The novel Huntiella omanensis mating gene, MAT1-2-7, is essential for ascomatal maturation

• Published in: Fungal genetics and biology 2020-04, Vol.137, p.103335-103335, Article 103335
• Main Authors: Wilson, Andi M., Wilken, P. Markus, van der Nest, Magriet A., Wingfield, Michael J., Wingfield, Brenda D.
• Format: Article
• Language: English
• Subjects: CRISPR-Cas9 genome editing; MAT gene characterization; Novel secondary MAT gene; Protoplast-based transformation; Sexual reproduction
• ISSN: 1087-1845; 1096-0937
• DOI: 10.1016/j.fgb.2020.103335

•A genome editing protocol has been developed for use in Huntiella species.•MAT1-2-7, a novel mating gene, is a true mating gene in Huntiella omanensis.•ΔMAT1-2-7 strains show delays in protoascomatal development and hyphal growth.•MAT1-2-7 is essential for ascomatal maturation. Sexual reproduction is a highly conserved feature of the eukaryotes, yet sexual compatibility is determined by a wide variety of mechanisms. In ascomycete fungi, sexual development is controlled by genes at the mating type (MAT) locus that confer either MAT1-1 or MAT1-2 mating identity. Although the locus harbours, at minimum, a single gene, the individual MAT loci of certain species, including Huntiella omanensis, encode for two or more genes. The MAT1-2 idiomorph of H. omanensis is made up of MAT1-2-1, a primary MAT gene that is highly conserved in the Pezizomycotina and possesses a well-characterized DNA binding motif, the HMG-box domain. The idiomorph also harbours a novel secondary MAT gene, named MAT1-2-7, with no recognizable functional domains. In this study, we developed a transformation and CRISPR-Cas9-based genome editing protocol to characterize the MAT1-2-7 gene with respect to its function in mating. We have shown that MAT1-2-7 is essential for sexual reproduction and that isolates carrying the truncated MAT1-2-7 gene are incapable of ascomatal maturation and further sexual development. MAT1-2-7 was also shown to influence the vegetative radial growth rate of H. omanensis, illustrating the pleiotropic effects often associated with MAT genes.