Studies on the ecology of actinomycetes in soil IV. Observations on the form and growth of streptomycetes in soil

Mayfield, C. I.; Williams, Stanley T.; Ruddick, S.M.; Hatfield, H.L.

doi:10.1016/0038-0717(72)90045-4

Cited by 95 publications

(57 citation statements)

References 25 publications

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“…Most of the Actinobacteria (the streptomycetes in particular) are saprophytic, soil-dwelling organisms that spend the majority of their life cycles as semidormant spores, especially under nutrientlimited conditions (6). However, the phylum has adapted to a wide range of ecological environments: actinomycetes are also present in soils, fresh and salt water, and the air.…”

Section: Biology Of Actinobacteriamentioning

confidence: 99%

Taxonomy, Physiology, and Natural Products of Actinobacteria

Barka

Vatsa

Sanchez

et al. 2016

Microbiol Mol Biol Rev

1,534

1,048

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SUMMARYActinobacteriaare Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla, and they are ubiquitously distributed in both aquatic and terrestrial ecosystems. ManyActinobacteriahave a mycelial lifestyle and undergo complex morphological differentiation. They also have an extensive secondary metabolism and produce about two-thirds of all naturally derived antibiotics in current clinical use, as well as many anticancer, anthelmintic, and antifungal compounds. Consequently, these bacteria are of major importance for biotechnology, medicine, and agriculture.Actinobacteriaplay diverse roles in their associations with various higher organisms, since their members have adopted different lifestyles, and the phylum includes pathogens (notably, species ofCorynebacterium,Mycobacterium,Nocardia,Propionibacterium, andTropheryma), soil inhabitants (e.g.,MicromonosporaandStreptomycesspecies), plant commensals (e.g.,Frankiaspp.), and gastrointestinal commensals (Bifidobacteriumspp.).Actinobacteriaalso play an important role as symbionts and as pathogens in plant-associated microbial communities. This review presents an update on the biology of this important bacterial phylum.

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Section: Biology Of Actinobacteriamentioning

confidence: 99%

Taxonomy, Physiology, and Natural Products of Actinobacteria

Barka

Vatsa

Sanchez

et al. 2016

Microbiol Mol Biol Rev

1,534

1,048

View full text Add to dashboard Cite

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“…Ecologically, actinobacteria and, particularly, the Streptomyces spp. are generally saprophytic, soil-dwelling organisms that spend the majority of their life cycles as semidormant spores (27). It has also been demonstrated that actinobacteria inhabit the rhizosphere of many plant species, including cereal crops such as wheat (13,15,30,37).…”

mentioning

confidence: 99%

Isolation and Identification of Actinobacteria from Surface-Sterilized Wheat Roots

Coombs

Franco

2003

Appl Environ Microbiol

506

343

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This is the first report of filamentous actinobacteria isolated from surface-sterilized root tissues of healthy wheat plants (Triticum aestivum L.). Wheat roots from a range of sites across South Australia were used as the source material for the isolation of the endophytic actinobacteria. Roots were surface-sterilized by using ethanol and sodium hypochlorite prior to the isolation of the actinobacteria. Forty-nine of these isolates were identified by using 16S ribosomal DNA (rDNA) sequencing and found to belong to a small group of actinobacterial genera including Streptomyces, Microbispora, Micromonospora, and Nocardiodes spp. Many of the Streptomyces spp. were found to be similar, on the basis of their 16S rDNA gene sequence, to Streptomyces spp. that had been isolated from potato scabs. In particular, several isolates exhibited high 16S rDNA gene sequence homology to Streptomyces caviscabies and S. setonii. None of these isolates, nor the S. caviscabies and S. setonii type strains, were found to carry the nec1 pathogenicity-associated gene or to produce the toxin thaxtomin, indicating that they were nonpathogenic. These isolates were recovered from healthy plants over a range of geographically and temporally isolated sampling events and constitute an important plant-microbe interaction.The actinobacteria have been well characterized in the literature due to their economic importance as producers of two-thirds of the microbially derived antibiotics known today (6, 23). The actinobacteria are characterized by their grampositive nature and high guanine-plus-cytosine (GϩC) content in their genomes. Ecologically, actinobacteria and, particularly, the Streptomyces spp. are generally saprophytic, soil-dwelling organisms that spend the majority of their life cycles as semidormant spores (27). It has also been demonstrated that actinobacteria inhabit the rhizosphere of many plant species, including cereal crops such as wheat (13,15,30,37).Some actinobacteria are also known to form more intimate associations with plants and colonize their internal tissues. Within the order Actinomycetales there are examples of both endophytic and plant-pathogenic species. The best-characterized examples of the plant-pathogenic actinobacteria are the potato scab-causing Streptomyces scabies, S. acidiscabies, and S. turgidiscabies. Pathogenicity has been associated with the presence of a conserved and transmissible pathogenicity island (PAI) in their genomes (9, 21). This PAI encodes for the biosynthesis of a phytotoxin, thaxtomin, and also contains plant virulence factor genes such as nec1 (8,22,26). Actinorhizae (Frankia spp.) have been extensively researched as an endophytic association between a plant and an actinobacterium (for reviews, see references 3, 4, and 5). However, examples of actinobacteria other than Frankia inhabiting the root tissues of healthy plants as endophytes are rare. Sardi et al. (35) reported the presence of actinobacteria in root samples of crops and Italian native plants, with the majority of the isolates be...

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“…Observa-se, também, que as variações das relações esporos/hifas entre os solos não-rizosférico e rizosférico não são significativas. Tal comportamento é semelhante ao observado anteriormente, no solo não cultivado (coberto com Brachiaria decumbens), e confirma observações anteriores de que a população de actinomicetos ocorre nos solos, principalmente na forma de esporos (Mayfield et al, 1972;Pereira, 1995), sendo responsáveis pela maioria das unidades formadoras de colônias em meio de cultura (Pereira, 1995).…”

Section: Solo De São Carlosunclassified

Efeito do cultivo da soja na dinâmica da população bacteriana, em solos de cerrado

Pereira

Neves

Gava

2000

Pesq. agropec. bras.

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Este trabalho teve por objetivo avaliar a influência do cultivo da soja sobre a dinâmica da população bacteriana, em dois solos de Cerrado do Estado de São Paulo, originalmente cobertos com Paspalum notatum (em Barretos) e Brachiaria decumbens (em São Carlos). Nesses solos, a densidade da população de bactérias em geral variou de 398,1 x 10³ a 467,7 x 10³ e de 123 x 10³ a 218,8 x 10³ ufc (unidades formadoras de colônias)/g de solo seco, respectivamente. O cultivo da soja, em ambos os solos, resultou em incrementos variados nos números de ufc/g de solo seco da população de bactérias em geral, das resistentes aos antibióticos estreptomicina e cloranfenicol, e de actinomicetos. A população de actinomicetos ocorreu no solo principalmente como esporos, e as variações das relações esporos/hifas entre os solos não-rizosférico e rizosférico não foram significativas. Os resultados evidenciam que o cultivo da soja influenciou de forma diferenciada a população desses solos.

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Studies on the ecology of actinomycetes in soil IV. Observations on the form and growth of streptomycetes in soil

Cited by 95 publications

References 25 publications

Taxonomy, Physiology, and Natural Products of Actinobacteria

Taxonomy, Physiology, and Natural Products of Actinobacteria

Isolation and Identification of Actinobacteria from Surface-Sterilized Wheat Roots

Efeito do cultivo da soja na dinâmica da população bacteriana, em solos de cerrado

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