Abstract
BackgroundTrichoderma reesei is one of the most frequently used filamentous fungi in industry for production of homologous and heterologous proteins. The ability to use sexual crossing in this fungus was discovered several years ago and opens up new perspectives for industrial strain improvement and investigation of gene regulation.ResultsHere we investigated the female sterile strain QM6a in comparison to the fertile isolate CBS999.97 and backcrossed derivatives of QM6a, which have regained fertility (FF1 and FF2 strains) in both mating types under conditions of sexual development. We found considerable differences in gene regulation between strains with the CBS999.97 genetic background and the QM6a background. Regulation patterns of QM6a largely clustered with the backcrossed FF1 and FF2 strains. Differential regulation between QM6a and FF1/FF2 as well as clustering of QM6a patterns with those of CBS999.97 strains was also observed. Consistent mating type dependent regulation was limited to mating type genes and those involved in pheromone response, but included also nta1 encoding a putative N-terminal amidase previously not associated with development. Comparison of female sterile QM6a with female fertile strains showed differential expression in genes encoding several transcription factors, metabolic genes and genes involved in secondary metabolism.ConclusionsEvaluation of the functions of genes specifically regulated under conditions of sexual development and of genes with highest levels of transcripts under these conditions indicated a relevance of secondary metabolism for sexual development in T. reesei. Among others, the biosynthetic genes of the recently characterized SOR cluster are in this gene group. However, these genes are not essential for sexual development, but rather have a function in protection and defence against competitors during reproduction.
Highlights
Trichoderma reesei is one of the most frequently used filamentous fungi in industry for production of homologous and heterologous proteins
In T. reesei, in contrast to many other fungi, sexual development is initiated upon growth on complex media such as Dattenböck et al Fungal Biol Biotechnol (2018) 5:9 malt extract agar (MEA) or potato dextrose agar (PDA) and occurs preferentially in light [14]
Gene expression patterns in strains with QM6a background versus CBS999.97 We performed transcriptome analysis under conditions facilitating sexual development and enable the associated chemical communication using the wild-isolate CBS999.97 in both mating types [6], the female sterile strain QM6a and female fertile derivatives of QM6a in both mating types (FF1 and FF2), which were prepared by repeated backcrossing [10, 22]
Summary
Trichoderma reesei is one of the most frequently used filamentous fungi in industry for production of homologous and heterologous proteins. Hypocrea jecorina) strains that dominated research and industry, QM6a, has been isolated during WWII in the tropics [1,2,3]. For decades it was considered asexual, which was a drawback for genetics research and industrial. Sexual development is dependent on the presence of a functional pheromone system in fungi [11] as well as on precisely defined environmental conditions [12, 13]. T. reesei has no conventional a-type peptide pheromone precursor, but employs a novel type of pheromones, with HPP1 as the first representative of h-type pheromones [16]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
