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Dow L, Gallart M, Ramarajan M, Law SR, Thatcher LF. Streptomyces and their specialised metabolites for phytopathogen control - comparative in vitro and in planta metabolic approaches. FRONTIERS IN PLANT SCIENCE 2023; 14:1151912. [PMID: 37389291 PMCID: PMC10301723 DOI: 10.3389/fpls.2023.1151912] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 05/30/2023] [Indexed: 07/01/2023]
Abstract
In the search for new crop protection microbial biocontrol agents, isolates from the genus Streptomyces are commonly found with promising attributes. Streptomyces are natural soil dwellers and have evolved as plant symbionts producing specialised metabolites with antibiotic and antifungal activities. Streptomyces biocontrol strains can effectively suppress plant pathogens via direct antimicrobial activity, but also induce plant resistance through indirect biosynthetic pathways. The investigation of factors stimulating the production and release of Streptomyces bioactive compounds is commonly conducted in vitro, between Streptomyces sp. and a plant pathogen. However, recent research is starting to shed light on the behaviour of these biocontrol agents in planta, where the biotic and abiotic conditions share little similarity to those of controlled laboratory conditions. With a focus on specialised metabolites, this review details (i) the various methods by which Streptomyces biocontrol agents employ specialised metabolites as an additional line of defence against plant pathogens, (ii) the signals shared in the tripartite system of plant, pathogen and biocontrol agent, and (iii) an outlook on new approaches to expedite the identification and ecological understanding of these metabolites under a crop protection lens.
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Affiliation(s)
- Lachlan Dow
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Acton, ACT, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Microbiomes for One Systems Health Future Science Platform, Acton, ACT, Australia
| | - Marta Gallart
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Acton, ACT, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Advanced Engineering Biology Future Science Platform, Acton, ACT, Australia
| | - Margaret Ramarajan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Acton, ACT, Australia
| | - Simon R. Law
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Acton, ACT, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Microbiomes for One Systems Health Future Science Platform, Acton, ACT, Australia
| | - Louise F. Thatcher
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Acton, ACT, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Microbiomes for One Systems Health Future Science Platform, Acton, ACT, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Advanced Engineering Biology Future Science Platform, Acton, ACT, Australia
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Liao Z, Song Z, Xu J, Ma Z, Bechthold A, Yu X. Identification of a gene from Streptomyces rimosus M527 negatively affecting rimocidin biosynthesis and morphological differentiation. Appl Microbiol Biotechnol 2020; 104:10191-10202. [PMID: 33057790 DOI: 10.1007/s00253-020-10955-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/01/2020] [Accepted: 10/07/2020] [Indexed: 12/17/2022]
Abstract
The polyene macrolide rimocidin, produced by Streptomyces rimosus M527, was found to be highly effective against a broad range of fungal plant pathogens. Current understanding of the regulatory mechanism of rimocidin biosynthesis and morphological differentiation in S. rimosus M527 is limited. NsdA is considered a negative regulator involved in morphological differentiation and biosynthesis of secondary metabolites in some Streptomyces species. In this study, nsdAsr was cloned from S. rimosus M527. The role of nsdAsr in rimocidin biosynthesis and morphological differentiation was investigated by gene deletion, complementation, and over-expression. A ΔnsdAsr mutant was obtained using CRISPR/Cas9. The mutant produced more rimocidin (46%) and accelerated morphological differentiation than the wild-type strain. Over-expression of nsdAsr led to a decrease in rimocidin production and impairment of morphological differentiation. Quantitative RT-PCR analysis revealed that transcription of rim genes responsible for rimocidin biosynthesis was upregulated in the ΔnsdAsr mutant but downregulated in the nsdAsr over-expression strain. Similar effects have been described for Streptomyces coelicolor M145 and the industrial toyocamycin-producing strain Streptomyces diastatochromogenes 1628. KEY POINTS: • A negative regulator for sporulation and rimocidin production was identified. • The CRISPR/Cas9 system was used for gene deletion in S. rimosus M527.
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Affiliation(s)
- Zhijun Liao
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, China
| | - Zhangqing Song
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, China
| | - Jie Xu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, China
| | - Zheng Ma
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, China.
| | - Andreas Bechthold
- Institute for Pharmaceutical Sciences, Pharmaceutical Biology and Biotechnology, University of Freiburg, 79104, Freiburg, Germany
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, China.
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Song Z, Ma Z, Bechthold A, Yu X. Effects of addition of elicitors on rimocidin biosynthesis in Streptomyces rimosus M527. Appl Microbiol Biotechnol 2020; 104:4445-4455. [PMID: 32221690 DOI: 10.1007/s00253-020-10565-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/10/2020] [Accepted: 03/20/2020] [Indexed: 01/25/2023]
Abstract
The polyene macrolide rimocidin, produced by Streptomyces rimosus M527, is highly effective against a broad range of fungal plant pathogens, but at low yields. Elicitation is an effective method of stimulating the yield of bioactive secondary metabolites. In this study, the biomass and filtrate of a culture broth of Escherichia coli JM109, Bacillus subtilis WB600, Saccharomyces cerevisiae, and Fusarium oxysporum f. sp. cucumerinum were employed as elicitors to promote rimocidin production in S. rimosus M527. Adding culture broth and biomass of S. cerevisiae (A3) and F. oxysporum f. sp. cucumerinum (B4) resulted in an increase of rimocidin production by 51.2% and 68.3% respectively compared with the production under normal conditions in 5-l fermentor. In addition, quantitative RT-PCR analysis revealed that the transcriptions of ten genes (rimA to rimK) located in the gene cluster involved in rimocidin biosynthesis in A3 or B4 elicitation experimental group were all higher than those of a control group. Using a β-glucuronidase (GUS) reporter system, GUS enzyme activity assay, and Western blot analysis, we discovered that elicitation of A3 or B4 increased protein synthesis in S. rimosus M527. These results demonstrate that the addition of elicitors is a useful approach to improve rimocidin production.Key Points • An effective strategy for enhancing rimocidin production in S. rimosus M527 is demonstrated. • Overproduction of rimocidin is a result of higher expressed structural genes followed by an increase in protein synthesis.
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Affiliation(s)
- Zhangqing Song
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, People's Republic of China
| | - Zheng Ma
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, People's Republic of China.
| | - Andreas Bechthold
- Institute for Pharmaceutical Sciences, Pharmaceutical Biology and Biotechnology, University of Freiburg, 79104, Freiburg, Germany
| | - Xiaoping Yu
- Zhejiang Provincial Key Laboratory of Biometrology and Inspection & Quarantine, College of Life Sciences, China Jiliang University, Xueyuan Street, Xiasha Higher Education District, Hangzhou, 310018, Zhejiang Province, People's Republic of China
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Streptomyces Differentiation in Liquid Cultures as a Trigger of Secondary Metabolism. Antibiotics (Basel) 2018; 7:antibiotics7020041. [PMID: 29757948 PMCID: PMC6022995 DOI: 10.3390/antibiotics7020041] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 02/08/2023] Open
Abstract
Streptomyces is a diverse group of gram-positive microorganisms characterised by a complex developmental cycle. Streptomycetes produce a number of antibiotics and other bioactive compounds used in the clinic. Most screening campaigns looking for new bioactive molecules from actinomycetes have been performed empirically, e.g., without considering whether the bacteria are growing under the best developmental conditions for secondary metabolite production. These screening campaigns were extremely productive and discovered a number of new bioactive compounds during the so-called “golden age of antibiotics” (until the 1980s). However, at present, there is a worrying bottleneck in drug discovery, and new experimental approaches are needed to improve the screening of natural actinomycetes. Streptomycetes are still the most important natural source of antibiotics and other bioactive compounds. They harbour many cryptic secondary metabolite pathways not expressed under classical laboratory cultures. Here, we review the new strategies that are being explored to overcome current challenges in drug discovery. In particular, we focus on those aimed at improving the differentiation of the antibiotic-producing mycelium stage in the laboratory.
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