Diversity and bioprospecting of actinomycete endophytes from the medicinal plants

Abstract

Significance and Impact of the Study: "Endophytes" -the microbes residing in the living tissues of plants are virtually omnipresent. Actinomycete endophytes are diverse in distribution within plant tissues, especially in the roots as they have a close association with the rhizhosphere. An introspection into diversity studies necessitates careful sampling, analysis, and isolation data from the biodiverse and nonbiodiverse regions represented by unique environments. The key to the recovery of novel species and their bioprospection lies in these regions.Keywords biodiversity "hotspots", bioprospecting, biosynthetic potentials, diversity, endophytic actinomycetes, novel taxa. AbstractThe endophytic actinomycetes constitute one of the fascinating group of microorganisms associated with a wide range of plant species. The diversity of actinomycetes in plants and their tissue parts is a matter of debate as no consensus are derived between individual studies. Nevertheless, their diversity correlates with the occurrence in plant species harboured in unique regions of biologically diverse areas called "hot spots." Recent advances in the isolation techniques have facilitated the isolation of rare taxa from these environments. The biosynthetic ability of the endophytic actinomycetes has proven beyond doubt that these organisms have the potential to synthesize an array of compounds with novelty in structure and bioactivity and as a result are preferred in the natural product screening programs. In the years to come, the scientific world may await to discover many more novel actinomycete taxa with metabolic diversity and applications in therapeutics.

DISTRIBUTION AND ANTIMICROBIAL ACTIVITY OF ENDOPHYTIC ACTINOMYCETES ISOLATED FROM Litsea cubeba (Lour.) Pers. IN NORTHERN PROVINCES OF VIETNAM

“…The highest number of isolated strains obtained from roots (n = 65, 45.5 %), followed by stems (n = 41, 28.7 %) and leaves (n = 37, 25.9 %) ( Figure 2a). This result was similar to recent studies showing that the number of actinomycetes isolated from roots was regularly higher than that from stems and leaves [11,12,13]. Studies on diversity of actinobacteria residing in medicinal plants based on morphology and amino acid composition of the whole-cell extract the percentage of endophytic actinobacteria recovered from different explants, Taechowisan et al, 2003 [14] found 64.2 % isolates from roots, 29.4 % from leaves, and 6.4 % from stems of 36 different plant species.…”

“…As showed in Figure 1, a wide variety of colony morphologies and mycelium colours was observed in all endophytic actinomycetes. Numerous studies indicated that species distribution and biological diversity of endophytic actinobacteria of medicinal plants are extensively influenced by isolation methods, plant species and sampling geographical area [11]. Gangwar et al, 2014 [12] successful isolated 40 actinomycetes strains from roots, stems, and leaves of Aloe vera, Mentha sp.…”

“…The endophytic actinobacteria are populations derived from the rhizosphere soil bacteria. They tend to grow near water and nutriments transport vessels in plant (roots and stems) which facilitate their nutrients absorbability and metabolism [11]. In addition, high essential oil content in leaves could be negative effect on microorganism life, for example essential oil in L. cubeba accounts for about 1.2 -2.4 % of total weight [5,15].…”

Streptomyces from traditional medicine: sources of new innovations in antibiotic discovery

“…Since then, many Streptomyces have been isolated from traditional plant medicines, especially in areas of low nutrient availability or extreme physiological conditions [27,28]. These Streptomyces can exist as endophytes that live at least a part of their life cycle inside plant tissues without causing damage, or epiphytes that live on the outside of the plants [29,30]. Proteobacteria and Actinobacteria have been reported as the most frequent endophytic species [31].…”

Draft Genome Sequence of Streptomyces sp. XY006, an Endophyte Isolated from Tea ( Camellia sinensis )

“…Endophytic bacteria, especially those belonging to the actinomycetes group, are an important yet underdeveloped microbial resource for novel natural products ( 1 – 4 ). As part of a larger research project aimed at discovering new biologically active compounds from endophytic actinomycetes, we isolated Streptomyces sp.…”