Project description:Collectively classified as white-rot fungi, certain basidiomycetes efficiently degrade the major structural polymers of wood cell walls. A small subset of these Agaricomycetes, exemplified by Phlebiopsis gigantea, is capable of colonizing freshly exposed conifer sapwood despite its high pitch content, which retards the establishment of other fungal species. The mechanism(s) by which P. gigantea tolerates and metabolizes resinous compounds have not been explored. Here, we report the annotated P. gigantea genome and compare profiles of its transcriptome and secretome when cultured on fresh-cut versus solvent-extracted loblolly pine. The P. gigantea genome contains a conventional repertoire of hydrolase genes involved in cellulose/hemicellulose degradation, whose patterns of expression were relatively unperturbed by the absence of extractives. The expression of genes typically ascribed to lignin degradation was also largely unaffected. In contrast, genes likely involved in the transformation and detoxification of pitch were highly induced in its presence. Their products included an ABC transporter, lipases, cytochrome P450s, glutathione S-transferase and aldehyde dehydrogenase. Other regulated genes of unknown function and several constitutively expressed genes are also likely involved in P. gigantea’s pitch metabolism. These results contribute to our fundamental understanding of conifer colonization and carbon cycling processes. Phlebiopsis gigantea was cultivated in media containing one of three carbon sources: freshly harvested loblolly pine (3 replicates), acetone extracted lobollly pine (3 replicates), or glucose (2 replicates). RNA was extracted and processed for Illumina sequencing as described below.
Project description:In this study, C. gigantea miRNAs and their target genes were investigated by extracting RNA from young roots, tender stems, young leaves, and flower buds of C. gigantea to establish a small RNA (sRNA) library and a degradome library to further sequence. This study identified 194 known miRNAs belonging to 52 miRNA families and 23 novel miRNAs. Among the miRNA families, 158 miRNAs from 27 miRNA families were highly conserved and existed in a plurality of plants. In addition, 60 different targets for 30 known families and one target for novel miRNA were identified by high-throughput sequencing and degradome analysis in C. gigantea. Our analyses showed that conserved miRNAs have higher expression levels and more family members as well as more targets than other miRNAs. Meanwhile, these conserved miRNAs were found to be involved in auxin signal transduction, regulation of transcription, and other developmental processes in plants, which will help further understanding regulatory mechanisms of C. gigantea miRNAs. The samples were collected from the young roots, tender shoots, young leaves and flower buds of wild C. gigantea growing in Jiangsu Province. TRIzol reagent (Invitrogen, USA) was used to extract the total RNAs [20]. An Illumina next-generation sequencing system, i.e. the 1 G Genome Analyzer sequencing platform, was utilized for sRNA sequencing. An Illumina HiSeq 2000 (LC Sciences, USA) was used for degradome sequencing.