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Worthy FR, Schaefer DA, Wanasinghe D, Xu JC, Wang LS, Wang XY. Acquisition of green algal photobionts enables both chlorolichens and chloro-cyanolichens to activate photosynthesis at low humidity without liquid water. AOB PLANTS 2024; 16:plae025. [PMID: 38770101 PMCID: PMC11102867 DOI: 10.1093/aobpla/plae025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 04/23/2024] [Indexed: 05/22/2024]
Abstract
Cyanobacteria require liquid water for photosynthesis, whereas green algae can photosynthesise with water vapour alone. We discovered that several Lobaria spp. which normally have cyanobacteria as the sole photobiont, in some regions of the trans-Himalayas also harboured green algae. We tested whether green algal acquisition was: limited to high elevations; obtained from neighbouring chloro-Lobaria species; enabled photosynthesis at low humidity. Lobaria spp. were collected from 2000 to 4000 m elevation. Spectrophotometry quantified green algal abundance by measuring chlorophyll b (absent in cyanobacteria). Thalli cross-sections visually confirmed green algal presence. We sequenced gene regions: Lobaria (ITS-EF-1α-RPB2), green algae (18S-RBC-L) and Nostoc (16S). Phylogenetic analysis determined myco-photobiont associations. We used a custom closed-circuit gas exchange system with an infrared gas analyser to measure CO2 exchange rates for desiccated specimens at 33%, 76%, 86% and 98% humidity. Cross-sections revealed that the photobiont layers in putative cyano-Lobaria contained both cyanobacteria and green algae, indicating that they should be considered chloro-cyanolichens. Chloro-Lobaria had no visible cephalodia nor cyanobacteria in the photobiont layer. Chloro-Lobaria and chloro-cyano-Lobaria had comparable levels of chlorophyll b. Chloro-Lobaria usually contained Symbiochloris. Chloro-cyano-Lobaria mainly associated with Parachloroidium and Nostoc; infrequently with Symbiochloris, Apatococcus, Chloroidium, Pseudochlorella, Trebouxia. Sequences from two green algal genera were obtained from within some thalli. Desiccated specimens of every Lobaria species could attain net photosynthesis with light exposure and 33% humidity. CO2 exchange dynamics over a five-day period differed between species. At all elevations, chloro-cyano-Lobaria spp. had abundant green algae in the photobiont layer, but green algal strains mostly differed to those of chloro-Lobaria spp. Both chloro-Lobaria and chloro-cyano-Lobaria were capable of conducting photosynthesis without liquid water. The data strongly suggest that they attained positive net photosynthesis.
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Affiliation(s)
- Fiona Ruth Worthy
- Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
- Honghe Centre for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Douglas Allen Schaefer
- Honghe Centre for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Dhanushka Wanasinghe
- Honghe Centre for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
- Department of Soil Science, College of Food and Agriculture Sciences, King Saud University, Riyadh 11362, Saudi Arabia
| | - Jian Chu Xu
- Honghe Centre for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Li Song Wang
- Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
| | - Xin Yu Wang
- Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, Yunnan 650201, China
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2
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Jung P, Briegel-Williams L, Büdel B, Schultz M, Nürnberg DJ, Grube M, D’Agostino PM, Kaštovský J, Mareš J, Lorenz M, González MLG, Forno MD, Westberg M, Chrismas N, Pietrasiak N, Whelan P, Dvořák P, Košuthová A, Gkelis S, Bauersachs T, Schiefelbein U, Giao VTP, Lakatos M. The underestimated fraction: diversity, challenges and novel insights into unicellular cyanobionts of lichens. ISME COMMUNICATIONS 2024; 4:ycae069. [PMID: 38966402 PMCID: PMC11222712 DOI: 10.1093/ismeco/ycae069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/10/2024] [Accepted: 05/03/2024] [Indexed: 07/06/2024]
Abstract
Lichens are remarkable and classic examples of symbiotic organisms that have fascinated scientists for centuries. Yet, it has only been for a couple of decades that significant advances have focused on the diversity of their green algal and/or cyanobacterial photobionts. Cyanolichens, which contain cyanobacteria as their photosynthetic partner, include up to 10% of all known lichens and, as such, studies on their cyanobionts are much rarer compared to their green algal counterparts. For the unicellular cyanobionts, i.e. cyanobacteria that do not form filaments, these studies are even scarcer. Nonetheless, these currently include at least 10 different genera in the cosmopolitan lichen order Lichinales. An international consortium (International Network of CyanoBionts; INCb) will tackle this lack of knowledge. In this article, we discuss the status of current unicellular cyanobiont research, compare the taxonomic resolution of photobionts from cyanolichens with those of green algal lichens (chlorolichens), and give a roadmap of research on how to recondition the underestimated fraction of symbiotic unicellular cyanobacteria in lichens.
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Affiliation(s)
- Patrick Jung
- Integrative Biotechnology, University of Applied Sciences Kaiserslautern, Pirmasens, Germany
| | - Laura Briegel-Williams
- Integrative Biotechnology, University of Applied Sciences Kaiserslautern, Pirmasens, Germany
| | - Burkhard Büdel
- Rhineland-Palatinate Technical University Kaiserslautern Landau, Kaiserslautern, Germany
| | - Matthias Schultz
- Herbarium Hamburgense, Institute of Plant Science and Microbiology, University of Hamburg, Hamburg, Germany
| | - Dennis J Nürnberg
- Institute for Experimental Physics, Freie Universität Berlin, Berlin, Germany
- Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin Germany
| | - Martin Grube
- Institute of Biology, University of Graz, Graz, Austria
| | - Paul M D’Agostino
- Technical University Dresden, Chair of Technical Biochemistry, Dresden, Germany
| | - Jan Kaštovský
- Department of Botany, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Jan Mareš
- Institute of Microbiology, The Czech Academy of Sciences, Třeboň, Czech Republic
| | - Maike Lorenz
- University of Goettingen, SAG Goettingen, Goettingen, Germany
| | | | | | | | | | | | | | - Petr Dvořák
- Palacký University Olomouc, Olomouc, Czech Republic
| | | | - Spyros Gkelis
- Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Thorsten Bauersachs
- Institute of Organic Biogeochemistry in Geo-Systems, RWTH Aachen University, Aachen, Germany
| | | | | | - Michael Lakatos
- Integrative Biotechnology, University of Applied Sciences Kaiserslautern, Pirmasens, Germany
| | - INCb
- International Network for research on unicellular CyanoBionts from lichens
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3
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Pino-Bodas R, Blázquez M, de los Ríos A, Pérez-Ortega S. Myrmecia, Not Asterochloris, Is the Main Photobiont of Cladonia subturgida ( Cladoniaceae, Lecanoromycetes). J Fungi (Basel) 2023; 9:1160. [PMID: 38132761 PMCID: PMC10744234 DOI: 10.3390/jof9121160] [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: 11/01/2023] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 12/23/2023] Open
Abstract
This study explores the diversity of photobionts associated with the Mediterranean lichen-forming fungus Cladonia subturgida. For this purpose, we sequenced the whole ITS rDNA region by Sanger using a metabarcoding method for ITS2. A total of 41 specimens from Greece, Italy, France, Portugal, and Spain were studied. Additionally, two specimens from Spain were used to generate four cultures. Our molecular studies showed that the genus Myrmecia is the main photobiont of C. subturgida throughout its geographic distribution. This result contrasts with previous studies, which indicated that the main photobiont for most Cladonia species is Asterochloris. The identity of Myrmecia was also confirmed by ultrastructural studies of photobionts within the lichen thalli and cultures. Photobiont cells showed a parietal chloroplast lacking a pyrenoid, which characterizes the species in this genus. Phylogenetic analyses indicate hidden diversity within this genus. The results of amplicon sequencing showed the presence of multiple ASVs in 58.3% of the specimens studied.
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Affiliation(s)
- Raquel Pino-Bodas
- Biodiversity and Conservation Area, Department of Biology and Geology, Physics and Inorganic Chemistry, Rey Juan Carlos University, C/Tulipán s/n, 28933 Móstoles, Spain
- Royal Botanic Gardens, Kew, Richmond, London TW9 3DS, UK
| | - Miguel Blázquez
- Department of Mycology, Real Jardín Botánico (CSIC), 28014 Madrid, Spain; (M.B.); (S.P.-O.)
| | | | - Sergio Pérez-Ortega
- Department of Mycology, Real Jardín Botánico (CSIC), 28014 Madrid, Spain; (M.B.); (S.P.-O.)
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4
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Composition, structure and robustness of Lichen guilds. Sci Rep 2023; 13:3295. [PMID: 36841885 PMCID: PMC9968342 DOI: 10.1038/s41598-023-30357-w] [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: 01/17/2023] [Accepted: 02/21/2023] [Indexed: 02/27/2023] Open
Abstract
Symbiosis is a major engine of evolutionary innovation underlying many extant complex organisms. Lichens are a paradigmatic example that offers a unique perspective on the role of symbiosis in ecological success and evolutionary diversification. Lichen studies have produced a wealth of information regarding the importance of symbiosis, but they frequently focus on a few species, limiting our understanding of large-scale phenomena such as guilds. Guilds are groupings of lichens that assist each other's proliferation and are intimately linked by a shared set of photobionts, constituting an extensive network of relationships. To characterize the network of lichen symbionts, we used a large data set ([Formula: see text] publications) of natural photobiont-mycobiont associations. The entire lichen network was found to be modular, but this organization does not directly match taxonomic information in the data set, prompting a reconsideration of lichen guild structure and composition. The multiscale nature of this network reveals that the major lichen guilds are better represented as clusters with several substructures rather than as monolithic communities. Heterogeneous guild structure fosters robustness, with keystone species functioning as bridges between guilds and whose extinction would endanger global stability.
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5
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Masumoto H, Sanders WB. The Lichen Photobiont Genus Rhizonema (cyanobacteria) Exhibits Diverse Modes of Branching, Both False and True. JOURNAL OF PHYCOLOGY 2022; 58:612-625. [PMID: 35567534 DOI: 10.1111/jpy.13256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
The recently described genus Rhizonema is among the most important cyanobacterial partners in lichen symbioses, but its morphological characterization in the genus diagnosis-true branching of the T-type-appears at odds with several published figures showing false branching. We investigated cyanobiont branching and cell division with light microscopy in two basidiolichens from Florida and one from Japan, including aposymbiotically cultured material of the latter. Mycobiont species identities (Cyphellostereum jamesianum, Dictyonema darwinianum, and D. moorei) and photobiont genus identity (Rhizonema) were corroborated with ITS and rbcLX sequences, respectively. Single and paired false branching occurred commonly in all three strains examined. False branches developed adjacent to necridic cells or heterocytes, or by separation of vegetative cells at compression folds in the trichome. Non-transverse cell divisions, usually oblique, were observed in two of the three Rhizonema strains examined. T-type true branches sometimes arose from such divisions, although oblique growth from the branch cell often resulted in ambiguous branch junctions. Additionally, Y-type true branches appeared to grow from contorted filaments. In cultured material, a kind of pseudo-branch sometimes arose from single- or several-celled segments liberated from trichome apices. The segments attached secondarily to filaments and grew there as apparent branches. We conclude that Rhizonema is a genus of considerable morphological flexibility, with multiple modes of branching possible in a single strain. While true branching or non-transverse divisions, when observable, may help distinguish Rhizonema from the phenotypically similar Scytonema, false branching occurs commonly in both genera, and therefore cannot be used to distinguish them.
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Affiliation(s)
- Hiroshi Masumoto
- Laboratory of Terrestrial Microbiology and Systematics, Graduate School of Global Environmental Studies, Kyoto University, Yoshida-Honmachi, Kyoto, 606-8501, Japan
| | - William B Sanders
- Department of Biological Sciences, Florida Gulf Coast University, 10501 FGCU Blvd. South, Ft. Myers, Florida, USA
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6
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Allen JL, Lendemer JC. A call to reconceptualize lichen symbioses. Trends Ecol Evol 2022; 37:582-589. [PMID: 35397954 DOI: 10.1016/j.tree.2022.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 12/23/2022]
Abstract
Several decades of research across disciplines have overturned historical perspectives of symbioses dominated by binary characterizations of highly specific species-species interactions. This paradigm shift has unlocked the previously underappreciated and overlooked dynamism of fungal mutualisms such as mycorrhizae. Lichens are another example of important fungal mutualisms where reconceptualization is urgently needed to realize their potential as model systems. This reconceptualization requires both an objective synthesis of new data and envisioning a revised integrative approach that unifies the spectrum of ecology and evolution. We propose a ten-theme framework that if pursued would propel lichens to the vanguard of symbiotic theory.
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Affiliation(s)
- Jessica L Allen
- Eastern Washington University, Biology Department, Cheney, WA 99004, USA.
| | - James C Lendemer
- Institute of Systematic Botany, The New York Botanical Garden, Bronx, NY 10458-5126, USA.
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7
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Cyphellostereum ushimanum sp. nov. (Hygrophoraceae, Agaricales) described from Amami-Oshima Island (Kagoshima Prefecture, Ryukyu Islands), Japan, with ultrastructural observations of its Rhizonema photobiont filaments penetrated longitudinally by a central haustorium. Mycol Prog 2022. [DOI: 10.1007/s11557-021-01766-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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8
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Rieseberg L, Warschefsky E, O'Boyle B, Taberlet P, Ortiz-Barrientos D, Kane NC, Sibbett B. Editorial 2022. Mol Ecol 2021; 31:1-30. [PMID: 34957606 DOI: 10.1111/mec.16328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/10/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Loren Rieseberg
- Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | - Pierre Taberlet
- Laboratoire d'Ecologie Alpine, CNRS UMR 5553, Université Univ. Grenoble Alpes, Grenoble Cedex 9, France
| | - Daniel Ortiz-Barrientos
- School of Biological Sciences, The University of Queenland, St. Lucia, Queensland, Australia
| | - Nolan C Kane
- University of Colorado at Boulder, Boulder, Colorado, USA
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9
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Jung P, Brust K, Schultz M, Büdel B, Donner A, Lakatos M. Opening the Gap: Rare Lichens With Rare Cyanobionts - Unexpected Cyanobiont Diversity in Cyanobacterial Lichens of the Order Lichinales. Front Microbiol 2021; 12:728378. [PMID: 34690969 PMCID: PMC8527099 DOI: 10.3389/fmicb.2021.728378] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/25/2021] [Indexed: 11/13/2022] Open
Abstract
The last decades of research led to a change in understanding of lichens that are now seen as self-sustaining micro-ecosystems, harboring diverse microbial organisms in tight but yet not fully understood relationships. Among the diverse interdependencies, the relationship between the myco- and photobiont is the most crucial, determining the shape, and ecophysiological properties of the symbiotic consortium. Roughly 10% of lichens associate with cyanobacteria as their primary photobiont, termed cyanolichens. Up to now, the diversity of cyanobionts of bipartite lichens resolved by modern phylogenetic approaches is restricted to the filamentous and heterocytous genera of the order Nostocales. Unicellular photobionts were placed in the orders Chroococcales, Pleurocapsales, and Chroococcidiopsidales. However, especially the phylogeny and taxonomy of the Chroococcidiopsidales genera remained rather unclear. Here we present new data on the identity and phylogeny of photobionts from cyanolichens of the genera Gonohymenia, Lichinella, Peccania, and Peltula from a broad geographical range. A polyphasic approach was used, combining morphological and cultivation-depending characteristics (microscopy, staining techniques, life cycle observation, baeocyte motility, and nitrogen fixation test) with phylogenetic analyses of the 16S rRNA and 16S–23S ITS gene region. We found an unexpectedly high cyanobiont diversity in the cyanobacterial lichens of the order Lichinales, including two new genera and seven new species, all of which were not previously perceived as lichen symbionts. As a result, we describe the novel unicellular Chroococcidiopsidales genera Pseudocyanosarcina gen. nov. with the species Pseudocyanosarcina phycocyania sp. nov. (from Peltula clavata, Australia) and Compactococcus gen. nov. with the species Compactococcus sarcinoides sp. nov. (from Gonohymenia sp., Australia) and the new Chroococcidiopsidales species Aliterella compacta sp. nov. (from Peltula clavata, Australia), Aliterella gigantea sp. nov. (from Peltula capensis; South Africa), Sinocapsa ellipsoidea sp. nov. (from Peccania cerebriformis, Austria), as well as the two new Nostocales species Komarekiella gloeocapsoidea sp. nov. (from Gonohymenia sp., Czechia) and Komarekiella globosa sp. nov. (from Lichinella cribellifera, Canary Islands, Spain). Our study highlights the role of cyanolichens acting as a key in untangling cyanobacterial taxonomy and diversity. With this study, we hope to stimulate further research on photobionts, especially of rare cyanolichens.
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Affiliation(s)
- Patrick Jung
- Department of Integrative Biotechnology, University of Applied Sciences Kaiserslautern, Pirmasens, Germany
| | - Katharina Brust
- Ecology Group, Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Matthias Schultz
- Institute for Plant Science and Microbiology, Herbarium Hamburgense, University of Hamburg, Hamburg, Germany
| | - Burkhard Büdel
- Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Antje Donner
- Faculty of Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Michael Lakatos
- Department of Integrative Biotechnology, University of Applied Sciences Kaiserslautern, Pirmasens, Germany
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10
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Kaasalainen U, Tuovinen V, Mwachala G, Pellikka P, Rikkinen J. Complex Interaction Networks Among Cyanolichens of a Tropical Biodiversity Hotspot. Front Microbiol 2021; 12:672333. [PMID: 34177853 PMCID: PMC8220813 DOI: 10.3389/fmicb.2021.672333] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
Interactions within lichen communities include, in addition to close mutualistic associations between the main partners of specific lichen symbioses, also more elusive relationships between members of a wider symbiotic community. Here, we analyze association patterns of cyanolichen symbionts in the tropical montane forests of Taita Hills, southern Kenya, which is part of the Eastern Afromontane biodiversity hotspot. The cyanolichen specimens analyzed represent 74 mycobiont taxa within the order Peltigerales (Ascomycota), associating with 115 different variants of the photobionts genus Nostoc (Cyanobacteria). Our analysis demonstrates wide sharing of photobionts and reveals the presence of several photobiont-mediated lichen guilds. Over half of all mycobionts share photobionts with other fungal species, often from different genera or even families, while some others are strict specialists and exclusively associate with a single photobiont variant. The most extensive symbiont network involves 24 different fungal species from five genera associating with 38 Nostoc photobionts. The Nostoc photobionts belong to two main groups, the Nephroma-type Nostoc and the Collema/Peltigera-type Nostoc, and nearly all mycobionts associate only with variants of one group. Among the mycobionts, species that produce cephalodia and those without symbiotic propagules tend to be most promiscuous in photobiont choice. The extent of photobiont sharing and the structure of interaction networks differ dramatically between the two major photobiont-mediated guilds, being both more prevalent and nested among Nephroma guild fungi and more compartmentalized among Peltigera guild fungi. This presumably reflects differences in the ecological characteristics and/or requirements of the two main groups of photobionts. The same two groups of Nostoc have previously been identified from many lichens in various lichen-rich ecosystems in different parts of the world, indicating that photobiont sharing between fungal species is an integral part of lichen ecology globally. In many cases, symbiotically dispersing lichens can facilitate the dispersal of sexually reproducing species, promoting establishment and adaptation into new and marginal habitats and thus driving evolutionary diversification.
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Affiliation(s)
- Ulla Kaasalainen
- Department of Geobiology, University of Göttingen, Göttingen, Germany.,Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland
| | - Veera Tuovinen
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | | | - Petri Pellikka
- Department of Geosciences and Geography, University of Helsinki, Helsinki, Finland.,State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan, China
| | - Jouko Rikkinen
- Finnish Museum of Natural History, University of Helsinki, Helsinki, Finland.,Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
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11
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Nelsen MP. Sharing and double-dating in the lichen world. Mol Ecol 2021; 30:1751-1754. [PMID: 33720470 DOI: 10.1111/mec.15884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/03/2021] [Indexed: 11/28/2022]
Abstract
Historic and modern efforts to understand lichen diversity and evolution have overwhelmingly concentrated on that of the fungal partner, which represents one of the most taxonomically diverse nutritional modes among the Fungi. But what about the algal and cyanobacterial symbionts? An explosion of studies on these cryptic symbionts over the past 20+ years has facilitated a richer understanding of their diversity, patterns of association, and the symbiosis itself. In a From the Cover article in this issue of Molecular Ecology, Dal Forno et al. (2021) provide new insight into one of the most fascinating lichen symbioses. By sequencing cyanobacterial symbionts from over 650 specimens, they reveal the presence of overlooked cyanobacterial diversity, evidence for symbiont sharing among distantly related fungi, and utilize a comparative dating framework to demonstrate temporal discordance among interacting fungal and cyanobacterial lineages.
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Affiliation(s)
- Matthew P Nelsen
- Negaunee Integrative Research Center and Grainger Bioinformatics Center, The Field Museum, Chicago, IL, USA
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12
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Dal Forno M, Lawrey JD, Sikaroodi M, Gillevet PM, Schuettpelz E, Lücking R. Extensive photobiont sharing in a rapidly radiating cyanolichen clade. Mol Ecol 2020; 30:1755-1776. [PMID: 33080083 DOI: 10.1111/mec.15700] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 09/24/2020] [Accepted: 10/13/2020] [Indexed: 01/21/2023]
Abstract
Recent studies have uncovered remarkable diversity in Dictyonema s.lat. basidiolichens, here recognized as subtribe Dictyonemateae. This group includes five genera and 148 species, but hundreds more await description. The photobionts of these lichens belong to Rhizonema, a recently resurrected cyanobacterial genus known by a single species. To further investigate photobiont diversity within Dictyonemateae, we generated 765 new cyanobacterial sequences from 635 specimens collected from 18 countries. The ITS barcoding locus supported the recognition of 200 mycobiont (fungal) species among these samples, but the photobiont diversity was comparatively low. Our analyses revealed three main divisions of Rhizonema, with two repeatedly recovered as monophyletic (proposed as new species), and the third mostly paraphyletic. The paraphyletic lineage corresponds to R. interruptum and partnered with mycobionts from all five genera in Dictyonemateae. There was no evidence of photobiont-mycobiont co-speciation, but one of the monophyletic lineages of Rhizonema appears to partner predominantly with one of the two major clades of Cora (mycobiont) with samples collected largely from the northern Andes. Molecular clock estimations indicate the Rhizonema species are much older than the fungal species in the Dictyonemateae, suggesting that these basidiolichens obtained their photobionts from older ascolichen lineages and the photobiont variation in extant lineages of Dictyonemateae is the result of multiple photobiont switches. These results support the hypothesis of lichens representing "fungal farmers," in which diverse mycobiont lineages associate with a substantially lower diversity of photobionts by sharing those photobionts best suited for the lichen symbiosis among multiple and often unrelated mycobiont lineages.
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Affiliation(s)
- Manuela Dal Forno
- Botanical Research Institute of Texas, Fort Worth, TX, USA.,Department of Botany, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
| | - James D Lawrey
- Department of Biology, George Mason University, Fairfax, VA, USA
| | | | | | - Eric Schuettpelz
- Department of Botany, Smithsonian Institution, National Museum of Natural History, Washington, DC, USA
| | - Robert Lücking
- Botanical Garden and Botanical Museum Berlin, Berlin, Germany.,Research Associate, Science & Education, The Field Museum, Chicago, IL, USA
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