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Isolation, abundance and phylogenetic affiliation of endophytic actinomycetes associated with medicinal plants and screening for their in vitro antimicrobial biosynthetic potential.

Passari AK, Mishra VK, Saikia R, Gupta VK, Singh BP - Front Microbiol (2015)

Bottom Line: Microorganisms associated with medicinal plants are of interest as the producers of important bioactive compounds.Further, antimicrobial properties and antibiotic sensitivity assay in combination with the results of amplification of biosynthetic genes polyketide synthase (PKS-I) and non-ribosomal peptide synthetase (NRPS) showed that the endophytic actinomycetes associated with the selected medicinal plants have broad-spectrum antimicrobial activity.Our results emphasize that endophytic actinomycetes associated with medicinal plants are an unexplored resource for the discovery of biologically active compounds.

View Article: PubMed Central - PubMed

Affiliation: Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Mizoram University Aizawl, India.

ABSTRACT
Microorganisms associated with medicinal plants are of interest as the producers of important bioactive compounds. To date, the diversity of culturable endophytic actinomycetes associated with medicinal plants is in its initial phase of exploration. In this study, 42 endophytic actinomycetes were isolated from different organs of seven selected medicinal plants. The highest number of isolates (n = 22, 52.3%) of actinomycetes was isolated from roots, followed by stems (n = 9, 21.4%), leaves (n = 6, 14.2%), flowers (n = 3, 7.1%), and petioles (n = 2, 4.7%). The genus Streptomyces was the most dominant among the isolates (66.6%) in both the locations (Dampa TRF and Phawngpuii NP, Mizoram, India). From a total of 42 isolates, 22 isolates were selected for further studies based on their ability to inhibit one of the tested human bacterial or fungal pathogen. Selected isolates were identified based on 16S rRNA gene analysis and subsequently the isolates were grouped to four different genera; Streptomyces, Brevibacterium, Microbacterium, and Leifsonia. Antibiotic sensitivity assay was performed to understand the responsible antimicrobials present in the isolates showing the antimicrobial activities and revealed that the isolates were mostly resistant to penicillin G and ampicillin. Further, antimicrobial properties and antibiotic sensitivity assay in combination with the results of amplification of biosynthetic genes polyketide synthase (PKS-I) and non-ribosomal peptide synthetase (NRPS) showed that the endophytic actinomycetes associated with the selected medicinal plants have broad-spectrum antimicrobial activity. This is the first report of the isolation of Brevibacterium sp., Microbacterium sp., and Leifsonia xyli from endophytic environments of medicinal plants, Mirabilis jalapa and Clerodendrum colebrookianum. Our results emphasize that endophytic actinomycetes associated with medicinal plants are an unexplored resource for the discovery of biologically active compounds.

No MeSH data available.


Appearance of actinomycetes like colonies emerging from the organs of the plant after 3 weeks of incubation. Arrows indicated the isolates.
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Figure 2: Appearance of actinomycetes like colonies emerging from the organs of the plant after 3 weeks of incubation. Arrows indicated the isolates.

Mentions: From 560 tissues, 42 presumed endophytic actinomycetes were isolated and were further characterized based on colonial morphology, ability to form aerial hyphae and substrate mycelia. Out of 42 isolates, the majority (n = 22, 52.38%) were isolated from roots followed by stem (n = 9, 21.42%), leaf (n = 6, 14.28%), flower (n = 3, 7.14%), and petiole (n = 2, 4.76%). Thirteen isolates were from starch casein nitrate agar (SCNA) medium, 10 isolates from actinomycetes isolation agar (AIA) medium, 10 from tap water yeast extract agar (TWYE) medium, 6 from glycerol asparagines agar medium (ISP5) and 3 isolates were obtained from malt yeast extract agar medium (ISP2). Most of the isolates showed moderate to slow growth on the media. After 1 month incubation, the colonies of the actinomycetes were observed with white, yellow, orange, brownish white and pale yellow colors (Table 1 and Figure 2). The Field Emission Gun—Scanning electron microscopy (FEG-SEM) result showed that the aerial mycelia produce spiral spore chains (Figure 3). Most of the tissues except flower and petiole in some cases yielded at least one isolate which indicates that endophytic actinomycetes isolates can colonize different tissues throughout the plants.


Isolation, abundance and phylogenetic affiliation of endophytic actinomycetes associated with medicinal plants and screening for their in vitro antimicrobial biosynthetic potential.

Passari AK, Mishra VK, Saikia R, Gupta VK, Singh BP - Front Microbiol (2015)

Appearance of actinomycetes like colonies emerging from the organs of the plant after 3 weeks of incubation. Arrows indicated the isolates.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4388002&req=5

Figure 2: Appearance of actinomycetes like colonies emerging from the organs of the plant after 3 weeks of incubation. Arrows indicated the isolates.
Mentions: From 560 tissues, 42 presumed endophytic actinomycetes were isolated and were further characterized based on colonial morphology, ability to form aerial hyphae and substrate mycelia. Out of 42 isolates, the majority (n = 22, 52.38%) were isolated from roots followed by stem (n = 9, 21.42%), leaf (n = 6, 14.28%), flower (n = 3, 7.14%), and petiole (n = 2, 4.76%). Thirteen isolates were from starch casein nitrate agar (SCNA) medium, 10 isolates from actinomycetes isolation agar (AIA) medium, 10 from tap water yeast extract agar (TWYE) medium, 6 from glycerol asparagines agar medium (ISP5) and 3 isolates were obtained from malt yeast extract agar medium (ISP2). Most of the isolates showed moderate to slow growth on the media. After 1 month incubation, the colonies of the actinomycetes were observed with white, yellow, orange, brownish white and pale yellow colors (Table 1 and Figure 2). The Field Emission Gun—Scanning electron microscopy (FEG-SEM) result showed that the aerial mycelia produce spiral spore chains (Figure 3). Most of the tissues except flower and petiole in some cases yielded at least one isolate which indicates that endophytic actinomycetes isolates can colonize different tissues throughout the plants.

Bottom Line: Microorganisms associated with medicinal plants are of interest as the producers of important bioactive compounds.Further, antimicrobial properties and antibiotic sensitivity assay in combination with the results of amplification of biosynthetic genes polyketide synthase (PKS-I) and non-ribosomal peptide synthetase (NRPS) showed that the endophytic actinomycetes associated with the selected medicinal plants have broad-spectrum antimicrobial activity.Our results emphasize that endophytic actinomycetes associated with medicinal plants are an unexplored resource for the discovery of biologically active compounds.

View Article: PubMed Central - PubMed

Affiliation: Molecular Microbiology and Systematics Laboratory, Department of Biotechnology, Mizoram University Aizawl, India.

ABSTRACT
Microorganisms associated with medicinal plants are of interest as the producers of important bioactive compounds. To date, the diversity of culturable endophytic actinomycetes associated with medicinal plants is in its initial phase of exploration. In this study, 42 endophytic actinomycetes were isolated from different organs of seven selected medicinal plants. The highest number of isolates (n = 22, 52.3%) of actinomycetes was isolated from roots, followed by stems (n = 9, 21.4%), leaves (n = 6, 14.2%), flowers (n = 3, 7.1%), and petioles (n = 2, 4.7%). The genus Streptomyces was the most dominant among the isolates (66.6%) in both the locations (Dampa TRF and Phawngpuii NP, Mizoram, India). From a total of 42 isolates, 22 isolates were selected for further studies based on their ability to inhibit one of the tested human bacterial or fungal pathogen. Selected isolates were identified based on 16S rRNA gene analysis and subsequently the isolates were grouped to four different genera; Streptomyces, Brevibacterium, Microbacterium, and Leifsonia. Antibiotic sensitivity assay was performed to understand the responsible antimicrobials present in the isolates showing the antimicrobial activities and revealed that the isolates were mostly resistant to penicillin G and ampicillin. Further, antimicrobial properties and antibiotic sensitivity assay in combination with the results of amplification of biosynthetic genes polyketide synthase (PKS-I) and non-ribosomal peptide synthetase (NRPS) showed that the endophytic actinomycetes associated with the selected medicinal plants have broad-spectrum antimicrobial activity. This is the first report of the isolation of Brevibacterium sp., Microbacterium sp., and Leifsonia xyli from endophytic environments of medicinal plants, Mirabilis jalapa and Clerodendrum colebrookianum. Our results emphasize that endophytic actinomycetes associated with medicinal plants are an unexplored resource for the discovery of biologically active compounds.

No MeSH data available.