Secondary metabolites from hypocrealean entomopathogenic fungi: genomics as a tool to elucidate the encoded parvome

AbstractFungal secondary metabolites are a rich source of valuable natural products. Genome sequencing have revealed an enormous potential from predicted biosynthetic gene clusters. It is however currently a time consuming task and an unfeasible task to characterize all biosynthetic gene cluster and to identify possible uses of the compounds. A rational approach is needed to identify promising gene clusters responsible for producing valuable compounds. Several valuable bioactive clusters have been shown to include a resistance gene which is a paralog of the target gene inhibited by the compound. This mechanism can be used to design a rational approach selecting those clusters.We have developed a pipeline FRIGG (Fungal Resistance Gene-directed Genome mining) identifying putative resistance genes found in biosynthetic gene clusters based on homology patterns of the cluster genes. The FRIGG pipeline has been run using 51 Aspergillus and Penicillium genomes, identifying 72 unique protein families with putative resistance genes using various settings in the pipeline. The pipeline was also able to identify the characterized resistance gene inpE from the Fellutamide B cluster thereby validating the approach.We have successfully developed an approach identifying putative valuable bio-active clusters based on a specific resistance mechanism. This approach will be highly useful as an ever increasing amount of genomic data becomes available — the art of identifying and selecting clusters producing novel valuable compounds will only become more crucial.ImportanceSpecies belonging to the Aspergillus genus are known to produce a large number of secondary metabolites, some of these compounds are bioactive and used as pharmaceuticals such as penicillin, cyclosporin and statin. With whole genome sequencing it became apparent that the genetic potential for secondary metabolite production is much bigger than expected. As an increasing number of species are whole genome sequenced an immense number of secondary metabolite genes are predicted and the question of how to selectively identify novel bioactive compounds from this information arises. To address this question, we have created a pipeline identifying genes likely involved in the production of bioactive compounds based on a resistance gene hypothesis approach.

Global biogeographic sampling of bacterial secondary metabolism

eLife ◽

10.7554/elife.05048 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 74

Author(s):

Zachary Charlop-Powers ◽

Jeremy G Owen ◽

Boojala Vijay B Reddy ◽

Melinda A Ternei ◽

Denise O Guimarães ◽

...

Keyword(s):

Secondary Metabolites ◽

Genome Sequencing ◽

Geographic Distance ◽

Gene Clusters ◽

Natural World ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Road Map ◽

Two Factors ◽

Natural Products Discovery

Recent bacterial (meta)genome sequencing efforts suggest the existence of an enormous untapped reservoir of natural-product-encoding biosynthetic gene clusters in the environment. Here we use the pyro-sequencing of PCR amplicons derived from both nonribosomal peptide adenylation domains and polyketide ketosynthase domains to compare biosynthetic diversity in soil microbiomes from around the globe. We see large differences in domain populations from all except the most proximal and biome-similar samples, suggesting that most microbiomes will encode largely distinct collections of bacterial secondary metabolites. Our data indicate a correlation between two factors, geographic distance and biome-type, and the biosynthetic diversity found in soil environments. By assigning reads to known gene clusters we identify hotspots of biomedically relevant biosynthetic diversity. These observations not only provide new insights into the natural world, they also provide a road map for guiding future natural products discovery efforts.

Whole-genome sequencing of the endemic Antarctic fungus Antarctomyces pellizariae reveals an ice-binding protein, a scarce set of secondary metabolites gene clusters and provides insights on Thelebolales phylogeny

Genomics ◽

10.1016/j.ygeno.2020.05.004 ◽

2020 ◽

Vol 112 (5) ◽

pp. 2915-2921 ◽

Cited By ~ 2

Author(s):

Thiago Mafra Batista ◽

Heron Oliveira Hilario ◽

Gabriel Antônio Mendes de Brito ◽

Rennan Garcias Moreira ◽

Carolina Furtado ◽

...

Keyword(s):

Secondary Metabolites ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Binding Protein ◽

Protein A ◽

Gene Clusters ◽

Whole Genome ◽

Ice Binding ◽

Ice Binding Protein

Resistance Gene-Directed Genome Mining of 50 Aspergillus Species

mSystems ◽

10.1128/msystems.00085-19 ◽

2019 ◽

Vol 4 (4) ◽

Cited By ~ 8

Author(s):

Inge Kjærbølling ◽

Tammi Vesth ◽

Mikael R. Andersen

Keyword(s):

Secondary Metabolites ◽

Whole Genome Sequencing ◽

Resistance Gene ◽

Secondary Metabolite ◽

Genome Sequencing ◽

Bioactive Compounds ◽

Genome Mining ◽

Whole Genome ◽

Metabolite Production ◽

Genetic Potential

Species belonging to the Aspergillus genus are known to produce a large number of secondary metabolites; some of these compounds are used as pharmaceuticals, such as penicillin, cyclosporine, and statin. With whole-genome sequencing, it became apparent that the genetic potential for secondary metabolite production is much larger than expected. As an increasing number of species are whole-genome sequenced, thousands of secondary metabolite genes are predicted, and the question of how to selectively identify novel bioactive compounds from this information arises. To address this question, we have created a pipeline to predict genes involved in the production of bioactive compounds based on a resistance gene hypothesis approach.

Tapping Into Actinobacterial Genomes for Natural Product Discovery

Frontiers in Microbiology ◽

10.3389/fmicb.2021.655620 ◽

2021 ◽

Vol 12 ◽

Author(s):

Tanim Arpit Singh ◽

Ajit Kumar Passari ◽

Anjana Jajoo ◽

Sheetal Bhasin ◽

Vijai Kumar Gupta ◽

...

Keyword(s):

Secondary Metabolites ◽

Genome Sequencing ◽

Genetic Regulation ◽

Gene Clusters ◽

Biosynthetic Gene Cluster ◽

Bioactive Molecules ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Genomic Approach ◽

New Gateway

The presence of secondary metabolite biosynthetic gene clusters (BGCs) makes actinobacteria well-known producers of diverse metabolites. These ubiquitous microbes are extensively exploited for their ability to synthesize diverse secondary metabolites. The extent of their ability to synthesize various molecules is yet to be evaluated. Current advancements in genome sequencing, metabolomics, and bioinformatics have provided a plethora of information about the mechanism of synthesis of these bioactive molecules. Accessing the biosynthetic gene cluster responsible for the production of metabolites has always been a challenging assignment. The genomic approach developments have opened a new gateway for examining and manipulating novel antibiotic gene clusters. These advancements have now developed a better understanding of actinobacterial physiology and their genetic regulation for the prolific production of natural products. These new approaches provide a unique opportunity to discover novel bioactive compounds that might replenish antibiotics’ exhausted stock and counter the microbes’ resistance crisis.

Epigenetic modification, co-culture and genomic methods for natural product discovery

Physical Sciences Reviews ◽

10.1515/psr-2018-0118 ◽

2018 ◽

Vol 4 (4) ◽

Author(s):

Sergi Herve Akone ◽

Cong-Dat Pham ◽

Huiqin Chen ◽

Antonius R. B. Ola ◽

Fidele Ntie-Kang ◽

...

Keyword(s):

Secondary Metabolites ◽

Bioactive Compounds ◽

Epigenetic Modification ◽

Gene Clusters ◽

Histone Deacetylation ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Mixed Fermentation ◽

Silent Genes ◽

Promising Source

Abstract Fungi and bacteria are encountered in many habitats where they live in complex communities interacting with one another mainly by producing secondary metabolites, which are organic compounds that are not directly involved in the normal growth, development, or reproduction of the organism. These organisms appear as a promising source for the discovery of novel bioactive natural products that may find their application in medicine. However, the production of secondary metabolites by those organisms when cultured axenically is limited as only a subset of biosynthetic genes is expressed under standard laboratory conditions leading to the search of new methods for the activation of the silent genes including epigenetic modification and co-cultivation. Biosynthetic gene clusters which produce secondary metabolites are known to be present in a heterochromatin state in which the transcription of constitutive genes is usually regulated by epigenetic modification including DNA methylation and histone deacetylation. Therefore, small-molecule epigenetic modifiers which promote changes in the structure of chromatin could control the expression of silent genes and may be rationally employed for the discovery of novel bioactive compounds. Co-cultivation, which is also known as mixed-fermentation, usually implies two or more microorganisms in the same medium in which the resulting competition is known to enhance the production of constitutively present compounds and/or to lead to the induction of cryptic metabolites that were not detected in axenic cultures of the considered axenic microorganism. Genomic strategies could help to identify biosynthetic gene clusters in fungal genomes and link them to their products by the means of novel algorithms as well as integrative pan-genomic approaches. Despite that all these techniques are still in their infancy, they appear as promising sources for the discovery of new bioactive compounds. This chapter presents recent ecological techniques for the discovery of new secondary metabolites that might find application in medicine.

Whole-Genome Sequencing Reveals a New Genospecies ofMethylobacteriumsp. GXS13, Isolated fromVitis viniferaL. Xylem Sap

Genome Announcements ◽

10.1128/genomea.01695-15 ◽

2016 ◽

Vol 4 (1) ◽

Cited By ~ 1

Author(s):

Wan Xin Lai ◽

Han Ming Gan ◽

André O. Hudson ◽

Michael A. Savka

Keyword(s):

Xylem Sap ◽

Gene Clusters ◽

Homoserine Lactone ◽

Whole Genome Sequence ◽

Whole Genome ◽

Acyl Homoserine Lactone ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Cell Wall Modification ◽

Cytokinin Synthesis

The whole-genome sequence of a new genospecies ofMethylobacteriumsp., named GXS13 and isolated from grapevine xylem sap, is reported and demonstrates potential for methylotrophy, cytokinin synthesis, and cell wall modification. In addition, biosynthetic gene clusters were identified for cupriachelin, carotenoid, and acyl-homoserine lactone using the antiSMASH server.

Phytoplankton trigger the production of cryptic metabolites in the marine actinobacteria Salinispora tropica

10.1101/2020.05.18.103358 ◽

2020 ◽

Author(s):

Audam Chhun ◽

Despoina Sousoni ◽

Maria del Mar Aguiló-Ferretjans ◽

Lijiang Song ◽

Christophe Corre ◽

...

Keyword(s):

Natural Products ◽

Secondary Metabolites ◽

Antibiotic Production ◽

Antimicrobial Effect ◽

Gene Clusters ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Marine Actinobacteria ◽

Salinispora Tropica ◽

Eukaryotic Phytoplankton

AbstractBacteria from the Actinomycete family are a remarkable source of natural products with pharmaceutical potential. The discovery of novel molecules from these organisms is, however, hindered because most of the biosynthetic gene clusters (BGCs) encoding these secondary metabolites are cryptic or silent and are referred to as orphan BGCs. While co-culture has proven to be a promising approach to unlock the biosynthetic potential of many microorganisms by activating the expression of these orphan BGCs, it still remains an underexplored technique. The marine actinobacteria Salinispora tropica, for instance, produces valuable compounds such as the anti-cancer molecule salinosporamide A but half of its putative BGCs are still orphan. Although previous studies have looked into using marine heterotrophs to induce orphan BGCs in Salinispora, the potential impact of co-culturing marine phototrophs with Salinispora has yet to be investigated. Following the observation of clear antimicrobial phenotype of the actinobacterium on a range of phytoplanktonic organisms, we here report the discovery of novel cryptic secondary metabolites produced by S. tropica in response to its co-culture with photosynthetic primary producers. An approach combining metabolomics and proteomics revealed that the photosynthate released by phytoplankton influences the biosynthetic capacities of S. tropica with both production of new molecules and the activation of orphan BGCs. Our work pioneers the use of phototrophs as a promising strategy to accelerate the discovery of novel natural products from actinobacteria.ImportanceThe alarming increase of antimicrobial resistance has generated an enormous interest in the discovery of novel active compounds. The isolation of new microbes to untap novel natural products is currently hampered because most biosynthetic gene clusters (BGC) encoded by these microorganisms are not expressed under standard laboratory conditions, i.e. mono-cultures. Here we show that co-culturing can be an easy way for triggering silent BGC. By combining state-of-the-art metabolomics and high-throughput proteomics, we characterized the activation of cryptic metabolites and silent biosynthetic gene clusters in the marine actinobacteria Salinispora tropica by the presence of phytoplankton photosynthate. We further suggest a mechanistic understanding of the antimicrobial effect this actinobacterium has on a broad range of prokaryotic and eukaryotic phytoplankton species and reveal a promising candidate for antibiotic production.

Phylogenetic Distribution of Secondary Metabolites in the Bacillus subtilis Species Complex

mSystems ◽

10.1128/msystems.00057-21 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Kat Steinke ◽

Omkar S. Mohite ◽

Tilmann Weber ◽

Ákos T. Kovács

Keyword(s):

Bacillus Subtilis ◽

Secondary Metabolites ◽

Secondary Metabolite ◽

Species Complex ◽

Gene Clusters ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Content Type ◽

Frameshift Mutations ◽

Metabolite Production

ABSTRACT Microbes produce a plethora of secondary (or specialized) metabolites that, although not essential for primary metabolism, benefit them to survive in the environment, communicate, and influence cell differentiation. Biosynthetic gene clusters (BGCs), responsible for the production of these secondary metabolites, are readily identifiable on bacterial genome sequences. Understanding the phylogeny and distribution of BGCs helps us to predict the natural product synthesis ability of new isolates. Here, we examined 310 genomes from the Bacillus subtilis group, determined the inter- and intraspecies patterns of absence/presence for all BGCs, and assigned them to defined gene cluster families (GCFs). This allowed us to establish patterns in the distribution of both known and unknown products. Further, we analyzed variations in the BGC structures of particular families encoding natural products, such as plipastatin, fengycin, iturin, mycosubtilin, and bacillomycin. Our detailed analysis revealed multiple GCFs that are species or clade specific and a few others that are scattered within or between species, which will guide exploration of the chemodiversity within the B. subtilis group. Surprisingly, we discovered that partial deletion of BGCs and frameshift mutations in selected biosynthetic genes are conserved within phylogenetically related isolates, although isolated from around the globe. Our results highlight the importance of detailed genomic analysis of BGCs and the remarkable phylogenetically conserved erosion of secondary metabolite biosynthetic potential in the B. subtilis group. IMPORTANCE Members of the B. subtilis species complex are commonly recognized producers of secondary metabolites, among those, the production of antifungals, which makes them promising biocontrol strains. While there are studies examining the distribution of well-known secondary metabolites in Bacilli, intraspecies clade-specific distribution has not been systematically reported for the B. subtilis group. Here, we report the complete biosynthetic potential within the B. subtilis group to explore the distribution of the biosynthetic gene clusters and to reveal an exhaustive phylogenetic conservation of secondary metabolite production within Bacillus that supports the chemodiversity within this species complex. We identify that certain gene clusters acquired deletions of genes and particular frameshift mutations, rendering them inactive for secondary metabolite biosynthesis, a conserved genetic trait within phylogenetically conserved clades of certain species. The overview guides the assignment of the secondary metabolite production potential of newly isolated Bacillus strains based on genome sequence and phylogenetic relatedness.

IMG-ABC: A Knowledge Base To Fuel Discovery of Biosynthetic Gene Clusters and Novel Secondary Metabolites

mBio ◽

10.1128/mbio.00932-15 ◽

2015 ◽

Vol 6 (4) ◽

Cited By ~ 66

Author(s):

Michalis Hadjithomas ◽

I-Min Amy Chen ◽

Ken Chu ◽

Anna Ratner ◽

Krishna Palaniappan ◽

...

Keyword(s):

Secondary Metabolites ◽

Secondary Metabolism ◽

Genomic Data ◽

Gene Clusters ◽

Metagenomic Data ◽

Integrated Analysis ◽

Analysis Tool ◽

Biosynthetic Gene ◽

Biosynthetic Gene Clusters ◽

Analysis Tools

ABSTRACTIn the discovery of secondary metabolites, analysis of sequence data is a promising exploration path that remains largely underutilized due to the lack of computational platforms that enable such a systematic approach on a large scale. In this work, we present IMG-ABC (https://img.jgi.doe.gov/abc), an atlas of biosynthetic gene clusters within the Integrated Microbial Genomes (IMG) system, which is aimed at harnessing the power of “big” genomic data for discovering small molecules. IMG-ABC relies on IMG's comprehensive integrated structural and functional genomic data for the analysis of biosynthetic gene clusters (BCs) and associated secondary metabolites (SMs). SMs and BCs serve as the two main classes of objects in IMG-ABC, each with a rich collection of attributes. A unique feature of IMG-ABC is the incorporation of both experimentally validated and computationally predicted BCs in genomes as well as metagenomes, thus identifying BCs in uncultured populations and rare taxa. We demonstrate the strength of IMG-ABC's focused integrated analysis tools in enabling the exploration of microbial secondary metabolism on a global scale, through the discovery of phenazine-producing clusters for the first time inAlphaproteobacteria. IMG-ABC strives to fill the long-existent void of resources for computational exploration of the secondary metabolism universe; its underlying scalable framework enables traversal of uncovered phylogenetic and chemical structure space, serving as a doorway to a new era in the discovery of novel molecules.IMPORTANCEIMG-ABC is the largest publicly available database of predicted and experimental biosynthetic gene clusters and the secondary metabolites they produce. The system also includes powerful search and analysis tools that are integrated with IMG's extensive genomic/metagenomic data and analysis tool kits. As new research on biosynthetic gene clusters and secondary metabolites is published and more genomes are sequenced, IMG-ABC will continue to expand, with the goal of becoming an essential component of any bioinformatic exploration of the secondary metabolism world.