Insights from the first putative biosynthetic gene cluster for a lichen depside and depsidone

Armaleo, Daniele; Sun, Xiameng; Culberson, Chicita F.

doi:10.3852/10-335

Cited by 102 publications

(119 citation statements)

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“…To date, several polyketide synthase (PKS) genes have been identified in different lichen-forming fungi [39-42], but no non-ribosomal peptide synthetase (NRPS) genes have been found. Analysis of the lichen-forming fungus E. pusillum genome revealed 2 NRPS genes and 14 PKS genes (Additional file 1: Table S4).…”

Section: Resultsmentioning

confidence: 99%

Genome characteristics reveal the impact of lichenization on lichen-forming fungus Endocarpon pusillum Hedwig (Verrucariales, Ascomycota)

et al. 2014

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BackgroundLichen is a classic mutualistic organism and the lichenization is one of the fungal symbioses. The lichen-forming fungus Endocarpon pusillum is living in symbiosis with the green alga Diplosphaera chodatii Bialsuknia as a lichen in the arid regions.Results454 and Illumina technologies were used to sequence the genome of E. pusillum. A total of 9,285 genes were annotated in the 37.5 Mb genome of E. pusillum. Analyses of the genes provided direct molecular evidence for certain natural characteristics, such as homothallic reproduction and drought-tolerance. Comparative genomics analysis indicated that the expansion and contraction of some protein families in the E. pusillum genome reflect the specific relationship with its photosynthetic partner (D. chodatii). Co-culture experiments using the lichen-forming fungus E. pusillum and its algal partner allowed the functional identification of genes involved in the nitrogen and carbon transfer between both symbionts, and three lectins without signal peptide domains were found to be essential for the symbiotic recognition in the lichen; interestingly, the ratio of the biomass of both lichen-forming fungus and its photosynthetic partner and their contact time were found to be important for the interaction between these two symbionts.ConclusionsThe present study lays a genomic analysis of the lichen-forming fungus E. pusillum for demonstrating its general biological features and the traits of the interaction between this fungus and its photosynthetic partner D. chodatii, and will provide research basis for investigating the nature of its drought resistance and symbiosis.

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Section: Resultsmentioning

confidence: 99%

Genome characteristics reveal the impact of lichenization on lichen-forming fungus Endocarpon pusillum Hedwig (Verrucariales, Ascomycota)

et al. 2014

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“…1). The PKSs include five from A. nidulans shown to produce orsellinic acid or derivatives (Ahuja et al, 2012), a PKS from Cladonia grayi hypothesized to be responsible for production of orsellinic acid in route to the synthesis of the orcinol depsidone grayanic acid (Armaleo et al, 2011), and a PKS from Coprinopsis cinerea shown in Saccharomyces cerevisiae to produce orsellinic acid (Ishiuchi et al, 2012). The resulting genealogy resolved the 32 PKSs into three major clades each with 100% bootstrap support.…”

Section: Phylogenetic Analyses Of Pks14mentioning

confidence: 99%

Fusarium graminearum PKS14 is involved in orsellinic acid and orcinol synthesis

Jørgensen

Frandsen

Nielsen

et al. 2014

Fungal Genetics and Biology

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a b s t r a c tThe available genome sequences show that the number of secondary metabolite genes in filamentous fungi vastly exceeds the number of known products. This is also true for the global plant pathogenic fungus Fusarium graminearum, which contains 15 polyketide synthase (PKS) genes, of which only 6 have been linked to products. To help remedy this, we focused on PKS14, which has only been shown to be expressed during plant infections or when cultivated on rice or corn meal (RM) based media. To enhance the production of the resulting product we introduced a constitutive promoter in front of PKS14 and cultivated two of the resulting mutants on RM medium. This led to the production of two compounds, which were only detected in the PKS14 overexpressing mutants and not in the wild type or PKS14 deletion mutants. The two compounds were tentatively identified as orsellinic acid and orcinol by comparing spectroscopic data (mass spectroscopy and chromatography) to authentic standards. NMR analysis of putative orcinol isolated from the PKS14 overexpressing mutant supported our identification. Orcinol and orsellinic acid, not previously detected in Fusarium, have primarily been detected in lichen fungi. Orsellinic acid is hypothesized to be the PKS release product which is transformed to orcinol through decarboxylation. Phylogenetic analyses of PKSs placed PKS14 in a subclade of known OA synthases. Expression analysis by microarray of 55 experiments identified seven genes near PKS14 that were expressed in a similar manner. One of the seven genes encodes a predicted carboxylase, which could be responsible for transforming orsellinic acid to orcinol.

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“…This procedure is similar to that proposed by Sala et al (1981) for the organic synthesis of some depsidones of Buellia canescens. However, Armaleo et al (2011) described the first lichen PKS cluster likely to be implicated in the biosynthesis of a depside and a depsidone. Among the many PKS genes in Cladonia grayi they are four, named CgrPKS13 to16, potentially responsible for grayanic acid biosynthesis.…”

Section: Depsidone Biosynthesismentioning

confidence: 99%