Transcriptional and Enzymatic Profiling of Pleurotus ostreatus Laccase Genes in Submerged and Solid-State Fermentation Cultures

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>The genome of the white rot basidiomycete<jats:named-content content-type="genus-species">Pleurotus ostreatus</jats:named-content>includes 12 phenol oxidase (laccase) genes. In this study, we examined their expression profiles in different fungal strains under different culture conditions (submerged and solid cultures) and in the presence of a wheat straw extract, which was used as an inducer of the laccase gene family. We used a reverse transcription-quantitative PCR (RT-qPCR)-based approach and focused on determining the reaction parameters (in particular, the reference gene set for the normalization and reaction efficiency determinations) used to achieve an accurate estimation of the relative gene expression values. The results suggested that (i) laccase gene transcription is upregulated in the induced submerged fermentation (iSmF) cultures but downregulated in the solid fermentation (SSF) cultures, (ii) the<jats:italic>Lacc2</jats:italic>and<jats:italic>Lacc10</jats:italic>genes are the main sources of laccase activity in the iSmF cultures upon induction with water-soluble wheat straw extracts, and (iii) an additional, as-yet-uncharacterized activity (Unk1) is specifically induced in SSF cultures that complements the activity of Lacc2 and Lacc10. Moreover, both the enzymatic laccase activities and the<jats:italic>Lacc</jats:italic>gene family transcription profiles greatly differ between closely related strains. These differences can be targeted for biotechnological breeding programs for enzyme production in submerged fermentation reactors.</jats:p>

Genome-wide functional analysis of SSR for an edible mushroom Pleurotus ostreatus

“…In PC15 genome, 9 genes were detected to encode manganese-peroxidase (mnp1-mnp9) (Salame et al, 2012), just one of them (mnp3) had the structure of SSR. Phenol oxidase (laccase) is another kind of enzyme especially for fungi to degrade lignin (Castanera et al, 2012). For 12 genes encoding laccase (lacc1-lacc12) in PC15 genome, just one of them (lacc1) contained the SSR segment.…”

Influence of initial pH of the growing medium on the activity, production and expression profiles of laccases produced by Pleurotus ostreatus in submerged fermentation

“…Luis et al (2005) found different expression levels of laccase genes in basidiomycetes isolated from soil. Castanera et al (2012) examined the expression profiling of laccases of different strains of P. ostreatus and found that the activity and expression of these enzymes depend on the strain used in solid state fermentation and in SmF. Several studies have been carried out in order to know the enzymatic inductor type and the enzymatic inductor concentration as well as the composition of the culture medium to increase the laccases activity, however, there is very little information on the effect of the initial pH of the growing medium on the molecular and enzymatic aspects of laccase of P. ostreatus.…”

Optimization of laccase production in the white-rot fungusPleurotus ostreatus(ACCC 52857) induced through yeast extract and copper

“…[10] Lacc2 and Lacc10 are highly expressed under submerged conditions. [11,27] Previous work in our lab showed that laccase activity and the degree of induction differed among different P. ostreatus strains isolated from different districts in China (unpublished data). A similar result was obtained in Flammulina velutipes.…”