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Journal ArticleDOI

Antagonistic actinomycetes from Moroccan soil to control the grapevine gray mold

TL;DR: It is demonstrated here that pre-inoculation of plantlets with these isolates allow them to withstand Botrytis cinerea, indicating the potential of developing effective actinomycetes from Moroccan habitats for the biological control of Botrytic mold.
Abstract: One hundred and forty-two different actinomycete strains were isolated from rhizosphere soil of Vitis vinifera L. sampled from four Moroccan areas. To evaluate the antifungal effect of the different collected actinomycete isolates, five fungi known to be phytopathogens (Pythium ultimum, Fusarium oxyysporum f. sp. albedinis, Sclerotium rolfsii,Verticillium dahliae and Botrytis cinerea) were used. Results showed that 24 isolates had an in vitro inhibitory effect toward at least 4 of the indicator fungi, but only 9 inhibited all these phytopathogens. These nine isolates were subsequently evaluated individually using in vitro grapevine plantlets for their ability to protect against plant gray mold. We demonstrate here that pre-inoculation of plantlets with these isolates allow them to withstand Botrytis cinerea. Six of these strains were shown to belong to the genus Streptomyces and three to the genus Micromonospora. These findings indicate the potential of developing effective actinomycetes from Moroccan habitats for the biological control of Botrytis cinerea.
Citations
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Journal ArticleDOI
TL;DR: Together, the evolution of high cellulolytic ability and diverse chemistry, shaped by their ecological roles in nature, make Actinobacteria a promising group for the bioenergy industry.
Abstract: The ancient phylum Actinobacteria is composed of phylogenetically and physiologically diverse bacteria that help Earth's ecosystems function. As free-living organisms and symbionts of herbivorous animals, Actinobacteria contribute to the global carbon cycle through the breakdown of plant biomass. In addition, they mediate community dynamics as producers of small molecules with diverse biological activities. Together, the evolution of high cellulolytic ability and diverse chemistry, shaped by their ecological roles in nature, make Actinobacteria a promising group for the bioenergy industry. Specifically, their enzymes can contribute to industrial-scale breakdown of cellulosic plant biomass into simple sugars that can then be converted into biofuels. Furthermore, harnessing their ability to biosynthesize a range of small molecules has potential for the production of specialty biofuels.

224 citations


Cites background from "Antagonistic actinomycetes from Mor..."

  • ...Plants are protected by the genera Streptomyces and Micromonospora, as well as by other Actinobacteria in the rhizosphere, which can help inhibit plant pathogens through the production of secondary metabolites (57, 81, 115)....

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Journal ArticleDOI
TL;DR: It is proposed that strain NEAU 119(T) represents a novel species, Actinoalloteichus nanshanensis sp.
Abstract: A Gram-positive, aerobic actinomycete, designated strain NEAU 119T, was isolated from the rhizosphere of a fig tree and was characterized using a polyphasic approach. The isolate formed branching, non-fragmenting vegetative hyphae and produced black pigment on yeast extract/malt extract (ISP medium 2). The G+C content of the DNA was 76.6 mol%. The organism had chemotaxonomic characteristics typical of the genus Actinoalloteichus and was closely related to the type strains of Actinoalloteichus cyanogriseus, Actinoalloteichus spitiensis and Actinoalloteichus hymeniacidonis, currently the only three recognized species of the genus Actinoalloteichus, sharing 16S rRNA gene similarities of 96.4, 96.6 and 98.1 %, respectively. However, the results of DNA–DNA hybridization studies demonstrated that the novel strain showed only 46.8 % relatedness with the type strain of A. hymeniacidonis. In addition, a set of phenotypic characteristics also readily distinguished strain NEAU 119T from the type strains of recognized species of the genus Actinoalloteichus. According to the above data, it is proposed that strain NEAU 119T represents a novel species, Actinoalloteichus nanshanensis sp. nov. The type strain of Actinoalloteichus nanshanensis is NEAU 119T ( = CGMCC 4.5714T = NBRC 106685T).

188 citations


Cites methods from "Antagonistic actinomycetes from Mor..."

  • ...The fatty acid C17 : 0 cyclopropane acid was only present in strain NEAU 119T. Genomic DNA of strain NEAU 119T was extracted as described previously by Lee et al. (2003) and PCR amplification of the 16S rRNA gene was carried out according to the procedures outlined by Loqman et al. (2009)....

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Journal ArticleDOI
TL;DR: These findings provide new insights into the antimicrobial activities of natural endophytes, particularly B. atrophaeus, and suggest this species may be a promising candidate as a biocontrol agent to confer resistance to Verticillium wilt disease and other phytopathogens in cotton and other crops.
Abstract: Endophytic bacteria associated with medicinal plants possess unique strategies that enhance growth and suvival of host plants, many of which are mediated by distinctive secondary metabolites. These bacteria and their secondary metabolites are important subjects for both basic and applied research aimed at sustainable agriculture. In the present study, 114 endophytic strains isolated from the wild ethnomedicinal plant Glycyrrhiza uralensis (licorice) were screened for their in vitro antimicrobial activities against common fungal pathogens of tomato (Fusarium oxysporum f. sp., Fulvia fulva, Alternaria solani), cotton (Fusarium oxysporum f. sp. Vesinfectum, Verticillium dahliae), pomegranite (Ceratocystis fimbriata), Cymbidinium (Colletotrichum gloeosporioides), and Tsao-ko (Pestalotiopsis microspora and Fusarium graminearum) and the common bacteria Staphylococcus aureus, Bacillus cereus, Salmonella enteritidis, and Escherichia coli. Several Bacillus strains, particularly Bacillus atrophaeus and Bacillus mojavensis, had a broad spectrum of antifungal and antibacterial activity. 16 strains, selected based on broad antimicrobial activity, were shown to contain at least one putative secondary metabolite-encoding gene (i.e., polyketide synthase or non-ribosomal peptide synthetase) and/or one lytic enzyme (i.e., protease, cellulase, lipase, chitinase), which may be important mediators of antagonistic activity against pathogens. Five strains, representing Bacillus atrophaeus and Bacillus mojavensis, were selected for plant growth chamber experiments based on strong in vitro antifungal activities. All five strains significantly reduced disease severity Arabidopsis thaliana plants challenged with V. dahlia infection. GC-MS analysis of cell-free extracts of Bacillus atrophaeus strain XEGI50 showed that at least 13 compounds were produced only during co-cultivation with V. dahlia, including putative compounds known to have antimicrobial activity, such as 1,2-benzenedicarboxylic acid, bis (2-methylpropyl) ester; 9,12-octadecadienoic acid (Z,Z)-, methyl ester; 9-octadecenoic acid, methyl ester, (E)-; and decanedioic acid, bis(2-ethylhexyl) ester. To our knowledge, this study is the first to report that bacteria isolated from G. uralensis have biocontrol abilities. Our findings provide new insights into the antimicrobial activities of natural endophytes, particularly B. atrophaeus, and suggest this species may a promising candidate as a biofertilizer to confer resistance to Verticillium wilt disease and other phytopathogens in cotton and other crops.

124 citations


Cites methods from "Antagonistic actinomycetes from Mor..."

  • ...A concentrate of each endophyte was placed onto the agar surface at 8 equidistant points, 2.5 cm from the plate periphery (Loqman et al., 2009)....

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Journal ArticleDOI
TL;DR: The current knowledge on new strains from the rhizo- and endosphere and their metabolites that can be used on grapevine plants to counteract pathogen attack needs to be discussed.
Abstract: Grapevine is one of the most important economic crops yielding berries, wine products as well as derivates. However, due to the large array of pathogens inducing diseases on this plant, considerable amounts of pesticides—with possible negative impact on the environment and health—have been used and are currently used in viticulture. To avoid negative impacts of such products and to ensure product quality, a substantial fraction of pesticides needs to be replaced in the near future. One solution can be related to the use of beneficial bacteria inhabiting the rhizo- and/or the endosphere of plants. These biocontrol bacteria and their secondary metabolites can reduce directly or indirectly pathogen diseases by affecting pathogen performance by antibiosis, competition for niches and nutrients, interference with pathogen signaling or by stimulation of host plant defenses. Due to the large demand for biocontrol of grapevine diseases, such biopesticides, their modes of actions and putative consequences of their uses need to be described. Moreover, the current knowledge on new strains from the rhizo- and endosphere and their metabolites that can be used on grapevine plants to counteract pathogen attack needs to be discussed. This is in particular with regard to the control of root rot, grey mould, trunk diseases, powdery and downy mildews, pierce’s disease, grapevine yellows as well as crown gall. Future prospects on specific beneficial microbes and their secondary metabolites that can be used as elicitors of plant defenses and/or as biocontrol agents with potential use in a more sustainable viticulture will be further discussed.

117 citations


Cites background or methods from "Antagonistic actinomycetes from Mor..."

  • ...Attempts to use members of the Actinomycetales such as Streptomyces spp. or Micromonospora spp. to control B. cinerea have also been studied (Loqman et al. 2009; Lebrihi et al. 2009a, b)....

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  • ...Some soil strains of these bacteria can allow grapevine in vitro plantlets to withstand grey rot (Loqman et al. 2009)....

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Journal ArticleDOI
TL;DR: The present results indicate that isolate KEH23 is a potential antibiotic producer agent for the biocontrol of plant and human pathogens.
Abstract: Sixteen antibiotic-producing Streptomyces sp. isolated from the North Cyprus soils were evaluated for their ability to inhibit in vitro against six filamentous fungi including human and plant pathogens. One promising strain, designed as KEH23 with strong antifungal activity, was selected for further studies. This isolate was identified as Streptomyces sp. based on a great variety of morphological, cultural, physiological and biochemical characteristics. Its antifungal activity was confirmed in batch culture. In order to standardize the antibiotic production some cultural conditions like different incubation temperatures (20.0, 25.0, 30.0 and 37.0°C), carbon sources (glucose, glycerol, starch and sucrose), pH (6.0, 7.0, 7.5, 8.0 and 9.0) and incubation time in hours (24, 48, 72, 96 and 120) were determined. During fermentation, growth, pH and antibiotic production were monitored at 12 h intervals. Penicillium sp. was most sensitive to the produced compound(s) followed by Candida albicans, Cladosporium oxysporum and Alternaria alternata with an inhibition zone 28.0, 20.0, 16.0 and 15.0 mm, respectively. In addition, antibacterial activity of this strain was determined against human pathogenic bacteria such as Staphylococcus aureus, Klebsiella pneumoniae, Kocuria rhizophila, Escherichia coli, Salmonella typhimurium and methicillin-resistant Staphylococcus aureus (MRSA). The present results indicate that isolate KEH23 is a potential antibiotic producer agent for the biocontrol of plant and human pathogens.

115 citations


Cites background from "Antagonistic actinomycetes from Mor..."

  • ...Although the exact mechanisms by which these actinomycetes isolates operate to reduce disease incidence is not elucidated, one possibility is that these biocontrol agents exert a direct inhibitory effect on hyphal growth and structure of fungal pathogens (Zakalyukina and Zenova, 2007; Loqman et al., 2009)....

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  • ...by the streptomycete cultures, when grown in PDA medium plates (Loqman et al., 2009)....

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  • ...…the exact mechanisms by which these actinomycetes isolates operate to reduce disease incidence is not elucidated, one possibility is that these biocontrol agents exert a direct inhibitory effect on hyphal growth and structure of fungal pathogens (Zakalyukina and Zenova, 2007; Loqman et al., 2009)....

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  • ...More recently, mycelium growth of Pythium ultimum, Fu-sarium oxysporum f. sp. albedinis, Sclerotium rolfsii, Verticillium dahliae and Botrytis cinerea was also inhibited by the streptomycete cultures, when grown in PDA medium plates (Loqman et al., 2009)....

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References
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Journal ArticleDOI
TL;DR: The methods used by collaborators in the ISP for emendation of descriptions of type and neotype strains of the genus Streptomyces (Actinomycetales) are presented.
Abstract: The methods used by collaborators in the International Streptomyces Project (ISP) for emendation of descriptions of type and neotype strains of the genus Streptomyces (Actinomycetales) are presented.

5,184 citations

Book
01 Jan 1985

2,501 citations


"Antagonistic actinomycetes from Mor..." refers methods in this paper

  • ...The purified selected actinomycete isolates were grown for 2 days at 28C with agitation in 500-ml flasks containing 100 ml of Hickey-Tresner medium containing 1 g l -1 yeast extract, 1 g l -1 beef extract, 2 g l -1 NZamine A, 10 g l -1 Dextrin, 20 mg l -1 CoCl2 � 6H2O ( Hopwood et al. 1985 )....

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Journal ArticleDOI
TL;DR: As agricultural production intensified over the past few decades, producers became more and more dependent on agrochemicals as a relatively reliable method of crop production.
Abstract: Pathogenic microorganisms affecting plant health are a major and chronic threat to food production and ecosystem stability worldwide As agricultural production intensified over the past few decades, producers became more and more dependent on agrochemicals as a relatively reliable method of crop

2,246 citations

Journal ArticleDOI
TL;DR: Les actinomycetes sont tres largement distribues dans les ecosystemes terrestres and the ecosystemes aquatiques.
Abstract: Les actinomycetes sont tres largement distribues dans les ecosystemes terrestres et les ecosystemes aquatiques. Ils incluent aussi des zoopathogenes et des phytopathogenes

934 citations


"Antagonistic actinomycetes from Mor..." refers background in this paper

  • ...Actinomycete counts were lower in alkaline soils than in neutral soils supporting the fact that, in general, actinomycetes prefer neutral to alkaline soils as a natural habitat as reported by Goodfellow and Williams (1983). According to data available in the literature, the species composition of actinomycetes in the plant rhizosphere is mainly determined by soil parameters, whereas the abundances of particular species depend largely on the plant (Kalakutskii and Sha-...

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Journal ArticleDOI
TL;DR: This review focuses on bark defenses, a front line against organisms trying to reach the nutrient-rich phloem, and questions about their coevolution with bark beetles are discussed.
Abstract: Conifers are long-lived organisms, and part of their success is due to their potent defense mechanisms. This review focuses on bark defenses, a front line against organisms trying to reach the nutrient-rich phloem. A major breach of the bark can lead to tree death, as evidenced by the millions of trees killed every year by specialized bark-invading insects. Different defense strategies have arisen in conifer lineages, but the general strategy is one of overlapping constitutive mechanical and chemical defenses overlaid with the capacity to up-regulate additional defenses. The defense strategy incorporates a graded response from 'repel', through 'defend' and 'kill', to 'compartmentalize', depending upon the advance of the invading organism. Using a combination of toxic and polymer chemistry, anatomical structures and their placement, and inducible defenses, conifers have evolved bark defense mechanisms that work against a variety of pests. However, these can be overcome by strategies including aggregation pheromones of bark beetles and introduction of virulent phytopathogens. The defense structures and chemicals in conifer bark are reviewed and questions about their coevolution with bark beetles are discussed.

929 citations