Genomic and Metabolomic Investigation of a Rhizosphere Isolate Streptomyces netropsis WLXQSS-4 Associated with a Traditional Chinese Medicine.

Songya Zhang,Lingxiao Zhang,Tao Liu,Jing Zhu,Hong Chen,Zhicong Chen,Tong Si

doi:10.3390/molecules26082147

Abstract

Rhizosphere microorganisms play important ecological roles in promoting herb growth and producing abundant secondary metabolites. Studies on the rhizosphere microbes of traditional Chinese medicines (TCMs) are limited, especially on the genomic and metabolic levels. In this study, we reported the isolation and characterization of a Steptomyces netropsis WLXQSS-4 strain from the rhizospheric soil of Clematis manshurica Rupr. Genomic sequencing revealed an impressive total of 40 predicted biosynthetic gene clusters (BGCs), whereas metabolomic profiling revealed 13 secondary metabolites under current laboratory conditions. Particularly, medium screening activated the production of alloaureothin, whereas brominated and chlorinated pimprinine derivatives were identified through precursor-directed feeding. Moreover, antiproliferative activities against Hela and A549 cancer cell lines were observed for five compounds, of which two also elicited potent growth inhibition in Enterococcus faecalis and Staphylococcus aureus, respectively. Our results demonstrated the robust secondary metabolism of S. netropsis WLXQSS-4, which may serve as a biocontrol agent upon further investigation.

Highlights

The plant-associated microbial communities in the rhizosphere sustain plant growth and health in many manners, including seed germination, nitrogen fixation, stress robustness, and pathogen defense
To exploit bioactive natural products from these communities, we studied the microbial isolates from the rhizosphere of Clematidis Radix et Rhizoma (Clematis manshurica Rupr.) as an original plant used in a traditional Chinese medicines (TCMs)
We focused on a specific Streptomyces isolate, S. netropsis WLXQSS-4, due to its noteworthy bioactivities

Summary

Introduction

The plant-associated microbial communities in the rhizosphere sustain plant growth and health in many manners, including seed germination, nitrogen fixation, stress robustness, and pathogen defense. Actinomycetes constitute a substantial portion of the soil microbial community and exhibited unique characteristics [1]. Actinomycetes maintain close physical contact with soil particles and plants through filaments and sporulation. They produce abundant secondary metabolites with antifungal, insecticidal, and antibacterial activities, which assist plants in fighting pathogens. Alternation of soil microbial communities is an important reason why many cultivated TCMs cannot be cropped continuously [3]. The bioactive secondary metabolites in some TCMs exhibited distinct correlations with plant-associated microbes [4]. We and others recently carried out a series of studies on the microorganisms

Methods

Results

Conclusion