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Background Saprophytic filamentous fungi are ubiquitous micro-organisms that play an essential role in photosynthetic carbon recycling. The wood-decayer Pycnoporus cinnabarinus is a model fungus for the study of plant cell wall decomposition and is used for a number of applications in green and white biotechnology. Results The 33.6 megabase genome of P. cinnabarinus was sequenced and assembled, and the 10,442 predicted genes were functionally annotated using a phylogenomic procedure. Indepth analyses were carried out for the numerous enzyme families involved in lignocellulosic biomass breakdown, for protein secretion and glycosylation pathways, and for mating type. The P. cinnabarinus genome sequence revealed a consistent repertoire of genes shared with wood-decaying basidiomycetes. P. cinnabarinus is thus fully equipped with the classical families involved in cellulose and hemicellulose degradation, whereas its pectinolytic repertoire appears relatively limited. In addition, P. cinnabarinus possesses a complete versatile enzymatic arsenal for lignin breakdown. We identified several genes encoding members of the three ligninolytic peroxidase types, namely lignin peroxidase, manganese peroxidase and versatile peroxidase. Comparative genome analyses were performed in fungi displaying different nutritional strategies (white-rot and brown-rot modes of decay). P. cinnabarinus presents a typical distribution of all the specific families found in the white-rot life style. Growth profiling of P. cinnabarinus was performed on 35 carbon sources including simple and complex substrates to study substrate utilization and preferences. P. cinnabarinus grew faster on crude plant substrates than on pure, mono- or polysaccharide substrates. Finally, proteomic analyses were conducted from liquid and solid-state fermentation to analyze the composition of the secretomes corresponding to growth on different substrates. The distribution of lignocellulolytic enzymes in the secretomes was strongly dependent on growth conditions, especially for lytic polysaccharide mono-oxygenases. Conclusions With its available genome sequence, P. cinnabarinus is now an outstanding model system for the study of the enzyme machinery involved in the degradation or transformation of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

The genus P ycnoporus forms a group of four species known especially for producing high redox potential laccases suitable for white biotechnology. A sample of 36 P ycnoporus strains originating from different geographical areas was studied to seek informative molecular markers for the typing of new strains in laboratory culture conditions and to analyse the phylogeographic relationships in this cosmopolitan group. ITS1-5.8 S- ITS2 ribosomal DNA and partial regions of β-tubulin and laccase lac3-1 gene were sequenced. Phylogenetic trees inferred from these sequences clearly differentiated the group of P ycnoporus cinnabarinus strains from the group of P ycnoporus puniceus strains into strongly supported clades (100% bootstrap value). Molecular clustering based on lac 3-1 sequences enabled the distribution of P ycnoporus sanguineus and P ycnoporus coccineus through four distinct, well supported clades and sub-clades. A neotropical sub-clade, grouping the P . sanguineus strains from French Guiana and Venezuela, corresponded to P . sanguineus sensu stricto. A paleotropical sub-clade, clustering the strains from Madagascar, Vietnam and New Caledonia, was defined as P ycnoporus cf. sanguineus. The Australian clade corresponded to P . coccineus sensu stricto. The Eastern Asian region clade, clustering the strains from China and Japan, formed a P . coccineus-like group. Laccase gene ( lac 3-1) analysis within the Pycnoporus species can highlight enzyme functional diversity associated with biogeographical origin. [ABSTRACT FROM AUTHOR]

The Pycnoporus fungi are white-rot basidiomycetes listed as food- and cosmetic-grade microorganisms. Three high redox potential laccases from Pycnoporus coccineus and Pycnoporus sanguineus were tested and compared, with the commercial Suberase® as reference, for their ability to synthesise natural active oligomers from rutin (quercetin-3-rutinoside, one of the best-known naturally occurring flavonoid glycosides). The aim of this work was to develop a process with technical parameters (solvent, temperature, reaction time and raw materials) that were easy to scale up for industrial production and compatible with cosmetic and pharmaceutical formulation guidelines. The aqueous mixture of glycerol/ethanol/buffer described in this study met this requirement and allowed the solubilisation of rutin and its oxidative bioconversion into oligomers. The four flavonoid oligomer mixtures synthesised using laccases as catalysts were analysed by high performance liquid chromatography-diode array detection-negative electrospray ionisation-multistage mass spectrometry. Their chromatographic elution profiles were compared and 16 compounds were characterised and identified as dimers and trimers of rutin. The oligorutins were different in Suberase® and Pycnoporus laccase reaction mixtures. They were evaluated for their antioxidant, anti-inflammatory and anti-ageing activities on specific enzymatic targets such as cyclooxygenase (COX-2) and human matrix metalloproteinase 3 (MMP-3). Expressed in terms of IC, the flavonoid oligomers displayed a 2.5- to 3-fold higher superoxide scavenging activity than monomeric rutin. Pycnoporus laccase and Suberase® oligorutins led to an inhibition of COX-2 of about 35% and 70%, respectively, while monomeric rutin showed a near-negligible inhibition effect, less than about 10%. The best results on MMP-3 activity were obtained with rutin oligomers from P. sanguineus IMB W006-2 laccase and Suberase® with about 70-75% inhibition. [ABSTRACT FROM AUTHOR]