Lichen Guilds Share Related Cyanobacterial Symbionts

Rikkinen, Jouko; Oksanen, Ilona; Lohtander, Katileena

doi:10.1126/science.1072961

Cited by 164 publications

(230 citation statements)

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“…This is true both for sexual species with horizontal photobiont transmission (P. canina, P. membranacea, P. rufescens) and for species that produce specialized asexually derived codispersal propagules (P. didactyla). Sharing of photobiont genotypes among different host species has also been reported previously among members of the Nephromataceae (Rikkinen et al, 2002;Lohtander et al, 2003;Wirtz et al, 2003), as well as within bryophytes (Costa et al, 2001) and cycads (Costa et al, 1999), but ours is the first study to include large enough sample sizes of both plant symbionts and lichen photobionts to infer that symbiont sharing among unrelated hosts is common. These results contradict earlier studies, based on smaller datasets, which suggested that species-level host specialization was prevalent in cyanolichens and that host species was a better predictor of symbiont genotype than geography (Paulsrud et al, , 2000.…”

Section: Discussionmentioning

confidence: 81%

Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera

O’Brien

Miądlikowska

Lutzoni

2005

European Journal of Phycology

114

116

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Heterocystous cyanobacteria form symbiotic associations with a wide range of plant and fungal hosts. We used a molecular phylogenetic approach to investigate the degree of host specialization of cyanobacteria associated with four closely related species of the lichenized fungus Peltigera, and to compare these strains with other symbiotic cyanobacteria. We conducted phylogenetic analyses on 16S, rbcLX, and trnL sequences from cyanobacteria associated with multiple specimens of each lichen species and from symbionts of other fungi and plants, as well as from free-living strains of Nostoc and related genera of cyanobacteria. The genus Nostoc comprises two divergent lineages, but symbiotic strains occur primarily within a single monophyletic lineage that also includes free-living representatives. Cyanobacteria from the same lichen species were often more closely related to strains from other species or to plant symbionts or free-living strains than to each other. These results indicate that host specialization is low for the genus Nostoc, and suggest that opportunities for coevolution with its partners may be rare.

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Section: Discussionmentioning

confidence: 81%

Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera

O’Brien

Miądlikowska

Lutzoni

2005

European Journal of Phycology

114

116

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“…strain 152. The lichen-symbiotic Nostoc form several lineages, including those associated with host fungi of the Nephroma guild (A-F) and the Peltigera guild (G-L) (4,12). This shows that the geographical origin of a lichen specimen does not predict the identity of the Nostoc symbiont, and that the production of detectable amounts of toxins is not restricted to well-defined groups within Nostoc.…”

Section: Resultsmentioning

confidence: 92%

“…However, the known diversity of symbiotic Nostoc in lichen symbiosis far exceeds that of free-living Nostoc (2, 3). Extensive sampling of lichen communities has shown that most lichenized fungi tend to associate with restricted groups of Nostoc genotypes (4,5). Nevertheless, the identity of the cyanobacterial symbiont has been found for just a small percentage of all cyanolichen species, and tropical cyanolichens, in particular, have received very little attention.…”

mentioning

confidence: 99%

Cyanobacteria produce a high variety of hepatotoxic peptides in lichen symbiosis

Kaasalainen¹,

Fewer

Jokela

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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150

124

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Lichens are symbiotic associations between fungi and photosynthetic algae or cyanobacteria. Microcystins are potent toxins that are responsible for the poisoning of both humans and animals. These toxins are mainly associated with aquatic cyanobacterial blooms, but here we show that the cyanobacterial symbionts of terrestrial lichens from all over the world commonly produce microcystins. We screened 803 lichen specimens from five different continents for cyanobacterial toxins by amplifying a part of the gene cluster encoding the enzyme complex responsible for microcystin production and detecting toxins directly from lichen thalli. We found either the biosynthetic genes for making microcystins or the toxin itself in 12% of all analyzed lichen specimens. A plethora of different microcystins was found with over 50 chemical variants, and many of the variants detected have only rarely been reported from free-living cyanobacteria. In addition, high amounts of nodularin, up to 60 μg g −1 , were detected from some lichen thalli. This microcystin analog and potent hepatotoxin has previously been known only from the aquatic bloom-forming genus Nodularia. Our results demonstrate that the production of cyanobacterial hepatotoxins in lichen symbiosis is a global phenomenon and occurs in many different lichen lineages. The very high genetic diversity of the mcyE gene and the chemical diversity of microcystins suggest that lichen symbioses may have been an important environment for diversification of these cyanobacteria.Nostoc | Peltigera | cyanolichen | secondary metabolites | chemical defence

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“…Clustering of Nostoc sp. PCC 73102 with Gunnera and lichen symbionts has been previously shown in other studies (Svenning et al, 2005;Rikkinen et al, 2002). Nostoc sp.…”

Section: Phylogenetic Analysismentioning

confidence: 93%

Differential patterns of evolution and distribution of the symbiotic behaviour in nostocacean cyanobacteria

Papaefthimiou

Hrouzek

Mugnai

et al. 2008

INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLO

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Many cyanobacteria commonly identified as belonging to the genus Nostoc are well-known cyanobionts (symbionts) of a wide variety of plants and fungi. They form symbioses with bryophytes, pteridophytes, gymnosperms and angiosperms that are considerably different in the type of reciprocal interaction between the host and the cyanobiont. The phylogenetic and taxonomic relationships among cyanobionts isolated from different hosts and Nostoc strains isolated from free-living conditions are still not well understood. We compared phylogeny and morphology of symbiotic cyanobacteria originating from different host plants (genera Gunnera, Azolla, Cycas, Dioon, Encephalartos, Macrozamia and Anthoceros) with free-living Nostoc isolates originating from different habitats. After preliminary clustering with ARDRA (amplified rDNA restriction analysis), phylogeny was reconstructed on the basis of 16S rRNA gene sequences and compared with morphological characterization, obtaining several supported clusters. Two main Nostoc clusters harboured almost all cyanobionts of Gunnera, Anthoceros and of several cycads, together with free-living strains of the species Nostoc muscorum, Nostoc calcicola, Nostoc edaphicum, Nostoc ellipsosporum and strains related to Nostoc commune. We suggest that the frequent occurrence of symbiotic strains within these clusters is explained by the intensive hormogonia production that was observed in many of the strains studied. However, no evidence for discrimination between symbiotic and free-living strains, either by molecular or morphological approaches, could be found. Sequences of Azolla cyanobiont filaments, taken directly from leaf cavities, clustered tightly with sequences from the planktic cyanobacterium Cylindrospermopsis raciborskii, from the benthic Anabaena cylindrica 133 and from Anabaena oscillarioides HINDAK 1984/43, with high bootstrap values. The phylogenetic analysis showed that two distinct patterns of evolution of symbiotic behaviour might exist for the nostocacean cyanobacteria, one leading to symbioses of Nostoc species with a wide variety of plants, the other leading to the association of a unique cyanobacterial type with the water fern Azolla.

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Lichen Guilds Share Related Cyanobacterial Symbionts

Cited by 164 publications

References 1 publication

Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera

Assessing host specialization in symbiotic cyanobacteria associated with four closely related species of the lichen fungusPeltigera

Cyanobacteria produce a high variety of hepatotoxic peptides in lichen symbiosis

Differential patterns of evolution and distribution of the symbiotic behaviour in nostocacean cyanobacteria

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