Reconstruction of structural evolution in the trnL intron P6b loop of symbiotic Nostoc (Cyanobacteria)

Olsson, Sanna; Kaasalainen, Ulla; Rikkinen, Jouko

doi:10.1007/s00294-011-0364-0

Cited by 16 publications

(19 citation statements)

References 39 publications

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“…; Olsson et al. ). Most Nostoc tRNA Leu (UAA) intron genotypes identified from the cephalodia of the tripartite lichen Nephroma arcticum also had a Class 1 repeat motif in the P6b region.…”

Section: Resultsmentioning

confidence: 97%

“…The analyses were performed with MrBayes v3.1.2 (Huelsenbeck and Ronquist ) as described in Olsson et al. (). Maximum‐likelihood analyses were performed with Garli v2.0 (Zwickl ).…”

Section: Methodsmentioning

confidence: 99%

“…The best fitting nucleotide substitution models were selected by jModel-Test using AIC and BIC (Posada 2008), and the GTR+I +Γ model was applied for all three regions in all analyses. The analyses were performed with MrBayes v3.1.2 (Huelsenbeck and Ronquist 2001) as described in Olsson et al (2012). Maximum-likelihood analyses were performed with Garli v2.0 (Zwickl 2006).…”

Section: Phylogenetic Analysis Of Fungal Its Sequencesmentioning

confidence: 99%

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Geographic mosaic of symbiont selectivity in a genus of epiphytic cyanolichens

Fedrowitz

Kaasalainen

Rikkinen

2012

Ecology and Evolution

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In symbiotic systems, patterns of symbiont diversity and selectivity are crucial for the understanding of fundamental ecological processes such as dispersal and establishment. The lichen genus Nephroma (Peltigerales, Ascomycota) has a nearly cosmopolitan distribution and is thus an attractive model for the study of symbiotic interactions over a wide range of spatial scales. In this study, we analyze the genetic diversity of Nephroma mycobionts and their associated Nostoc photobionts within a global framework. The study is based on Internal Transcribed Spacer (ITS) sequences of fungal symbionts and tRNALeu (UAA) intron sequences of cyanobacterial symbionts. The full data set includes 271 Nephroma and 358 Nostoc sequences, with over 150 sequence pairs known to originate from the same lichen thalli. Our results show that all bipartite Nephroma species associate with one group of Nostoc different from Nostoc typically found in tripartite Nephroma species. This conserved association appears to have been inherited from the common ancestor of all extant species. While specific associations between some symbiont genotypes can be observed over vast distances, both symbionts tend to show genetic differentiation over wide geographic scales. Most bipartite Nephroma species share their Nostoc symbionts with one or more other fungal taxa, and no fungal species associates solely with a single Nostoc genotype, supporting the concept of functional lichen guilds. Symbiont selectivity patterns within these lichens are best described as a geographic mosaic, with higher selectivity locally than globally. This may reflect specific habitat preferences of particular symbiont combinations, but also the influence of founder effects.

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“…; Olsson et al. ). Most Nostoc tRNA Leu (UAA) intron genotypes identified from the cephalodia of the tripartite lichen Nephroma arcticum also had a Class 1 repeat motif in the P6b region.…”

Section: Resultsmentioning

confidence: 97%

“…The analyses were performed with MrBayes v3.1.2 (Huelsenbeck and Ronquist ) as described in Olsson et al. (). Maximum‐likelihood analyses were performed with Garli v2.0 (Zwickl ).…”

Section: Methodsmentioning

confidence: 99%

Section: Phylogenetic Analysis Of Fungal Its Sequencesmentioning

confidence: 99%

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Geographic mosaic of symbiont selectivity in a genus of epiphytic cyanolichens

Fedrowitz

Kaasalainen

Rikkinen

2012

Ecology and Evolution

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“…For the mcyE and 16S genes the GTR+Γ and GTR+I+Γ model was applied, respectively. The best-fitting nucleotide substitution models were selected, analyses were performed, and figures were drawn and edited as previously described (43).…”

Section: Methodsmentioning

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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“…The structural evolution in the P6b region of trnL sequences was studied further by Olsson et al (2012). All the analyzed sequences were amplified from the monophyletic group of lichen symbiotic Nostoc that characterizes all lichens of the Nephroma guild.…”

Section: From Single Thalli To Global Distribution Patternsmentioning

confidence: 99%

Molecular studies on cyanobacterial diversity in lichen symbioses

Rikkinen¹

2013

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Citation: Rikkinen J (2013) Molecular studies on cyanobacterial diversity in lichen symbioses. In: Boonpragob K, Crittenden P, Lumbsch HT (Eds) Lichens: from genome to ecosystems in a changing world. MycoKeys 6: 3-32. doi:10.3897/mycokeys.6.3869 AbstractSymbioses between cyanobacteria and lichen-forming fungi occur worldwide in a wide range of terrestrial environments, ranging from tropical rainforests to hot and cold deserts. The evolutionary success of these symbioses is evident from the wide range of fungal groups that have established associations with cyanobacteria. The diversity of symbiotic cyanobacteria is also high, and it is obvious that symbioses between different cyanobacteria and different lichen-forming fungi have evolved on multiple occasions. From the late 1990s cyanobacterial lichens have been the subject of a steadily increasing number of molecular investigations. This chronological review examines how these studies have contributed to present knowledge and highlights some conceptual developments that have been instrumental in the process.

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Reconstruction of structural evolution in the trnL intron P6b loop of symbiotic Nostoc (Cyanobacteria)

Cited by 16 publications

References 39 publications

Geographic mosaic of symbiont selectivity in a genus of epiphytic cyanolichens

Geographic mosaic of symbiont selectivity in a genus of epiphytic cyanolichens

Cyanobacteria produce a high variety of hepatotoxic peptides in lichen symbiosis

Molecular studies on cyanobacterial diversity in lichen symbioses

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