Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.H...Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.However,these antibiotics often target the growth factors of the pathogenic bacteria,leading to the accumulation and emergence of drug-resistant strains,which exacerbates antibiotic resistance.Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria.Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance.TypeⅢsecretion system(T3SS)serves as a crucial virulence determinant in Gram-negative pathogens,and its non-essentials for pathogen growth renders it an ideal target.Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens.Therefore,targeting T3SS in pathogenic bacteria,while preserving their growth,has emerged as a novel avenue for the development of antimicrobial drugs.In recent years,a multitude of small molecular inhibitors targeting T3SS have been identified.This article offers a comprehensive review of T3SS inhibitors in plant pathogens,while also presenting the latest research advancements in this research direction.展开更多
Bacillus strains isolated from the rhizosphere soil of potato roots were evaluated for the potential antagonistic activity against fungal pathogens in vitro and in vivo. Two bacterial isolates were identified as new B...Bacillus strains isolated from the rhizosphere soil of potato roots were evaluated for the potential antagonistic activity against fungal pathogens in vitro and in vivo. Two bacterial isolates were identified as new Bacillus subtilis strains by 16S rRNA and GyrB gene sequencing and were designated GM2 and GM5, respectively. Strains were characterized by their ability to inhibit growth of a number of phytopathogenic fungi. It was shown that GM5 strain inhibited growth of phytopathogenic fungi more effectively than GM2 strain. Both strains were capable of producing a number of hydrolytic enzymes as well as antimicrobial metabolites (ammonia and HCN). In addition, GM2 strain also produced siderophores. Four genes encoding antimicrobial peptides were identified in the genome of GM2 strain: ituC, bmyB, bacA and srfA. Genome of GM5 contained two genes encoding for antimicrobial peptides, srfA and fenD. Purified lipopeptide fraction from GM5 but not from GM2 strain was able to control Fusarium solani spread in the plate assay. Furthermore, Bacillus subtilis strain GM2 promoted growth of wheat but only GM5 strain was able to protect wheat seedlings from Fusarium oxysporum infection.展开更多
Acetohydroxyacid synthase(AHAS) was considered as a promising target for antifungal agents.Herein,three series of novel sulfonylureas(SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized...Acetohydroxyacid synthase(AHAS) was considered as a promising target for antifungal agents.Herein,three series of novel sulfonylureas(SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy.The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities.Based on the preliminary fungicidal activities,a CoMFA model was constructed and the 3 D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities.In order to study interaction mechanism,10 k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities.It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS.Thus,the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphyt o pathogenic fungal agents.展开更多
A specific and sensitive polymerase chain reaction (PCR) assay based on the internal transcribed spacer (ITS) region of rDNA sequences was developed to detect endophytic and phytopathogenic fungi from needles of the J...A specific and sensitive polymerase chain reaction (PCR) assay based on the internal transcribed spacer (ITS) region of rDNA sequences was developed to detect endophytic and phytopathogenic fungi from needles of the Japanese black pine, Pinus thunbergii. Sequences of the ITS regions of Lophodermium conigenum, Lecanosticta acicola, Pestalotiopsis neglecta, Rhizosphaera kalkhoffii, and Septorioides pini-thunbergii were compared, and each specific primer pair for these species was designed. First, the designed primer pairs were tested for their specificity to detect each species. A PCR product was amplified only each combination of species and its specific primer pair, confirming the specificity of the designed primer pairs. These primer pairs were also tested on DNA extracted from the needles of P. thunbergii. The PCR products were amplified not only in needles with lesions but also in healthy needles without symptoms. Furthermore, several endophytic and phytopathogenic fungi could be simultaneously detected from the same region in a needle. The PCR-mediated detection method developed in this study will be a valuable tool for the detection of the endophytic and phytopathogenic fungi, not only as a rapid diagnostic tool for early detection but also for monitoring variations in both the quality and quantity of the endophytic and phytopathogenic fungi in needles in Japanese black pines.展开更多
Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fe...Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fertility and enhancing plant defense mechanisms. A total of 111 bacterial strains were isolated from various habitats of Pakistan and screened for solubilization of silicate, phosphate and potassium on respective media. Out of these, 35 bacterial isolates were capable of solubilizing either silicate, phosphate or potassium. Amongst these 7 bacterial isolates were capable of solubilizing all three minerals tested. The highest silicate (zone diameter 54 mm) and phosphate solubilization (zone diameter 55 mm) was observed for bacterial isolate NR-2 while the highest potassium solubilization was observed for NE-4b (zone diameter 11 mm). Dual culture antagonistic assays were carried out by using these bacterial isolates against four plant pathogenic fungi Magnaporthae grisae, Rhizoctonia solani, Altarnaria alternata and Macrophomina pheasolina. Mean zone of inhibition of these bacterial isolates against the four pathogenic fungi ranged between 4 mm to 39 mm. The largest zone of inhibition against all four bacterial strains was recorded for bacterial isolate NR-2 followed by NE-4b. These strains will be further investigated for their plant growth promoting activities in the future.展开更多
Background: Viruses can cause different diseases in plants. To prevent viral infections, plants are treated with chemical compounds and antiviral agents. Chemical antiviral agents usually have narrow specificity, whic...Background: Viruses can cause different diseases in plants. To prevent viral infections, plants are treated with chemical compounds and antiviral agents. Chemical antiviral agents usually have narrow specificity, which limits their wide application. Alternative antiviral strategy is associated with the use of microbial enzymes, which are less toxic and are readily decomposed without accumulation of harmful substances. The aim of this work is to study the effect of Bacillus pumilus ribonuclease on various phytopathogenic viruses with specific focus on the ability of enzyme to eliminate them from plant explants in vitro. Materials and methods: Extracellular ribonuclease of B. pumilus is tested as an antiviral agent. To study the antiviral effect of RNase, depending on concentration and the time of application several plant-virus model systems are used. Virus detection is conducted by serological testing and RT-PCR. Results: Bacillus pumilus ribonuclease possesses antiviral activity against plant Rna-viruses RCMV (red clover mottle virus), PVX (Potato Virus X) and AMV (Alfalfa Mosaic Virus). The maximum inhibitory effect against actively replicating viruses is observed when plants are treated with the enzyme in the concentration of 100 ug/ml prior to infection. In case of local necrosis ribonuclease in the concentration of 1 ug/ml completely inhibits the development of RCMV virus on bean plants. The enzyme is able to penetrate plants and inhibit the development of viral infection, inhibiting effect for untreated surfaces decreased on average for 20%. It is also found that B. pumilus ribonuclease protects apical explants of sprouts of potato tubers from PVM and PVS viruses. Conclusion: B. pumilus ribonuclease possesses antiviral activity against plant Rna-viruses and produces viruses-free plants in the apical meristem culture.展开更多
Plant-pathogenic fungi significantly affect crop yield and quality.Understanding pathogenic mechanisms and reducing yield losses from plant diseases are therefore crucial for global food security.Epigenetics has becom...Plant-pathogenic fungi significantly affect crop yield and quality.Understanding pathogenic mechanisms and reducing yield losses from plant diseases are therefore crucial for global food security.Epigenetics has become a central focus in fungal biology research,and recent refinements in high-throughput sequencing technologies have drawn attention to the role of histone methylation in fungal pathogenicity.Due to their diversity and complexity,histone methylations play crucial roles in epigenetic and transcriptional regulation.In this review,we summarize recent progress in understanding histone methylation in plant-pathogenic fungi and examine how these modifications influence fungal pathogenicity.Ultimately,we aim to offer insight for creating fungal disease control strategies through the lens of histone methylation.展开更多
Acalypha gaumeri(Euphorbiaceae)is the only endemic species of the genus in the Yucatan Peninsula.It is dioecious and has antifungal properties against various phytopathogens.In the present study,molecular identificati...Acalypha gaumeri(Euphorbiaceae)is the only endemic species of the genus in the Yucatan Peninsula.It is dioecious and has antifungal properties against various phytopathogens.In the present study,molecular identification of A.gaumeri was performed using the rbcL region,confirming its belonging to the Acalypha genus.Its genetic diversity was evaluated using 10 SPAR markers(ISSR and DAMD)from 60 individuals collected from female and male plants of the Kiuic,Tinum and Yaxcaba ex-situ populations.The results showed a high level of genetic polymorphism(PIC=0.980)and significant differences among the populations.Ethanol and aqueous extracts from leaves,stems,and roots of both genders and three populations were evaluated against three phytopathogenic fungi.Only the ethanol extracts of the roots showed inhibitory antifungal activity,whereas Kiuic and Tinum,both male and female individuals,showed inhibitory effects at 1000μg/mL against the three pathogens.The ethanol extract of the female flowering plant of Kiuic showed activity at minimum inhibitory concentrations of 250μg/mL against Alternaria chrysanthemi CICY004 and 500μg/mL against Colletotrichum gloeosporioides CICY002 and Penicillium oxalicum ITC25.Chromatographic profile of the ethanol extracts confirmed the presence of alkaloidal components in the ex-situ cultivated plants,which were analyzed by HPLC.The results revealed that the peaks at T_(R) of 7.60,7.88,and 8.49 min were the most abundant components(9.95%-21.93%),with differences between female and male plants of the three populations.This research confirms that A.gaumeri cultivated and genetically characterized is a potential raw material to develop an eco-friendly product for the control of fungal diseases in crops.展开更多
Some phytopathogenic bacteria including Xanthomonas oryzae pv. oryzae （a rice leaf bacterial blight pathogen） and its virulent gene mutant XooM3105,Xanthomonas campestris pv. campestris, Erwinia carotovora subsp, ca...Some phytopathogenic bacteria including Xanthomonas oryzae pv. oryzae （a rice leaf bacterial blight pathogen） and its virulent gene mutant XooM3105,Xanthomonas campestris pv. campestris, Erwinia carotovora subsp, carotovora and so on, could release active oxygen such as O<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> by themselves.Ca<sup>2+</sup>, NADPH and O<sub>2</sub> concentration regulated the response. The response is sensitive to heat and proteinase. These results show that the component releasing active oxygen in the bacterial plant pathogen may involve special protein and enzyme and be secreted to culture liquid. Various components of rice tissue can significantly induce the release of active oxygen in Xanthomonas oryzae pv. oryzae.展开更多
To ensure the production of food crops,a series of cryptolepine derivatives were synthesised,after which their antibacterial activities and mechanism of action against three plant pathogens were investigated.Our bioas...To ensure the production of food crops,a series of cryptolepine derivatives were synthesised,after which their antibacterial activities and mechanism of action against three plant pathogens were investigated.Our bioassay results indicated that most of the target compounds displayed potent inhibitory effects against Xanthomonas oryzae(X.oryzae)and Xanthomonas axonopodis pv.citri(X.axonopodis pv.c.).Remarkably,compound 9 exhibited the best in vitro antibacterial activity against X.oryzae,with a minimum inhibitory concentration(MIC)value of 0.78μg·mL^(-1).Compound 2 exhibited the best in vitro antibacterial activity against X.axonopodis pv.c.,with an MIC value of 0.39μg·mL^(-1).These activities were superior to those of copper quinolate(MIC=6.25,25μg·mL^(-1))and thiodiazole copper(MIC=100,200μg·mL^(-1))against X.oryzae and X.axonopodis pv.c.In vivo experiments demonstrated the promising applicability of compound 9 for the control of rice bacterial infections.Furthermore,compound 9 was selected as a candidate to conduct preliminary analyses of the antibacterial mechanisms of cryptolepine derivatives.Scanning electron microscopy and transmission electron microscopy observations,extracellular polysaccharide production,biofilm formation,transcriptomic,quantitative reverse transcription-polymerase chain reaction analyses,and molecular docking assays were performed.Collectively,our findings demonstrated that compound 9 might act via multifarious mechanisms to down-regulate virulence factors and cause cell death.展开更多
Tomato is an economically important crop that is susceptible to biotic and abiotic stresses,situations that negatively affect the crop cycle.Biotic stress is caused by phytopathogens such as Fusarium oxysporum f.sp.ly...Tomato is an economically important crop that is susceptible to biotic and abiotic stresses,situations that negatively affect the crop cycle.Biotic stress is caused by phytopathogens such as Fusarium oxysporum f.sp.lycopersici(FOL),responsible for vascular wilt,a disease that causes economic losses of up to 100%in crops of interest.Nanomaterials represent an area of opportunity for pathogen control through stimulations that modify the plant development program,achieving greater adaptation and tolerance to stress.The aim of this study was to evaluate the antimicrobial capacity of the nanoparticles and the concentrations used in tomato plants infected with FOL.To this end,a two-stage experiment was conducted.In Stage 1,the effects of the nanomaterials(Graphene nanoplatelets[GP],Zinc oxide nanoparticles[ZnO NPs],Magnesium oxide nanoparticles[MgO NPs])were evaluated both alone and in combination to determine the most effective method of controlling FOL-induced disease.In Stage 2,the most effective combination of nanomaterials(ZnO+GP)was evaluated at four concentrations ranging from 100 to 400 mg L^(−1).To evaluate the effectiveness of the treatments,we determined the incidence and severity of the disease,agronomic parameters,as well as the following biochemical variables:chlorophylls,β-carotene,vitamin C,phenols,flavonoids,hydrogen peroxide,superoxide anion,and malondialdehyde.The results show various positive effects,highlighting the efficiency of the ZnO+GP at 200mg L^(−1),which reduced the severity by approximately 20%,in addition to increasing agronomic variables and reducing reactive oxygen species.Moreover,the results show that the application of these nanomaterials increases vegetative development and defense against biotic stress.The use of nanomaterials such as zinc oxide,magnesium oxide and graphene can be an effective tool in the control of the severity of Fusarium oxysporum disease.展开更多
The article presents data on the screening of rhizobacteria and active isolates isolated from the humus layer of natural humus soils against phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum and their re...The article presents data on the screening of rhizobacteria and active isolates isolated from the humus layer of natural humus soils against phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum and their resistance to various concentrations of NaCl (0%, 1%, 5%, 7%, 10%). The results of studies on the synthesis of phytohormones with the properties of microorganisms that enhance plant growth and development are presented. Antagonistically active bacterial strains that grew even at high salt concentrations were identified using MALDI-TOF analysis. They were identified as XD 4.3 Bacillus subtilis and XDN6 Bacillus cereus, respectively.展开更多
The Rpd3 histone deacetylase complex is a multiple-subunit complex that mediates the regulation of chromatin accessibility and gene expression.Sin3,the largest subunit of Rpd3 complex,is conserved in a broad range of ...The Rpd3 histone deacetylase complex is a multiple-subunit complex that mediates the regulation of chromatin accessibility and gene expression.Sin3,the largest subunit of Rpd3 complex,is conserved in a broad range of eukaryotes.Despite being a molecular scaffold for complex assembly,the functional sites and mechanism of action of Sin3 remain unexplored.In this study,we functionally characterized a glutamate residue(E810)in Fg Sin3,the ortholog of yeast Sin3 in Fusarium graminearum(known as wheat scab fungus).Our findings indicate that E810 was important for the functions of Fg Sin3 in regulating vegetative growth,sexual reproduction,wheat infection,and DON biosynthesis.Furthermore,the E810K missense mutation restored the reduced H4 acetylation caused by the deletion of FNG1,the ortholog of the human inhibitor of growth(ING1)gene in F.graminearum.Correspondingly,the defects of the fng1 mutant were also partially rescued by the E810K mutation in Fg Sin3.Sequence alignment and evolutionary analysis revealed that E810 residue is well-conserved in fungi,animals,and plants.Based on Alphafold2 structure modeling,E810 localized on the Fg Rpd3–Fg Sin3 interface for the formation of a hydrogen bond with Fg Rpd3.Mutation of E810 disrupts the hydrogen bond and likely affects the Fg Rpd3–Fg Sin3 interaction.Taken together,E810 of Fg Sin3 is functionally associated with Fng1 in the regulation of H4 acetylation and related biological processes,probably by affecting the assembly of the Rpd3 complex.展开更多
Several Trichoderma species serve as biocontrol agents in agriculture through their phytopathogen growth inhibition capabilities.However,the antagonistic mechanism of certain strains primarily operates through direct ...Several Trichoderma species serve as biocontrol agents in agriculture through their phytopathogen growth inhibition capabilities.However,the antagonistic mechanism of certain strains primarily operates through direct action.This study aims to explore an effective strain with comprehensive capabilities and elucidate its practical viability and action mechanism.Trichoderma gamsii strain TC959,exhibiting robust antagonistic and plant growth-promoting properties,was identified.The strain directly inhibits plant pathogen through the production of secondary metabolites,siderophores,and chitinase/xylanase,while promotes plant growth via indole-3-acetic acid/gibberellin release.Additionally,the strain activates induced systemic resistance by enhancing the chlorophyll a/b ratio and jasmonic acid content in pepper seedlings through root colonization,leading to elevated defense-related gene expression,antioxidant enzyme activity,and indole-3-acetic acid/gibberellin production.These mechanisms collectively enhance disease resistance and promote plant growth.Moreover,TC959 demonstrates superior resistance to oxidation and chemical fungicides,facilitating strain viability maintenance and ensuring healthy pepper seedling development.The study concludes that strain TC959 exhibits significant biocontrol potential and comprehensive functions against pepper damping-off disease,warranting further practical applications.展开更多
Orobanche spp. （broomrapes） are holoparasitic plants distributed predominantly in the Northern Hemisphere parasitizing the roots of a range of plant species mainly in wild ecosystems. Orobanche species cause severe ...Orobanche spp. （broomrapes） are holoparasitic plants distributed predominantly in the Northern Hemisphere parasitizing the roots of a range of plant species mainly in wild ecosystems. Orobanche species cause severe yield reduction of many important crops. There are only very few herbicides which are able to selectively control broomrapes and different approaches have been put forward to develop natural product based pesticides to control Orobanche. Several phytopathogenic fungi were evaluated for their use as potential mycoherbicide and for ability to produce toxic metabolites which could be applied as herbicides. Using the alternative approach ＂suicidal germination＂, interesting results were obtained by testing two microbial metabolites （fusicoccins and ophiobolin A） especially with Orobanche species whose germination is not induced by the synthetic strigolactone GR24. From pea root exudates, peagol and peagoldione, close related to strigolactones, and three polyphenols, named peapolyphenols A-C, together with already well known polyphenol and a chalcone, were isolated. They showed a selective stimulation of Orobanche seed germination with the last two and peapolyphenol A showing a specific stimulatory activity on O. foetida. This review describes the most recent results achieved on Orobanche bio-control, mainly focusing on those regarding O. ramosa, O. crenata and O. foetida.展开更多
Six new(1–6)and seven known depsidones(7–13)were isolated from the culture of an ant(Monomorium chinensis)-derived fungus Spiromastix sp.MY-1.Their structures were elucidated by extensive spectroscopic analysis incl...Six new(1–6)and seven known depsidones(7–13)were isolated from the culture of an ant(Monomorium chinensis)-derived fungus Spiromastix sp.MY-1.Their structures were elucidated by extensive spectroscopic analysis including high resolution MS,1D and 2D NMR data.The new bromide depsidones were obtained through supplementing potassium bromide in the fermentation medium of Spiromastix sp.MY-1.All isolated compounds showed various bioactivities against the tested phytopathogenic bacteria.Particularly,new bromide compound 4,named spiromastixone S,exhibited the strongest activity against Xanthomonas oryzae pv.oryzae with a MIC value of 5.2μmol·^L(−1).展开更多
The phytopathogenic fungus Venturia inaequalis causes scab of apple. Once this fungus penetrates the plant surface, it forms a specialized body called a stroma between the inner cuticle surface and the epidermal cell ...The phytopathogenic fungus Venturia inaequalis causes scab of apple. Once this fungus penetrates the plant surface, it forms a specialized body called a stroma between the inner cuticle surface and the epidermal cell wall. A novel Venturia inaequalis 5704 (Cin3) and three expressed sequence tags (ESTs);38, 6987, and 4010 are strongly up-regulated in the early stages of infection. The CIN3 and three ESTs using two vectors pMAL-c2 and pET 21 were expressed in Escherichia coli. Recombinant proteins expression, solubility and yields were analyzed. 38, 5704 (Cin3) and 6987 re- combinant proteins were expressed in soluble form and while 4010 was expressed in inclusion bodies. Re- solution on native-PAGE, the recombinant proteins;38, 5704 (Cin3), 6987 were shown to be present in dimmer, tetramer and polymer. A method was de- veloped, consisting of induction of expression at va- rious temperatures, and using enriched broth with 4% glycerol together with slow shaking, led to a decrease in concentration of nascent polypeptide and production of soluble recombinant proteins of;38, 5704 (Cin3), 6987 and 4010. Resolution on native- PAGE, the recombinant proteins were shown to be present as monomer.展开更多
Peanuts can be affected by the presence of pathogenic microorganisms. The fungus <i>Thecaphora frezii</i> (<i>T. frezii</i>), which belongs to the taxonomic class Ustilaginomycetes, is the caus...Peanuts can be affected by the presence of pathogenic microorganisms. The fungus <i>Thecaphora frezii</i> (<i>T. frezii</i>), which belongs to the taxonomic class Ustilaginomycetes, is the causal agent of the disease known as “peanut smut”. The life cycle of this fungus includes three stages, namely teliospores, basidiospores and hyphae. In the hyphae stage, infection occurs in the peanut plant, which requires the involvement of some enzymes secreted by the fungus. These include the Plant Cell Wall-Degrading Enzymes (PCWDEs), which degrade various polysaccharides. This study aimed to identify the presence of transcript for enzymes belonging to the PCWDEs from three stages of <i>T. frezii</i>. For this, total RNA was extracted from the three ontogenetic stages of <i>T. frezii</i>. These samples were analyzed using an RNA-Seq approach and some transcripts were quantified using Real Time PCR. The analysis of the data provided by the RNA-Seq of the three <i>T. frezii</i> stages, it was possible to identify some transcripts that could encode enzymes compatible with polysaccharides degradation that are part of the plant cell wall. In <i>T. frezii</i> transcriptome, 40 deduced proteins would be enzymes with functions of PCWDEs were identified. They were divided into 27 glycoside hydrolases;two polysaccharide lyases;three carbohydrate esterases and eight enzymes with auxiliary activities. In addition, the fungal SNF1 gene was identified whose activity could be affected by high glucose level, and indirectly influence the levels of some PCWDEs. The analysis of the PCWDEs could help to understand part of the fungal infection process and possibly find substances that can control its development.展开更多
Across all Russia global climate change is observed. Consequences of climatic changes, undoubtedly, will be reflected in distribution of harmful organisms, their injuriousness and will demand development of new approa...Across all Russia global climate change is observed. Consequences of climatic changes, undoubtedly, will be reflected in distribution of harmful organisms, their injuriousness and will demand development of new approaches in plant protection. Over the last 10 years, the spread of cereal crop diseases in the Northwest Russia has been monitored. The purpose of researches is to find new diseases in the Northwest region of Russia. Disease progression was mainly monitored 3 or 4 times during the growing season, from germination to crop maturity. As a result in this region the new diseases were found. In 2005-2007 the causal agent of yellow leaf spot Pyrenophora tritici-repentis was found on wheat. Fusarium graminearum historically has two areas in Russia： the North Caucasus and the Far East. However, since 2003 F. graminearum appeared on the territory of the North-West of Russia. Septoria tritici became the main pathogen of wheat in the North-Western Region.. In 2013 Ramularia collo-cygni was found in Arkhangelsk region. These observations suggest that global warming of climate leads to an expansion south species pathogen to the north regions of Russia.展开更多
The chemical compositions of the essential oils from the leaves and flowers of Callistemon viminalis and their insecticide and fungitoxic activities were determined. The essential oil was extracted by the hydrodistill...The chemical compositions of the essential oils from the leaves and flowers of Callistemon viminalis and their insecticide and fungitoxic activities were determined. The essential oil was extracted by the hydrodistillation method using a modified Clevenger apparatus. The chemical characterization was performed by GC-MS and GC-FID. The evaluation of the insecticidal activity was performed with the Myzus persicae aphid, and the antifungal potential was determined via the inhibition of the mycelial growth of Alternaria alternata, Fusarium oxysorum and Botrytis cinérea phytopathogenic fungi. The principal components of the essential oils from the leaves and flowers were eucalyptol (84.60% and 61.47%), α-pinene (10.28% and 21.48%) and α-terpineol (2.59% and 2.79%), respectively. The use of a 0.5% concentration of the essential oil from the flowers influenced the preference of aphids and their reproduction. The number of adult aphids decreased within a period of 48 hours in the presence of the essential oil from the leaves. In the test with no chance of choice, the mean number of adults decreased with both oils within 48 hours. No inhibition of the mycelial growth of the A. alternate microorganism was observed in any of the treatments with the two essential oils. However, the growth of F. oxysporum and B. cinerea fungi was inhibited. The mycelial growth of F. oxysporum was inhibited with the concentration of 100 μL·Lˉ1 of the oil from the flowers and 250 μL·Lˉ1 of the oil from the leaves. The inhibition of the growth of B. cinerea was observed at concentrations of 500 and 100 μL·Lˉ1 for the oils from the flowers and leaves, respectively. The essential oils presented insecticidal and antifungal potentials. However, further studies are needed for these oils to be used in integrated pest management.展开更多
基金the financial support from the National Key Research and Development Program of China(No.2023YFD1701100)the National Natural Science Foundation of China(No.32072450)+2 种基金the National Science Fund for Distinguished Young Scholars of Guangdong Province(No.2021B1515020107)the Opening Foundation of Hubei Key Laboratory of Novel Reactor and Green Chemical Technology(No.NRG202306)the Opening Foundation of Guangdong Province Key Laboratory of Microbial Signals and Disease Control(No.MSDC2023-19)。
文摘Plant bacterial diseases have infiicted substantial economic losses in global crop,fruit,and vegetable production.The conventional methods for managing these diseases typically rely on the application of antibiotics.However,these antibiotics often target the growth factors of the pathogenic bacteria,leading to the accumulation and emergence of drug-resistant strains,which exacerbates antibiotic resistance.Innovative methods are urgently needed to treat and prevent the toxicity caused by these pathogenic bacteria.Targeting virulence mechanisms in pathogens is a globally recognized and effective strategy for mitigating bacterial resistance.TypeⅢsecretion system(T3SS)serves as a crucial virulence determinant in Gram-negative pathogens,and its non-essentials for pathogen growth renders it an ideal target.Targeting the T3SS holds significant potential to alleviate selective pressure for resistance mutations in pathogens.Therefore,targeting T3SS in pathogenic bacteria,while preserving their growth,has emerged as a novel avenue for the development of antimicrobial drugs.In recent years,a multitude of small molecular inhibitors targeting T3SS have been identified.This article offers a comprehensive review of T3SS inhibitors in plant pathogens,while also presenting the latest research advancements in this research direction.
文摘Bacillus strains isolated from the rhizosphere soil of potato roots were evaluated for the potential antagonistic activity against fungal pathogens in vitro and in vivo. Two bacterial isolates were identified as new Bacillus subtilis strains by 16S rRNA and GyrB gene sequencing and were designated GM2 and GM5, respectively. Strains were characterized by their ability to inhibit growth of a number of phytopathogenic fungi. It was shown that GM5 strain inhibited growth of phytopathogenic fungi more effectively than GM2 strain. Both strains were capable of producing a number of hydrolytic enzymes as well as antimicrobial metabolites (ammonia and HCN). In addition, GM2 strain also produced siderophores. Four genes encoding antimicrobial peptides were identified in the genome of GM2 strain: ituC, bmyB, bacA and srfA. Genome of GM5 contained two genes encoding for antimicrobial peptides, srfA and fenD. Purified lipopeptide fraction from GM5 but not from GM2 strain was able to control Fusarium solani spread in the plate assay. Furthermore, Bacillus subtilis strain GM2 promoted growth of wheat but only GM5 strain was able to protect wheat seedlings from Fusarium oxysporum infection.
基金supported by the National Natural Science Foundation of China(Nos.21702173,21502229)Fundamental Research Funds for the Central Universities(No.2682016CX104)Miaozi Project of Scientific and Technological Innovation of Sichuan Province(No.2018090)
文摘Acetohydroxyacid synthase(AHAS) was considered as a promising target for antifungal agents.Herein,three series of novel sulfonylureas(SUs) 9-11 containing aromatic-substituted pyrimidines were designed and synthesized according to pharmacophore-combination and bioisosterism strategy.The in vitro fungicidal activities against ten phytopathogenic fungi indicated that most of the title compounds exhibited broad-spectrum and excellent fungicidal activities.Based on the preliminary fungicidal activities,a CoMFA model was constructed and the 3 D-QSAR analysis indicated that either a bulky group around the 5-position of the pyrimidine ring or electropositive group around the 2-position of the benzene ring would be favour to fungicidal activities.In order to study interaction mechanism,10 k was automatically docked into yeast AHAS and it further indicated that bearing bulky groups-aryl at the pyrimidine ring was critical to enhance antifungal activities.It revealed that the antifungal activity of derivatives 9-11 probably results from the inhibition of fungal AHAS.Thus,the present results strongly showed that SUs should be considered as lead compounds or model molecules to develop novel antiphyt o pathogenic fungal agents.
文摘A specific and sensitive polymerase chain reaction (PCR) assay based on the internal transcribed spacer (ITS) region of rDNA sequences was developed to detect endophytic and phytopathogenic fungi from needles of the Japanese black pine, Pinus thunbergii. Sequences of the ITS regions of Lophodermium conigenum, Lecanosticta acicola, Pestalotiopsis neglecta, Rhizosphaera kalkhoffii, and Septorioides pini-thunbergii were compared, and each specific primer pair for these species was designed. First, the designed primer pairs were tested for their specificity to detect each species. A PCR product was amplified only each combination of species and its specific primer pair, confirming the specificity of the designed primer pairs. These primer pairs were also tested on DNA extracted from the needles of P. thunbergii. The PCR products were amplified not only in needles with lesions but also in healthy needles without symptoms. Furthermore, several endophytic and phytopathogenic fungi could be simultaneously detected from the same region in a needle. The PCR-mediated detection method developed in this study will be a valuable tool for the detection of the endophytic and phytopathogenic fungi, not only as a rapid diagnostic tool for early detection but also for monitoring variations in both the quality and quantity of the endophytic and phytopathogenic fungi in needles in Japanese black pines.
文摘Silicate solubilizing bacteria (SSB) can play an efficient role in soil by solubilizing insoluble forms of silicates. In addition to this some SSB can also solubilize potassium and phosphates, hence increasing soil fertility and enhancing plant defense mechanisms. A total of 111 bacterial strains were isolated from various habitats of Pakistan and screened for solubilization of silicate, phosphate and potassium on respective media. Out of these, 35 bacterial isolates were capable of solubilizing either silicate, phosphate or potassium. Amongst these 7 bacterial isolates were capable of solubilizing all three minerals tested. The highest silicate (zone diameter 54 mm) and phosphate solubilization (zone diameter 55 mm) was observed for bacterial isolate NR-2 while the highest potassium solubilization was observed for NE-4b (zone diameter 11 mm). Dual culture antagonistic assays were carried out by using these bacterial isolates against four plant pathogenic fungi Magnaporthae grisae, Rhizoctonia solani, Altarnaria alternata and Macrophomina pheasolina. Mean zone of inhibition of these bacterial isolates against the four pathogenic fungi ranged between 4 mm to 39 mm. The largest zone of inhibition against all four bacterial strains was recorded for bacterial isolate NR-2 followed by NE-4b. These strains will be further investigated for their plant growth promoting activities in the future.
文摘Background: Viruses can cause different diseases in plants. To prevent viral infections, plants are treated with chemical compounds and antiviral agents. Chemical antiviral agents usually have narrow specificity, which limits their wide application. Alternative antiviral strategy is associated with the use of microbial enzymes, which are less toxic and are readily decomposed without accumulation of harmful substances. The aim of this work is to study the effect of Bacillus pumilus ribonuclease on various phytopathogenic viruses with specific focus on the ability of enzyme to eliminate them from plant explants in vitro. Materials and methods: Extracellular ribonuclease of B. pumilus is tested as an antiviral agent. To study the antiviral effect of RNase, depending on concentration and the time of application several plant-virus model systems are used. Virus detection is conducted by serological testing and RT-PCR. Results: Bacillus pumilus ribonuclease possesses antiviral activity against plant Rna-viruses RCMV (red clover mottle virus), PVX (Potato Virus X) and AMV (Alfalfa Mosaic Virus). The maximum inhibitory effect against actively replicating viruses is observed when plants are treated with the enzyme in the concentration of 100 ug/ml prior to infection. In case of local necrosis ribonuclease in the concentration of 1 ug/ml completely inhibits the development of RCMV virus on bean plants. The enzyme is able to penetrate plants and inhibit the development of viral infection, inhibiting effect for untreated surfaces decreased on average for 20%. It is also found that B. pumilus ribonuclease protects apical explants of sprouts of potato tubers from PVM and PVS viruses. Conclusion: B. pumilus ribonuclease possesses antiviral activity against plant Rna-viruses and produces viruses-free plants in the apical meristem culture.
基金supported by Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(2021C02064)the National Natural Science Foundation of China(32370200).
文摘Plant-pathogenic fungi significantly affect crop yield and quality.Understanding pathogenic mechanisms and reducing yield losses from plant diseases are therefore crucial for global food security.Epigenetics has become a central focus in fungal biology research,and recent refinements in high-throughput sequencing technologies have drawn attention to the role of histone methylation in fungal pathogenicity.Due to their diversity and complexity,histone methylations play crucial roles in epigenetic and transcriptional regulation.In this review,we summarize recent progress in understanding histone methylation in plant-pathogenic fungi and examine how these modifications influence fungal pathogenicity.Ultimately,we aim to offer insight for creating fungal disease control strategies through the lens of histone methylation.
基金supported by the SECIHTI project PDCPN-2015-266,México.
文摘Acalypha gaumeri(Euphorbiaceae)is the only endemic species of the genus in the Yucatan Peninsula.It is dioecious and has antifungal properties against various phytopathogens.In the present study,molecular identification of A.gaumeri was performed using the rbcL region,confirming its belonging to the Acalypha genus.Its genetic diversity was evaluated using 10 SPAR markers(ISSR and DAMD)from 60 individuals collected from female and male plants of the Kiuic,Tinum and Yaxcaba ex-situ populations.The results showed a high level of genetic polymorphism(PIC=0.980)and significant differences among the populations.Ethanol and aqueous extracts from leaves,stems,and roots of both genders and three populations were evaluated against three phytopathogenic fungi.Only the ethanol extracts of the roots showed inhibitory antifungal activity,whereas Kiuic and Tinum,both male and female individuals,showed inhibitory effects at 1000μg/mL against the three pathogens.The ethanol extract of the female flowering plant of Kiuic showed activity at minimum inhibitory concentrations of 250μg/mL against Alternaria chrysanthemi CICY004 and 500μg/mL against Colletotrichum gloeosporioides CICY002 and Penicillium oxalicum ITC25.Chromatographic profile of the ethanol extracts confirmed the presence of alkaloidal components in the ex-situ cultivated plants,which were analyzed by HPLC.The results revealed that the peaks at T_(R) of 7.60,7.88,and 8.49 min were the most abundant components(9.95%-21.93%),with differences between female and male plants of the three populations.This research confirms that A.gaumeri cultivated and genetically characterized is a potential raw material to develop an eco-friendly product for the control of fungal diseases in crops.
文摘Some phytopathogenic bacteria including Xanthomonas oryzae pv. oryzae （a rice leaf bacterial blight pathogen） and its virulent gene mutant XooM3105,Xanthomonas campestris pv. campestris, Erwinia carotovora subsp, carotovora and so on, could release active oxygen such as O<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> by themselves.Ca<sup>2+</sup>, NADPH and O<sub>2</sub> concentration regulated the response. The response is sensitive to heat and proteinase. These results show that the component releasing active oxygen in the bacterial plant pathogen may involve special protein and enzyme and be secreted to culture liquid. Various components of rice tissue can significantly induce the release of active oxygen in Xanthomonas oryzae pv. oryzae.
基金the National Natural Science Foundation of China(Grant Nos.22177043 and 21877056)the Natural Science Foundation of Gansu Province(Grant No.20JR5RA311)the Key Program for International S&T Cooperation Projects of Gansu Province of China(Grant No.18YF1WA115).
文摘To ensure the production of food crops,a series of cryptolepine derivatives were synthesised,after which their antibacterial activities and mechanism of action against three plant pathogens were investigated.Our bioassay results indicated that most of the target compounds displayed potent inhibitory effects against Xanthomonas oryzae(X.oryzae)and Xanthomonas axonopodis pv.citri(X.axonopodis pv.c.).Remarkably,compound 9 exhibited the best in vitro antibacterial activity against X.oryzae,with a minimum inhibitory concentration(MIC)value of 0.78μg·mL^(-1).Compound 2 exhibited the best in vitro antibacterial activity against X.axonopodis pv.c.,with an MIC value of 0.39μg·mL^(-1).These activities were superior to those of copper quinolate(MIC=6.25,25μg·mL^(-1))and thiodiazole copper(MIC=100,200μg·mL^(-1))against X.oryzae and X.axonopodis pv.c.In vivo experiments demonstrated the promising applicability of compound 9 for the control of rice bacterial infections.Furthermore,compound 9 was selected as a candidate to conduct preliminary analyses of the antibacterial mechanisms of cryptolepine derivatives.Scanning electron microscopy and transmission electron microscopy observations,extracellular polysaccharide production,biofilm formation,transcriptomic,quantitative reverse transcription-polymerase chain reaction analyses,and molecular docking assays were performed.Collectively,our findings demonstrated that compound 9 might act via multifarious mechanisms to down-regulate virulence factors and cause cell death.
文摘Tomato is an economically important crop that is susceptible to biotic and abiotic stresses,situations that negatively affect the crop cycle.Biotic stress is caused by phytopathogens such as Fusarium oxysporum f.sp.lycopersici(FOL),responsible for vascular wilt,a disease that causes economic losses of up to 100%in crops of interest.Nanomaterials represent an area of opportunity for pathogen control through stimulations that modify the plant development program,achieving greater adaptation and tolerance to stress.The aim of this study was to evaluate the antimicrobial capacity of the nanoparticles and the concentrations used in tomato plants infected with FOL.To this end,a two-stage experiment was conducted.In Stage 1,the effects of the nanomaterials(Graphene nanoplatelets[GP],Zinc oxide nanoparticles[ZnO NPs],Magnesium oxide nanoparticles[MgO NPs])were evaluated both alone and in combination to determine the most effective method of controlling FOL-induced disease.In Stage 2,the most effective combination of nanomaterials(ZnO+GP)was evaluated at four concentrations ranging from 100 to 400 mg L^(−1).To evaluate the effectiveness of the treatments,we determined the incidence and severity of the disease,agronomic parameters,as well as the following biochemical variables:chlorophylls,β-carotene,vitamin C,phenols,flavonoids,hydrogen peroxide,superoxide anion,and malondialdehyde.The results show various positive effects,highlighting the efficiency of the ZnO+GP at 200mg L^(−1),which reduced the severity by approximately 20%,in addition to increasing agronomic variables and reducing reactive oxygen species.Moreover,the results show that the application of these nanomaterials increases vegetative development and defense against biotic stress.The use of nanomaterials such as zinc oxide,magnesium oxide and graphene can be an effective tool in the control of the severity of Fusarium oxysporum disease.
文摘The article presents data on the screening of rhizobacteria and active isolates isolated from the humus layer of natural humus soils against phytopathogenic fungi Rhizoctonia solani and Fusarium oxysporum and their resistance to various concentrations of NaCl (0%, 1%, 5%, 7%, 10%). The results of studies on the synthesis of phytohormones with the properties of microorganisms that enhance plant growth and development are presented. Antagonistically active bacterial strains that grew even at high salt concentrations were identified using MALDI-TOF analysis. They were identified as XD 4.3 Bacillus subtilis and XDN6 Bacillus cereus, respectively.
基金supported by the grants from the National Natural Science Foundation of China(32102181)the Shaanxi Science Fund for Distinguished Young Scholars,China(2022JC-14)。
文摘The Rpd3 histone deacetylase complex is a multiple-subunit complex that mediates the regulation of chromatin accessibility and gene expression.Sin3,the largest subunit of Rpd3 complex,is conserved in a broad range of eukaryotes.Despite being a molecular scaffold for complex assembly,the functional sites and mechanism of action of Sin3 remain unexplored.In this study,we functionally characterized a glutamate residue(E810)in Fg Sin3,the ortholog of yeast Sin3 in Fusarium graminearum(known as wheat scab fungus).Our findings indicate that E810 was important for the functions of Fg Sin3 in regulating vegetative growth,sexual reproduction,wheat infection,and DON biosynthesis.Furthermore,the E810K missense mutation restored the reduced H4 acetylation caused by the deletion of FNG1,the ortholog of the human inhibitor of growth(ING1)gene in F.graminearum.Correspondingly,the defects of the fng1 mutant were also partially rescued by the E810K mutation in Fg Sin3.Sequence alignment and evolutionary analysis revealed that E810 residue is well-conserved in fungi,animals,and plants.Based on Alphafold2 structure modeling,E810 localized on the Fg Rpd3–Fg Sin3 interface for the formation of a hydrogen bond with Fg Rpd3.Mutation of E810 disrupts the hydrogen bond and likely affects the Fg Rpd3–Fg Sin3 interaction.Taken together,E810 of Fg Sin3 is functionally associated with Fng1 in the regulation of H4 acetylation and related biological processes,probably by affecting the assembly of the Rpd3 complex.
基金supported by the National Key Research and Development Program of China(2022YFC2303000).
文摘Several Trichoderma species serve as biocontrol agents in agriculture through their phytopathogen growth inhibition capabilities.However,the antagonistic mechanism of certain strains primarily operates through direct action.This study aims to explore an effective strain with comprehensive capabilities and elucidate its practical viability and action mechanism.Trichoderma gamsii strain TC959,exhibiting robust antagonistic and plant growth-promoting properties,was identified.The strain directly inhibits plant pathogen through the production of secondary metabolites,siderophores,and chitinase/xylanase,while promotes plant growth via indole-3-acetic acid/gibberellin release.Additionally,the strain activates induced systemic resistance by enhancing the chlorophyll a/b ratio and jasmonic acid content in pepper seedlings through root colonization,leading to elevated defense-related gene expression,antioxidant enzyme activity,and indole-3-acetic acid/gibberellin production.These mechanisms collectively enhance disease resistance and promote plant growth.Moreover,TC959 demonstrates superior resistance to oxidation and chemical fungicides,facilitating strain viability maintenance and ensuring healthy pepper seedling development.The study concludes that strain TC959 exhibits significant biocontrol potential and comprehensive functions against pepper damping-off disease,warranting further practical applications.
文摘Orobanche spp. （broomrapes） are holoparasitic plants distributed predominantly in the Northern Hemisphere parasitizing the roots of a range of plant species mainly in wild ecosystems. Orobanche species cause severe yield reduction of many important crops. There are only very few herbicides which are able to selectively control broomrapes and different approaches have been put forward to develop natural product based pesticides to control Orobanche. Several phytopathogenic fungi were evaluated for their use as potential mycoherbicide and for ability to produce toxic metabolites which could be applied as herbicides. Using the alternative approach ＂suicidal germination＂, interesting results were obtained by testing two microbial metabolites （fusicoccins and ophiobolin A） especially with Orobanche species whose germination is not induced by the synthetic strigolactone GR24. From pea root exudates, peagol and peagoldione, close related to strigolactones, and three polyphenols, named peapolyphenols A-C, together with already well known polyphenol and a chalcone, were isolated. They showed a selective stimulation of Orobanche seed germination with the last two and peapolyphenol A showing a specific stimulatory activity on O. foetida. This review describes the most recent results achieved on Orobanche bio-control, mainly focusing on those regarding O. ramosa, O. crenata and O. foetida.
基金supported by the National Key Research and Development Programs(Nos.2018YFA0902000 and 2017YFC0506200)the National Natural Science Foundation of China(Nos.81991524 and 81673333)+1 种基金the Hainan Provincial Basic and Applied Basic Research Fund for High-Level Talents in Natural Science(Nos.2019RC306 and 2019RC352)the Central Public-interest Scientific Institution Basal Research Fund for CATAS-ITBB(Nos.1630052019011 and 1630052022016)。
文摘Six new(1–6)and seven known depsidones(7–13)were isolated from the culture of an ant(Monomorium chinensis)-derived fungus Spiromastix sp.MY-1.Their structures were elucidated by extensive spectroscopic analysis including high resolution MS,1D and 2D NMR data.The new bromide depsidones were obtained through supplementing potassium bromide in the fermentation medium of Spiromastix sp.MY-1.All isolated compounds showed various bioactivities against the tested phytopathogenic bacteria.Particularly,new bromide compound 4,named spiromastixone S,exhibited the strongest activity against Xanthomonas oryzae pv.oryzae with a MIC value of 5.2μmol·^L(−1).
文摘The phytopathogenic fungus Venturia inaequalis causes scab of apple. Once this fungus penetrates the plant surface, it forms a specialized body called a stroma between the inner cuticle surface and the epidermal cell wall. A novel Venturia inaequalis 5704 (Cin3) and three expressed sequence tags (ESTs);38, 6987, and 4010 are strongly up-regulated in the early stages of infection. The CIN3 and three ESTs using two vectors pMAL-c2 and pET 21 were expressed in Escherichia coli. Recombinant proteins expression, solubility and yields were analyzed. 38, 5704 (Cin3) and 6987 re- combinant proteins were expressed in soluble form and while 4010 was expressed in inclusion bodies. Re- solution on native-PAGE, the recombinant proteins;38, 5704 (Cin3), 6987 were shown to be present in dimmer, tetramer and polymer. A method was de- veloped, consisting of induction of expression at va- rious temperatures, and using enriched broth with 4% glycerol together with slow shaking, led to a decrease in concentration of nascent polypeptide and production of soluble recombinant proteins of;38, 5704 (Cin3), 6987 and 4010. Resolution on native- PAGE, the recombinant proteins were shown to be present as monomer.
文摘Peanuts can be affected by the presence of pathogenic microorganisms. The fungus <i>Thecaphora frezii</i> (<i>T. frezii</i>), which belongs to the taxonomic class Ustilaginomycetes, is the causal agent of the disease known as “peanut smut”. The life cycle of this fungus includes three stages, namely teliospores, basidiospores and hyphae. In the hyphae stage, infection occurs in the peanut plant, which requires the involvement of some enzymes secreted by the fungus. These include the Plant Cell Wall-Degrading Enzymes (PCWDEs), which degrade various polysaccharides. This study aimed to identify the presence of transcript for enzymes belonging to the PCWDEs from three stages of <i>T. frezii</i>. For this, total RNA was extracted from the three ontogenetic stages of <i>T. frezii</i>. These samples were analyzed using an RNA-Seq approach and some transcripts were quantified using Real Time PCR. The analysis of the data provided by the RNA-Seq of the three <i>T. frezii</i> stages, it was possible to identify some transcripts that could encode enzymes compatible with polysaccharides degradation that are part of the plant cell wall. In <i>T. frezii</i> transcriptome, 40 deduced proteins would be enzymes with functions of PCWDEs were identified. They were divided into 27 glycoside hydrolases;two polysaccharide lyases;three carbohydrate esterases and eight enzymes with auxiliary activities. In addition, the fungal SNF1 gene was identified whose activity could be affected by high glucose level, and indirectly influence the levels of some PCWDEs. The analysis of the PCWDEs could help to understand part of the fungal infection process and possibly find substances that can control its development.
文摘Across all Russia global climate change is observed. Consequences of climatic changes, undoubtedly, will be reflected in distribution of harmful organisms, their injuriousness and will demand development of new approaches in plant protection. Over the last 10 years, the spread of cereal crop diseases in the Northwest Russia has been monitored. The purpose of researches is to find new diseases in the Northwest region of Russia. Disease progression was mainly monitored 3 or 4 times during the growing season, from germination to crop maturity. As a result in this region the new diseases were found. In 2005-2007 the causal agent of yellow leaf spot Pyrenophora tritici-repentis was found on wheat. Fusarium graminearum historically has two areas in Russia： the North Caucasus and the Far East. However, since 2003 F. graminearum appeared on the territory of the North-West of Russia. Septoria tritici became the main pathogen of wheat in the North-Western Region.. In 2013 Ramularia collo-cygni was found in Arkhangelsk region. These observations suggest that global warming of climate leads to an expansion south species pathogen to the north regions of Russia.
文摘The chemical compositions of the essential oils from the leaves and flowers of Callistemon viminalis and their insecticide and fungitoxic activities were determined. The essential oil was extracted by the hydrodistillation method using a modified Clevenger apparatus. The chemical characterization was performed by GC-MS and GC-FID. The evaluation of the insecticidal activity was performed with the Myzus persicae aphid, and the antifungal potential was determined via the inhibition of the mycelial growth of Alternaria alternata, Fusarium oxysorum and Botrytis cinérea phytopathogenic fungi. The principal components of the essential oils from the leaves and flowers were eucalyptol (84.60% and 61.47%), α-pinene (10.28% and 21.48%) and α-terpineol (2.59% and 2.79%), respectively. The use of a 0.5% concentration of the essential oil from the flowers influenced the preference of aphids and their reproduction. The number of adult aphids decreased within a period of 48 hours in the presence of the essential oil from the leaves. In the test with no chance of choice, the mean number of adults decreased with both oils within 48 hours. No inhibition of the mycelial growth of the A. alternate microorganism was observed in any of the treatments with the two essential oils. However, the growth of F. oxysporum and B. cinerea fungi was inhibited. The mycelial growth of F. oxysporum was inhibited with the concentration of 100 μL·Lˉ1 of the oil from the flowers and 250 μL·Lˉ1 of the oil from the leaves. The inhibition of the growth of B. cinerea was observed at concentrations of 500 and 100 μL·Lˉ1 for the oils from the flowers and leaves, respectively. The essential oils presented insecticidal and antifungal potentials. However, further studies are needed for these oils to be used in integrated pest management.
