Lobophorin Producing Endophytic Streptomyces olivaceus JB1 Associated With Maesa japonica (Thunb.) Moritzi & Zoll.

Abstract

In this study, we focused on endophytes of Maesa japonica (Thunb.) Moritzi & Zoll. and the plant-microbe interaction at metabolite levels. We isolated seven endophytes associated with M. japonica (JB1−7), and focused on Streptomyces olivaceus JB1 because of antibacterial activities of its secondary metabolites. We confirmed lobophorin analogs production from the bacterial strain JB1 by using spectroscopic techniques such as NMR, UV, and LC/Q-TOF-MS. In the LC/MS system, thirteen reported lobophorin analogs and twelve unreported analogs were detected. Among metabolites, lobophorin A was clearly detected in the dried foliar residues of M. japonica which implies that JB1 resides in the host and accumulates its secondary metabolites likely interacting with the plant. Antimicrobial activity tests of the secondary metabolites against undesirable contaminants isolated from the external surface of M. japonica supported the host and microbe mutualistic relationship. In the meantime, lobophorin producing Streptomyces spp. were isolated from marine environments such as marine sediments, algae, corals, and sponges. As lobophorin producing Streptomyces is isolated commonly from marine environments, we conducted a saline water stress tolerance test with JB1 showing saline medium does not accelerate the growth of the bacterium.

Genomic and Metabolomic Analyses of Nocardiopsis maritima YSL2 as the Mycorrhizosphere Bacterium of Suaeda maritima (L.) Dumort

“…Bacteria adapted to high-salinity or acidic environments are prevalent among various halophyte symbionts, where they play crucial roles. , These bacteria attach to the roots or stems of halophytes, either absorbing salt and nutrients or regulating salt concentration, consequently extending the lifespan of the halophytes. In our study of the interaction between endophytes and plants, we isolated a total of nine bacterial strains from the episphere of Suaeda maritima . − Among them, YSL2 exhibited the highest antimicrobial activity on agar plates. Furthermore, 16S rRNA analysis of the nine isolated bacteria (YSL1–9) revealed that bacterial strain YSL2 exhibited the highest novelty, sharing 99.5% identity with the closest known species, N .…”

Unlocking the potential of bacterial endophytes from medicinal plants for drug discovery

“…One of the two congeners of hydroxamate siderophores aculeolamides identified in this study was active against Mycobacterium tuberculosis and Plasmodium falciparum but had only negligible cytotoxicity. Um et al (2022) recently described the isolation of several congeners of the spirotetronate macrolide lobophorin from Streptomyces olivaceus JB1, an endophytic actinomycete bacterium from Maesa japonica (broad flat-rock tree). In this case, lobophorins could also be detected in the extracts from the dried leaves of the plant, suggesting that S. olivaceus JB1 could be responsible for the production of these compounds in planta.…”