Transcription factors of Schizophyllum commune involved in mushroom formation and modulation of vegetative growth

Abstract

Mushrooms are the most conspicuous fungal structures. Transcription factors (TFs) Bri1 and Hom1 of the model fungus Schizophyllum commune are involved in late stages of mushroom development, while Wc-2, Hom2, and Fst4 function early in development. Here, it is shown that Bri1 and Hom1 also stimulate vegetative growth, while biomass formation is repressed by Wc-2, Hom2, and Fst4. The Δbri1Δbri1 and the Δhom1Δhom1 strains formed up to 0.6 fold less biomass when compared to wild-type, while Δwc-2Δwc-2, Δhom2Δhom2, and Δfst4Δfst4 strains formed up to 2.8 fold more biomass. Inactivation of TF gene tea1, which was downregulated in the Δwc-2Δwc-2, Δhom2Δhom2, and Δfst4Δfst4 strains, resulted in a strain that was severely affected in mushroom development and that produced 1.3 fold more biomass than the wild-type. In contrast, introducing a constitutive active version of hom2 that had 4 predicted phosphorylation motifs eliminated resulted in radial growth inhibition and prompt fructification in both Δhom2 and wild-type strains, even in sterile monokaryons. Together, it is concluded that TFs involved in mushroom formation also modulate vegetative growth. Among these TFs is the homeodomain protein Hom2, being the first time that this class of regulatory proteins is implicated in repression of vegetative growth in a eukaryote.

Comparative genomics reveals unique wood‐decay strategies and fruiting body development in the Schizophyllaceae

“…S5). This is consistent with previous RNA‐Seq based reports (Pelkmans et al ., ) in Schizophyllum and other species (Morin et al ., ; Plaza et al ., ; Zhou et al ., ; Pelkmans et al ., ), except for hom1 and gat1 , which, in the present data, behaved differently, probably due to the different resolution of developmental stage data. The expression profiles of all eight genes were similar between A. ampla and S. commune .…”

“…Fruiting body production is a highly integrated developmental process triggered by a changing environment, such as a drop in temperature, nutrient depletion or shifts in light conditions K€ ues & Navarro-Gonz alez, 2015;Sakamoto et al, 2018). It results from the concerted expression of structural and regulatory genes (Martin et al, 2008;Stajich et al, 2010;Ohm et al, 2011;Muraguchi et al, 2015;Nagy et al, 2016;Lau et al, 2018) as well as other processes, such as alternative splicing Krizs an et al, 2019), allele-specific gene expression and probably selective protein modification (Pelkmans et al, 2017;Krizs an et al, 2019). Known structural genes include ones coding for hydrophobins (Lugones et al, 1996;W€ osten et al, 1999;Bayry et al, 2012), lectins (Cooper et al, 1997;Boulianne et al, 2000;Hassan et al, 2015) and several cell wall chitin and glucan-active CAZymes (Wessels, 1994;Fukuda et al, 2008;Sakamoto et al, 2011), and probably include genes for ceratoplatanins, which are expansin-like proteins (Sipos et al, 2017;Krizs an et al, 2019), among others.…”

“…Known structural genes include ones coding for hydrophobins (Lugones et al, 1996;W€ osten et al, 1999;Bayry et al, 2012), lectins (Cooper et al, 1997;Boulianne et al, 2000;Hassan et al, 2015) and several cell wall chitin and glucan-active CAZymes (Wessels, 1994;Fukuda et al, 2008;Sakamoto et al, 2011), and probably include genes for ceratoplatanins, which are expansin-like proteins (Sipos et al, 2017;Krizs an et al, 2019), among others. Regulators of fruiting body development have been characterized in several species, in particular in Coprinopsis cinerea Cheng et al, 2013;de Sena-Tomas et al, 2013;Muraguchi et al, 2015;Masuda et al, 2016) and S. commune (Ohm et al, 2010(Ohm et al, , 2011Pelkmans et al, 2017). Despite advances in this field, several aspects of fruiting body development are poorly known, including, for example, what genes have conserved developmental roles across fruiting body-forming fungi or how cell-cell communication is orchestrated in developing fruiting bodies.…”

High-throughput targeted gene deletion in the model mushroom Schizophyllum commune using pre-assembled Cas9 ribonucleoproteins

“…Their total economic value is estimated at 63 billion USD 3 . However, the biological mechanisms underlying mushroom formation are poorly understood, primarily due to a lack of efficient genetic tools, which are essential for a deep understanding of these developmental processes 4–9 . Next-generation sequencing has yielded a vast amount of genome and expression data, but there is a relative lack of functional characterization of gene function in mushroom-forming fungi 10–14 .…”

“…The basidiomycete Schizophyllum commune is a model organism for mushroom formation: it completes its lifecycle in the lab in ten days and many genomic and genetic tools are available 4,10,15 . Targeted gene deletion succeeded in four mushroom-forming species to date 5,8,16,17 and the majority were made in S. commune , although even in this organism only 23 gene deletions have been reported 4–6,15,18–26 . The main bottleneck in gene deletion in mushroom-forming fungi is the relatively low incidence of homologous recombination (HR) and relatively high incidence of non-homologous end-joining (NHEJ) 5 .…”