environments that have been reported,are known for producing bioactive compounds with agricultural and biotechnological applications.In this study,we in...Species of the genus Paenibacillus,especially those from extreme environments that have been reported,are known for producing bioactive compounds with agricultural and biotechnological applications.In this study,we investigated the genomic and biochemical potential of Paenibacillus sp.VCA1 strain isolated from a thermophilic environment.Taxonomic identification was performed using whole genome similarity analysis,TETRA four-nucleotide frequency of occurrence analysis,ANI average nucleotide identity analysis,and gene distance analysis using digital DNA-DNA hybridization(dDDH).Functional analysis of the strain VCA1 was performed by detecting genes,enzymes,and genome subsystems involved in biocontrol and plant growth promotion,which was carried out using the RAST(Rapid Annotation using Subsystem Technology),the seed server and antiSAMSH(antibiotics&Secondary Metabolite Analysis Shell).Genetic analyses showed the existence of 11 fatty acid and isoprenoid production genes,56 motility and chemotaxis genes,29 N-acetylglucosamine genes,and five siderophore genes.Finally,the antifungal and emulsifying activities demonstrated that strain VCA1 has activity against Fusarium oxysporum strain 45ta using integrated genomic and experimental validation,and the antifungal properties of the Paenibacillus sp.VCA1 has suggested potential use as a biocontrol agent against phytopathogenic fungi,and its continuous study can have beneficial applications in sustainable agriculture and biotechnology.展开更多
Tree endophytic fungi play an important role in reducing insect herbivory,either by repelling them or kill-ing them directly.Identifying which fungi show such activ-ity could lead to new environmentally friendly pesti...Tree endophytic fungi play an important role in reducing insect herbivory,either by repelling them or kill-ing them directly.Identifying which fungi show such activ-ity could lead to new environmentally friendly pesticides.In this study,the Mediterranean basin climate conditions are projected to harshen in the next decades,will increase vulnerability of tree species to pest invasions.Endophytic fungi were isolated from wood and leaves of Quercus pyr-enaica,Q.ilex and Q.suber and tested for virulence against adults of the mealworm beetle,Tenebrio molitor L.using a direct contact method.Only 3 of 111 sporulating isolates had entomopathogenic activity,all identified as Lecanicillium lecanii.The pathogenicity of L.lecanii on T.molitor resulted in a median lethal time(TL50)of 14-16 d.Compared with commercial products,L.lecanii caused faster insect death than the nematode Steinernema carpocapsae and nuclear polyhedrosis virus(no effect on T.molitor survival),and slower than Beauveria bassiana(TL50=5),Beauveria pseu-dobassiana(TL50=8d)and Bacillus thuriengensis(80%mortality first day after inoculation).Mortality was also accelerated under water stress,reducing TL50 by an addi-tional 33%.Remarkably,water stress alone had a comparable effect on mortality to that of L.lecanii isolates.This study confirms T.molitor as a good model insect for pathogenicity testing and agrees with management policies proposed in the EU Green Deal.展开更多
The effectiveness of current control measures against Aedes mosquitoes remains low, resulting in persistent epidemics in urban areas. The emergence of resistant mosquito populations to chemical insecticides highlights...The effectiveness of current control measures against Aedes mosquitoes remains low, resulting in persistent epidemics in urban areas. The emergence of resistant mosquito populations to chemical insecticides highlights the need for novel, environmentally friendly, cost-effective control strategies. This study explored the potential of environmental bacterial isolates to biocontrol wild Aedes larvae. Initially, we collected bacterial samples from infectious masses of Aedes fluviatilis larvae. The isolated bacteria were identified using biochemical, enzymatic, and molecular methods, including 16S rRNA sequencing and MALDI-TOF. Previously, Aeromonas hydrophila and Bacillus thuringiensis isolated from these infectious masses showed limited Aedes larval inhibition. Consequently, we screened additional environmental isolates from the bacteriotheque. Six isolates previously identified were tested: Chromobacterium violaceum, Enterobacter cloacae, Bacillus cereus, Bacillus sphaericus, and two strains of Bacillus thuringiensis israelensis. Among these strains, B. thuringiensis and C. violaceum exhibited significant inhibitory activities against wild Aedes larvae. Bacillus thuringiensis cultures grown under daylight conditions showed a slight ability to inhibit Aedes larvae. The potential of B. thuringiensis and C. violaceum strains studied, along with optimized culture growth conditions, will be further investigated to develop bioinsecticide products to provide safer and more sustainable alternatives for controlling larvae of Aedes mosquitoes.展开更多
[Objective] For preparing the biopesticide of Bacillus subtilis B579 with high spore concentration,the sporulation conditions were optimized.[Method] Two-step fermentation control strategy was used,in which,the first ...[Objective] For preparing the biopesticide of Bacillus subtilis B579 with high spore concentration,the sporulation conditions were optimized.[Method] Two-step fermentation control strategy was used,in which,the first phase（0-10 h）was to improve cell growth,and the second phase（10-30 h）was to promote spore formation.Four factors including initial glucose concentration,fermentation pH,temperature（in the second phase）and shaking speed（in the second phase）were optimized using the methods of single factor test and orthogonal experiment.[Result] The initial glucose concentration showed a significant effect on sporulation.The optimal conditions for the spore formation of B.subtilis B579 were as follows：initial glucose concentration 5 g/L,fermentation pH 7.0,the temperature for the first phase 37 ℃,and the shaking speed for the first phase 180 r/min,the temperature for the second phase 40 ℃,and the shaking speed for the second phase 200 r/min;in addition,the first phase was 10 h and the second phase of fermentation was conducted for 30 h.Under such conditions,the spore concentration and spore formation rate could reach 9.43×108 CFU/ml and 90.99%,respectively,which represented 6.70-fold and 2.43-fold increase compared with those before optimization.[Conclusion] The spores concentration of biocontrol agent was improved using two-step control strategy,which provided the basis for biopesticide production in large scale.展开更多
[Objective] The aim was to understand defense mechanism of pear after inoculated Botryosphaeria berengeriana f. sp. piricolan and mechanism of antioxidant enzymes of biocontrol bacteria. [Method] Pears were treated by...[Objective] The aim was to understand defense mechanism of pear after inoculated Botryosphaeria berengeriana f. sp. piricolan and mechanism of antioxidant enzymes of biocontrol bacteria. [Method] Pears were treated by Botryosphaeria berengeriana f. sp. piricolan and bio control bacteria, and the change of antioxidant enzymes were determined. [Result] The biocontrol bacteria had little effect on MDA;the content of MDA treated by B. berengeriana reached high peak in 48 h, was 10.22nmol/g which was 1.86 times of CK; the content of MDA treated by B. berengeriana and biocontrol bacteria reached high peak in 24 h, was 8.92 nmol/g which was1.62 times of CK. The content of SOD treated by biocontrol bacteria reached high peak in 48 h, was 126.69 U/[g（FW）·min] which was 1.54 times of CK; the contents of SOD treated by B. berengeriana as well as B. berengeriana and biocontrol bacteria reached high peak in 24 h, were 122.10 and 135.32 U/[g（FW）·min] which were 1.48 and 1.65 times of CK respectively; the contents of POD on biocontrol bacteria treatment, B. ana treatment as well as B. berengeriana and biocontrol bacteria treatment reached high peak in 24 h, were 385.34, 342.50 and 290.00 U/[g（FW）·min] which were 1.83, 1.62 and 1.38 times of CK respectively. The contents of CAT on biocontrol bacteria treatment, B. rengeriana treatment as well as B. berengeriana and biocontrol bacteria treatment reached high peak in 6 h, were 133.33,114.17 and 113.35 U/[g（FW）·min] which were 1.33, 1.14 and 1.13 times of CK respectively. The biocontrol bacteria had little difference in CK; the content of PPO of B. berengeriana treatment reached high peak in 12 h, was 81.86 U/[g（FW）·min]which was 1.76 times of CK; B. berengeriana and biocontrol bacteria treatment reached high peak in 24 h, was 70.00 U/[g（FW）·min] which was 1.50 times of CK.[Conclusion] B. berengeriana and biocontrol bacteria had more effect on MDA; both B. berengeriana and biocontrol bacteria could increase the excitation of SOD enzyme activity; both B. berengeriana and biocontrol bacteria could increase the excitation of POD enzyme activity; both B. berengeriana and biocontrol bacteria could increase the excitation of CAT enzyme activity; using biocontrol bacteria alone had not obvious effect on PPO, B. berengeriana could increase the excitation of PPO enzyme activity.展开更多
A transcriptomic database was constructed to study the biocontrol mechanisms of Trichoderma harzianum ACCC30371 using high quality UniGenes following growth in eight culture media[(1/2PD,minimal medium MM(containing d...A transcriptomic database was constructed to study the biocontrol mechanisms of Trichoderma harzianum ACCC30371 using high quality UniGenes following growth in eight culture media[(1/2PD,minimal medium MM(containing dextrose 10 g L^-1),C starvation medium(derived from MM without dextrose),N starvation medium(derived from MM without ammonium sulphate),and four kinds of phytopathogenic fungi cell wall media].A 4 Gbp transcriptome was generated and 96.7%of the database had a sequencing error rate less than 1%.A total of 25,013 UniGene sequences were obtained with a mean length of 1135 nt.There were 2571 sequences longer than 3000 nt.The National Center for Biotechnology Information Accession number of this transcriptome is SRR8382572.There were 16,360 Unigenes annotated to the Nr protein database,9875 to the SwissProt database,10,266 to the KEGG database,7164 to the COG database,and 1508 to the GO database along with their protein functional annotations.There were 16,723 functional genes identified.We identified 402 bio-control genes,including 14 related to competition,311 to mycoparasitism,76 to antibiosis,and one related to eliciting a plant response.This shows that T.harzianum ACCC30371 has integrated biocontrol mechanisms,and of these mechanisms,mycoparasitism is the most prevalent.Antibiosis and induced systemic resistance also play important roles.These results provide a foundation for further research into the biocontrol mechanisms of Trichoderma,as well as the development and utilization of biological fungicides.展开更多
[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orth...[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orthogonal design, the effects of combined application of two biocontrol agents against pepper blight and organic fertilizer on control effects against pepper blight and the yield of hot pepper were studied in greenhouse hot pepper base in Ledu County of Qinghai Province. [ Result] The effects of various factors affecting the relative control effect against pepper blight in sequence were biecontrol agent A5 〉 biecontrol agent B2 〉 organic fertilizer, and the optimal combination was organic fertilizer 1 800 kg/hm^2, agent B2 30 kg/hm^2 and agent A5 45 kg/hm^2. The effects on hot pepper yield in sequence were organic fertilizer 〉 biocontrol agent B2 〉 biocontrol agent AS, and the optimal combination was organic fertilizer 900 kg/hm^2 , agent 132 15 kg/hm^2, agent A5 22.5 kg/hm2. [ Conclusion] Combined with control effect of pepper blight and yield benefit, the application technique of biocontrol agents pro- moted in local hot pepper production could be confirmed as follows ： agent A5 45 kg/hm^2, agent B2 15 kg/hm^2, organic fertilizer 900 kg/hm^2 ; the field control effect at this moment could reach 76.31%, the yield could reach 35 573 kg/hm^2 , and the newly increased output value could be 13 029 yuan/hm^2 with input and output ratio of 1： 7.9.展开更多
Biocontrol by Trichoderma has been studied mainly with selected isolates of T. harzianum, T. atroviride and T. asperellum, which are members of sections Pachybasium and Trichoderma. In contrast, species from section L...Biocontrol by Trichoderma has been studied mainly with selected isolates of T. harzianum, T. atroviride and T. asperellum, which are members of sections Pachybasium and Trichoderma. In contrast, species from section Longibrachiatum have only rarely been studied. On the other hand, one taxon from this section-Hypocrea jecorina (anamorph: Trichoderma reesei)-has been widely used for the production of cellulolytic and hemicellulolytic enzymes and recombinant proteins. As far as Trichoderma is concerned, molecular genetic methods and tools are most advanced in H. jecorina, and its genome has recently been fully sequenced, thus making this taxon a model organism for the genus. Here we will demonstrate that H. jecorina is able to antagonize plant pathogenic fungi in plate confrontation tests, and can protect tomato and cucumber plants against Pythium ultimum blight. Using this as a model case, we made use of available H. jecorina mutants to investigate (a) whether carbon catabolite repression via the Cre1-regulator protein has an impact on biocontrol, and (b) whether cellulase gene expression is necessary for biocontrol of P. ultimum. In the first case, plate confrontation tests and in planta experiments yielded opposite results, i.e. while a Cre1 mutant was more active in antagonization of fungi on plates, the survival rates of P. ultimum-inoculated cucumber plants was lower than with the H. jecorina wild-type strain. Mutants of H. jecorina, unable to form cellulases, were still able to antagonize fungi on plates and provided similar protection of tomatos against P. ultimum as the wild type, indicating that the pronounced biocontrol ability of H. jecorina against fungi with cellulose-containing cell-walls is not due to its high cellulolytic activity. A strain disrupted in the light-modulator gene envoy (Schmoll et al., ms submitted) exhibited in planta biocontrol activity strongly exceeding that of the wild-type strain, thereby providing a first link between Trichoderma biocontrol and light. In view of the numerous other metabolic and regulatory mutants of H. jecorina available, we suggest that this fungus should increasingly be used in basic studies on the biochemistry and genetics of biocontrol.展开更多
[Objective] The aim was to explore biocontrol approaches of strawberry an-thracnose. [Method] With hyphal growth inhibition method, bacteriostatic activities of Bacil us subtilis and Osthole on strawberry anthracnose ...[Objective] The aim was to explore biocontrol approaches of strawberry an-thracnose. [Method] With hyphal growth inhibition method, bacteriostatic activities of Bacil us subtilis and Osthole on strawberry anthracnose were measured and field test was carried out. [Result] The results show that both of Bacil us subtilis and Osthole were of higher bacteriostatic activity on strawberry anthracnose, and the values of EC50 were 0.007 5 mg/L and 1.063 0 ml/L, respectively. The result of field test show that the prevention effects of Bacil us subtilis （600-750 g/hm2） and 25% prochloraz （600 ml/hm2） both achieved higher than 76%, 7 and 14 d after triple medical applica-tions with rains sheltered or in open field. But the effects were of extremely signifi-cant differences with that of Osthole （1 800-2 700 ml/hm2） （P〈0.01）. [Conclusion] Bacil us subtilis can be made use of for control ing strawberry anthracnose.展开更多
Biocontrol agents are safe and environmental friendly alternatives for pesticides in agriculture application. Trichoderma viride WEBL0703 performed a high level of antagonistic activity toward a broad spectrum of phyt...Biocontrol agents are safe and environmental friendly alternatives for pesticides in agriculture application. Trichoderma viride WEBL0703 performed a high level of antagonistic activity toward a broad spectrum of phytopathogens and was determined as a biocontrol agent, which was produced by solid state fermentation using grape marc and wine lees. The maximum yield of T. viride conidia was up to 6.65 × 10^9 CFU/g initial dry substrate （IDS） after 10 d fermentation. As important enzymes for protecting plants from disease, chitinase, β-glucanase, and pectinase yields were 47.8 U/g IDS, 8.32 U/g IDS and 9.83 U/g IDS, respectively. These results show that it is feasible to convert winery wastes to a value-added and environmental friendly biocontrol agent.展开更多
A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investiga...A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater （MGW） and potato wastewater （PW） as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW （1：9）.展开更多
Several bacterial strains were isolated from different rhizospheres. Among these, strain PDY7 exhibited strong antibacterial activity against the rice bacterial blight （BB） pathogen Xanthomonas oryzae pv. oryzae （...Several bacterial strains were isolated from different rhizospheres. Among these, strain PDY7 exhibited strong antibacterial activity against the rice bacterial blight （BB） pathogen Xanthomonas oryzae pv. oryzae （Xoo） by the laboratory dual plate assays. The antibacterial property of the strain PDY7 was further investigated for the production of 2,4-diacetylphloroglucinol （DAPG）, which amplified a characteristic of 629-bp DNA fragment by PCR-based screening method using phlD primers. The application of phlD positive strains was carefully evaluated for disease control and growth promotion of rice plants under field conditions. The selected strain PDY7 suppressed the rice BB by 58.83% and 51.88% under glass house and field conditions, respectively. In addition, the strain PDY7 showed significant two-fold increase in root length （18.08 cm）, shoot length （29.81 cm）, and grain yield （96.07 g）. Strain PDY7 promoted the growth of rice plants by production of indole-3-acetic acid （IAA）, which was determined by high performance liquid chromatography （HPLC） analysis. Our findings suggest that PDY7 belongs to the P. fluorescens group and can serve as potential biocontrol of BB as well as biofertilizer agent for growth promotion of rice.展开更多
Streptomyces rubrogriseus HDZ-9-47,isolated from eggs of Meloidogyne spp.,was evaluated as a potential biocontrol agent of Meloidogyne incognita under in vitro and protective field.Microscopic observations showed that...Streptomyces rubrogriseus HDZ-9-47,isolated from eggs of Meloidogyne spp.,was evaluated as a potential biocontrol agent of Meloidogyne incognita under in vitro and protective field.Microscopic observations showed that HDZ-9-47 parasitized eggs of M.incognita within 7 days.In vitro,the culture filtrate of HDZ-9-47 caused 97.0%mortality of second-stage juveniles（J2s）of M.incognita and inhibited more than 50%egg hatching.In the field,compared with the control,the rootknot index and J2s density in the treatment of drench the broth contained 1012 HDZ-9-47 spores were respectively reduced by 51.1 and 80.7%at 90 days post transplantation,which were better than that in other application doses and methods.In addition,reduction rates of root-knot index and J2s density of the treatment of combined application of HDZ-9-47 with biofumigation was 87.1 and 91.0%,respectively,better than either of HDZ-9-47 or biofumigation used alone or fosthiazate treatment.And tomato yield also increased by 16.1%.Together,our results suggest that HDZ-9-47 could be an effective biocontrol agent of M.incognita,and that application of HDZ-9-47 combined with cabbage residue biofumigation was a promising and sustainable option for M.incognita control.展开更多
[Objective] The aim was to study effect of Chaetomium globosum ND35 on plant growth and preliminary study of its biocontrol efficacy, and provide basis for popularization and application of this strain.[ Method] With ...[Objective] The aim was to study effect of Chaetomium globosum ND35 on plant growth and preliminary study of its biocontrol efficacy, and provide basis for popularization and application of this strain.[ Method] With endophytic fungus C. globosum ND35 as a tested strain, effect of C. globosumND35 on plant growth and its biocontrol on five plant diseases were investigated in the greenhouse and field,[Result]The results showed that ND35 promoted growth of lateral root and diameter of breast height of poplar. ND35 can induce poplar to resist Poplar Valsa Canker caused by Valsa sordida and Poplar Rust caused by Melampsora puplicola. ND35 was also able to induce tomato and bean to resist Botrytis cinera. Biocontrol of Bean Stem Rot Rhizoctonia by ND35 was effective as well. [Conclusion] Induced systemic resistance by endophytic C. globosum ND35 plays an important role in biocontrol of plant diseases.展开更多
Modern agribusiness plays a vital role in safeguarding and improving the production,quality,and quantity of food,feed,fiber,and fuel.Growing concerns over the impact of chemical pesticides on health and the environmen...Modern agribusiness plays a vital role in safeguarding and improving the production,quality,and quantity of food,feed,fiber,and fuel.Growing concerns over the impact of chemical pesticides on health and the environment have stimulated the industry to search for alternative and greener solutions.Over the last years,the RNA interference(RNAi)process has been identified as a very promising new approach to complement the arsenal of foliar spray,soil,or seed treatments applied as chemical and biological pest control agents,and of plant-incorporated protectants(PIPs).RNA-based active ingredients(AIs)possess a unique mode of action and can be implemented via both genetic modification(GM)and biocontrol approaches.RNA-based AIs promise to deliver the selectivity and sustainability desired in future crop protection agents.This is due to their utilization of a natural process to exert control and their high level of selectivity,which leads to reduced risk for non-target organisms(NTOs).This review discusses the advantages and limitations of RNA-based solutions in crop protection and recent research progress toward RNA-based biocontrols against the Colorado potato beetle(CPB),corn rootworm(CRW),and soy stink bug(SSB).Many challenges still exist on the road to the implementation of a broad range of RNA-based products and their widespread use and application.Despite these challenges,it can be expected that RNA-based AIs will become valuable new tools complementing the current arsenal of crop-protection solutions.展开更多
Peach brown rot, caused by Monilinia fructicola, is one of the most serious peach diseases. A strain belonging to the Actinomycetales, named Streptomyces blastmyceticus JZB130180, was found to have a strong inhib-itor...Peach brown rot, caused by Monilinia fructicola, is one of the most serious peach diseases. A strain belonging to the Actinomycetales, named Streptomyces blastmyceticus JZB130180, was found to have a strong inhib-itory effect on M. fructicola in confrontation culture. Following the inoculation of peaches in vitro, it was revealed that the fermentation broth of S. blastmyceticus JZB130180 had a significant inhibitory effect on disease development by M. fructicola. The fermentation broth of S. blastmyceticus JZB130180 had an EC50(concentration for 50% of maximal effect) of 38.3 μg/mL against M. fructicola, as determined in an indoor toxicity test. Analysis of the physicochemical properties of the fermentation broth revealed that it was tolerant of acid and alkaline conditions, temperature, and ultraviolet radiation. In addition, chitinase, cellulase, and protease were also found to be secreted by the strain. The results of this study suggest that S. blastmyceticus JZB130180 may be used for the biocontrol of peach brown rot.展开更多
Bacillus thuringiensis Bt185 and its insecticidal spectrum-expanded engineering strains are considered as potential biocontrol agents to soil insect Holotrichia parallela,Holotrichia oblita or Anomala corpulenta.Here ...Bacillus thuringiensis Bt185 and its insecticidal spectrum-expanded engineering strains are considered as potential biocontrol agents to soil insect Holotrichia parallela,Holotrichia oblita or Anomala corpulenta.Here we reported the complete genome of strain Bt185,it harbors eight plasmids,and plasmid p BT1850294 carries three cry8 genes.展开更多
Methicillin-resistant Staphylococcus aureus (MRSA) is among the most alarming pathogens affecting both humans and the global bovine industry. The current control measures in hospitals and on farms for MRSA have proven...Methicillin-resistant Staphylococcus aureus (MRSA) is among the most alarming pathogens affecting both humans and the global bovine industry. The current control measures in hospitals and on farms for MRSA have proven to be inadequate leaving a need for new rapid control methods to curb MRSA infections in situ. New control measures for bacterial infection are widely sought, with particular interest in the applications for bacteriophages (phages) as a biocontrol or therapeutic agent. The current study uses a wild highly lytic phage isolated from cow’s milk taken from three farms in Baghdad, Iraq. The resulting phage was able to rescue 100% of the mice from a median lethal dose (LD50) or (1 × 108 CFU mL-1 per mouse) for MRSA wild isolates achieved when the phage: bacteria ratio was 100:1. Even when treatment was delayed for 6 h post lethal infection, to the point where all mice were moribund, 80% of them were rescued by a single injection of this phage preparation. Based on the current results, a comprehensive study is needed to guide further research on the MRSA phage as a biocontrol for MRSA mastitis in dairy cows to replace or reduce the use of antibiotics in animal husbandry.展开更多
Clonostachys rosea (syn. Gliocladium roseum) IK726 was originally selected as an effective biocontrol agent (BCA) against cereal seed borne diseases caused by Fusarium culmorum and Bipolaris sorokiniana. We have studi...Clonostachys rosea (syn. Gliocladium roseum) IK726 was originally selected as an effective biocontrol agent (BCA) against cereal seed borne diseases caused by Fusarium culmorum and Bipolaris sorokiniana. We have studied the efficacy of the antagonist against different pathogens in several crops and found that the antagonist also is able to control Alternaria radicina and A. dauci on carrot seeds and different cold-storage fungi in acorns. IK726 is also able to reduce severity of soil borne Pythium spp. in cabbage, carrot and sugar beet. In addition, growth-promoting effects of IK726 have been demonstrated in barley and tomato. In order to develop and improve application methods and control strategies, essential basic studies of ecology and the mechanisms of control of IK726 is needed and has led us to use various molecular tools. The UP-PCR technology is used for strain recognition and we have developed GUS and GFP-transformants that resembles the wildtype strain in ecological fitness parameters. Using either the GUS-transformant or UP-PCR we have found that IK726, when applied with seeds, reproduces and survives several months in the rhizosphere of field grown barley and carrot. The GFP-transformant is used to study the behavior and in situ interactions of the antagonist with pathogens and plants. Using the GFP marker, we have observed conidial germination, colonization and conidiogenesis in natural soil, in vermiculite and on carrot and barley seed and roots and on barley leaves. Moreover in situ interactions with Alternaria on carrot material have been studied. The modes of action of C. rosea are not well understood but enzymatic activity, mycoparasitism, substrate competition, antibiosis and induced resistance are thought to play a role. Barley treated with C. rosea IK726 has an enhanced chitinolytic and glucanolytic activity compared to the activity in non-treated barley in pot experiments with field soil. Identification of chitinases from IK726 and studies of their role in interactions with pathogens have therefore been addressed in a recently initiated project. Preliminary results indicate that IK726 produces three types of chitinases, which seem to be regulated by glucose. Development of degenerated primers for cloning of an endochitinase is in progress.展开更多
Trichoderma spp. is a filamentous soil fungus known as an effective biocontrol agent of a range of important airborne and soilborne pathogens, it has universal distribution and economic importance. This article review...Trichoderma spp. is a filamentous soil fungus known as an effective biocontrol agent of a range of important airborne and soilborne pathogens, it has universal distribution and economic importance. This article reviewed the researches on biocontrol mechanism for plant diseases and application of Trichoderma spp., especially Trichoderma harzianum in recent years展开更多
基金funded by Tecnologico Nacional de Mexico/IT de Tuxtla Gutierrez with project number 22847.25-PFunding came from the“Consejo Nacional de Humanidades,Ciencias y Tecnologias”(CONAHCYT,Mexico),with Project No.320299.
文摘Species of the genus Paenibacillus,especially those from extreme environments that have been reported,are known for producing bioactive compounds with agricultural and biotechnological applications.In this study,we investigated the genomic and biochemical potential of Paenibacillus sp.VCA1 strain isolated from a thermophilic environment.Taxonomic identification was performed using whole genome similarity analysis,TETRA four-nucleotide frequency of occurrence analysis,ANI average nucleotide identity analysis,and gene distance analysis using digital DNA-DNA hybridization(dDDH).Functional analysis of the strain VCA1 was performed by detecting genes,enzymes,and genome subsystems involved in biocontrol and plant growth promotion,which was carried out using the RAST(Rapid Annotation using Subsystem Technology),the seed server and antiSAMSH(antibiotics&Secondary Metabolite Analysis Shell).Genetic analyses showed the existence of 11 fatty acid and isoprenoid production genes,56 motility and chemotaxis genes,29 N-acetylglucosamine genes,and five siderophore genes.Finally,the antifungal and emulsifying activities demonstrated that strain VCA1 has activity against Fusarium oxysporum strain 45ta using integrated genomic and experimental validation,and the antifungal properties of the Paenibacillus sp.VCA1 has suggested potential use as a biocontrol agent against phytopathogenic fungi,and its continuous study can have beneficial applications in sustainable agriculture and biotechnology.
基金supported by LIFE project MYCORESTORE“Innovative use of mycological resources for resilient and productive Mediterranean forests threatened by climate change,LIFE18 CCA/ES/001110”projects VA178P23 and VA208P20 funded by JCYL(Spain),both co-financed by FEDER(UE)budget.
文摘Tree endophytic fungi play an important role in reducing insect herbivory,either by repelling them or kill-ing them directly.Identifying which fungi show such activ-ity could lead to new environmentally friendly pesticides.In this study,the Mediterranean basin climate conditions are projected to harshen in the next decades,will increase vulnerability of tree species to pest invasions.Endophytic fungi were isolated from wood and leaves of Quercus pyr-enaica,Q.ilex and Q.suber and tested for virulence against adults of the mealworm beetle,Tenebrio molitor L.using a direct contact method.Only 3 of 111 sporulating isolates had entomopathogenic activity,all identified as Lecanicillium lecanii.The pathogenicity of L.lecanii on T.molitor resulted in a median lethal time(TL50)of 14-16 d.Compared with commercial products,L.lecanii caused faster insect death than the nematode Steinernema carpocapsae and nuclear polyhedrosis virus(no effect on T.molitor survival),and slower than Beauveria bassiana(TL50=5),Beauveria pseu-dobassiana(TL50=8d)and Bacillus thuriengensis(80%mortality first day after inoculation).Mortality was also accelerated under water stress,reducing TL50 by an addi-tional 33%.Remarkably,water stress alone had a comparable effect on mortality to that of L.lecanii isolates.This study confirms T.molitor as a good model insect for pathogenicity testing and agrees with management policies proposed in the EU Green Deal.
文摘The effectiveness of current control measures against Aedes mosquitoes remains low, resulting in persistent epidemics in urban areas. The emergence of resistant mosquito populations to chemical insecticides highlights the need for novel, environmentally friendly, cost-effective control strategies. This study explored the potential of environmental bacterial isolates to biocontrol wild Aedes larvae. Initially, we collected bacterial samples from infectious masses of Aedes fluviatilis larvae. The isolated bacteria were identified using biochemical, enzymatic, and molecular methods, including 16S rRNA sequencing and MALDI-TOF. Previously, Aeromonas hydrophila and Bacillus thuringiensis isolated from these infectious masses showed limited Aedes larval inhibition. Consequently, we screened additional environmental isolates from the bacteriotheque. Six isolates previously identified were tested: Chromobacterium violaceum, Enterobacter cloacae, Bacillus cereus, Bacillus sphaericus, and two strains of Bacillus thuringiensis israelensis. Among these strains, B. thuringiensis and C. violaceum exhibited significant inhibitory activities against wild Aedes larvae. Bacillus thuringiensis cultures grown under daylight conditions showed a slight ability to inhibit Aedes larvae. The potential of B. thuringiensis and C. violaceum strains studied, along with optimized culture growth conditions, will be further investigated to develop bioinsecticide products to provide safer and more sustainable alternatives for controlling larvae of Aedes mosquitoes.
基金Supported by the Natural Science Foundation of Tianjin(09JCZDJC19100)Scientific Research Fund of Tianjin Scienceand Technology University(20090403)~~
文摘[Objective] For preparing the biopesticide of Bacillus subtilis B579 with high spore concentration,the sporulation conditions were optimized.[Method] Two-step fermentation control strategy was used,in which,the first phase（0-10 h）was to improve cell growth,and the second phase（10-30 h）was to promote spore formation.Four factors including initial glucose concentration,fermentation pH,temperature（in the second phase）and shaking speed（in the second phase）were optimized using the methods of single factor test and orthogonal experiment.[Result] The initial glucose concentration showed a significant effect on sporulation.The optimal conditions for the spore formation of B.subtilis B579 were as follows：initial glucose concentration 5 g/L,fermentation pH 7.0,the temperature for the first phase 37 ℃,and the shaking speed for the first phase 180 r/min,the temperature for the second phase 40 ℃,and the shaking speed for the second phase 200 r/min;in addition,the first phase was 10 h and the second phase of fermentation was conducted for 30 h.Under such conditions,the spore concentration and spore formation rate could reach 9.43×108 CFU/ml and 90.99%,respectively,which represented 6.70-fold and 2.43-fold increase compared with those before optimization.[Conclusion] The spores concentration of biocontrol agent was improved using two-step control strategy,which provided the basis for biopesticide production in large scale.
文摘[Objective] The aim was to understand defense mechanism of pear after inoculated Botryosphaeria berengeriana f. sp. piricolan and mechanism of antioxidant enzymes of biocontrol bacteria. [Method] Pears were treated by Botryosphaeria berengeriana f. sp. piricolan and bio control bacteria, and the change of antioxidant enzymes were determined. [Result] The biocontrol bacteria had little effect on MDA;the content of MDA treated by B. berengeriana reached high peak in 48 h, was 10.22nmol/g which was 1.86 times of CK; the content of MDA treated by B. berengeriana and biocontrol bacteria reached high peak in 24 h, was 8.92 nmol/g which was1.62 times of CK. The content of SOD treated by biocontrol bacteria reached high peak in 48 h, was 126.69 U/[g（FW）·min] which was 1.54 times of CK; the contents of SOD treated by B. berengeriana as well as B. berengeriana and biocontrol bacteria reached high peak in 24 h, were 122.10 and 135.32 U/[g（FW）·min] which were 1.48 and 1.65 times of CK respectively; the contents of POD on biocontrol bacteria treatment, B. ana treatment as well as B. berengeriana and biocontrol bacteria treatment reached high peak in 24 h, were 385.34, 342.50 and 290.00 U/[g（FW）·min] which were 1.83, 1.62 and 1.38 times of CK respectively. The contents of CAT on biocontrol bacteria treatment, B. rengeriana treatment as well as B. berengeriana and biocontrol bacteria treatment reached high peak in 6 h, were 133.33,114.17 and 113.35 U/[g（FW）·min] which were 1.33, 1.14 and 1.13 times of CK respectively. The biocontrol bacteria had little difference in CK; the content of PPO of B. berengeriana treatment reached high peak in 12 h, was 81.86 U/[g（FW）·min]which was 1.76 times of CK; B. berengeriana and biocontrol bacteria treatment reached high peak in 24 h, was 70.00 U/[g（FW）·min] which was 1.50 times of CK.[Conclusion] B. berengeriana and biocontrol bacteria had more effect on MDA; both B. berengeriana and biocontrol bacteria could increase the excitation of SOD enzyme activity; both B. berengeriana and biocontrol bacteria could increase the excitation of POD enzyme activity; both B. berengeriana and biocontrol bacteria could increase the excitation of CAT enzyme activity; using biocontrol bacteria alone had not obvious effect on PPO, B. berengeriana could increase the excitation of PPO enzyme activity.
基金The work was supported by the Fundamental Research Funds of the Central University,China(Grant Number 2572017AA03 and Grant Number 2572014BA15).
文摘A transcriptomic database was constructed to study the biocontrol mechanisms of Trichoderma harzianum ACCC30371 using high quality UniGenes following growth in eight culture media[(1/2PD,minimal medium MM(containing dextrose 10 g L^-1),C starvation medium(derived from MM without dextrose),N starvation medium(derived from MM without ammonium sulphate),and four kinds of phytopathogenic fungi cell wall media].A 4 Gbp transcriptome was generated and 96.7%of the database had a sequencing error rate less than 1%.A total of 25,013 UniGene sequences were obtained with a mean length of 1135 nt.There were 2571 sequences longer than 3000 nt.The National Center for Biotechnology Information Accession number of this transcriptome is SRR8382572.There were 16,360 Unigenes annotated to the Nr protein database,9875 to the SwissProt database,10,266 to the KEGG database,7164 to the COG database,and 1508 to the GO database along with their protein functional annotations.There were 16,723 functional genes identified.We identified 402 bio-control genes,including 14 related to competition,311 to mycoparasitism,76 to antibiosis,and one related to eliciting a plant response.This shows that T.harzianum ACCC30371 has integrated biocontrol mechanisms,and of these mechanisms,mycoparasitism is the most prevalent.Antibiosis and induced systemic resistance also play important roles.These results provide a foundation for further research into the biocontrol mechanisms of Trichoderma,as well as the development and utilization of biological fungicides.
文摘[ Objective ] The paper was to explore the combined application technique of organic fertilizer and two biocontrol agents against pepper blight in green- house hot pepper in Qinghai Province. [Method] By L4 （23）orthogonal design, the effects of combined application of two biocontrol agents against pepper blight and organic fertilizer on control effects against pepper blight and the yield of hot pepper were studied in greenhouse hot pepper base in Ledu County of Qinghai Province. [ Result] The effects of various factors affecting the relative control effect against pepper blight in sequence were biecontrol agent A5 〉 biecontrol agent B2 〉 organic fertilizer, and the optimal combination was organic fertilizer 1 800 kg/hm^2, agent B2 30 kg/hm^2 and agent A5 45 kg/hm^2. The effects on hot pepper yield in sequence were organic fertilizer 〉 biocontrol agent B2 〉 biocontrol agent AS, and the optimal combination was organic fertilizer 900 kg/hm^2 , agent 132 15 kg/hm^2, agent A5 22.5 kg/hm2. [ Conclusion] Combined with control effect of pepper blight and yield benefit, the application technique of biocontrol agents pro- moted in local hot pepper production could be confirmed as follows ： agent A5 45 kg/hm^2, agent B2 15 kg/hm^2, organic fertilizer 900 kg/hm^2 ; the field control effect at this moment could reach 76.31%, the yield could reach 35 573 kg/hm^2 , and the newly increased output value could be 13 029 yuan/hm^2 with input and output ratio of 1： 7.9.
文摘Biocontrol by Trichoderma has been studied mainly with selected isolates of T. harzianum, T. atroviride and T. asperellum, which are members of sections Pachybasium and Trichoderma. In contrast, species from section Longibrachiatum have only rarely been studied. On the other hand, one taxon from this section-Hypocrea jecorina (anamorph: Trichoderma reesei)-has been widely used for the production of cellulolytic and hemicellulolytic enzymes and recombinant proteins. As far as Trichoderma is concerned, molecular genetic methods and tools are most advanced in H. jecorina, and its genome has recently been fully sequenced, thus making this taxon a model organism for the genus. Here we will demonstrate that H. jecorina is able to antagonize plant pathogenic fungi in plate confrontation tests, and can protect tomato and cucumber plants against Pythium ultimum blight. Using this as a model case, we made use of available H. jecorina mutants to investigate (a) whether carbon catabolite repression via the Cre1-regulator protein has an impact on biocontrol, and (b) whether cellulase gene expression is necessary for biocontrol of P. ultimum. In the first case, plate confrontation tests and in planta experiments yielded opposite results, i.e. while a Cre1 mutant was more active in antagonization of fungi on plates, the survival rates of P. ultimum-inoculated cucumber plants was lower than with the H. jecorina wild-type strain. Mutants of H. jecorina, unable to form cellulases, were still able to antagonize fungi on plates and provided similar protection of tomatos against P. ultimum as the wild type, indicating that the pronounced biocontrol ability of H. jecorina against fungi with cellulose-containing cell-walls is not due to its high cellulolytic activity. A strain disrupted in the light-modulator gene envoy (Schmoll et al., ms submitted) exhibited in planta biocontrol activity strongly exceeding that of the wild-type strain, thereby providing a first link between Trichoderma biocontrol and light. In view of the numerous other metabolic and regulatory mutants of H. jecorina available, we suggest that this fungus should increasingly be used in basic studies on the biochemistry and genetics of biocontrol.
基金Supported by Jiangsu Agricultural Science and Technology Support Program(BE2012378)Six Talents Peaks Program of Jiangsu Province in 2013(2013-NY-001)Jiangsu Agricultural Scientific and Technological Self-innovation Foundation[CX(11)2018]~~
文摘[Objective] The aim was to explore biocontrol approaches of strawberry an-thracnose. [Method] With hyphal growth inhibition method, bacteriostatic activities of Bacil us subtilis and Osthole on strawberry anthracnose were measured and field test was carried out. [Result] The results show that both of Bacil us subtilis and Osthole were of higher bacteriostatic activity on strawberry anthracnose, and the values of EC50 were 0.007 5 mg/L and 1.063 0 ml/L, respectively. The result of field test show that the prevention effects of Bacil us subtilis （600-750 g/hm2） and 25% prochloraz （600 ml/hm2） both achieved higher than 76%, 7 and 14 d after triple medical applica-tions with rains sheltered or in open field. But the effects were of extremely signifi-cant differences with that of Osthole （1 800-2 700 ml/hm2） （P〈0.01）. [Conclusion] Bacil us subtilis can be made use of for control ing strawberry anthracnose.
基金supported by the Australian Research Council International Linkage Fellowship(No.LX0560210)the National Natural Science Foundation of China(No.30600082).
文摘Biocontrol agents are safe and environmental friendly alternatives for pesticides in agriculture application. Trichoderma viride WEBL0703 performed a high level of antagonistic activity toward a broad spectrum of phytopathogens and was determined as a biocontrol agent, which was produced by solid state fermentation using grape marc and wine lees. The maximum yield of T. viride conidia was up to 6.65 × 10^9 CFU/g initial dry substrate （IDS） after 10 d fermentation. As important enzymes for protecting plants from disease, chitinase, β-glucanase, and pectinase yields were 47.8 U/g IDS, 8.32 U/g IDS and 9.83 U/g IDS, respectively. These results show that it is feasible to convert winery wastes to a value-added and environmental friendly biocontrol agent.
基金supported by the National Natural Science Foundation of China (No. 30600082)the Knowledge Innovation Program of Chinese Academy of Sciences (No.KSCX2-YW-G-054-2)the Key Technologies R&D Program of China (No. 2008BADA7B01)
文摘A phyllosphere bacterial strain EBL-06 was isolated from wheat leaves. The morphology, cultural characteristics, phospholipid fatty acids, physiological and antagonistic fungus activities of this strain were investigated. A phylogenetic tree was constructed by comparing with the published 16S rDNA sequences of the relevant bacteria. The results showed that the isolate EBL-06 was a strain of Paenibacillus polymyxa; this strain performed a high level of antagonistic fungus activity toward a broad spectrum of phytopathogens, such as Botrytis cinerea, Cladosporium cucumerinum, Fusarium spp. The isolate EBL-06 can grow well using monosodium glutamate wastewater （MGW） and potato wastewater （PW） as culture medium. The maximum yield of 6.5 × 10^9 CFU/mL of the isolate EBL-06 anti-fungus biocontrol agent was reached in 15 hr cultivation at 28℃, pH 6.0-7.5 using the mixture of MGW and PW （1：9）.
文摘Several bacterial strains were isolated from different rhizospheres. Among these, strain PDY7 exhibited strong antibacterial activity against the rice bacterial blight （BB） pathogen Xanthomonas oryzae pv. oryzae （Xoo） by the laboratory dual plate assays. The antibacterial property of the strain PDY7 was further investigated for the production of 2,4-diacetylphloroglucinol （DAPG）, which amplified a characteristic of 629-bp DNA fragment by PCR-based screening method using phlD primers. The application of phlD positive strains was carefully evaluated for disease control and growth promotion of rice plants under field conditions. The selected strain PDY7 suppressed the rice BB by 58.83% and 51.88% under glass house and field conditions, respectively. In addition, the strain PDY7 showed significant two-fold increase in root length （18.08 cm）, shoot length （29.81 cm）, and grain yield （96.07 g）. Strain PDY7 promoted the growth of rice plants by production of indole-3-acetic acid （IAA）, which was determined by high performance liquid chromatography （HPLC） analysis. Our findings suggest that PDY7 belongs to the P. fluorescens group and can serve as potential biocontrol of BB as well as biofertilizer agent for growth promotion of rice.
基金financially supported by the National Basic Research Program of China (2013CB127501)the National Key Research and Development Program of China (2016YFD0201003)the National Natural Science Foundation of China (31272021, 31571987)
文摘Streptomyces rubrogriseus HDZ-9-47,isolated from eggs of Meloidogyne spp.,was evaluated as a potential biocontrol agent of Meloidogyne incognita under in vitro and protective field.Microscopic observations showed that HDZ-9-47 parasitized eggs of M.incognita within 7 days.In vitro,the culture filtrate of HDZ-9-47 caused 97.0%mortality of second-stage juveniles（J2s）of M.incognita and inhibited more than 50%egg hatching.In the field,compared with the control,the rootknot index and J2s density in the treatment of drench the broth contained 1012 HDZ-9-47 spores were respectively reduced by 51.1 and 80.7%at 90 days post transplantation,which were better than that in other application doses and methods.In addition,reduction rates of root-knot index and J2s density of the treatment of combined application of HDZ-9-47 with biofumigation was 87.1 and 91.0%,respectively,better than either of HDZ-9-47 or biofumigation used alone or fosthiazate treatment.And tomato yield also increased by 16.1%.Together,our results suggest that HDZ-9-47 could be an effective biocontrol agent of M.incognita,and that application of HDZ-9-47 combined with cabbage residue biofumigation was a promising and sustainable option for M.incognita control.
基金Supported by National Natural Science Foundation of China(30872024,30571498)Students Research Training (SRT) of Shandong Agricultural University (0802024)~~
文摘[Objective] The aim was to study effect of Chaetomium globosum ND35 on plant growth and preliminary study of its biocontrol efficacy, and provide basis for popularization and application of this strain.[ Method] With endophytic fungus C. globosum ND35 as a tested strain, effect of C. globosumND35 on plant growth and its biocontrol on five plant diseases were investigated in the greenhouse and field,[Result]The results showed that ND35 promoted growth of lateral root and diameter of breast height of poplar. ND35 can induce poplar to resist Poplar Valsa Canker caused by Valsa sordida and Poplar Rust caused by Melampsora puplicola. ND35 was also able to induce tomato and bean to resist Botrytis cinera. Biocontrol of Bean Stem Rot Rhizoctonia by ND35 was effective as well. [Conclusion] Induced systemic resistance by endophytic C. globosum ND35 plays an important role in biocontrol of plant diseases.
文摘Modern agribusiness plays a vital role in safeguarding and improving the production,quality,and quantity of food,feed,fiber,and fuel.Growing concerns over the impact of chemical pesticides on health and the environment have stimulated the industry to search for alternative and greener solutions.Over the last years,the RNA interference(RNAi)process has been identified as a very promising new approach to complement the arsenal of foliar spray,soil,or seed treatments applied as chemical and biological pest control agents,and of plant-incorporated protectants(PIPs).RNA-based active ingredients(AIs)possess a unique mode of action and can be implemented via both genetic modification(GM)and biocontrol approaches.RNA-based AIs promise to deliver the selectivity and sustainability desired in future crop protection agents.This is due to their utilization of a natural process to exert control and their high level of selectivity,which leads to reduced risk for non-target organisms(NTOs).This review discusses the advantages and limitations of RNA-based solutions in crop protection and recent research progress toward RNA-based biocontrols against the Colorado potato beetle(CPB),corn rootworm(CRW),and soy stink bug(SSB).Many challenges still exist on the road to the implementation of a broad range of RNA-based products and their widespread use and application.Despite these challenges,it can be expected that RNA-based AIs will become valuable new tools complementing the current arsenal of crop-protection solutions.
基金Project supported by the Beijing Municipal Science and Technology Plan Projects(No.D151100003915002)the Special Project for Innovation Ability Construction from the Beijing Academy of Agriculture and Forestry Sciences(No.KJCX20170415)+2 种基金the Beijing Agriculture Innovation Consortium(No.BAIC07-2018)the Science and Technology Innovation Ability Construction Fund from the Beijing Academy of Agriculture and Forestry Sciences(No.KJCX20170107)the Science and Technology Innovation Team of the Beijing Academy of Agriculture and Forestry Sciences(No.JNKST201607),China
文摘Peach brown rot, caused by Monilinia fructicola, is one of the most serious peach diseases. A strain belonging to the Actinomycetales, named Streptomyces blastmyceticus JZB130180, was found to have a strong inhib-itory effect on M. fructicola in confrontation culture. Following the inoculation of peaches in vitro, it was revealed that the fermentation broth of S. blastmyceticus JZB130180 had a significant inhibitory effect on disease development by M. fructicola. The fermentation broth of S. blastmyceticus JZB130180 had an EC50(concentration for 50% of maximal effect) of 38.3 μg/mL against M. fructicola, as determined in an indoor toxicity test. Analysis of the physicochemical properties of the fermentation broth revealed that it was tolerant of acid and alkaline conditions, temperature, and ultraviolet radiation. In addition, chitinase, cellulase, and protease were also found to be secreted by the strain. The results of this study suggest that S. blastmyceticus JZB130180 may be used for the biocontrol of peach brown rot.
基金supported by the National Natural Science Foundation of China (31301731, 31428020)the National Science and Technology Major Project (2014ZX08009013B)
文摘Bacillus thuringiensis Bt185 and its insecticidal spectrum-expanded engineering strains are considered as potential biocontrol agents to soil insect Holotrichia parallela,Holotrichia oblita or Anomala corpulenta.Here we reported the complete genome of strain Bt185,it harbors eight plasmids,and plasmid p BT1850294 carries three cry8 genes.
文摘Methicillin-resistant Staphylococcus aureus (MRSA) is among the most alarming pathogens affecting both humans and the global bovine industry. The current control measures in hospitals and on farms for MRSA have proven to be inadequate leaving a need for new rapid control methods to curb MRSA infections in situ. New control measures for bacterial infection are widely sought, with particular interest in the applications for bacteriophages (phages) as a biocontrol or therapeutic agent. The current study uses a wild highly lytic phage isolated from cow’s milk taken from three farms in Baghdad, Iraq. The resulting phage was able to rescue 100% of the mice from a median lethal dose (LD50) or (1 × 108 CFU mL-1 per mouse) for MRSA wild isolates achieved when the phage: bacteria ratio was 100:1. Even when treatment was delayed for 6 h post lethal infection, to the point where all mice were moribund, 80% of them were rescued by a single injection of this phage preparation. Based on the current results, a comprehensive study is needed to guide further research on the MRSA phage as a biocontrol for MRSA mastitis in dairy cows to replace or reduce the use of antibiotics in animal husbandry.
文摘Clonostachys rosea (syn. Gliocladium roseum) IK726 was originally selected as an effective biocontrol agent (BCA) against cereal seed borne diseases caused by Fusarium culmorum and Bipolaris sorokiniana. We have studied the efficacy of the antagonist against different pathogens in several crops and found that the antagonist also is able to control Alternaria radicina and A. dauci on carrot seeds and different cold-storage fungi in acorns. IK726 is also able to reduce severity of soil borne Pythium spp. in cabbage, carrot and sugar beet. In addition, growth-promoting effects of IK726 have been demonstrated in barley and tomato. In order to develop and improve application methods and control strategies, essential basic studies of ecology and the mechanisms of control of IK726 is needed and has led us to use various molecular tools. The UP-PCR technology is used for strain recognition and we have developed GUS and GFP-transformants that resembles the wildtype strain in ecological fitness parameters. Using either the GUS-transformant or UP-PCR we have found that IK726, when applied with seeds, reproduces and survives several months in the rhizosphere of field grown barley and carrot. The GFP-transformant is used to study the behavior and in situ interactions of the antagonist with pathogens and plants. Using the GFP marker, we have observed conidial germination, colonization and conidiogenesis in natural soil, in vermiculite and on carrot and barley seed and roots and on barley leaves. Moreover in situ interactions with Alternaria on carrot material have been studied. The modes of action of C. rosea are not well understood but enzymatic activity, mycoparasitism, substrate competition, antibiosis and induced resistance are thought to play a role. Barley treated with C. rosea IK726 has an enhanced chitinolytic and glucanolytic activity compared to the activity in non-treated barley in pot experiments with field soil. Identification of chitinases from IK726 and studies of their role in interactions with pathogens have therefore been addressed in a recently initiated project. Preliminary results indicate that IK726 produces three types of chitinases, which seem to be regulated by glucose. Development of degenerated primers for cloning of an endochitinase is in progress.
基金Supported by Chinese National Programs for High Technology Research and Development(2003AA241140)
文摘Trichoderma spp. is a filamentous soil fungus known as an effective biocontrol agent of a range of important airborne and soilborne pathogens, it has universal distribution and economic importance. This article reviewed the researches on biocontrol mechanism for plant diseases and application of Trichoderma spp., especially Trichoderma harzianum in recent years
