Exploration and Morphological Characterization of Non-pathogenic Streptomyces sp. from Mangrove Rhizosphere Ecosystem
TL;DR
The mangrove rhizosphere provides a promising and morphologically diverse source of non-pathogenic Streptomyces isolates and provides preliminary information as a basis for selecting isolates for further biological control studies.
Abstract
Background: Streptomyces spp. are well known for their ability to produce antibiotic compounds with potential applications in plant disease management, but research in mangrove ecosystems tends to be limited. This study aims to explore and characterize Streptomyces isolates from the mangrove rhizosphere based on morphological characteristics and pathogenicity properties to find candidates as biocontrol agents. Methods: Morphological characterization was carried out macroscopically and microscopically, while hypersensitivity tests and soft rot tests were carried out to determine non-pathogenic properties. Results: A total of 24 isolates of Streptomyces sp. were successfully isolated with the morphological characteristics of circular colonies, filamentous and curved colony edges, convex, flat, raised, and umbonate colony elevations, aerial mycelial pigmentation with six color variations, and substrate mycelial pigmentation with six color variations. Microscopically, two types of spore chains were obtained, namely open spiral and closed spiral. All isolates were nonpathogenic based on the negative results of the hypersensitivity test and soft rot test. Conclusion: The mangrove rhizosphere provides a promising and morphologically diverse source of non-pathogenic Streptomyces isolates. Identification in this study was limited to morphological characterization; therefore, molecular analysis is needed to confirm the isolate species. These findings provide preliminary information as a basis for selecting isolates for further biological control studies.