The role of PKAc1 in gene regulation and trichodimerol production in Trichoderma reesei

Abstract

Background Trichoderma reesei represents a model system for investigation of plant cell wall degradation and its connection to light response. The cyclic adenosine monophosphate pathway (cAMP pathway) plays an important role in both physiological outputs, being crucial for regulation of photoreceptor function as well as for cellulase regulation on different carbon sources. Phosphorylation of photoreceptors and of the carbon catabolite repressor CRE1 was shown in ascomycetes, indicating a relevance of protein kinase A in regulation of the target genes of these transcription factors as well as an impact on regulation of induction specific genes. Moreover, the cAMP pathway impacts growth and development. Results Here, we investigated gene regulation by the catalytic subunit of protein kinase A (PKAc1) upon growth on cellulose. We found distinct gene sets for regulation upon growth in light and darkness with an overlap of only 13 genes. PKAc1 regulates metabolic genes as well as transport and defense functions. The overlap of gene regulation by PKAc1 with the genes representing the cAMP dependent regulatory output of the photoreceptor ENV1 indicates an involvement of PKA in this pathway, which counteracts its effects by contrasting regulation. Moreover, we found considerable overlap with the gene sets regulated under cellulase inducing conditions and by the carbon catabolite repressor CRE1. Our analysis also showed that PKAc1 regulates the genes of the SOR cluster associated with the biosynthesis of sorbicillinoids. The homologue of gin4, encoding a CAMK type kinase, which is regulated by PKAc1, CRE1 and YPR2 showed a moderate impact on trichodimerol production. We isolated trichodimerol as representative sorbicillin compound and established a method for its quantification in large sample sets using high performance thin layer chromatography (HPTLC), which can be broadly applied for secondary metabolite screening of mutants or different growth conditions. Due to the high expression levels of the SOR cluster under conditions of sexual development we crosschecked the relevance of PKAc1 under these conditions. We could show that PKAc1 impacts biosynthesis of trichodimerol in axenic growth and upon mating. Conclusions We conclude that PKAc1 is involved in light dependent regulation of plant cell wall degradation, including carbon catabolite repression as well as secondary metabolism and development in T. reesei.

Redesigning transcription factor Cre1 for alleviating carbon catabolite repression in Trichoderma reesei

“…5 ). This result is consistent with previous study that phosphorylation of Cre1 affects its nuclear import and export [ 30 ] and plays an important role in cellulase production in T. reesei [ 31 ]. Thus, we suggested that phosphorylation of the C-terminal of Cre1 plays an important role on its subcellular localization and has a direct relationship with CCR.…”

Precision Engineering of the Transcription Factor Cre1 in Hypocrea jecorina (Trichoderma reesei) for Efficient Cellulase Production in the Presence of Glucose

“…Among the potential phosphorylation target sites in the region covering amino acids 387-390 at the C-terminus of Cre1, S388 maybe be phosphorylated by PKA, in contrast to S387, T389, and T390. As a conserved nutrient-sensing pathway, the cAMP-PKA pathway plays an important role in the response to environmental carbon availability to activate or repress the relevant downstream genetic pathways (Ortiz-Urquiza and Keyhani, 2015;Hinterdobler et al, 2019) . In Aspergillus fumigatus and Neurospora crassa, PKA is activated in the presence of glucose, thereby inhibiting alternative carbon source usage due to CCR (Brown et al, 2014;Huberman et al, 2016).…”

The Lipoxygenase Lox1 Is Involved in Light‐ and Injury-Response, Conidiation, and Volatile Organic Compound Biosynthesis in the Mycoparasitic Fungus Trichoderma atroviride

“…HPTLC analysis was done according to Hinterdobler et al (2019) with some modifications. Metabolites were extracted from the agar by supersonication for 15 min in a mixture of 5 ml water (p.A.)…”