All you wanted was a shot at me, that Gumbo got instead. Mark thought over her words as he ate more gumbo. It turned out to be a Gumbo sound check in full swing. A nice place to eat especially if your a lover of gumbo as I am. As for the relationship between gumbo and bouillabaisse, I can find very little. Eric tried to escape, but Gumbo was too fast for him.

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The aim of this study is the evaluation of antagonistic isolates of pathogenic fungi F. Our results showed clearly that these isolates have a significant effect on seed germination and seedling growth. However, results argue that these actinomycetes isolates show a very interesting activity compared to the commercial fungicide. As a result, these bacteria isolates can be used as biocontrol agents against Fusarium wilt disease of wheat, which have a beneficial effect on growth parameters.

Growth Parameters and Biological Control Mechanisms. Advances in Microbiology, 6, Received 15 June ; accepted 8 August ; published 11 August 1. Introduction Wheat is the most commonly grown crop in the world, representing a major resource for food [1]. Wheat and other small grain cereals may be attacked by a wide range of Fusarium spp. The economic impact of Fusarium damage on wheat has a great importance throughout the world [4]. Pathogenic fungi can survive for a long time in the soil, and then it is difficult to be controlled [5].

To fight against these pathogens via unlimited application of pesticides in soil can cause environmental pollution [6]. Also, the effectiveness of chemical fungicides is often compromised by the emergence of resistant pathogens [7].

Due to the worsening problems in fungal diseases control, further research is needed to identify alternative methods of protecting plants less dependent on chemicals and more respectful to the environment [8]. However, biological control is a promising method that involves antagonistic microorganisms like actinomy- cetes.

These uses are deemed to apply the best form of living cells because of their ability to colonize plant roots, to control microorganisms plant pathogens and spores shaped adapted to stable products formation [9] [10]. Actinomycetes are an important part of the microbial community in soil dispersion surface; it gives the aptitude to colonize the rhizosphere through their antagonists and competitive characters, and their many secondary metabolites production that has chemical structures with different biological activities [11].

Streptomyces genus can produce plant growth regulators such as Indole Acetic Acid IAA , antibiotics and lytic enzymes as biocontrol agents against F. These diseases have controlled by synthetic fungicides or chemical compounds.

However, chemical control generates enormous negative impacts on the environment, and the repeated use of these chemical molecules causes resistance among these pathogens. This study focuses on the biological ability of actinomycetes to fight against these pathogens. They are often isolated from samples of different ecosystems for producing substances inhibitory activities against plant pathogens, using suitable culture media and then selecting the successful stem through the identification of their in vitro antagonistic activity.

Materials and Methods 2. The suspension was serially diluted up to Using the method of Pochon and Tardieux [13] three samples of g to 5 cm of the top soil away from roots have been taken from the rhizosphere of 3 endemic plants zones; then putted in plastic bags and analyzed directly Daucus sahariensis Murb Astragalus gombo Coss.

Table 1. Media for isolation, seeding, and recognition of actinomycetes isolates. Then seeded depositing 0. They marked by their macroscopic and microscopic appearance of hard colonies; small size with a round shape surrounded by microfilaments Figure 2 a , Figure 2 b and then crop diversity was thus carefully analyzed and investigated.

Purification and Conservation An aliquot of 0. Visual observation using light microscopy and Gram-straining performed for further identification. The color of mycelium and soluble pigment were examined in ISP2 medium and determined by comparison with chips color of in the color harmony manual [17]. The absorbance of the reaction mixture was measured at nm and the IAA content of the culture filtrate was quantified using a standard curve with known concentrations of pure IAA Sigma.

They were allowed to imbibe water overnight at room temperature. Pre-germinated seeds grown in Petri dishes, which experiments were performed in controlled environmental conditions using plant growth chamber.

Two seed lots were used such as seeds inoculated with F. Germination rate determined after three days after seeding and growth morpho- physiological parameters, such as the number of leaves, leaf area, root length, and chlorophyll content determined after four weeks.

Actinomycetes Antimicrobial Activities Antimicrobial activities of actinomycetes isolates were evaluated by cross-striations method on ISP2. It consists in seeding actinomycetes isolates in a single line on the surface of the solid medium. Results were obtained after 36 to 48 h by measuring the distance between the edges of inhibition of target strain and actinomycetes isolates.

Actinomycetes seeded, on PDA Potato Dextrose Agar , the device of the Petri dish away from the edge of the box by 3 mm , with a streak of 6mm wide. A disk of 7 mm diameter mushroom cultivation eight days old deposed share of actinomycetes culture.

The distance between mushroom and disc edge of the box is 15 mm. For each fungal isolate a control treatment was provided, with disc deposited on PDA medium without actinomycetes. Fungus colonies diameter was measured for all treatments including the control [21].

According to Williams and Willis [22] ; Aghighi et al. Control sample contains only a washer of F. Daily reading is done on sample control culture. Antifungal activity of actinomycetes isolates was underscored by cross streaks method on the ISP2 environment, agar-cylinder method and confrontation method in Petri dish [24]. The target seeds used were filamentous fungi and pathogenic bacteria. The following protocol showed the antifungal activity and biological control against plant diseases by actinomycetes isolates that produce antibiotics Figure 2 c.

Both of 8 treated and untreated seeds of HD with the fungicide seeded on MS medium supplemented with 3 ml of Fusarium suspension and 3 ml of actinomycetes suspension. Antagonistic Actinomycetes Isolate Potential on Fusarium Wither of Wheat Seeds and Disease Expression We have studied actinomycetes action on Fusarium mycelium growth to assess the effectiveness of actinomycetes suspensions on Hidhab HD variety seeds.

Spores of phytopathogenic fungus F. The resulting liquid was filtered through 4 layers of cotton to remove debris from the mycelium. The filtrate obtained containing spores washed twice with sterile distilled water, and spore suspension centrifuged at rpm for 5 min. It noted that we have used in this study the MS medium [20] supplemented with 0. Data Analysis Measurements related to the enumeration of isolated actinomycetes and their behavior towards the culture medium used and macro-morphological characterizations, and their antagonistic activities mentioned.

Data were processed by the analysis of variance, using Crop-Stat 7. Results 3. Seed Germination Percentage Seed germination capacity of bread wheat T. These results, confirm that the treatment by fungicide has a depressive effect on the pathogen and therefore a positive effect on the germination rate Figure 3 a. However, seedlings treated and untreated with the commercial fungicide and inoculated with D8 and D5 isolates in the presence of F.

While plantlets seeds inoculated with AST1 isolate in the presence of the commercial fungicide, have developed a leaf area 8 cm2 , and in the absence of this fungicide 17 cm2. For the D2 isolate, leaf area is 18 cm2 for plantlets treated seeds and 23 cm2 for those from untreated seeds Figure 3 c. While root length is 5 to 6. Seeds inoculated with AST1 isolate in the absence of fungicide reaches a 3 cm length of roots Figure 3.

Figure 3 d. Biological Control Mechanisms 3. Biocontrol Agents Microbial antagonists widely used for the biocontrol of fungal plant diseases. Many species of actinobacteria, particularly those belonging to the genus Streptomycetes, are well known as antifungal biocontrol agents that inhibit several plant pathogenic fungi.

Results of this study indicate that seed germination strongly inhibited when inoculated by pathogenic fungi Figure 5 a. It indicated that HD variety seedlings treated with D5, D2, and AST1 isolates have the double character of both stimulation growth and biocontrol agent, Figure 5 b.

It shows that increased index of germination observed from, the wheat seeds indicating the potential of actino- mycetes isolates to inhibit pathogenicity and by this means increase germination. Discussion The role of microorganisms in biological control of plants against diseases showed that the use of microorganisms to fight against the enemy culture bio-pesticides is a plant protection means respecting the environment.

Figure 4. Actinomycetes isolates effects on chlorophyll content within F. Seeds inoculated with F. Yekkour et al. Certainly, most parasites, fungi or weeds of the plants have one or more natural microbial enemies, and it will be necessary to know the pathogenic fungi development cycle and antagonist activity conditions.

Streptomycetes soil produce hydroxamate-type siderophore, could inhibit plant pathogens growth and thus reduce their action by competing for the phenomenon for iron [27] - [29].

Or by stimulation of plant defenses [30] - [33]. Thus, the results obtained in this study on Fusarium soft wheat will contribute positively to the improvement of biocontrol process against these diseases. Analysis of variance revealed a very highly significant effect on germination rate for foliage, and significant for leaves number and root length.

As against the number of leaves is a differential between treated seeds by a fungicide with a high number of leaves especially for seeds inoculated with D2 and D8 isolates, while for untreated one, leaves number reduced for both isolates compare to AST1isolate. D5 isolate has a high number of leaves for either treated or untreated seeds with fungicide, whereas, this isolate has a beneficial effect on the development of leaf area.

Also, analysis results show that D5 isolate has a remarkable influence on the root length. Seeds treatment by actinomycetes isolates from different rhizospheric areas of endemic plants gave important results of PGPR effects, resulting in improved growth parameters studied. However, D5 isolate has a very important effect on growth compared to the fungicide effect.

These results certainly participate in the biocontrol process [34]. Thus, actinomycetes isolates used in this study may be affiliated with plant growth promoting rhizobacteria PGPR. Then, it is known that PGPR may also protect plants against phytopathogenic infections. Biocontrol assay of actinomycetes isolates against F. That is very important for all seeds inoculated with the four Figure 6. Indole acetic acid IAA production by the antagonistic actinomycetes isolates different lowercase letters a, b and c on top of the histograms indicate significant differences or homogenous groups.

Table 2. Measured variables average values of actinomycetes isolates and fungicide used for growth parameters studied. Table 3. Measured variables average values of actinomycetes isolates and fungicide used for studied growth parameters.


Astragalus gombo

Related Research Articles Locoweed is a common name in North America for any plant that produces swainsonine, a phytotoxin harmful to livestock. Worldwide, swainsonine is produced by a small number of species, most in three genera of the flowering plant family Fabaceae: Oxytropis and Astragalus in North America, and Swainsona in Australia. The term locoweed usually refers only to the North American species of Oxytropis and Astragalus, but this article includes the other species as well. Some references may list Datura stramonium as locoweed. Astragalus alpinus is a species of flowering plant in the legume family known by the common name alpine milkvetch.


Astragalus gombo

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