A CRE1- regulated cluster is responsible for light dependent production of dihydrotrichotetronin in Trichoderma reesei

Abstract

Changing light conditions, caused by the rotation of earth resulting in day and night or growth on the surface or within a substrate, result in considerably altered physiological processes in fungi. For the biotechnological workhorse Trichoderma reesei, regulation of glycoside hydrolase gene expression, especially cellulase expression was shown to be a target of light dependent gene regulation. Analysis of regulatory targets of the carbon catabolite repressor CRE1 under cellulase inducing conditions revealed a secondary metabolite cluster to be differentially regulated in light and darkness and by photoreceptors. We found that this cluster is involved in production of trichodimerol and that the two polyketide synthases of the cluster are essential for biosynthesis of dihydrotrichotetronine (syn. bislongiquinolide or bisorbibutenolide). Additionally, an indirect influence on production of the peptaibol antibiotic paracelsin was observed. The two polyketide synthetase genes as well as the monooxygenase gene of the cluster were found to be connected at the level of transcription in a positive feedback cycle in darkness, but negative feedback in light, indicating a cellular sensing and response mechanism for the products of these enzymes. The transcription factor TR_102497/YPR2 residing within the cluster regulates the cluster genes in a light dependent manner. Additionally, an interrelationship of this cluster with regulation of cellulase gene expression was detected. Hence the regulatory connection between primary and secondary metabolism appears more widespread than previously assumed, indicating a sophisticated distribution of resources either to degradation of substrate (feed) or to antagonism of competitors (fight), which is influenced by light.

SUB1 has photoreceptor dependent and independent functions in sexual development and secondary metabolism in Trichoderma reesei

“…We focused on the polyketide trichodimerol (Shirota et al ., ), a fungal metabolite with potential anticancer activity (Serwe et al ., ) and the peptaibol antibiotic paracelsin (Brückner et al ., ) as model substances. Both metabolites were previously shown to be produced in T. reesei (Brückner et al ., ; Monroy et al ., ). The supernatants of cultures were analyzed with quantitative mass spectrometry for known secreted fungal metabolites.…”

Constitutive hyperproduction of sorbicillinoids in Trichoderma reesei ZC121

“…In previous studies, the ability of T. reesei to produce sorbicillinoids was reported to vary with different carbon sources [ 19 , 37 – 39 ]. To see whether the superior sorbicillinoids’ production of strain ZC121 compared to strain RUT-C30 is dependent on carbon source, both the sorbicillinoids and cellulase production of strains ZC121 were measured during the time course of growth on TMM containing cellulose, lactose, glucose, galactose or glycerol as the individual carbon source (Fig.…”

“…Other carbon sources, such as lactose, glycerol, and galactose have been reported to be utilized by T. reesei to produce remarkable amounts of sorbicillinoids. Furthermore, the sorbicillinoids’ production in fungi has been reported to be generally impacted by culture conditions, such as carbon source [ 9 , 37 ], light exposure time [ 39 ], temperature, and pH. By contrast, the recombinant strain ZC121 displayed hyperproduction of sorbicillinoids regardless the culture conditions, so long as T. reesei can grow well.…”

Omics Analyses of Trichoderma reesei CBS999.97 and QM6a Indicate the Relevance of Female Fertility to Carbohydrate-Active Enzyme and Transporter Levels

“…For industrial application of T. reesei , the ability to produce secondary metabolites is of high importance. Recently, connections between primary and secondary metabolism were indeed shown ( 9 , 10 ). Comparison of the genome of T. reesei with the genomes of the potent biocontrol fungi Trichoderma atroviride and Trichoderma virens indicated that at least part of the mycoparasitism-specific gene content was lost in evolution in T. reesei ( 5 , 11 ).…”