scholarly journals Targeted induction of a silent fungal gene cluster encoding the bacteria-specific germination inhibitor fumigermin

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Maria Cristina Stroe ◽  
Tina Netzker ◽  
Kirstin Scherlach ◽  
Thomas Krüger ◽  
Christian Hertweck ◽  
...  

Microorganisms produce numerous secondary metabolites (SMs) with various biological activities. Many of their encoding gene clusters are silent under standard laboratory conditions because for their activation they need the ecological context, such as the presence of other microorganisms. The true ecological function of most SMs remains obscure, but understanding of both the activation of silent gene clusters and the ecological function of the produced compounds is of importance to reveal functional interactions in microbiomes. Here, we report the identification of an as-yet uncharacterized silent gene cluster of the fungus Aspergillus fumigatus, which is activated by the bacterium Streptomyces rapamycinicus during the bacterial-fungal interaction. The resulting natural product is the novel fungal metabolite fumigermin, the biosynthesis of which requires the polyketide synthase FgnA. Fumigermin inhibits germination of spores of the inducing S. rapamycinicus, and thus helps the fungus to defend resources in the shared habitat against a bacterial competitor.

BIOspektrum ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 731-733
Author(s):  
Mario K. C. Krespach ◽  
Maria C. Stroe ◽  
Axel A. Brakhage

AbstractA key role in the communication between fungi and bacteria is played by natural products. Many of their encoding gene clusters are silent under standard laboratory conditions. Interspecies “talk” between microorganisms represents an ecological trigger to activate such silent gene clusters and leads to the formation of novel natural products by the involved species. The understanding of both the activation of silent gene clusters and the ecological function of the produced compounds is of importance to reveal functional microbial interactions required to shape microbiomes.


2020 ◽  
Vol 11 ◽  
Author(s):  
Jin Lü ◽  
Qingshan Long ◽  
Zhilong Zhao ◽  
Lu Chen ◽  
Weijun He ◽  
...  

Bacteria of the genus Saccharopolyspora produce important polyketide antibiotics, including erythromycin A (Sac. erythraea) and spinosad (Sac. spinosa). We herein report the development of an industrial erythromycin-producing strain, Sac. erythraea HOE107, into a host for the heterologous expression of polyketide biosynthetic gene clusters (BGCs) from other Saccharopolyspora species and related actinomycetes. To facilitate the integration of natural product BGCs and auxiliary genes beneficial for the production of natural products, the erythromycin polyketide synthase (ery) genes were replaced with two bacterial attB genomic integration sites associated with bacteriophages ϕC31 and ϕBT1. We also established a highly efficient conjugation protocol for the introduction of large bacterial artificial chromosome (BAC) clones into Sac. erythraea strains. Based on this optimized protocol, an arrayed BAC library was effectively transferred into Sac. erythraea. The large spinosad gene cluster from Sac. spinosa and the actinorhodin gene cluster from Streptomyces coelicolor were successfully expressed in the ery deletion mutant. Deletion of the endogenous giant polyketide synthase genes pkeA1-pkeA4, the product of which is not known, and the flaviolin gene cluster (rpp) from the bacterium increased the heterologous production of spinosad and actinorhodin. Furthermore, integration of pJTU6728 carrying additional beneficial genes dramatically improved the yield of actinorhodin in the engineered Sac. erythraea strains. Our study demonstrated that the engineered Sac. erythraea strains SLQ185, LJ161, and LJ162 are good hosts for the expression of heterologous antibiotics and should aid in expression-based genome-mining approaches for the discovery of new and cryptic antibiotics from Streptomyces and rare actinomycetes.


2007 ◽  
Vol 6 (7) ◽  
pp. 1210-1218 ◽  
Author(s):  
Daren W. Brown ◽  
Robert A. E. Butchko ◽  
Mark Busman ◽  
Robert H. Proctor

ABSTRACT Fumonisins are mycotoxins produced by some Fusarium species and can contaminate maize or maize products. Ingestion of fumonisins is associated with diseases, including cancer and neural tube defects, in humans and animals. In fungi, genes involved in the synthesis of mycotoxins and other secondary metabolites are often located adjacent to each other in gene clusters. Such genes can encode structural enzymes, regulatory proteins, and/or proteins that provide self-protection. The fumonisin biosynthetic gene cluster includes 16 genes, none of which appear to play a role in regulation. In this study, we identified a previously undescribed gene (FUM21) located adjacent to the fumonisin polyketide synthase gene, FUM1. The presence of a Zn(II)2Cys6 DNA-binding domain in the predicted protein suggested that FUM21 was involved in transcriptional regulation. FUM21 deletion (Δfum21) mutants produce little to no fumonisin in cracked maize cultures but some FUM1 and FUM8 transcripts in a liquid GYAM medium. Complementation of a Δfum21 mutant with a wild-type copy of the gene restored fumonisin production. Analysis of FUM21 cDNAs identified four alternative splice forms (ASFs), and microarray analysis indicated the ASFs were differentially expressed. Based on these data, we present a model for how FUM21 ASFs may regulate fumonisin biosynthesis.


2012 ◽  
Vol 78 (12) ◽  
pp. 4468-4480 ◽  
Author(s):  
Lena Studt ◽  
Philipp Wiemann ◽  
Karin Kleigrewe ◽  
Hans-Ulrich Humpf ◽  
Bettina Tudzynski

ABSTRACTFusarium fujikuroiproduces a variety of secondary metabolites, of which polyketides form the most diverse group. Among these are the highly pigmented naphthoquinones, which have been shown to possess different functional properties for the fungus. A group of naphthoquinones, polyketides related to fusarubin, were identified inFusariumspp. more than 60 years ago, but neither the genes responsible for their formation nor their biological function has been discovered to date. In addition, although it is known that the sexual fruiting bodies in which the progeny of the fungus develops are darkly colored by a polyketide synthase (PKS)-derived pigment, the structure of this pigment has never been elucidated. Here we present data that link the fusarubin-type polyketides to a defined gene cluster, which we designatefsr, and demonstrate that the fusarubins are the pigments responsible for the coloration of the perithecia. We studied their regulation and the function of the single genes within the cluster by a combination of gene replacements and overexpression of the PKS-encoding gene, and we present a model for the biosynthetic pathway of the fusarubins based on these data.


2001 ◽  
Vol 183 (12) ◽  
pp. 3663-3679 ◽  
Author(s):  
Hideaki Nojiri ◽  
Hiroyo Sekiguchi ◽  
Kana Maeda ◽  
Masaaki Urata ◽  
Sei-Ichiro Nakai ◽  
...  

ABSTRACT The nucleotide sequences of the 27,939-bp-long upstream and 9,448-bp-long downstream regions of thecarAaAaBaBbCAc(ORF7)Ad genes of carbazole-degrading Pseudomonas sp. strain CA10 were determined. Thirty-two open reading frames (ORFs) were identified, and the car gene cluster was consequently revealed to consist of 10 genes (carAaAaBaBbCAcAdDFE) encoding the enzymes for the three-step conversion of carbazole to anthranilate and the degradation of 2-hydroxypenta-2,4-dienoate. The high identities (68 to 83%) with the enzymes involved in 3-(3-hydroxyphenyl)propionic acid degradation were observed only for CarFE. This observation, together with the fact that two ORFs are inserted between carDand carFE, makes it quite likely that thecarFE genes were recruited from another locus. In the 21-kb region upstream from carAa, aromatic-ring-hydroxylating dioxygenase genes (ORF26, ORF27, and ORF28) were found. Inductive expression in carbazole-grown cells and the results of homology searching indicate that these genes encode the anthranilate 1,2-dioxygenase involved in carbazole degradation. Therefore, these ORFs were designated antABC. Four homologous insertion sequences, IS5car1 to IS5car4, were identified in the neighboring regions ofcar and ant genes. IS5car2and IS5car3 constituted the putative composite transposon containing antABC. One-ended transposition of IS5car2 together with the 5′ portion ofantA into the region immediately upstream ofcarAa had resulted in the formation of IS5car1 and ORF9. In addition to the insertion sequence-dependent recombination, gene duplications and presumed gene fusion were observed. In conclusion, through the above gene rearrangement, the novel genetic structure of the cargene cluster has been constructed. In addition, it was also revealed that the car and ant gene clusters are located on the megaplasmid pCAR1.


2004 ◽  
Vol 70 (11) ◽  
pp. 6353-6362 ◽  
Author(s):  
Michelle C. Moffitt ◽  
Brett A. Neilan

ABSTRACT Nodularia spumigena is a bloom-forming cyanobacterium which produces the hepatotoxin nodularin. The complete gene cluster encoding the enzymatic machinery required for the biosynthesis of nodularin in N. spumigena strain NSOR10 was sequenced and characterized. The 48-kb gene cluster consists of nine open reading frames (ORFs), ndaA to ndaI, which are transcribed from a bidirectional regulatory promoter region and encode nonribosomal peptide synthetase modules, polyketide synthase modules, and tailoring enzymes. The ORFs flanking the nda gene cluster in the genome of N. spumigena strain NSOR10 were identified, and one of them was found to encode a protein with homology to previously characterized transposases. Putative transposases are also associated with the structurally related microcystin synthetase (mcy) gene clusters derived from three cyanobacterial strains, indicating a possible mechanism for the distribution of these biosynthetic gene clusters between various cyanobacterial genera. We propose an alternative hypothesis for hepatotoxin evolution in cyanobacteria based on the results of comparative and phylogenetic analyses of the nda and mcy gene clusters. These analyses suggested that nodularin synthetase evolved from a microcystin synthetase progenitor. The identification of the nodularin biosynthetic gene cluster and evolution of hepatotoxicity in cyanobacteria reported in this study may be valuable for future studies on toxic cyanobacterial bloom formation. In addition, an appreciation of the natural evolution of nonribosomal biosynthetic pathways will be vital for future combinatorial engineering and rational design of novel metabolites and pharmaceuticals.


Author(s):  
Aileen Bayot Custodio ◽  
Edwin Plata Alcantara

A phage P1-derived artificial chromosome (PAC) library was constructed from genomic DNA of Streptomyces sp. PCS3-D2. Polymerase chain reaction (PCR) screening of the PAC library revealed two clones, PAC16D and P222O, which were positively identified to harbor polyketide synthase (PKS) Type I and PKS Type III gene clusters, respectively. Restriction enzyme digestion showed that PAC16D and PAC222O contained a 130 kb and a 140 kb insert, respectively. Results of sequencing and bioinformatics analyses revealed that PAC16D comprised of a full-length PKS type I bafilomycin gene cluster while PAC222O harbored truncated siderophore and putative gene clusters as well as a complete PKS III biosynthetic gene cluster. The PKS III gene cluster had three genes similar to alkyl resorcinol biosynthetic genes, however majority of the novel gene cluster had little similarity to known PKS Type III gene clusters. The successful cloning and identification of these gene clusters from Streptomyces sp. PCS3-D2 serve as the jump off point to further genetic manipulation in order to produce the insecticidal natural product in a heterologous host.


Marine Drugs ◽  
2019 ◽  
Vol 17 (7) ◽  
pp. 388 ◽  
Author(s):  
Li Liao ◽  
Shiyuan Su ◽  
Bin Zhao ◽  
Chengqi Fan ◽  
Jin Zhang ◽  
...  

Rare actinobacterial species are considered as potential resources of new natural products. Marisediminicola antarctica ZS314T is the only type strain of the novel actinobacterial genus Marisediminicola isolated from intertidal sediments in East Antarctica. The strain ZS314T was able to produce reddish orange pigments at low temperatures, showing characteristics of carotenoids. To understand the biosynthetic potential of this strain, the genome was completely sequenced for data mining. The complete genome had 3,352,609 base pairs (bp), much smaller than most genomes of actinomycetes. Five biosynthetic gene clusters (BGCs) were predicted in the genome, including a gene cluster responsible for the biosynthesis of C50 carotenoid, and four additional BGCs of unknown oligosaccharide, salinixanthin, alkylresorcinol derivatives, and NRPS (non-ribosomal peptide synthetase) or amino acid-derived compounds. Further experimental characterization indicated that the strain may produce C.p.450-like carotenoids, supporting the genomic data analysis. A new xanthorhodopsin gene was discovered along with the analysis of the salinixanthin biosynthetic gene cluster. Since little is known about this genus, this work improves our understanding of its biosynthetic potential and provides opportunities for further investigation of natural products and strategies for adaptation to the extreme Antarctic environment.


2015 ◽  
Vol 81 (13) ◽  
pp. 4339-4350 ◽  
Author(s):  
Qi Zhang ◽  
James R. Doroghazi ◽  
Xiling Zhao ◽  
Mark C. Walker ◽  
Wilfred A. van der Donk

ABSTRACTLanthionine-containing peptides (lanthipeptides) are a rapidly growing family of polycyclic peptide natural products belonging to the large class of ribosomally synthesized and posttranslationally modified peptides (RiPPs). Lanthipeptides are widely distributed in taxonomically distant species, and their currently known biosynthetic systems and biological activities are diverse. Building on the recent natural product gene cluster family (GCF) project, we report here large-scale analysis of lanthipeptide-like biosynthetic gene clusters fromActinobacteria. Our analysis suggests that lanthipeptide biosynthetic pathways, and by extrapolation the natural products themselves, are much more diverse than currently appreciated and contain many different posttranslational modifications. Furthermore, lanthionine synthetases are much more diverse in sequence and domain topology than currently characterized systems, and they are used by the biosynthetic machineries for natural products other than lanthipeptides. The gene cluster families described here significantly expand the chemical diversity and biosynthetic repertoire of lanthionine-related natural products. Biosynthesis of these novel natural products likely involves unusual and unprecedented biochemistries, as illustrated by several examples discussed in this study. In addition, class IV lanthipeptide gene clusters are shown not to be silent, setting the stage to investigate their biological activities.


2016 ◽  
Vol 82 (22) ◽  
pp. 6611-6623 ◽  
Author(s):  
Muireann Egan ◽  
Hao Jiang ◽  
Mary O'Connell Motherway ◽  
Stefan Oscarson ◽  
Douwe van Sinderen

ABSTRACTBifidobacteria constitute a specific group of commensal bacteria typically found in the gastrointestinal tract (GIT) of humans and other mammals.Bifidobacterium brevestrains are numerically prevalent among the gut microbiota of many healthy breastfed infants. In the present study, we investigated glycosulfatase activity in a bacterial isolate from a nursling stool sample,B. breveUCC2003. Two putative sulfatases were identified on the genome ofB. breveUCC2003. The sulfated monosaccharideN-acetylglucosamine-6-sulfate (GlcNAc-6-S) was shown to support the growth ofB. breveUCC2003, whileN-acetylglucosamine-3-sulfate,N-acetylgalactosamine-3-sulfate, andN-acetylgalactosamine-6-sulfate did not support appreciable growth. By using a combination of transcriptomic and functional genomic approaches, a gene cluster designatedats2was shown to be specifically required for GlcNAc-6-S metabolism. Transcription of theats2cluster is regulated by a repressor open reading frame kinase (ROK) family transcriptional repressor. This study represents the first description of glycosulfatase activity within theBifidobacteriumgenus.IMPORTANCEBifidobacteria are saccharolytic organisms naturally found in the digestive tract of mammals and insects.Bifidobacterium brevestrains utilize a variety of plant- and host-derived carbohydrates that allow them to be present as prominent members of the infant gut microbiota as well as being present in the gastrointestinal tract of adults. In this study, we introduce a previously unexplored area of carbohydrate metabolism in bifidobacteria, namely, the metabolism of sulfated carbohydrates.B. breveUCC2003 was shown to metabolizeN-acetylglucosamine-6-sulfate (GlcNAc-6-S) through one of two sulfatase-encoding gene clusters identified on its genome. GlcNAc-6-S can be found in terminal or branched positions of mucin oligosaccharides, the glycoprotein component of the mucous layer that covers the digestive tract. The results of this study provide further evidence of the ability of this species to utilize mucin-derived sugars, a trait which may provide a competitive advantage in both the infant gut and adult gut.


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