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Pasinato A, Singh G. Bioinformatic exploration of RiPP biosynthetic gene clusters in lichens. Fungal Biol Biotechnol 2025; 12:6. [PMID: 40317021 PMCID: PMC12048977 DOI: 10.1186/s40694-025-00197-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2025] [Accepted: 04/13/2025] [Indexed: 05/04/2025] Open
Abstract
BACKGROUND Ribosomally synthesized and posttranslationally modified peptides (RiPPs) represent a relatively recent addition to the biosynthetic gene cluster (BGC) repertoire of fungi. These BGCs are primarily involved in toxins production and defense-related functions and resulting metabolites also have a significant therapeutic potential. While only a limited number of fungal RiPPs, primarily from a few model fungi, have been characterized, genome mining approaches show that RiPP BGCs are nearly ubiquitous across the fungal kingdom. However, the RiPP biosynthetic landscape of fungi involved in intricate relationship as symbiosis, such as lichen-forming fungi (LFF), remains unexplored. RESULTS This study presents the first comprehensive survey of RiPP BGCs across 111 LFF genomes employing an integrative framework that combines genome mining, phylogenetic inference, and gene network reconstruction. We identified 987 RiPP BGCs, constituting approximately 17% of the total biosynthetic diversity in LFF, a proportion significantly higher than previously estimated. Most lichen RiPP BGCs are unique and do not cluster with any known RiPP gene cluster. We found two RiPP BGCs that were shared among the members of the family Parmeliaceae (Lecanoromycetes), with the signature gene homologous to ustiloxin signature enzyme, indicating a putative similarity to fungal mycotoxin-related BGCs. While one of these BGCs, members of Clan R1, contains the accessory genes for dikaritin synthesis (tyrosinase and methyltransferase), the accessory genes of other BGCs, members of Clan R2, have not yet been reported from any characterized fungal RiPP BGC but only from bacteria. Additionally, for lichen RiPP BGCs that do not cluster with any known BGCs in the RiPP network, we unraveled the presence of the conserved HXXHC motif in the signature gene and, based on this we report the widespread distribution of putative dikaritin homologs across Lecanoromycetes. CONCLUSIONS This study highlights the presence and distribution of RiPP BGCs in Lecanoromycetes and identifies two conserved RiPP clusters putatively homologous to dikaritins (involved in mycotoxin production) within the Lecanoromycete family Parmeliaceae and a general prevalence of putative signature dikaritin genes (not the cluster) in Lecanoromycetes. Our study highlights the widespread presence of putative mycotoxin-related BGCs in lichenized fungi.
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Affiliation(s)
- Anna Pasinato
- Department of Biology, University of Padova, Via U. Bassi, 58/B, Padova, 35121, Italy
- National Biodiversity Future Center (NBFC), Piazza Marina, 61, Palermo, 90133, Italy
| | - Garima Singh
- Department of Biology, University of Padova, Via U. Bassi, 58/B, Padova, 35121, Italy.
- National Biodiversity Future Center (NBFC), Piazza Marina, 61, Palermo, 90133, Italy.
- Botanical Garden of Padua, University of Padova, Padova, Italy.
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Singh G, Dal Grande F, Martin FM, Medema MH. Breaking into nature's secret medicine cabinet: lichens - a biochemical goldmine ready for discovery. THE NEW PHYTOLOGIST 2025; 246:437-449. [PMID: 40007421 PMCID: PMC11923402 DOI: 10.1111/nph.70003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2024] [Accepted: 01/18/2025] [Indexed: 02/27/2025]
Abstract
Secondary metabolites are a crucial source of bioactive compounds playing a key role in the development of new pharmaceuticals. Recently, biosynthetic research has benefited significantly from progress on various fronts, including reduced sequencing costs, improved genome/metabolome mining strategies, and expanding tools/databases to compare and characterize chemical diversity. Steady advances in these fields are crucial for research on non-modal organisms such as lichen-forming fungi (LFF). Although most fungi produce bioactive metabolites, biosynthetic research on LFF (c. 21% of known fungi) lags behind, primarily due to experimental challenges. However, in recent years, several such challenges have been tackled, and, in parallel, a critical foundation of genomic data and pipelines has been established to accomplish the valorization of this potential. Integrating these concurrent advances to accelerate biochemical research in LFF provides a promising opportunity for new discoveries. This review summarizes the following: recent advances in fungal and LFF omics, and chemoinformatics research; studies on LFF biosynthesis, including chemical diversity and evolutionary/phylogenetic aspects; and experimental milestones in LFF biosynthetic gene functions. At the end, we outline a vision and strategy to combine the progress in these research areas to harness the biochemical potential of LFF for pharmaceutical development.
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Affiliation(s)
- Garima Singh
- Department of BiologyUniversity of PadovaVia U. Bassi 58/B35121PadovaItaly
- Botanical GardenUniversity of PadovaVia Orto Botanico 1535123PadovaItaly
| | - Francesco Dal Grande
- Department of BiologyUniversity of PadovaVia U. Bassi 58/B35121PadovaItaly
- Botanical GardenUniversity of PadovaVia Orto Botanico 1535123PadovaItaly
| | - Francis M. Martin
- Université de Lorraine, INRAE, UMR Interactions Arbre/Micro‐organismes, Centre INRAE Grand‐Est Nancy54280ChampenouxFrance
- The National Key Laboratory of Ecological Security and Sustainable Development in the Arid Region, Northwest Institute of Eco‐Environment and ResourcesChinese Academy of Sciences730000LanzhouChina
| | - Marnix H. Medema
- Bioinformatics GroupWageningen UniversityDroevendaalsesteeg 16708PBWageningenthe Netherlands
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Singh G, Pasinato A, Yriarte ALC, Pizarro D, Divakar PK, Schmitt I, Dal Grande F. Are there conserved biosynthetic genes in lichens? Genome-wide assessment of terpene biosynthetic genes suggests ubiquitous distribution of the squalene synthase cluster. BMC Genomics 2024; 25:936. [PMID: 39375591 PMCID: PMC11457338 DOI: 10.1186/s12864-024-10806-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 09/17/2024] [Indexed: 10/09/2024] Open
Abstract
Lichen-forming fungi (LFF) are prolific producers of functionally and structurally diverse secondary metabolites, most of which are taxonomically exclusive and play lineage-specific roles. To date, widely distributed, evolutionarily conserved biosynthetic pathways in LFF are not known. However, this idea stems from polyketide derivatives, since most biochemical research on lichens has concentrated on polyketide synthases (PKSs). Here, we present the first systematic identification and comparison of terpene biosynthetic genes of LFF using all the available Lecanoromycete reference genomes and 22 de novo sequenced ones (111 in total, representing 60 genera and 23 families). We implemented genome mining and gene networking approaches to identify and group the biosynthetic gene clusters (BGCs) into networks of similar BGCs. Our large-scale analysis led to the identification of 724 terpene BGCs with varying degrees of pairwise similarity. Most BGCs in the dataset were unique with no similarity to a previously known fungal or bacterial BGC or among each other. Remarkably, we found two BGCs that were widely distributed in LFF. Interestingly, both conserved BGCs contain the same core gene, i.e., putatively a squalene/phytoene synthase (SQS), involved in sterol biosynthesis. This indicates that early gene duplications, followed by gene losses/gains and gene rearrangement are the major evolutionary factors shaping the composition of these widely distributed SQS BGCs across LFF. We provide an in-depth overview of these BGCs, including the transmembrane, conserved, variable and LFF-specific regions. Our study revealed that lichenized fungi do have a highly conserved BGC, providing the first evidence that a biosynthetic gene may constitute essential genes in lichens.
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Affiliation(s)
- Garima Singh
- Department of Biology, University of Padova, Via U. Bassi, 58/B, 35121, Padua, Italy.
- Botanical Garden of Padova, University of Padova, Padua, Italy.
| | - Anna Pasinato
- Department of Biology, University of Padova, Via U. Bassi, 58/B, 35121, Padua, Italy
| | | | - David Pizarro
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid (UCM), Madrid, 28040, Spain
| | - Pradeep K Divakar
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid (UCM), Madrid, 28040, Spain
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt Am Main, 60325, Germany
- Department of Biosciences, Institute of Ecology Evolution and Diversity, Goethe UniversityFrankfurt,, Max-Von-Laue-Str. 13, Frankfurt am Main, 60438, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt Am Main, 60325, Germany
| | - Francesco Dal Grande
- Department of Biology, University of Padova, Via U. Bassi, 58/B, 35121, Padua, Italy
- Botanical Garden of Padova, University of Padova, Padua, Italy
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Leksin I, Shelyakin M, Zakhozhiy I, Kozlova O, Beckett R, Minibayeva F. Ultraviolet-induced melanisation in lichens: physiological traits and transcriptome profile. PHYSIOLOGIA PLANTARUM 2024; 176:e14512. [PMID: 39221518 DOI: 10.1111/ppl.14512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 08/14/2024] [Accepted: 08/20/2024] [Indexed: 09/04/2024]
Abstract
Lichens are important components of high-latitude boreal and Arctic habitats. While stress tolerant, they are among the most sensitive ecosystem components to climate change, in particular, an increase in ultraviolet light (UV) arising from polar ozone depletion and deforestation. This study is the first to explore the effects of UV-B on gene expression in lichens to predict metabolic pathways involved in tolerance. Using transcriptome profiling and bioinformatic analyses, here we studied the effects of UV-B on gene expression in lichens using Lobaria pulmonaria (L.) Hoff. as a model species. UV-B exposure causes significant browning of the upper cortex of the thallus, which correlates to an increased expression of biosynthetic gene clusters involved in the synthesis of eu- and allomelanins and melanin precursors. Based on transcriptome analyses, we suggest that the biosynthesis of melanins and other secondary metabolites, such as naphthalene derivates, tropolones, anthraquinones, and xanthones, is a trade-off that lichens pay to protect essential metabolic processes such as photosynthesis and respiration. Expression profiles of general stress-associated genes, in particular, related to reactive oxygen species scavenging, protection of proteins, and DNA repair, clearly indicate that the mycobiont is the more UV-B-responsive and susceptible partner in lichen symbiosis. Our findings demonstrate that UV-B stress activates an intricate gene network involved in tolerance mechanisms of lichen symbionts. Knowledge obtained here may enable the prediction of likely effects on lichen biodiversity caused by climate change and pollution.
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Affiliation(s)
- Ilya Leksin
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russian Federation
| | - Mikhail Shelyakin
- Institute of Biology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences
| | - Ilya Zakhozhiy
- Institute of Biology of Komi Science Centre of the Ural Branch of the Russian Academy of Sciences
| | - Olga Kozlova
- Kazan (Volga Region) Federal University, Kazan, Russian Federation
| | - Richard Beckett
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russian Federation
- University of KwaZulu-Natal, Scottsville, South Africa
| | - Farida Minibayeva
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center, Russian Academy of Sciences, Kazan, Russian Federation
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Rosabal D, Pino-Bodas R. A Review of Laboratory Requirements to Culture Lichen Mycobiont Species. J Fungi (Basel) 2024; 10:621. [PMID: 39330381 PMCID: PMC11433509 DOI: 10.3390/jof10090621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2024] [Revised: 08/23/2024] [Accepted: 08/27/2024] [Indexed: 09/28/2024] Open
Abstract
Lichens are symbiotic associations between fungi (the mycobiont) and algae or cyanobacteria (the photobionts). They synthesize a large number of secondary metabolites, many of which are potential sources of novel molecules with pharmacological and industrial applications. The advancement of in vitro culture methods of lichen-forming fungi would allow the comprehensive application of these compounds at large scales, enable improvements in the synthesis, facilitate understanding of the role of the partners in the synthesis of these compounds and increase our knowledge about the genes associated with secondary metabolites production. The aim of this work is to summarize the nutritional and physicochemical requirements that have been used to date to culture different lichen-forming fungi species. In total, the requirements for the cultivation of 110 species are presented. This review can provide a starting point for future experiments and help advance the methods of culturing lichenized fungi. The type of diaspore selected to isolate the mycobiont, the composition of the isolation and culture media and the corresponding physicochemical parameters are essential in designing an efficient lichen culture system, allowing the achievement of a suitable growth of lichen-forming fungi and the subsequent production of secondary metabolites.
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Affiliation(s)
- Dania Rosabal
- Medical Science Faculty, Saint Joseph University, Roseau ZC 00109-8000, Dominica
| | - Raquel Pino-Bodas
- Biologia, Geologia, Fisica and Quimica Department, Universidad Rey Juan Carlos, 28008 Madrid, Spain;
- Instituto de Investigación en Cambio Global de la Universidad Rey Juan Carlos (IICG-URJC), 28008 Madrid, Spain
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Liu R, Paguirigan JA, Hur JS, Kim W. Cercosporamide, a polyketide-derived fungal metabolite, serves as an antifungal agent against phytopathogenic fungi. MYCOSCIENCE 2024; 65:19-27. [PMID: 39239118 PMCID: PMC11371548 DOI: 10.47371/mycosci.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 09/07/2024]
Abstract
An endophytic fungus, Phoma sp. NG-25, produces a set of structurally related polyketides including cercosporamide, phomodione, and usnic acid, among which, cercosporamide has been reported to have strong antifungal and anticancer activities. In this study, Phoma sp. NG-25 was grown in seven growth media to determine the optimal culture condition conducive for cercosporamide production. Cercosporamide production peaked on the eighteenth day of incubation in beef peptone dextrose (BPD) broth media. The cercosporamide titer reached to an average of 77.5 µg/mL in BPD. Paper disk diffusion assay revealed that culture filtrate containing cercosporamide as a major constituent inhibited the growth of taxonomically diverse plant pathogens, including ascomycetous, basidiomycetous, and oomycete fungi. Cercosporamide exhibited strong antifungal activities against two pepper anthracnose pathogens, Colletotrichum gloeosporioides and C. scovillei with EC50 values of 3.8 and 7.0 µg/mL, respectively. This study suggests the potential application of cercosporamide as an effective antifungal agent in controlling anthracnose in pepper.
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Affiliation(s)
- Rundong Liu
- a Korean Lichen Research Institute, Sunchon National University
| | - Jaycee Augusto Paguirigan
- a Korean Lichen Research Institute, Sunchon National University
- b Department of Biological Sciences, College of Science, University of Santo Tomas
| | - Jae-Seoun Hur
- a Korean Lichen Research Institute, Sunchon National University
| | - Wonyong Kim
- a Korean Lichen Research Institute, Sunchon National University
- c Department of Applied Biology, College of Agriculture and Life Sciences, Chonnam National University
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Ahmad N, Ritz M, Calchera A, Otte J, Schmitt I, Brueck T, Mehlmer N. Biosynthetic gene cluster synteny: Orthologous polyketide synthases in Hypogymnia physodes, Hypogymnia tubulosa, and Parmelia sulcata. Microbiologyopen 2023; 12:e1386. [PMID: 37877655 PMCID: PMC10582450 DOI: 10.1002/mbo3.1386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/15/2023] [Accepted: 09/26/2023] [Indexed: 10/26/2023] Open
Abstract
Lichens are symbiotic associations consisting of a photobiont (algae or cyanobacteria) and a mycobiont (fungus), which together generate a variety of unique secondary metabolites. To access this biosynthetic potential for biotechnological applications, deeper insights into the biosynthetic pathways and corresponding gene clusters are necessary. Here, we provide a comparative view of the biosynthetic gene clusters of three lichen mycobionts derived from Hypogymnia physodes, Hypogymnia tubulosa, and Parmelia sulcata. In addition, we present a high-quality PacBio metagenome of Parmelia sulcata, from which we extracted the mycobiont bin containing 214 biosynthetic gene clusters. Most biosynthetic gene clusters in these genomes were associated with T1PKSs, followed by NRPSs and terpenes. This study focused on biosynthetic gene clusters related to polyketide synthesis. Based on ketosynthase homology, we identified nine highly syntenic clusters present in all three species. Among the four clusters belonging to nonreducing PKSs, two are putatively linked to lichen substances derived from orsellinic acid (orcinol depsides and depsidones, e.g., lecanoric acid, physodic acid, lobaric acid), one to compounds derived from methylated forms of orsellinic acid (beta orcinol depsides, e.g., atranorin), and one to melanins. Five clusters with orthologs in all three species are linked to reducing PKSs. Our study contributes to sorting and dereplicating the vast PKS diversity found in lichenized fungi. High-quality sequences of biosynthetic gene clusters of these three common species provide a foundation for further exploration into biotechnological applications and the molecular evolution of lichen substances.
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Affiliation(s)
- Nadim Ahmad
- Department of Chemistry, Werner Siemens Chair of Synthetic Biotechnology, TUM School of Natural SciencesTechnical University of Munich (TUM)GarchingGermany
| | - Manfred Ritz
- Department of Chemistry, Werner Siemens Chair of Synthetic Biotechnology, TUM School of Natural SciencesTechnical University of Munich (TUM)GarchingGermany
| | - Anjuli Calchera
- Senckenberg Biodiversity and Climate Research Centre (SBiK‐F)Frankfurt am MainGermany
| | - Jürgen Otte
- Senckenberg Biodiversity and Climate Research Centre (SBiK‐F)Frankfurt am MainGermany
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre (SBiK‐F)Frankfurt am MainGermany
- Institute of Ecology, Evolution and DiversityGoethe University FrankfurtFrankfurt am MainGermany
| | - Thomas Brueck
- Department of Chemistry, Werner Siemens Chair of Synthetic Biotechnology, TUM School of Natural SciencesTechnical University of Munich (TUM)GarchingGermany
| | - Norbert Mehlmer
- Department of Chemistry, Werner Siemens Chair of Synthetic Biotechnology, TUM School of Natural SciencesTechnical University of Munich (TUM)GarchingGermany
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Paguirigan JAG, Kim JA, Hur JS, Kim W. Identification of a biosynthetic gene cluster for a red pigment cristazarin produced by a lichen-forming fungus Cladonia metacorallifera. PLoS One 2023; 18:e0287559. [PMID: 37352186 PMCID: PMC10289310 DOI: 10.1371/journal.pone.0287559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/07/2023] [Indexed: 06/25/2023] Open
Abstract
Lichens are known to produce many novel bioactive metabolites. To date, approximately 1,000 secondary metabolites have been discovered, which are predominantly produced by the lichen mycobionts. However, despite the extensive studies on production of lichen secondary metabolites, little is known about the responsible biosynthetic gene clusters (BGCs). Here, we identified a putative BGC that is implicated in production of a red pigment, cristazarin (a naphthazarin derivative), in Cladonia metacorallifera. Previously, cristazarin was shown to be specifically induced in growth media containing fructose as a sole carbon source. Thus, we performed transcriptome analysis of C. metacorallifera growing on different carbon sources including fructose to identify the BGC for cristazarin. Among 39 polyketide synthase (PKS) genes found in the genome of C. metacorallifera, a non-reducing PKS (coined crz7) was highly expressed in growth media containing either fructose or glucose. The borders of a cristazarin gene cluster were delimited by co-expression patterns of neighboring genes of the crz7. BGCs highly conserved to the cristazarin BGC were also found in C. borealis and C. macilenta, indicating that these related species also have metabolic potentials to produce cristazarin. Phylogenetic analysis revealed that the Crz7 is sister to fungal PKSs that biosynthesize an acetylated tetrahydoxynaphthalene as a precursor of melanin pigment. Based on the phylogenetic placement of the Crz7 and putative functions of its neighboring genes, we proposed a plausible biosynthetic route for cristazarin. In this study, we identified a lichen-specific BGC that is likely involved in the biosynthesis of a naphthazarin derivative, cristazarin, and confirmed that transcriptome profiling under inducing and non-inducing conditions is an effective strategy for linking metabolites of interest to biosynthetic genes.
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Affiliation(s)
- Jaycee Augusto Gumiran Paguirigan
- Korean Lichen Research Institute, Sunchon National University, Suncheon, Korea
- Department of Biological Sciences, College of Science, University of Santo Tomas, Manila, Philippines
| | - Jung A. Kim
- Korean Lichen Research Institute, Sunchon National University, Suncheon, Korea
| | - Jae-Seoun Hur
- Korean Lichen Research Institute, Sunchon National University, Suncheon, Korea
| | - Wonyong Kim
- Korean Lichen Research Institute, Sunchon National University, Suncheon, Korea
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Ahmad N, Ritz M, Calchera A, Otte J, Schmitt I, Brueck T, Mehlmer N. Biosynthetic Potential of Hypogymnia Holobionts: Insights into Secondary Metabolite Pathways. J Fungi (Basel) 2023; 9:546. [PMID: 37233257 PMCID: PMC10219277 DOI: 10.3390/jof9050546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 04/21/2023] [Accepted: 04/25/2023] [Indexed: 05/27/2023] Open
Abstract
Lichens are symbiotic associations consisting of a photobiont (algae or cyanobacteria) and a mycobiont (fungus). They are known to produce a variety of unique secondary metabolites. To access this biosynthetic potential for biotechnological applications, deeper insights into the biosynthetic pathways and corresponding gene clusters are necessary. Here we provide a comprehensive view of the biosynthetic gene clusters of all organisms comprising a lichen thallus: fungi, green algae, and bacteria. We present two high-quality PacBio metagenomes, in which we identified a total of 460 biosynthetic gene clusters. Lichen mycobionts yielded 73-114 clusters, other lichen associated ascomycetes 8-40, green algae of the genus Trebouxia 14-19, and lichen-associated bacteria 101-105 clusters. The mycobionts contained mainly T1PKSs, followed by NRPSs, and terpenes; Trebouxia reads harbored mainly clusters linked to terpenes, followed by NRPSs and T3PKSs. Other lichen-associated ascomycetes and bacteria contained a mix of diverse biosynthetic gene clusters. In this study, we identified for the first time the biosynthetic gene clusters of entire lichen holobionts. The yet untapped biosynthetic potential of two species of the genus Hypogymnia is made accessible for further research.
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Affiliation(s)
- Nadim Ahmad
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Manfred Ritz
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Anjuli Calchera
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
| | - Jürgen Otte
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany
- Institute of Ecology, Evolution and Diversity, Goethe University Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Thomas Brueck
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
| | - Norbert Mehlmer
- Werner Siemens Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich (TUM), 85748 Garching, Germany
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Yuan X, Li Y, Luo T, Bi W, Yu J, Wang Y. Genomic Analysis of the Xanthoria elegans and Polyketide Synthase Gene Mining Based on the Whole Genome. MYCOBIOLOGY 2023; 51:36-48. [PMID: 36846628 PMCID: PMC9946308 DOI: 10.1080/12298093.2023.2175428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 12/29/2022] [Accepted: 12/29/2022] [Indexed: 06/18/2023]
Abstract
Xanthoria elegans is a lichen symbiosis, that inhabits extreme environments and can absorb UV-B. We reported the de novo sequencing and assembly of X. elegans genome. The whole genome was approximately 44.63 Mb, with a GC content of 40.69%. Genome assembly generated 207 scaffolds with an N50 length of 563,100 bp, N90 length of 122,672 bp. The genome comprised 9,581 genes, some encoded enzymes involved in the secondary metabolism such as terpene, polyketides. To further understand the UV-B absorbing and adaptability to extreme environments mechanisms of X. elegans, we searched the secondary metabolites genes and gene-cluster from the genome using genome-mining and bioinformatics analysis. The results revealed that 7 NR-PKSs, 12 HR-PKSs and 2 hybrid PKS-PKSs from X. elegans were isolated, they belong to Type I PKS (T1PKS) according to the domain architecture; phylogenetic analysis and BGCs comparison linked the putative products to two NR-PKSs and three HR-PKSs, the putative products of two NR-PKSs were emodin xanthrone (most likely parietin) and mycophelonic acid, the putative products of three HR-PKSs were soppilines, (+)-asperlin and macrolactone brefeldin A, respectively. 5 PKSs from X. elegans build a correlation between the SMs carbon skeleton and PKS genes based on the domain architecture, phylogenetic and BGC comparison. Although the function of 16 PKSs remains unclear, the findings emphasize that the genes from X. elegans represent an unexploited source of novel polyketide and utilization of lichen gene resources.
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Affiliation(s)
- Xiaolong Yuan
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, Huanggang Normal University, Huanggang, Hubei, People’ Republic of China
- Yunnan Key Laboratory of Forest Plant Cultivation and Utilization/National Forestry and Grassland Administration Key Laboratory of Yunnan Rare and Endangered Species Conservation and Propagation, Yunnan Academy of Forestry and Grassland, Kunming, Yunnan, People’ Republic of China
| | - Yunqing Li
- Yunnan Key Laboratory of Forest Plant Cultivation and Utilization/National Forestry and Grassland Administration Key Laboratory of Yunnan Rare and Endangered Species Conservation and Propagation, Yunnan Academy of Forestry and Grassland, Kunming, Yunnan, People’ Republic of China
| | - Ting Luo
- Yunnan Key Laboratory of Forest Plant Cultivation and Utilization/National Forestry and Grassland Administration Key Laboratory of Yunnan Rare and Endangered Species Conservation and Propagation, Yunnan Academy of Forestry and Grassland, Kunming, Yunnan, People’ Republic of China
| | - Wei Bi
- Yunnan Key Laboratory of Forest Plant Cultivation and Utilization/National Forestry and Grassland Administration Key Laboratory of Yunnan Rare and Endangered Species Conservation and Propagation, Yunnan Academy of Forestry and Grassland, Kunming, Yunnan, People’ Republic of China
| | - Jiaojun Yu
- Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization, Huanggang Normal University, Huanggang, Hubei, People’ Republic of China
| | - Yi Wang
- Yunnan Key Laboratory of Forest Plant Cultivation and Utilization/National Forestry and Grassland Administration Key Laboratory of Yunnan Rare and Endangered Species Conservation and Propagation, Yunnan Academy of Forestry and Grassland, Kunming, Yunnan, People’ Republic of China
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Singh G. Linking Lichen Metabolites to Genes: Emerging Concepts and Lessons from Molecular Biology and Metagenomics. J Fungi (Basel) 2023; 9:160. [PMID: 36836275 PMCID: PMC9964704 DOI: 10.3390/jof9020160] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/19/2023] [Accepted: 01/21/2023] [Indexed: 01/26/2023] Open
Abstract
Lichen secondary metabolites have tremendous pharmaceutical and industrial potential. Although more than 1000 metabolites have been reported from lichens, less than 10 have been linked to the genes coding them. The current biosynthetic research focuses strongly on linking molecules to genes as this is fundamental to adapting the molecule for industrial application. Metagenomic-based gene discovery, which bypasses the challenges associated with culturing an organism, is a promising way forward to link secondary metabolites to genes in non-model, difficult-to-culture organisms. This approach is based on the amalgamation of the knowledge of the evolutionary relationships of the biosynthetic genes, the structure of the target molecule, and the biosynthetic machinery required for its synthesis. So far, metagenomic-based gene discovery is the predominant approach by which lichen metabolites have been linked to their genes. Although the structures of most of the lichen secondary metabolites are well-documented, a comprehensive review of the metabolites linked to their genes, strategies implemented to establish this link, and crucial takeaways from these studies is not available. In this review, I address the following knowledge gaps and, additionally, provide critical insights into the results of these studies, elaborating on the direct and serendipitous lessons that we have learned from them.
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Affiliation(s)
- Garima Singh
- Department of Biology, University of Padova, 35122 Padova, Italy
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12
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Llewellyn T, Nowell RW, Aptroot A, Temina M, Prescott TAK, Barraclough TG, Gaya E. Metagenomics Shines Light on the Evolution of "Sunscreen" Pigment Metabolism in the Teloschistales (Lichen-Forming Ascomycota). Genome Biol Evol 2023; 15:6986375. [PMID: 36634008 PMCID: PMC9907504 DOI: 10.1093/gbe/evad002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/25/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023] Open
Abstract
Fungi produce a vast number of secondary metabolites that shape their interactions with other organisms and the environment. Characterizing the genes underpinning metabolite synthesis is therefore key to understanding fungal evolution and adaptation. Lichenized fungi represent almost one-third of Ascomycota diversity and boast impressive secondary metabolites repertoires. However, most lichen biosynthetic genes have not been linked to their metabolite products. Here we used metagenomic sequencing to survey gene families associated with production of anthraquinones, UV-protectant secondary metabolites present in various fungi, but especially abundant in a diverse order of lichens, the Teloschistales (class Lecanoromycetes, phylum Ascomycota). We successfully assembled 24 new, high-quality lichenized-fungal genomes de novo and combined them with publicly available Lecanoromycetes genomes from taxa with diverse secondary chemistry to produce a whole-genome tree. Secondary metabolite biosynthetic gene cluster (BGC) analysis showed that whilst lichen BGCs are numerous and highly dissimilar, core enzyme genes are generally conserved across taxa. This suggests metabolite diversification occurs via re-shuffling existing enzyme genes with novel accessory genes rather than BGC gains/losses or de novo gene evolution. We identified putative anthraquinone BGCs in our lichen dataset that appear homologous to anthraquinone clusters from non-lichenized fungi, suggesting these genes were present in the common ancestor of the subphylum Pezizomycotina. Finally, we identified unique transporter genes in Teloschistales anthraquinone BGCs that may explain why these metabolites are so abundant and ubiquitous in these lichens. Our results support the importance of metagenomics for understanding the secondary metabolism of non-model fungi such as lichens.
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Affiliation(s)
| | - Reuben W Nowell
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire, SL5 7PY, UK,Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Andre Aptroot
- Instituto de Biociências, Universidade Federal de Mato Grosso do Sul, Avenida Costa e Silva s/n Bairro Universitário, Campo Grande, Mato Grosso do Sul CEP 79070-900, Brazil
| | - Marina Temina
- Institute of Evolution, University of Haifa, 199 Aba Khoushy Ave, Mount Carmel, Haifa, 3498838, Israel
| | - Thomas A K Prescott
- Comparative Fungal Biology, Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, TW9 3DS, UK
| | - Timothy G Barraclough
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire, SL5 7PY, UK,Department of Biology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Ester Gaya
- Comparative Fungal Biology, Royal Botanic Gardens, Kew, Jodrell Laboratory, Richmond, TW9 3DS, UK
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13
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Egbert S, Hoffman JR, McMullin RT, Lendemer JC, Sorensen JL. Unraveling usnic acid: a comparison of biosynthetic gene clusters between two reindeer lichen (Cladonia rangiferina and C. uncialis). Fungal Biol 2022; 126:697-706. [PMID: 36517138 DOI: 10.1016/j.funbio.2022.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/09/2022] [Accepted: 08/15/2022] [Indexed: 01/07/2023]
Abstract
Lichenized fungi are known for their production of a diversity of secondary metabolites, many of which have broad biological and pharmacological applications. By far the most well-studied of these metabolites is usnic acid. While this metabolite has been well-known and researched for decades, the gene cluster responsible for its production was only recently identified from the species Cladonia uncialis. Usnic acid production varies considerably in the genus Cladonia, even among closely related taxa, and many species, such as C. rangiferina, have been inferred to be incapable of producing the metabolite based on analysis by thin-layer chromatography (TLC). We sequenced and examined the usnic acid biosynthetic gene clusters, or lack thereof, from four closely related Cladonia species (C. oricola, C. rangiferina, C. stygia, and C. subtenuis), and compare them against those of C. uncialis. We complement this comparison with tiered chemical profile analyses to confirm the presence or absence of usnic acid in select samples, using both HPLC and LC-MS. Despite long-standing reporting that C. rangiferina lacks the ability to produce usnic acid, we observed functional gene clusters from the species and detected usnic acid when extracts were examined by LC-MS. By contrast, C. stygia and C. oricola, have been previously described as lacking the ability to produce usnic acid, lacked the gene cluster entirely, and no usnic acid could be detected in C. oricola extracts via HPLC or LC-MS. This work suggests that chemical profiles attained through inexpensive and low-sensitivity methods like TLC may fail to detect low abundance metabolites that can be taxonomically informative. This study also bolsters understanding of the usnic acid gene cluster in lichens, revealing differences among domains of the polyketide synthase which may explain observed differences in expression. These results reinforce the need for comprehensive characterization of lichen secondary metabolite profiles with sensitive LC-MS methods.
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Affiliation(s)
- Susan Egbert
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Jordan R Hoffman
- Department of Biology, Graduate Center, City University of New York, The New York, USA; Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458-5126, USA
| | - R Troy McMullin
- Research and Collections, Canadian Museum of Nature, PO Box 3443, Station D, Ottawa, Ontario, K1P 6P4, Canada
| | - James C Lendemer
- Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458-5126, USA.
| | - John L Sorensen
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
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14
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Singh G, Dal Grande F, Schmitt I. Genome mining as a biotechnological tool for the discovery of novel biosynthetic genes in lichens. FRONTIERS IN FUNGAL BIOLOGY 2022; 3:993171. [PMID: 37746187 PMCID: PMC10512267 DOI: 10.3389/ffunb.2022.993171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/30/2022] [Indexed: 09/26/2023]
Abstract
Natural products (NPs) and their derivatives are a major contributor to modern medicine. Historically, microorganisms such as bacteria and fungi have been instrumental in generating drugs and lead compounds because of the ease of culturing and genetically manipulating them. However, the ever-increasing demand for novel drugs highlights the need to bioprospect previously unexplored taxa for their biosynthetic potential. Next-generation sequencing technologies have expanded the range of organisms that can be explored for their biosynthetic content, as these technologies can provide a glimpse of an organism's entire biosynthetic landscape, without the need for cultivation. The entirety of biosynthetic genes can be compared to the genes of known function to identify the gene clusters potentially coding for novel products. In this study, we mine the genomes of nine lichen-forming fungal species of the genus Umbilicaria for biosynthetic genes, and categorize the biosynthetic gene clusters (BGCs) as "associated product structurally known" or "associated product putatively novel". Although lichen-forming fungi have been suggested to be a rich source of NPs, it is not known how their biosynthetic diversity compares to that of bacteria and non-lichenized fungi. We found that 25%-30% of biosynthetic genes are divergent as compared to the global database of BGCs, which comprises 1,200,000 characterized biosynthetic genes from plants, bacteria, and fungi. Out of 217 BGCs, 43 were highly divergant suggesting that they potentially encode structurally and functionally novel NPs. Clusters encoding the putatively novel metabolic diversity comprise polyketide synthases (30), non-ribosomal peptide synthetases (12), and terpenes (1). Our study emphasizes the utility of genomic data in bioprospecting microorganisms for their biosynthetic potential and in advancing the industrial application of unexplored taxa. We highlight the untapped structural metabolic diversity encoded in the lichenized fungal genomes. To the best of our knowledge, this is the first investigation identifying genes coding for NPs with potentially novel properties in lichenized fungi.
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Affiliation(s)
- Garima Singh
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
- Department of Biology, University of Padova, Padova, Italy
| | - Francesco Dal Grande
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
- Department of Biology, University of Padova, Padova, Italy
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt am Main, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
- Institute of Ecology, Diversity and Evolution, Goethe University, Frankfurt am Main, Germany
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15
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Ureña-Vacas I, González-Burgos E, Divakar PK, Gómez-Serranillos MP. Lichen Depsidones with Biological Interest. PLANTA MEDICA 2022; 88:855-880. [PMID: 34034351 DOI: 10.1055/a-1482-6381] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Depsidones are some of the most abundant secondary metabolites produced by lichens. These compounds have aroused great pharmacological interest due to their activities as antioxidants, antimicrobial, and cytotoxic agents. Hence, this paper aims to provide up-to-date knowledge including an overview of the potential biological interest of lichen depsidones. So far, the most studied depsidones are fumarprotocetraric acid, lobaric acid, norstictic acid, physodic acid, salazinic acid, and stictic acid. Their pharmacological activities have been mainly investigated in in vitro studies and, to a lesser extent, in in vivo studies. No clinical trials have been performed yet. Depsidones are promising cytotoxic agents that act against different cell lines of animal and human origin. Moreover, these compounds have shown antimicrobial activity against both Gram-positive and Gram-negative bacteria and fungi, mainly Candida spp. Furthermore, depsidones have antioxidant properties as revealed in oxidative stress in vitro and in vivo models. Future research should be focused on further investigating the mechanism of action of depsidones and in evaluating new potential actions as well as other depsidones that have not been studied yet from a pharmacological perspective. Likewise, more in vivo studies are prerequisite, and clinical trials for the most promising depsidones are encouraged.
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Affiliation(s)
- Isabel Ureña-Vacas
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid (Spain)
| | - Elena González-Burgos
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid (Spain)
| | - Pradeep Kumar Divakar
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid (Spain)
| | - M Pilar Gómez-Serranillos
- Department of Pharmacology, Pharmacognosy and Botany, Faculty of Pharmacy, Complutense University of Madrid (Spain)
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16
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A Candidate Gene Cluster for the Bioactive Natural Product Gyrophoric Acid in Lichen-Forming Fungi. Microbiol Spectr 2022; 10:e0010922. [PMID: 35867425 PMCID: PMC9430680 DOI: 10.1128/spectrum.00109-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Natural products of lichen-forming fungi are structurally diverse and have a variety of medicinal properties. Despite this, they have limited implementation in industry mostly because the corresponding genes are unknown for most of their natural products. Here, we implement a long-read sequencing and bioinformatic approach to identify the putative biosynthetic gene cluster of the bioactive natural product gyrophoric acid (GA). Using 15 high-quality genomes representing nine GA-producing species of the lichen-forming fungal genus Umbilicaria, we identify the most likely GA cluster and investigate the cluster gene organization and composition across the nine species. Our results show that GA clusters are promiscuous within Umbilicaria, and only three genes are conserved across species, including the polyketide synthase (PKS) gene. In addition, our results suggest that the same cluster codes for different, but structurally similar compounds, namely, GA, umbilicaric-, and hiascic acid, bringing new evidence that lichen metabolite diversity is also generated through regulatory mechanisms at the molecular level. Ours is the first study to identify the most likely GA cluster and, thus, provides essential information to open new avenues for biotechnological approaches to producing and modifying GA and similar lichen-derived compounds. GA PKS is the first tridepside PKS to be identified. IMPORTANCE The implementation of natural products in the pharmaceutical industry relies on the possibility of modifying the natural product (NP) pathway to optimize yields and pharmacological effects. Characterization of genes and pathways underlying natural product biosynthesis is a major bottleneck for exploiting the medicinal properties of the natural products. Genome mining is a promising and relatively cost- and time-effective approach to utilize unexplored NP resources for drug discovery. In this study, we identify the most likely gene cluster for the lichen-forming fungal depside gyrophoric acid in nine Umbilicaria species. This compound shows cytotoxic and antiproliferative properties against several cancer cell lines and is also a broad-spectrum antimicrobial agent. This information paves the way for generating GA analogs with modified properties by selective activation/deactivation of genes.
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17
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A comparative genomic analysis of lichen-forming fungi reveals new insights into fungal lifestyles. Sci Rep 2022; 12:10724. [PMID: 35750715 PMCID: PMC9232553 DOI: 10.1038/s41598-022-14340-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/06/2022] [Indexed: 11/18/2022] Open
Abstract
Lichen-forming fungi are mutualistic symbionts of green algae or cyanobacteria. We report the comparative analysis of six genomes of lichen-forming fungi in classes Eurotiomycetes and Lecanoromycetes to identify genomic information related to their symbiotic lifestyle. The lichen-forming fungi exhibited genome reduction via the loss of dispensable genes encoding plant-cell-wall-degrading enzymes, sugar transporters, and transcription factors. The loss of these genes reflects the symbiotic biology of lichens, such as the absence of pectin in the algal cell wall and obtaining specific sugars from photosynthetic partners. The lichens also gained many lineage- and species-specific genes, including those encoding small secreted proteins. These genes are primarily induced during the early stage of lichen symbiosis, indicating their significant roles in the establishment of lichen symbiosis.Our findings provide comprehensive genomic information for six lichen-forming fungi and novel insights into lichen biology and the evolution of symbiosis.
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18
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Gerasimova JV, Beck A, Werth S, Resl P. High Diversity of Type I Polyketide Genes in Bacidia rubella as Revealed by the Comparative Analysis of 23 Lichen Genomes. J Fungi (Basel) 2022; 8:449. [PMID: 35628705 PMCID: PMC9146135 DOI: 10.3390/jof8050449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 04/20/2022] [Accepted: 04/22/2022] [Indexed: 12/21/2022] Open
Abstract
Fungi involved in lichen symbioses produce a large array of secondary metabolites that are often diagnostic in the taxonomic delimitation of lichens. The most common lichen secondary metabolites-polyketides-are synthesized by polyketide synthases, particularly by Type I PKS (TI-PKS). Here, we present a comparative genomic analysis of the TI-PKS gene content of 23 lichen-forming fungal genomes from Ascomycota, including the de novo sequenced genome of Bacidia rubella. Firstly, we identify a putative atranorin cluster in B. rubella. Secondly, we provide an overview of TI-PKS gene diversity in lichen-forming fungi, and the most comprehensive Type I PKS phylogeny of lichen-forming fungi to date, including 624 sequences. We reveal a high number of biosynthetic gene clusters and examine their domain composition in the context of previously characterized genes, confirming that PKS genes outnumber known secondary substances. Moreover, two novel groups of reducing PKSs were identified. Although many PKSs remain without functional assignments, our findings highlight that genes from lichen-forming fungi represent an untapped source of novel polyketide compounds.
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Affiliation(s)
- Julia V. Gerasimova
- Systematics, Biodiversity and Evolution of Plants, LMU Munich, 80638 Munich, Germany; (A.B.); (S.W.); (P.R.)
- Botanische Staatssammlung München, SNSB-BSM, 80638 Munich, Germany
| | - Andreas Beck
- Systematics, Biodiversity and Evolution of Plants, LMU Munich, 80638 Munich, Germany; (A.B.); (S.W.); (P.R.)
- Botanische Staatssammlung München, SNSB-BSM, 80638 Munich, Germany
| | - Silke Werth
- Systematics, Biodiversity and Evolution of Plants, LMU Munich, 80638 Munich, Germany; (A.B.); (S.W.); (P.R.)
| | - Philipp Resl
- Systematics, Biodiversity and Evolution of Plants, LMU Munich, 80638 Munich, Germany; (A.B.); (S.W.); (P.R.)
- Institute of Biology, University of Graz, 8010 Graz, Austria
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19
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Depside and Depsidone Synthesis in Lichenized Fungi Comes into Focus through a Genome-Wide Comparison of the Olivetoric Acid and Physodic Acid Chemotypes of Pseudevernia furfuracea. Biomolecules 2021; 11:biom11101445. [PMID: 34680078 PMCID: PMC8533459 DOI: 10.3390/biom11101445] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/25/2021] [Accepted: 09/28/2021] [Indexed: 12/13/2022] Open
Abstract
Primary biosynthetic enzymes involved in the synthesis of lichen polyphenolic compounds depsides and depsidones are non-reducing polyketide synthases (NR-PKSs), and cytochrome P450s. However, for most depsides and depsidones the corresponding PKSs are unknown. Additionally, in non-lichenized fungi specific fatty acid synthases (FASs) provide starters to the PKSs. Yet, the presence of such FASs in lichenized fungi remains to be investigated. Here we implement comparative genomics and metatranscriptomics to identify the most likely PKS and FASs for olivetoric acid and physodic acid biosynthesis, the primary depside and depsidone defining the two chemotypes of the lichen Pseudevernia furfuracea. We propose that the gene cluster PF33-1_006185, found in both chemotypes, is the most likely candidate for the olivetoric acid and physodic acid biosynthesis. This is the first study to identify the gene cluster and the FAS likely responsible for olivetoric acid and physodic acid biosynthesis in a lichenized fungus. Our findings suggest that gene regulation and other epigenetic factors determine whether the mycobiont produces the depside or the depsidone, providing the first direct indication that chemotype diversity in lichens can arise through regulatory and not only through genetic diversity. Combining these results and existing literature, we propose a detailed scheme for depside/depsidone synthesis.
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Identification of a lichen depside polyketide synthase gene by heterologous expression in Saccharomyces cerevisiae. Metab Eng Commun 2021; 13:e00172. [PMID: 34430202 PMCID: PMC8365352 DOI: 10.1016/j.mec.2021.e00172] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/12/2021] [Accepted: 04/25/2021] [Indexed: 12/25/2022] Open
Abstract
Lichen-forming fungi produce a variety of secondary metabolites including bioactive polyketides. Advances in DNA and RNA sequencing have led to a growing database of new lichen gene clusters encoding polyketide synthases (PKS) and associated ancillary activities. Definitive assignment of a PKS gene to a metabolic product has been challenging in the lichen field due to a lack of established gene knockout or heterologous gene expression systems. Here, we report the reconstitution of a non-reducing PKS gene from the lichen Pseudevernia furfuracea and successful heterologous expression of the synthetic lichen PKS gene in engineered Saccharomyces cerevisiae. We show that P. furfuracea PFUR17_02294 produces lecanoric acid, the depside dimer of orsellinic acid, at 360 mg/L in small-scale yeast cultures. Our results unequivocally identify PFUR17_02294 as a lecanoric acid synthase and establish that a single lichen PKS synthesizes two phenolic rings and joins them by an ester linkage to form the depside product.
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Usnic Acid and Usnea barbata (L.) F.H. Wigg. Dry Extracts Promote Apoptosis and DNA Damage in Human Blood Cells through Enhancing ROS Levels. Antioxidants (Basel) 2021; 10:antiox10081171. [PMID: 34439420 PMCID: PMC8388874 DOI: 10.3390/antiox10081171] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/17/2021] [Accepted: 07/19/2021] [Indexed: 12/16/2022] Open
Abstract
Nowadays, numerous biomedical studies performed on natural compounds and plant extracts aim to obtain highly selective pharmacological activities without unwanted toxic effects. In the big world of medicinal plants, Usnea barbata (L) F.H. Wigg (U. barbata) and usnic acid (UA) are well-known for their therapeutical properties. One of the most studied properties is their cytotoxicity on various tumor cells. This work aims to evaluate their cytotoxic potential on normal blood cells. Three dry U. barbata extracts in various solvents: ethyl acetate (UBEA), acetone (UBA), and ethanol (UBE) were prepared. From UBEA we isolated usnic acid with high purity by semipreparative chromatography. Then, UA, UBA, and UBE dissolved in 1% dimethyl sulfoxide (DMSO) and diluted in four concentrations were tested for their toxicity on human blood cells. The blood samples were collected from a healthy non-smoker donor; the obtained blood cell cultures were treated with the tested samples. After 24 h, the cytotoxic effect was analyzed through the mechanisms that can cause cell death: early and late apoptosis, caspase 3/7 activity, nuclear apoptosis, autophagy, reactive oxygen species (ROS) level and DNA damage. Generally, the cytotoxic effect was directly proportional to the increase of concentrations, usnic acid inducing the most significant response. At high concentrations, usnic acid and U. barbata extracts induced apoptosis and DNA damage in human blood cells, increasing ROS levels. Our study reveals the importance of prior natural products toxicity evaluation on normal cells to anticipate their limits and benefits as potential anticancer drugs.
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22
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Kim W, Liu R, Woo S, Kang KB, Park H, Yu YH, Ha HH, Oh SY, Yang JH, Kim H, Yun SH, Hur JS. Linking a Gene Cluster to Atranorin, a Major Cortical Substance of Lichens, through Genetic Dereplication and Heterologous Expression. mBio 2021; 12:e0111121. [PMID: 34154413 PMCID: PMC8262933 DOI: 10.1128/mbio.01111-21] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023] Open
Abstract
The depside and depsidone series compounds of polyketide origin accumulate in the cortical or medullary layers of lichen thalli. Despite the taxonomic and ecological significance of lichen chemistry and its pharmaceutical potentials, there has been no single piece of genetic evidence linking biosynthetic genes to lichen substances. Thus, we systematically analyzed lichen polyketide synthases (PKSs) for categorization and identification of the biosynthetic gene cluster (BGC) involved in depside/depsidone production. Our in-depth analysis of the interspecies PKS diversity in the genus Cladonia and a related Antarctic lichen, Stereocaulon alpinum, identified 45 BGC families, linking lichen PKSs to 15 previously characterized PKSs in nonlichenized fungi. Among these, we identified highly syntenic BGCs found exclusively in lichens producing atranorin (a depside). Heterologous expression of the putative atranorin PKS gene (coined atr1) yielded 4-O-demethylbarbatic acid, found in many lichens as a precursor compound, indicating an intermolecular cross-linking activity of Atr1 for depside formation. Subsequent introductions of tailoring enzymes into the heterologous host yielded atranorin, one of the most common cortical substances of macrolichens. Phylogenetic analysis of fungal PKS revealed that the Atr1 is in a novel PKS clade that included two conserved lichen-specific PKS families likely involved in biosynthesis of depsides and depsidones. Here, we provide a comprehensive catalog of PKS families of the genus Cladonia and functionally characterize a biosynthetic gene cluster from lichens, establishing a cornerstone for studying the genetics and chemical evolution of diverse lichen substances. IMPORTANCE Lichens play significant roles in ecosystem function and comprise about 20% of all known fungi. Polyketide-derived natural products accumulate in the cortical and medullary layers of lichen thalli, some of which play key roles in protection from biotic and abiotic stresses (e.g., herbivore attacks and UV irradiation). To date, however, no single lichen product has been linked to respective biosynthetic genes with genetic evidence. Here, we identified a gene cluster family responsible for biosynthesis of atranorin, a cortical substance found in diverse lichen species, by categorizing lichen polyketide synthase and reconstructing the atranorin biosynthetic pathway in a heterologous host. This study will help elucidate lichen secondary metabolism, harnessing the lichen's chemical diversity, hitherto obscured due to limited genetic information on lichens.
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Affiliation(s)
- Wonyong Kim
- Korean Lichen Research Institute, Sunchon National University, Suncheon, South Korea
| | - Rundong Liu
- Korean Lichen Research Institute, Sunchon National University, Suncheon, South Korea
| | - Sunmin Woo
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Sookmyung Women's University, Seoul, South Korea
| | - Kyo Bin Kang
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Sookmyung Women's University, Seoul, South Korea
| | - Hyun Park
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, South Korea
| | - Young Hyun Yu
- College of Pharmacy, Sunchon National University, Suncheon, South Korea
- Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, South Korea
| | - Hyung-Ho Ha
- College of Pharmacy, Sunchon National University, Suncheon, South Korea
- Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, South Korea
| | - Seung-Yoon Oh
- Department of Biology and Chemistry, Changwon National University, Changwon, South Korea
| | - Ji Ho Yang
- Korean Lichen Research Institute, Sunchon National University, Suncheon, South Korea
| | - Hangun Kim
- College of Pharmacy, Sunchon National University, Suncheon, South Korea
- Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, South Korea
| | - Sung-Hwan Yun
- Department of Medical Sciences, Soonchunhyang University, Asan, South Korea
| | - Jae-Seoun Hur
- Korean Lichen Research Institute, Sunchon National University, Suncheon, South Korea
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Shishido TK, Wahlsten M, Laine P, Rikkinen J, Lundell T, Auvinen P. Microbial Communities of Cladonia Lichens and Their Biosynthetic Gene Clusters Potentially Encoding Natural Products. Microorganisms 2021; 9:1347. [PMID: 34206222 PMCID: PMC8304397 DOI: 10.3390/microorganisms9071347] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 01/04/2023] Open
Abstract
Lichens have been widely used in traditional medicine, especially by indigenous communities worldwide. However, their slow growth and difficulties in the isolation of lichen symbionts and associated microbes have hindered the pharmaceutical utilisation of lichen-produced compounds. Advances in high-throughput sequencing techniques now permit detailed investigations of the complex microbial communities formed by fungi, green algae, cyanobacteria, and other bacteria within the lichen thalli. Here, we used amplicon sequencing, shotgun metagenomics, and in silico metabolomics together with compound extractions to study reindeer lichens collected from Southern Finland. Our aim was to evaluate the potential of Cladonia species as sources of novel natural products. We compared the predicted biosynthetic pathways of lichen compounds from isolated genome-sequenced lichen fungi and our environmental samples. Potential biosynthetic genes could then be further used to produce secondary metabolites in more tractable hosts. Furthermore, we detected multiple compounds by metabolite analyses, which revealed connections between the identified biosynthetic gene clusters and their products. Taken together, our results contribute to metagenomic data studies from complex lichen-symbiotic communities and provide valuable new information for use in further biochemical and pharmacological studies.
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Affiliation(s)
- Tânia Keiko Shishido
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; (P.L.); (P.A.)
| | - Matti Wahlsten
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; (M.W.); (T.L.)
| | - Pia Laine
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; (P.L.); (P.A.)
| | - Jouko Rikkinen
- Finnish Museum of Natural History, Botany Unit, University of Helsinki, P.O. Box 7, 00014 Helsinki, Finland;
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland
| | - Taina Lundell
- Department of Microbiology, Faculty of Agriculture and Forestry, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; (M.W.); (T.L.)
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland; (P.L.); (P.A.)
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Singh G, Calchera A, Schulz M, Drechsler M, Bode HB, Schmitt I, Dal Grande F. Climate-specific biosynthetic gene clusters in populations of a lichen-forming fungus. Environ Microbiol 2021; 23:4260-4275. [PMID: 34097344 DOI: 10.1111/1462-2920.15605] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/16/2022]
Abstract
Natural products can contribute to abiotic stress tolerance in plants and fungi. We hypothesize that biosynthetic gene clusters (BGCs), the genomic elements that underlie natural product biosynthesis, display structured differences along elevation gradients. We analysed biosynthetic gene variation in natural populations of the lichen-forming fungus Umbilicaria pustulata. We collected a total of 600 individuals from the Mediterranean and cold-temperate climates. Population genomic analyses indicate that U. pustulata contains three clusters that are highly differentiated between the Mediterranean and cold-temperate populations. One entire cluster is exclusively present in cold-temperate populations, and a second cluster is putatively dysfunctional in all cold-temperate populations. In the third cluster variation is fixed in all cold-temperate populations due to hitchhiking. In these two clusters the presence of consistent allele frequency differences among replicate populations/gradients suggests that selection rather than drift is driving the pattern. We advocate that the landscape of fungal biosynthetic genes is shaped by both positive and hitchhiking selection. We demonstrate, for the first time, the presence of climate-associated BGCs and BGC variations in lichen-forming fungi. While the associated secondary metabolites of the candidate clusters are presently unknown, our study paves the way for targeted discovery of natural products with ecological significance.
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Affiliation(s)
- Garima Singh
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany
| | - Anjuli Calchera
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany
| | - Meike Schulz
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany
| | - Moritz Drechsler
- Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt, 60438, Germany.,Department Natural Products in Organismic Interactions, Max-Planck-Institute for Terrestrial Microbiology, Marburg, 35043, Germany
| | - Helge B Bode
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany.,Molekulare Biotechnologie, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt, 60438, Germany.,Department Natural Products in Organismic Interactions, Max-Planck-Institute for Terrestrial Microbiology, Marburg, 35043, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe Universität Frankfurt, Frankfurt, 60438, Germany
| | - Imke Schmitt
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany.,Institute of Ecology, Evolution and Diversity, Fachbereich Biowissenschaften, Goethe Universität Frankfurt, Frankfurt, 60438, Germany
| | - Francesco Dal Grande
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Frankfurt, 60325, Germany.,LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, 60325, Germany
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