scholarly journals Distribution and conservation of known secondary metabolite biosynthesis gene clusters in the genomes of geographically diverse Microcystis aeruginosa strains

2020 ◽  
Vol 71 (5) ◽  
pp. 701 ◽  
Author(s):  
Leanne A. Pearson ◽  
Nicholas D. Crosbie ◽  
Brett A. Neilan
Keyword(s):  
Gene Cluster ◽  
Secondary Metabolite ◽  
Microcystis Aeruginosa ◽  
Gene Clusters ◽  
Biologically Active ◽  
Biosynthesis Gene Cluster ◽  
Phosphatase Inhibitors ◽  
Biosynthesis Gene ◽  
Screening Study ◽  
Non Ribosomal Peptides

The cyanobacterium Microcystis aeruginosa has been linked to toxic blooms worldwide. In addition to producing hepatotoxic microcystins, many strains are capable of synthesising a variety of biologically active compounds, including protease and phosphatase inhibitors, which may affect aquatic ecosystems and pose a risk to their use. This study explored the distribution, composition and conservation of known secondary metabolite (SM) biosynthesis gene clusters in the genomes of 27 M. aeruginosa strains isolated from six different Köppen–Geiger climates. Our analysis identified gene clusters with significant homology to nine SM biosynthesis gene clusters spanning four different compound classes: non-ribosomal peptides, hybrid polyketide–non-ribosomal peptides, cyanobactins and microviridins. The aeruginosin, microviridin, cyanopeptolin and microcystin biosynthesis gene clusters were the most frequently observed, but hybrid polyketide–non-ribosomal peptide biosynthesis clusters were the most common class overall. Although some biogeographic relationships were observed, taxonomic markers and geography were not reliable indicators of SM biosynthesis cluster distribution, possibly due to previous genetic deletions or horizontal gene transfer events. The only cyanotoxin biosynthesis gene cluster identified in our screening study was the microcystin synthetase (mcy) gene cluster, suggesting that the production of non-microcystin cyanotoxins by this taxon, such as anatoxin-a or paralytic shellfish poison analogues, is either absent or rare.

scholarly journals A Pseudoalteromonas clade with remarkable biosynthetic potential

2021 ◽  
Author(s):  
Rocky Chau ◽  
Leanne A. Pearson ◽  
Jesse Cain ◽  
John A. Kalaitzis ◽  
Brett A. Neilan
Keyword(s):  
Natural Products ◽  
Gene Cluster ◽  
Genome Mining ◽  
Gene Clusters ◽  
Average Density ◽  
Biologically Active ◽  
Biosynthesis Gene Cluster ◽  
Diverse Range ◽  
Siderophore Biosynthesis ◽  
Biosynthesis Gene

Pseudoalteromonas species produce a diverse range of biologically active compounds, including those biosynthesized by non-ribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). Here we report the biochemical and genomic analysis of Pseudoalteromonas sp. HM-SA03, isolated from the blue-ringed octopus, Hapalochalaena sp. Genome mining for secondary metabolite pathways revealed seven putative NRPS/PKS biosynthesis gene clusters, including those for the biosynthesis of alterochromides, pseudoalterobactins, alteramides and four hitherto novel compounds. Among these was a novel siderophore biosynthesis gene cluster with unprecedented architecture (NRPS-PKS-NRPS-PKS-NRPS-PKS-NRPS). Alterochromide production in HM-SA03 was also confirmed by liquid chromatography-mass spectrometry. An investigation of the biosynthetic potential of 42 publicly available Pseudoalteromonas genomes indicated that some of these gene clusters are distributed throughout the genus. Through phylogenetic analysis, a particular subset of strains formed a clade with extraordinary biosynthetic potential, with an average density of ten biosynthesis gene clusters per genome. In contrast, the majority of Pseudoalteromonas strains outside this clade contained an average of three clusters encoding complex biosynthesis. These results highlight the under-explored potential of Pseudoalteromonas as a source of new natural products. Importance This study demonstrates that the Pseudoalteromonas strain, HM-SA03, isolated from the venomous blue-ringed octopus, Hapalochalaena sp., is a biosynthetically talented organism, capable of producing alterochromides and potentially six other specialized metabolites. We have identified a pseudoalterobactin biosynthesis gene cluster and proposed a pathway for the production of the associated siderophore. A novel siderophore biosynthesis gene cluster with unprecedented architecture was also identified in the HM-SA03 genome. Finally, we have demonstrated that HM-SA03 belongs to a phylogenetic clade of strains with extraordinary biosynthetic potential. While our results do not support a role of HM-SA03 in Hapalochalaena sp. venom (tetrodotoxin) production, they emphasize the untapped potential of Pseudoalteromonas as a source of novel natural products.

scholarly journals Identification of a Polyketide Synthase Gene Responsible for Ascochitine Biosynthesis in Ascochyta fabae and Its Abrogation in Sister Taxa

mSphere ◽  
2019 ◽  
Vol 4 (5) ◽  
Author(s):  
Wonyong Kim ◽  
Judith Lichtenzveig ◽  
Robert A. Syme ◽  
Angela H. Williams ◽  
Tobin L. Peever ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Secondary Metabolite ◽  
Polyketide Synthase ◽  
Animal Health ◽  
Gene Clusters ◽  
Biosynthesis Gene Cluster ◽  
Content Type ◽  
Pathogenicity Factor ◽  
Biosynthesis Gene ◽  
Ascochyta Fabae

ABSTRACT The polyketide-derived secondary metabolite ascochitine is produced by species in the Didymellaceae family, including but not restricted to Ascochyta species pathogens of cool-season food legumes. Ascochitine is structurally similar to the well-known mycotoxin citrinin and exhibits broad-spectrum phytotoxicity and antimicrobial activities. Here, we identified a polyketide synthase (PKS) gene (denoted pksAC) responsible for ascochitine production in the filamentous fungus Ascochyta fabae. Deletion of the pksAC prevented production of ascochitine and its derivative ascochital in A. fabae. The putative ascochitine biosynthesis gene cluster comprises 11 genes that have undergone rearrangement and gain-and-loss events relative to the citrinin biosynthesis gene cluster in Monascus ruber. Interestingly, we also identified pksAC homologs in two recently diverged species, A. lentis and A. lentis var. lathyri, that are sister taxa closely related to ascochitine producers such as A. fabae and A. viciae-villosae. However, nonsense mutations have been independently introduced in coding sequences of the pksAC homologs of A. lentis and A. lentis var. lathyri that resulted in loss of ascochitine production. Despite its reported phytotoxicity, ascochitine was not a pathogenicity factor in A. fabae infection and colonization of faba bean (Vicia faba L.). Ascochitine was mainly produced from mature hyphae at the site of pycnidial formation, suggesting a possible protective role of the compound against other microbial competitors in nature. This report highlights the evolution of gene clusters harnessing the structural diversity of polyketides and a mechanism with the potential to alter secondary metabolite profiles via single nucleotide polymorphisms in closely related fungal species. IMPORTANCE Fungi produce a diverse array of secondary metabolites, many of which are of pharmacological importance whereas many others are noted for mycotoxins, such as aflatoxin and citrinin, that can threaten human and animal health. The polyketide-derived compound ascochitine, which is structurally similar to citrinin mycotoxin, has been considered to be important for pathogenicity of legume-associated Ascochyta species. Here, we identified the ascochitine polyketide synthase (PKS) gene in Ascochyta fabae and its neighboring genes that may be involved in ascochitine biosynthesis. Interestingly, the ascochitine PKS genes in other legume-associated Ascochyta species have been mutated, encoding truncated PKSs. This indicated that point mutations may have contributed to genetic diversity for secondary metabolite production in these fungi. We also demonstrated that ascochitine is not a pathogenicity factor in A. fabae. The antifungal activities and production of ascochitine during sporulation suggested that it may play a role in competition with other saprobic fungi in nature.

Fur from Microcystis aeruginosa binds in vitro promoter regions of the microcystin biosynthesis gene cluster

2006 ◽  
Vol 67 (9) ◽  
pp. 876-881 ◽  
Author(s):  
Beatriz Martin-Luna ◽  
Emma Sevilla ◽  
José A. Hernandez ◽  
M. Teresa Bes ◽  
Maria F. Fillat ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Microcystis Aeruginosa ◽  
Promoter Regions ◽  
Biosynthesis Gene Cluster ◽  
Biosynthesis Gene

scholarly journals Activation of a Silent Fungal Polyketide Biosynthesis Pathway through Regulatory Cross Talk with a Cryptic Nonribosomal Peptide Synthetase Gene Cluster

2010 ◽  
Vol 76 (24) ◽  
pp. 8143-8149 ◽  
Author(s):  
Sebastian Bergmann ◽  
Alexander N. Funk ◽  
Kirstin Scherlach ◽  
Volker Schroeckh ◽  
Ekaterina Shelest ◽  
...  
Keyword(s):  
Natural Products ◽  
Gene Cluster ◽  
Secondary Metabolite ◽  
Cross Talk ◽  
Regulatory Gene ◽  
Gene Clusters ◽  
Nonribosomal Peptide Synthetase ◽  
Nonribosomal Peptide ◽  
Peptide Synthetase ◽  
Biosynthesis Gene

ABSTRACT Filamentous fungi produce numerous natural products that constitute a consistent source of potential drug leads, yet it seems that the majority of natural products are overlooked since most biosynthesis gene clusters are silent under standard cultivation conditions. Screening secondary metabolite genes of the model fungus Aspergillus nidulans, we noted a silent gene cluster on chromosome II comprising two nonribosomal peptide synthetase (NRPS) genes, inpA and inpB, flanked by a regulatory gene that we named scpR for secondary metabolism cross-pathway regulator. The induced expression of the scpR gene using the promoter of the alcohol dehydrogenase AlcA led to the transcriptional activation of both the endogenous scpR gene and the NRPS genes. Surprisingly, metabolic profiling of the supernatant of mycelia overexpressing scpR revealed the production of the polyketide asperfuranone. Through transcriptome analysis we found that another silent secondary metabolite gene cluster located on chromosome VIII coding for asperfuranone biosynthesis was specifically induced. Quantitative reverse transcription-PCR proved the transcription not only of the corresponding polyketide synthase (PKS) biosynthesis genes, afoE and afoG, but also of their activator, afoA, under alcAp-scpR-inducing conditions. To exclude the possibility that the product of the inp cluster induced the asperfuranone gene cluster, a strain carrying a deletion of the NRPS gene inpB and, in addition, the alcAp-scpR overexpression cassette was generated. In this strain, under inducing conditions, transcripts of the biosynthesis genes of both the NRPS-containing gene cluster inp and the asperfuranone gene cluster except gene inpB were detected. Moreover, the existence of the polyketide product asperfuranone indicates that the transcription factor ScpR controls the expression of the asperfuranone biosynthesis gene cluster. This expression as well as the biosynthesis of asperfuranone was abolished after the deletion of the asperfuranone activator gene afoA, indicating that ScpR binds to the afoA promoter. To the best of our knowledge, this is the first report of regulatory cross talk between two biosynthesis gene clusters located on different chromosomes.

scholarly journals The Swinholide Biosynthesis Gene Cluster from a Terrestrial Cyanobacterium, Nostoc sp. Strain UHCC 0450

2017 ◽  
Vol 84 (3) ◽  
Author(s):  
Anu Humisto ◽  
Jouni Jokela ◽  
Liwei Liu ◽  
Matti Wahlsten ◽  
Hao Wang ◽  
...  
Keyword(s):  
Natural Products ◽  
Actin Cytoskeleton ◽  
Gene Cluster ◽  
Marine Sponge ◽  
Gene Clusters ◽  
Fold Axis ◽  
Biosynthesis Gene Cluster ◽  
Content Type ◽  
Biosynthesis Gene ◽  
Axis Of Symmetry

ABSTRACT Swinholides are 42-carbon ring polyketides with a 2-fold axis of symmetry. They are potent cytotoxins that disrupt the actin cytoskeleton. Swinholides were discovered from the marine sponge Theonella sp. and were long suspected to be produced by symbiotic bacteria. Misakinolide, a structural variant of swinholide, was recently demonstrated to be the product of a symbiotic heterotrophic proteobacterium. Here, we report the production of swinholide A by an axenic strain of the terrestrial cyanobacterium Nostoc sp. strain UHCC 0450. We located the 85-kb trans -AT polyketide synthase (PKS) swinholide biosynthesis gene cluster from a draft genome of Nostoc sp. UHCC 0450. The swinholide and misakinolide biosynthesis gene clusters share an almost identical order of catalytic domains, with 85% nucleotide sequence identity, and they group together in phylogenetic analysis. Our results resolve speculation around the true producer of swinholides and demonstrate that bacteria belonging to two distantly related phyla both produce structural variants of the same natural product. In addition, we described a biosynthesis cluster from Anabaena sp. strain UHCC 0451 for the synthesis of the cytotoxic and antifungal scytophycin. All of these biosynthesis gene clusters were closely related to each other and created a group of cytotoxic macrolide compounds produced by trans -AT PKSs of cyanobacteria and proteobacteria. IMPORTANCE Many of the drugs in use today originate from natural products. New candidate compounds for drug development are needed due to increased drug resistance. An increased knowledge of the biosynthesis of bioactive compounds can be used to aid chemical synthesis to produce novel drugs. Here, we show that a terrestrial axenic culture of Nostoc cyanobacterium produces swinholides, which have been previously found only from marine sponge or samples related to them. Swinholides are polyketides with a 2-fold axis of symmetry, and they are potent cytotoxins that disrupt the actin cytoskeleton. We describe the biosynthesis gene clusters of swinholide from Nostoc cyanobacteria, as well as the related cytotoxic and antifungal scytophycin from Anabaena cyanobacteria, and we study the evolution of their trans -AT polyketide synthases. Interestingly, swinholide is closely related to misakinolide produced by a symbiotic heterotrophic proteobacterium, demonstrating that bacteria belonging to two distantly related phyla and different habitats can produce similar natural products.

A hypothesis to explain how LaeA specifically regulates certain secondary metabolite biosynthesis gene clusters

2011 ◽  
Vol 4 (1) ◽  
pp. 53-58 ◽  
Author(s):  
K. Ehrlich ◽  
B. Mack ◽  
J. Cary ◽  
D. Bhatnagar ◽  
S. Kale
Keyword(s):  
Dna Binding ◽  
Gene Cluster ◽  
Secondary Metabolite ◽  
Filamentous Fungi ◽  
Gene Clusters ◽  
Dna Binding Protein ◽  
Global Regulator ◽  
Biosynthesis Gene ◽  
Secondary Metabolite Biosynthesis ◽  
Specific Control

Biosynthesis of mycotoxins involves transcriptional co-regulation of sets of clustered genes. We hypothesise that specific control of transcription of genes in these clusters by LaeA, a global regulator of secondary metabolite production and development in many filamentous fungi, results from its interaction with a Cys6Zn2 DNA-binding protein unique to the gene cluster.

Identification of the kinanthraquinone biosynthetic gene cluster by expression of an atypical response regulator

2021 ◽  
Vol 85 (3) ◽  
pp. 714-721
Author(s):  
Risa Takao ◽  
Katsuyuki Sakai ◽  
Hiroyuki Koshino ◽  
Hiroyuki Osada ◽  
Shunji Takahashi
Keyword(s):  
Heterologous Expression ◽  
Gene Cluster ◽  
Secondary Metabolite ◽  
Response Regulator ◽  
Bac Library ◽  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Gene Organization ◽  
Biosynthetic Gene ◽  
Streptomyces Sp

ABSTRACT Recent advances in genome sequencing have revealed a variety of secondary metabolite biosynthetic gene clusters in actinomycetes. Understanding the biosynthetic mechanism controlling secondary metabolite production is important for utilizing these gene clusters. In this study, we focused on the kinanthraquinone biosynthetic gene cluster, which has not been identified yet in Streptomyces sp. SN-593. Based on chemical structure, 5 type II polyketide synthase gene clusters were listed from the genome sequence of Streptomyces sp. SN-593. Among them, a candidate gene cluster was selected by comparing the gene organization with grincamycin, which is synthesized through an intermediate similar to kinanthraquinone. We initially utilized a BAC library for subcloning the kiq gene cluster, performed heterologous expression in Streptomyces lividans TK23, and identified the production of kinanthraquinone and kinanthraquinone B. We also found that heterologous expression of kiqA, which belongs to the DNA-binding response regulator OmpR family, dramatically enhanced the production of kinanthraquinones.

Sign in / Sign up

Export Citation Format

Share Document