scholarly journals A comparison between Pseudomonas aureofaciens (chlororaphis) and P. fluorescens in biological control of cotton seedling damping-off disease

2014 ◽  
Vol 54 (2) ◽  
pp. 115-121
Author(s):  
Samavat Samaneh ◽  
Asghar Heydari ◽  
Hamid Reza Zamanizadeh ◽  
Saeed Rezaee ◽  
Ali Alizadeh Aliabadi
Keyword(s):  
Biological Control ◽  
Greenhouse Experiment ◽  
Plant Diseases ◽  
Dual Culture ◽  
Damping Off ◽  
Wild Type ◽  
Cotton Seedling ◽  
Pseudomonas Aureofaciens ◽  
Volatile Metabolites ◽  
Bacterial Antagonists

Abstract Due to the importance of the biological control of plant diseases, testing and introducing new biocontrol-active microorganisms is a major concern among plant pathologists. The causal agent of cotton seedling damping-off disease is Rhizoctonia solani. In this regard, we tried to investigate the antagonistic activities of Pseudomonas aureofaciens (chlororaphis) 30–84 (phenazine producing wild type and non-phenazine producing mutant) strains on R. solani, in comparison with some isolates of P. fluorescent under both in vitro (laboratory) and in vivo (greenhouse) conditions. In the laboratory experiment, the inhibitory effects of all the bacteria, on the growth of R. solani, were evaluated using the dual culture procedure. Results showed that five isolates of P. fluorescent along with both strains of P. aureofaciens significantly inhibited the growth of R. solani. Effective bacterial antagonists were then evaluated in a greenhouse experiment where cotton seeds were coated with their suspensions and were sown in pasteurised field-soil. The soil had been pre-inoculated with a virulent isolate of R. solani. The efficacy of the bacterial antagonists was evaluated by counting the number of surviving seedlings in different treatments, at 15 and 60 days after sowing, for determining pre- and post-emergence damping-off incidence. According to the results of the greenhouse experiment, at both intervals, two isolates of P. fluorescens along with both strains of P. aureofaciens caused significant increases in the number of healthy seedlings, in comparison with the untreated control, and a commonly used fungicide (carboxin-thiram). The efficacy of phenazine producing a wild type strain of P. aureofaciens was higher than its non-phenazine producing mutant, indicating that phenazine plays an important role in the antagonistic activity of P. aureofaciens. Effective bacterial antagonists were then studied for their antagonistic mechanisms. The results showed that all four bacteria employed different mechanisms. The bacteria produced siderophore, and volatile metabolites and non-volatile metabolites, in their antagonistic activities. The results of this study suggest that P. auerofaciens may be a new biocontrol agent for controlling cotton seedling mortality disease.

scholarly journals Survival of GacS/GacA Mutants of the Biological Control Bacterium Pseudomonas aureofaciens 30-84 in the Wheat Rhizosphere

2002 ◽  
Vol 68 (7) ◽  
pp. 3308-3314 ◽  
Author(s):  
Scott T. Chancey ◽  
Derek W. Wood ◽  
Elizabeth A. Pierson ◽  
Leland S. Pierson
Keyword(s):  
Biological Control ◽  
De Novo ◽  
Regulatory System ◽  
Pathogenic Fungi ◽  
Plant Diseases ◽  
Natural Soil ◽  
Wild Type ◽  
Replacement Series ◽  
Wheat Seedlings ◽  
Pseudomonas Aureofaciens

ABSTRACT GacS/GacA comprises a two-component regulatory system that controls the expression of secondary metabolites required for the control of plant diseases in many pseudomonads. High mutation frequencies of gacS and gacA have been observed in liquid culture. We examined whether gacS/gacA mutants could competitively displace the wild-type populations on roots and thus pose a threat to the efficacy of biological control. The survival of a gac mutant alone and in competition with the wild type on roots was examined in the biological control strain Pseudomonas aureofaciens 30-84. In this bacterium, GacS/GacA controls the expression of phenazine antibiotics that are inhibitory to plant pathogenic fungi and enhance the competitive survival of the bacterium. Wheat seedlings were inoculated with strain 30-84, and bacteria were recovered from roots after 21 days in sterile or nonsterile soil to check for the presence of gacS or gacA mutants. Although no mutants were detected in the inoculum, gacS/gacA mutants were recovered from 29 out of 31 roots and comprised up to 36% of the total bacterial populations. Southern hybridization analysis of the recovered gacA mutants did not indicate a conserved mutational mechanism. Replacement series analysis on roots utilizing strain 30-84 and a gacA mutant (30-84.gacA) or a gacS mutant (30-84.A2) demonstrated that although the mutant population partially displaced the wild type in sterile soil, it did not do so in natural soil. In fact, in natural soil final rhizosphere populations of wild-type strain 30-84 starting from mixtures were at least 1.5 times larger than would be predicted from their inoculation ratio and generally were greater than or equal to the population of wild type alone despite lower inoculation rates. These results indicate that although gacS/gacA mutants survive in natural rhizosphere populations, they do not displace wild-type populations. Better survival of wild-type populations in mixtures with mutants suggests that mutants arising de novo or introduced within the inoculum may be beneficial for the survival of wild-type populations in the rhizosphere.

The antagonistic properties of Trichoderma spp. inhabiting woods for potential biological control of wood-damaging fungi

Holzforschung ◽  
2012 ◽  
Vol 66 (7) ◽  
pp. 883-887 ◽  
Author(s):  
Jaejung Lee ◽  
Nayoon Huh ◽  
Joo Hyun Hong ◽  
Beom Seok Kim ◽  
Gyu-Hyeok Kim ◽  
...  
Keyword(s):  
Biological Control ◽  
Chitinase Activity ◽  
Dual Culture ◽  
Trichoderma Spp ◽  
Trichoderma Longibrachiatum ◽  
Antagonistic Effects ◽  
Volatile Metabolites ◽  
Antagonistic Potential ◽  
Trichoderma Aureoviride

Abstract The antagonistic potential of Trichoderma spp. for biological control of wood-damaging fungi was investigated in the present paper. In vitro assays to investigate antifungal characteristics of Trichoderma spp. were conducted with various wood-damaging fungi. Exo-chitinase activity of the isolates was also measured. Three typical wood decayers and three sap-stainers served as target fungi. The antagonistic abilities of each Trichoderma species differed markedly according to the target fungus. The growth inhibition rates shown by the non-volatile metabolites against the wood decayers reached 100% for Trichoderma harzianum KUC1459. The antibiotics produced by Trichoderma dorotheae KUC5027, a recently reported species of Trichoderma, revealed strong antagonistic effects against sap-stainers. Trichoderma gamsii KUC1747 effectively inhibited the growth of all wood-damaging fungi in dual culture tests. The exo-chitinases of Trichoderma longibrachiatum KUC1540, Trichoderma aureoviride KUC1335, and T. harzianum KUC1459 showed significantly high activity.

scholarly journals Application of new bioformulations of Pseudomonas aureofaciens for biocontrol of cotton seedling damping-off

2014 ◽  
Vol 54 (4) ◽  
pp. 334-339 ◽  
Author(s):  
Samaneh Samavat ◽  
Asghar Heydari ◽  
Hamid Reza Zamanizadeh ◽  
Saeed Rezaee ◽  
Ali Alizadeh Aliabadi
Keyword(s):  
Biological Control ◽  
Rice Bran ◽  
Soybean Meal ◽  
Fungal Pathogens ◽  
Biocontrol Agent ◽  
Disease Incidence ◽  
Bacterial Suspension ◽  
Damping Off ◽  
Pseudomonas Aureofaciens ◽  
Phenazine Production

Abstract Pseudomonas aureofaciens (30-84) is a phenazine producing bacterium and reported as asuccessful biocontrol agent of some plant fungal pathogens. In the present study, the possibility of biological control of cotton damping-off caused by Rhizoctonia solani (AG-4) through phenazine production by the 30-84 strain, was investigated. In the search for the development of bioformulations of Pa (m) (PhzR–) and Pa (w) (PhzR+) strains of 30-84, four new carriers including soybean meal (SM), cottonseed meal (CM), rice bran (RB), and talc powder (TAL) were selected. The efficacy of bacterial formulations in reducing disease incidence was evaluated in four intervals (15, 30, 45, and 60 days after sowing), and compared with each bacterial suspension efficacy under green-house conditions. The results revealed that organic carriers were more effective than talc powder. It was also found that all the bioformulations were more efficient than each bacterial suspension. The most effective in reducing disease incidence was Pa (w) + RB. In contrast, Pa (m), Pa (m) + TAL, and Pa (m) + RB did not significantly suppress the disease in comparison with the infested control. Thus, phenazine production as a main biocontrol mechanism of P. aureofaciens (30-84) may be affected by the kind of carriers used for the bioformulation development.

scholarly journals Application of plant extracts and Trichoderma harzianum for the management of tomato seedling damping-off caused by Rhizoctonia solani

2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Mapula T.P. Hlokwe ◽  
Mapotso Kena ◽  
David N. Mamphiswana
Keyword(s):  
Biological Control ◽  
Rhizoctonia Solani ◽  
Plant Extracts ◽  
Trichoderma Harzianum ◽  
Moringa Oleifera ◽  
Plant Diseases ◽  
Yield Reduction ◽  
Biotic Factors ◽  
Damping Off ◽  
Tomato Seedling

Seedling production under smallholder farming systems can be negatively affected by both abiotic and biotic factors. Seedling damping-off caused by Rhizoctonia solani is one of the major biotic factors which causes significant yield reduction. Management is mainly based on the application of synthetic fungicides and cultural practices. However, both methods have limitations which result in their inefficiency. Several studies have reported on the use of plant extracts and biological control to manage plant diseases. The aim of this study was to formulate an effective and practical approach to manage tomato seedling dampingoff using extracts of Monsonia burkeana and Moringa oleifera and a biological control agent Trichoderma harzianum. The efficacy of both extracts was investigated under laboratory conditions to determine the most suppressive concentration to R. solani growth. Methanolic extracts from both plants significantly suppressed pathogen growth at different concentrations. M. burkeana significantly reduced R. solani growth at 8 g/mL (71%) relative to control whilst Moringa oleifera extract reduced pathogen growth by 60% at a concentration of 6 g/mL. The highest suppressive concentrations were further evaluated under greenhouse conditions to test their efficacy on seedling damping-off. In damping-off treatments, both plant extracts and T. harzianum also significantly reduced (p=0.5) pre- and post-emergence dampingoff incidence. M. burkeana recorded the highest suppression at 78%, followed by M. oleifera at 64%. Trichoderma harzianum reduced incidence of damping-off by 60% and this was higher than both plant extract treatments.

scholarly journals Selection and Assessment of Plant Growth-Promoting Rhizobacteria for Biological Control of Multiple Plant Diseases

2017 ◽  
Vol 107 (8) ◽  
pp. 928-936 ◽  
Author(s):  
Ke Liu ◽  
Molli Newman ◽  
John A. McInroy ◽  
Chia-Hui Hu ◽  
Joseph W. Kloepper
Keyword(s):  
Biological Control ◽  
Plant Growth ◽  
Broad Spectrum ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Diseases ◽  
Damping Off ◽  
In Planta ◽  
Plant Growth Promoting ◽  
Growth Promoting

A study was designed to screen individual strains of plant growth-promoting rhizobacteria (PGPR) for broad-spectrum disease suppression in vitro and in planta. In a preliminary screen, 28 of 196 strains inhibited eight different tested pathogens in vitro. In a secondary screen, these 28 strains showed broad spectrum antagonistic activity to six different genera of pathogens, and 24 of the 28 strains produced five traits reported to be related to plant growth promotion, including nitrogen fixation, phosphate solubilization, indole-3-acetic acid production, siderophore production, and biofilm formation. In advanced screens, the 28 PGPR strains selected in vitro were tested in planta for biological control of multiple plant diseases including bacterial spot of tomato caused by Xanthomonas axonopodis pv. vesicatoria, bacterial speck of tomato caused by Pseudomonas syringae pv. tomato, damping-off of pepper caused by Rhizoctonia solani, and damping-off of cucumber caused by Pythium ultimum. In all, 5 of the 28 tested strains significantly reduced three of the four tested diseases, and another 19 strains showed biological control to two tested diseases. To understand the observed broad-spectrum biocontrol capacity, antiSMASH was used to predict secondary metabolite clusters of selected strains. Multiple gene clusters encoding for secondary metabolites, e.g., bacillibactin, bacilysin, and microcin, were detected in each strain. In conclusion, selected individual PGPR strains showed broad-spectrum biocontrol activity to multiple plant diseases.

scholarly journals Cotton Seedling Preemergence Damping-Off Incited by Rhizopus oryzae and Pythium spp. and Its Biological Control with Trichoderma spp.

2002 ◽  
Vol 92 (2) ◽  
pp. 177-180 ◽  
Author(s):  
C. R. Howell
Keyword(s):  
Biological Control ◽  
Wheat Bran ◽  
Seed Treatment ◽  
Rhizopus Oryzae ◽  
Infested Soil ◽  
Damping Off ◽  
Trichoderma Spp ◽  
Cotton Seedling ◽  
Germination Stimulants ◽  
Infested Field

Planting the cotton cv. Sure-Grow 747 in cotton seedling disease plots during the 2001 growing season resulted in high levels of preemergence damping-off among the seedlings. Four cotton pathogens, Pythium aphanidermatum, P. ultimum, an unidentified Pythium sp., and Rhizopus oryzae, were isolated from diseased seed embryos and seedlings. Disease incited by the Pythium spp. could be controlled by seed treatment with Metalaxyl, but disease incited by R. oryzae could not. Seed treatment with Metalaxyl in naturally infested field soil was only partially effective; therefore, symptoms in 47% of the diseased seedlings could be attributed to R. oryzae. Susceptibility to disease appeared to be related to release in the spermosphere, by the germinating seeds, of compounds that stimulate pathogen propagule germination, because exudates from seed of the suscept Sure-Grow 747 and extracts from wheat bran induced pathogen germination and growth, whereas exudates from resistant cv. Stoneville 213 did not. However, even Stoneville 213 became susceptible when infested soil was amended with wheat bran. Seed treatment with preparations of Trichoderma virens parent, mutant, and hybrid strains gave effective biological control of preemergence damping-off. Disease control was attributable to metabolism by the biocontrol agent of pathogen germination stimulants released by the seed, because amendment of pathogen-infested soil with the propagule germination stimulants in wheat bran negated the protective effect of the seed treatment.

scholarly journals Antifungal potential of crude extracts of Trichoderma spp.

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Eder Marques ◽  
Irene Martins ◽  
Sueli Correa Marques de Mello
Keyword(s):  
Biological Control ◽  
Broad Spectrum ◽  
Plant Pathogens ◽  
Pathogenic Fungi ◽  
Plant Diseases ◽  
Bioactive Molecules ◽  
Plant Pathogenic Fungi ◽  
Trichoderma Spp ◽  
Volatile Metabolites ◽  
Antibiotic Effect

Abstract Antibiosis is the mechanism by which certain microorganisms respond to the presence of others, secreting compounds or metabolites capable of inhibiting or impeding their development. The crude extract of Trichoderma contains a mixture of secondary compounds, which may show antibiotic effect, and has been used for the prospect of this fungus for biological control and other industrial purposes. Faced with the increasing demand of agriculture for ecologically compatible alternatives for the management of diseases, this work aimed to investigate the spectrum of action of Non-Volatile Metabolites (NVMs) of Trichoderma isolates against different plant pathogenic fungi. The antagonistic potential of NVMs was evaluated through the incorporation method of the filtered liquid extract in PDA medium. The assays showed that all the NVMs produced inhibited the fungus Sclerotinia sclerotiorum similarly. On the other hand, strains CEN1245 and CEN1274, both belonging to the species Trichoderma brevicompactum, showed broad spectrum against Sclerotium rolfsii, Colletotrichum gloesporioides, Verticillium dahliae, Fusarium oxysporum and Cylindrocladium sp. The present study describes isolates producing non-volatile metabolites with broad spectrum of antifungal action, as well as pathogen-specific. The Trichoderma spp. NVMs obtained from different soil samples cultivated with vegetables, cassava and maize were efficient in inhibiting plant pathogenic fungi belonging to other patossystems, such as forest or fruit, which could increase their potential application in biological control of plant diseases. In addition, these antagonistic fungi should be studied in greater depth for the identification of bioactive molecules of industrial interest or in commercial formulations of products for biological control of plant pathogens.

Influence of nutrients on growth ofEpicoccum nigrum

1996 ◽  
Vol 42 (7) ◽  
pp. 647-654 ◽  
Author(s):  
Ting Zhou ◽  
R. D. Reeleder ◽  
S. A. Sparace
Keyword(s):  
Amino Acids ◽  
Biological Control ◽  
Glutamic Acid ◽  
Biological Control Agent ◽  
Plant Diseases ◽  
White Mold ◽  
Malt Extract ◽  
Dual Culture ◽  
Potato Dextrose Broth ◽  
Inhibition Zones

Epicoccum nigrum is a potential biological control agent for certain plant diseases, such as white mold of bean caused by Sclerotinia sclerotiorum. To provide information that could be used to improve the production and efficacy of E. nigrum, the effects of nutrients, including specific carbohydrate sources and amino acids, on mycelial growth, sporulation, germination of conidia, and elongation of germ tubes were determined. In dual cultures of E. nigrum and S. sclerotiorum, the effects of nutrients on widths of inhibition zones between the two fungi were assessed. Standard mycological media supported faster radial growth than media with single carbohydrate sources and individual amino acids, but glutamic acid combined with maltose or dextrose was similar with respect to stimulation of sporulation when compared with media such as V8 juice and yeast extract agars. Dual culture inhibition zones were greater in certain simple media (dextrose and lysine, sucrose and lysine, and maltose and lysine) than in standard media. For germination and germ tube elongation, sucrose and maltose were superior to most other carbohydrate sources tested, and lysine and glutamic acid were superior amino acid sources. When standard broth media were compared for production of antifungal compounds by E. nigrum, both potato dextrose broth and malt extract broth were superior to Czapek solution. Culture filtrates of E. nigrum grown in potato dextrose broth were more inhibitory towards S. sclerotiorum than filtrates from malt extract cultures.Key words: biological control, white mold, Epicoccum purpurascens, antibiosis.

scholarly journals Evaluation of Trichoderma asperellum B1902 in Controlling Fusarium Wilt of Cavendish Banana Cultivar

2021 ◽  
Vol 50 (9) ◽  
pp. 2549-2561
Author(s):  
Sharifah Siti Maryam Syd Abdul Rahman ◽  
Nur Ain Izzati Mohd Zainudin ◽  
Nor Azwady Abd. Aziz
Keyword(s):  
Biological Control ◽  
Fusarium Wilt ◽  
Wilt Disease ◽  
Internal Transcribed Spacers ◽  
Plant Diseases ◽  
Dual Culture ◽  
Species Identity ◽  
Trichoderma Species ◽  
Culture Test ◽  
Fusarium Wilt Disease

Trichoderma species is one of the microorganisms with antagonistic properties as biological control agents. In the banana industry, Fusarium wilt disease caused by Fusarium oxysporum f. sp. cubense (Foc) has been practically managed using chemical pesticides that led to environmental disruptions, ineffective conditions and disease resistance. In preliminary study, T. asperellum gave better result compared to other species in inhibiting the growth of Foc in in vitro condition. Therefore, the aim of this study was to examine the effects of T. asperellum as a biological control of Fusarium wilt disease of banana. A total of 326 fungal isolates were isolated from soil samples obtained around Malaysia and identified as Trichoderma species based on phenotype characteristics. The species identity for the best candidates from dual culture test was confirmed based on internal transcribed spacers (ITS) and translation elongation factor 1 alpha (TEF-1α) sequence identity. In dual culture test, findings showed that three isolates with a high percentage inhibition of radial growth (PIRG) were observed in plates of T. asperellum isolates B1902 (84.85%), T2007 (77.78%) and C1667 (75.76%), which successfully inhibited the growth of F. oxysporum f. sp. cubense isolate 9888. Based on in vivo test, the best candidate was T. asperellum B1902 with lower disease severity index (DSI) value of 0.2 compared to the inoculated control with DSI of 3.6. As a conclusion, T. asperellum B1902 can be used as an alternative treatment in managing Fusarium wilt disease. Hence, future study should be focused on applying T. asperellum as a biocontrol agent in the field and controlling other plant diseases in the agricultural plantation.

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