Control Of Fungal Plant Diseases Research Articles

Control of human and plant fungal pathogens using pentaene macrolide 32, 33-didehydroroflamycoin.

The aim of this study was to address the toxicity of recently described polyene macrolide 32, 33-didehydroroflamycoin (DDHR) on a wide range of fungal pathogens and its potential to control plant fungal diseases. The antifungal activity of DDHR in vitro was examined against common human and plant pathogenic fungi using a broth microdilution assay and a disk diffusion assay. Minimum inhibitory concentrations ranged from 12·5 to 35 μg ml(-1) . A radial growth inhibition assay showed that DDHR inhibited mycelia growth, inducing mycelial necrosis and affecting sporulation. During the in vivo assay on apple fruits administration of DDHR 1 h before fungal inoculation inhibited spreading of the infection. Importantly, DDHR exhibited no phytotoxic effects on the model plant, Capsicum annum, verified by the plant growth rate and chlorophyll content. DDHR inhibits growth of various plant pathogens in vitro with the strongest activity against Alternaria alternata, Colletotrichum acutatum and Penicillium expansum, and protects apple fruits from decay. This is the first report of the inhibitory effect of DDHR on important pathogenic fungal isolates. DDHR could be a good scaffold for developing new antifungal agents for fruit and vegetable protection.

Control efficacy against rice sheath blight of Platycladus orientalis extract and its antifungal active compounds

The control efficacy of Platycladus orientalis extract against Rhizoctonia sonali Kuhn, the causal agent of rice sheath blight, was evaluated by pot experiments under greenhouse conditions, and the antifungal compounds were isolated and identified through antifungal bioassay-guided fractionation using R. sonali as a tested fungus. The results indicate that the extracts from P. orientalis exhibited a significant reduction in the severity of rice sheath blight. The petroleum ether fraction partitioned from the ethanolic crude extract, showing the highest antifungal activity, was further separated, and two diterpenoid compounds with antifungal property, totarol and sclareol, were isolated and identified from the active subfractions. Totarol and sclareol possessed antifungal activity against most of the tested fungal pathogens of cereal crops such as R. solani, R. cerealis and Fusarium graminearum, indicating a similar broad antifungal spectrum. These findings suggest that the P. orientalis extract and its derived active compounds may be promising candidate agents for controlling plant fungal diseases like rice sheath blight.

Non-thermal plasma treatment diminishes fungal viability and up-regulates resistance genes in a plant host.

Reactive oxygen and nitrogen species can have either harmful or beneficial effects on biological systems depending on the dose administered and the species of organism exposed, suggesting that application of reactive species can possibly produce contradictory effects in disease control, pathogen inactivation and activation of host resistance. A novel technology known as atmospheric-pressure non-thermal plasma represents a means of generating various reactive species that adversely affect pathogens (inactivation) while simultaneously up-regulating host defense genes. The anti-microbial efficacy of this technology was tested on the plant fungal pathogen Fusarium oxysporum f.sp. lycopersici and its susceptible host plant species Solanum lycopercicum. Germination of fungal spores suspended in saline was decreased over time after exposed to argon (Ar) plasma for 10 min. Although the majority of treated spores exhibited necrotic death, apoptosis was also observed along with the up-regulation of apoptosis related genes. Increases in the levels of peroxynitrite and nitrite in saline following plasma treatment may have been responsible for the observed spore death. In addition, increased transcription of pathogenesis related (PR) genes was observed in the roots of the susceptible tomato cultivar (S. lycopercicum) after exposure to the same Ar plasma dose used in fungal inactivation. These data suggest that atmospheric-pressure non-thermal plasma can be efficiently used to control plant fungal diseases by inactivating fungal pathogens and up-regulating mechanisms of host resistance.

Diverse double-stranded RNA viruses infecting fungi

Most of reported fungal viruses (mycoviruses) have double-stranded RNA (dsRNA) genomes. This may reflect the simple, easy method for mycovirus hunting that entails detection of dsRNAs as a sign of viral infections. There are an increasing number of screens of various fungi, particularly phytopathogenic fungi for viruses pathogenic to host fungi or able to confer hypovirulence to them. This bases on an attractive research field of biological control of fungal plant diseases using viruses (virocontrol), mainly targeting important phytopathogenic fungi. While isolated viruses usually induce asymptomatic symptoms, they show a considerably high level of diversity. As of 2014, fungal dsRNA viruses are classified into six families: Reoviridae, Totiviridae, Chrysoviridae, Partitiviridae, Megabirnaviridae and Quadriviridae. These exclude unassigned mycoviruses which will definitely be placed into distinct families and/or genera. In this review article, dsRNA viruses isolated from the kingdom Fungi including as-yet-unclassified taxa are overviewed. Some recent achievements in the related field are briefly introduced as well.

Contribution of Arbuscular Mycorrhizal Fungi (AM Fungi) and Rhizobium Inoculation on Crop Growth and Chemical Properties of Rhizospheric Soils in High Plants

Soil microorganisms commonly named biofertilizers can be used to decrease input of fertilizers, pesticides and other chemicals in Agriculture. Among soil microorganisms, arbuscular mycorrhizal (AM) fungi and Rhizobium spp. can promote plant growth and control plant fungal diseases. However these microorganisms are not yet used in commercial biocontrol products. Integration of Arbuscular Mycorrhizal Fungi with Rhizobium sp. thus appears to be a promising approach for sustainable agriculture especially in legume crops where the net influence of this combination is supposed to be very high compare to other types of crop families. Arbuscular Mycorrhizal fungi and root-nodule bacterium Rhizobium are two root symbionts. Arbuscular mycorrhizal fungi increases soil nutrients and water absorption, while root-nodule bacteria fix atmospheric nitrogen and produce antibiotics and phytoalexins. These microbes modify the quality and abundance of rhizosphere microflora and alter overall microbial activity of the rhizosphere. They induce changes in the host root exudation pattern. A procedure for successful development of these microorganisms is required by selection and screening of efficient isolates. Knowledge of culture systems that are adapted to their establishment and multiplication is needed. Arbuscular mycorrhizal fungi provide specific niches for bacteria. Arbuscular mycorrhizal bacteria improve nutrient acquisition in plants and subsequently, growth of the particular crops is advantaged indeed. Arbuscular mycorrhizal bacteria may contribute to ability of arbuscular mycorrhizal fungi to inhibit pathogens acquire mineral nutrients and modify plant root growth. Combined use of these microorganisms is more beneficial than their use alone. Together, they Influence plant root morphology changes and chemical properties of Rhizospheric soils of high plants with the significant extent. These symbionts also interact with other beneficial microorganisms synergistically and can be exploited for sustainable agriculture. The sound influence of these symbionts on root morphology and growth of the whole

Novel Endophytic Trichoderma spp. Isolated from Healthy Coffea arabica Roots are Capable of Controlling Coffee Tracheomycosis

One of the biggest threats to coffee growers in East Africa are emerging vascular wilt diseases (tracheomycosis) caused by Fusarium spp. Many Trichoderma species are known to be natural antagonists of these pathogens and are widely used in biological control of fungal plant diseases. More recently, several Trichoderma spp., which exhibited high antifungal activity have been isolated as endophytes. Consequently, we have investigated the presence and the antagonistic activity of endophytic Trichoderma isolated from roots of healthy coffee plants (Coffea arabica) from the major coffee growing regions of Ethiopia. Our results showed that community of Trichoderma spp. in roots of C. arabica contains fungi from coffee rhizosphere, as well as putatively obligate endophytic fungi. The putatively “true” endophytic species, until now, isolated only from coffee plant ecosystems in Ethiopia and recently described as T. flagellatum and novel T. sp. C.P.K. 1812 were able to antagonize Fusarium spp., which cause coffee tracheomycosis. Moreover, we found that strains of these species are also highly antagonistic against other phytopathogenic fungi, such as Alternaria alternata, Botryotinia fuckeliana (anamorph: Botrytis cinerea), and Sclerotinia sclerotiorum.

Application of Photocatalytic Nanomaterials in Prevention from <i>Sphaerothecaf uliginea In Vivo</i>

This study was conducted to investigate the efficiency of TiO2 photocatalytic nanomaterial as a novel environment-friendly disinfectant to control plant fungal diseases (Sphaerothecaf uliginea) by its photochemical sterilization ability in cucumber plants. Anatase nano-TiO2 sol, a neutral, viscous aqueous colloid of 1.4% TiO2, was synthesized by sol-gel method. Control efficiencies of nano-TiO2 sol in preventing from powdery mildew were measured by field experimental method with cucumber seedling naturally infected Sphaerothecaf uliginea. Results showed that spraying certain content of nano-TiO2 sol could form continuous and stable antibacterial films on blade surfaces which could not only significantly reduce lesion areas, disease incidences and disease indexes of powdery mildew but also make the leaves turn much greener. It was initially confirmed that nano-TiO2 sol could effectively delay and inhibit the development and pervasion of cucumber powdery mildew. These results indicate that nano-TiO2 sol can be developed as environment-friendly fungicide in preventing from plant disease developments.

Inhibitory Effect of Plant Extracts on Conidial Germination of the Phytopathogenic Fungus <i>Fusarium oxysporum</i>

In an attempt to reduce the use of synthetic fungicides, extensive investigations into the possible exploitation of plant compounds as natural commercial products were performed. The present paper describes the antifungal activity of botanic extracts on the development of Fusarium oxysporum, f.s.p. lycopersici. The tests in vitro were carried out in a multi-well plate assay. The tested plants were classified based on the optical density reached by germinating conidia 24, 48 and 72 hours after inoculation. Among 500 plant species tested, about 84% did not exert significant inhibition, 7.6% showed low inhibition, 5.2% had an intermediate level of antifungal activity, and only 3% inhibited fungal germination completely. These findings suggest that some botanic extracts tested possess antifungal activities against Fusarium oxysporum and could be used as potential antifungal agents for the control of fungal plant diseases.

Chemical composition, insecticidal, and antifungal activities of fruit essential oils of three colombian Zanthoxylum species

This study determined the chemical composition of essential oils isolated from Zanthoxylum monophyllum (Lam.) P. Wilson, Z. rhoifolium Lam., and Z. fagara (L.) Sarg. fruits by steam distillation, as well as testing antifungal and insecticidal activities of essential oils as potential pesticides. Gas chromatography-mass spectrometry (GC/MS) analysis identified 57 compounds. The main constituents in Z. rhoifolium oil were β-Myrcene (59.03%), β-phellandrene (21.47%), and germacrene D (9.28%), the major constituents of Z. monophyllum oil were sabinene (25.71%), 1,8-cineole (9.19%), and cis-4-thujanol (9.19%), whereas fruit oil of Z. fagara mainly contained germacrene D-4-ol (21.1%), elemol (8.35%), and α-cadinol (8.22%). Zanthoxylum fagara showed the highest activity on Colletotrichum acutatum Simmonds (EC50 153.9 μL L -1 air), and Z. monophyllum was the most active against Fusarium oxysporum Schlechtend: Fr. f. sp. lycopersici (EC50 140.1 μL L -1 air). Zanthoxylum monophyllum essential oil showed significant fumigant activity against Sitophilus oryzae (L.). This study demonstrated that Zanthoxylum essential oils exhibit important fungicidal activity on F. oxysporum and C. acutatum, which could become an alternative to synthetic fungicides to control plant fungal diseases, and Z. monophyllum oil is a potential fumigant against S. oryzae.

Development of proteomics-based fungicides: new strategies for environmentally friendly control of fungal plant diseases.

Proteomics has become one of the most relevant high-throughput technologies. Several approaches have been used for studying, for example, tumor development, biomarker discovery, or microbiology. In this “post-genomic” era, the relevance of these studies has been highlighted as the phenotypes determined by the proteins and not by the genotypes encoding them that is responsible for the final phenotypes. One of the most interesting outcomes of these technologies is the design of new drugs, due to the discovery of new disease factors that may be candidates for new therapeutic targets. To our knowledge, no commercial fungicides have been developed from targeted molecular research, this review will shed some light on future prospects. We will summarize previous research efforts and discuss future innovations, focused on the fight against one of the main agents causing a devastating crops disease, fungal phytopathogens.

Biological efficiency of polyphenolic extracts from pecan nuts shell ( Carya Illinoensis), pomegranate husk ( Punica granatum) and creosote bush leaves ( Larrea tridentata Cov.) against plant pathogenic fungi

Bioactive compounds extracted from plants or agro-industrial residues have great potential as novel fungicide sources for controlling pathogenic fungi. In this study antifungal activity of polyphenolic extracts from Larrea tridentata leaves, Carya illinoensis shells and Punica granatum husk were evaluated in vitro against eight different plant pathogenic fungi and ten isolates of Fusarium oxysporum. Phenolic solutions of gallic and ellagic acids were also tested at different concentrations. The polyphenolic extracts tested have a high efficiency to inhibit the mycelial growth of Pythium sp., Colletotrichum truncatum, Colletotrichum coccodes, Alternaria alternata, Fusarium verticillioides, Fusarium solani, Fusarium sambucinum, and Rhizoctonia solani. L. tridentata polyphenolic extracts also efficiently inhibited the mycelial growth of eight out of ten F. oxysporum isolates. These results showed that the polyphenolic extracts tested possess antifungal activities against a broad spectrum of plant pathogenic fungi and could be used as potential antifungal agents for the control of fungal plant diseases.

Mycofumigation withOxyporus latemarginatusEF069 for control of postharvest apple decay and Rhizoctonia root rot on moth orchid

To characterize the volatile antifungal compound produced by Oxyporus latemarginatus EF069 and to examine in vitro and in vivo fumigation activity of the fungus. An antifungal volatile-producing strain, O. latemarginatus EF069 inhibited the mycelial growth of Alternaria alternata, Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum f. sp. lycopersici, and Rhizoctonia solani by mycofumigation. An antifungal volatile compound was isolated from the hexane extract of wheat bran-rice hull cultures of O. latemarginatus EF069 by repeated silica gel column chromatography and identified as 5-pentyl-2-furaldehyde (PTF). The purified PTF inhibited mycelial growth of R. solani in a dose-dependent manner. The mycofumigation with solid cultures of EF069 also reduced effectively the development of postharvest apple decay caused by B. cinerea and Rhizoctonia root rot of moth orchid caused by R. solani. Oxyporus latemarginatus EF069 showed in vitro and in vivo fumigation activity against plant pathogenic fungi by producing 5-pentyl-2-furaldehyde. Oxyporus latemarginatus EF069 producing an antifungal volatile compound may be used as a biofumigant for the control of fungal plant diseases.

Biological control of fungal plant diseases using antagonistic bacteria

Biological control of fungal plant diseases using antagonistic bacteria

Effect of volatile substances of Streptomycesplatensis F-1 on control of plant fungal diseases

Headspace volatile substances (VS) produced by Streptomyces platensis F-1 were preliminarily identified using GC–MS. The effects of VS released by S. platensis F-1 on the control of leaf blight/seedling blight of rice caused by Rhizoctonia solani, leaf blight of oilseed rape caused by Sclerotinia sclerotiorum and fruit rot of strawberry caused by Botrytis cinerea, as well as on the growth of these three pathogenic fungi, were investigated. Results showed that sixteen volatile compounds were tentatively identified in 1-week-old cultures of S. platensis F-1 grown on autoclaved wheat seeds. They could be chemically grouped into alcohols, esters, acids, alkanes, ketones and alkenes. The most abundant composition in volatiles of S. platensis F-1 is geosmin, an earthy-muddy–smelling compound. Two antifungal compounds, phenylethyl alcohol and (+)-epi-bicyclesesquiphellandrene, were detected in the volatile profile of S. platensis F-1. Consistent fumigation of healthy tissues of rice, oilseed rape and strawberry to VS of S. platensis effectively reduced the incidence and/or the severity of leaf blight/seedling blight of rice ( R. solani), leaf blight of oilseed rape ( S. sclerotiorum) and fruit rot of strawberry ( B. cinerea). A significant ( P < 0.05) suppression of the mycelial growth of R. solani, S. sclerotiorum and B. cinerea by the VS of S. platensis was observed. The potential of using VS of S. platensis F-1 as a biofumigant to control plant fungal diseases is discussed.

Using Serratia plymuthica to control fungal pathogens of plants.

Abstract Interest in biological control of plant pathogens has increased in recent years fuelled by trends in agriculture towards greater sustainability and public concerns over the use of hazardous pesticides in the environment. Most studies on the biological control of fungal plant pathogens have tended to focus on the use of antagonistic rhizobacterial strains belonging to the genus Pseudomonas or Bacillus . However, the development of biocontrol products based on isolates belonging to the Gram-negative genus Serratia is now gaining momentum. Serratia plymuthica is a ubiquitous bacterium that has been preferentially recovered from rhizospheres all over the world, both as a free-living and endophytic organism. Specific strains of S. plymuthica produce a broad palette of antimicrobial compounds and might hold great potential as broad-spectrum biocontrol agents. This review surveys the advances of biocontrol research with respect to plant-associated S. plymuthica strains focusing on the principles and mechanisms of action of S. plymuthica and their use or potential use for the biological control of fungal plant diseases. A cursory overview of the taxonomy and ecology of S. plymuthica is also provided. We highlight recent progress in the identification of antifungal secondary metabolites produced by S. plymuthica and pay special attention to the regulatory mechanisms underpinning the production of the latter metabolites. Finally, we discuss several strategies that may provide a basis to improve the efficacy of S. plymuthica -mediated biocontrol.

Toxicity of black nightshade (Solanum nigrum) extracts on Alternaria brassicicola, causal agent of black leaf spot of Chinese cabbage (Brassica pekinensis)

AbstractRoot extracts of black nightshade (Solanum nigrum) were analyzed for activity against isolates ABA‐31 and ABA‐104 of Alternaria brassicicola, the causal agent of black leaf spot of Chinese cabbage (Brassica pekinensis). Preliminary results showed that dried root tissues of black nightshade extracted with 70% ethanol contained antifungal properties against A. brassicicola. Ethanol root extracts were used for further fractionations using ethyl acetate, n‐butanol and water. Among the three extracts, the n‐butanol fraction showed the strongest antifungal activity by its suppression of conidial germination of A. brassicicola. The n‐butanol extract of S. nigrum roots was fractionated further into six fractions (I–VI). Among the six fractions tested, fraction V showed a strong inhibitory effect on conidial germination of A. brassicicola and thereby suppressed lesion development of black leaf spot of Chinese cabbage at a concentration of 25 ppm or higher. Nuclear magnetic resonance analysis indicated that fraction V contained a mixture of saponins, and results of further bio‐guided fractionation and bioassay suggested that saponins in fraction V were key chemical components in the control of A. brassicicola. The potential of using black nightshade for developing natural products for the control of fungal plant diseases is discussed.

Prospects for Controlling Plant Fungal Diseases ? Alternatives Based on Chemical Ecology and Biotechnology

For Abstract see ChemInform Abstract in Full Text.

AWARD LECTURE / CONFÉRENCE D'HONNEUR Prospects for controlling plant fungal diseases — Alternatives based on chemical ecology and biotechnology

Plants produce a diverse array of secondary metabolites associated with important defence and resistance mechanisms. In general, within the same plant family the chemical structures of these metabolites are related and suggest common biogenetic precursors. Crucifers are known to produce constitutive and induced tryptophan derived metabolites. Pathogenic fungi can resist such defences utilizing a variety of processes, as for example, enzymatic detoxification. On the other hand, to facilitate their penetration and colonization of the plant tissues, fungal phytopathogens can produce phytotoxic metabolites, some of which are selectively toxic to host-plants. However, plants may be resistant to these pathogens partly due to their ability to detoxify these selective phytotoxins. Nonetheless, the outcome of these interactions frequently favours the pathogen and can lead to enormous yield losses or even major plant epidemics. An overview of some of the most recent studies of metabolic pathways and stress responses in crucifers and several of their pathogens is presented. Potential strategies to prevent and control plant microbial diseases based on chemical ecology studies and biotechnology will be discussed. Key words: phytoalexin, phytotoxin, chemical defence, metabolic detoxification, destruxin B.

Biological control of fungal plant diseases

Research has demonstrated the agricultural potential of biological control. For airborne pathogens as well as for soilborne pathogens similar strategies based on different targets in the life cycle of the pathogen can be distinguished, viz. (1) microbial protection of the host against infection, (2) microbial reduction of pathogen sporulation and (3) microbial interference with pathogen survival.

Control of fungal plant diseases using putrescine analogues.

Control of fungal plant diseases using putrescine analogues.