Tetracycline-controlled (TetON) gene expression system for the smut fungus Ustilago maydis

• Published in: Frontiers in fungal biology Vol. 3; p. 1029114
• Main Authors: Ingole, Kishor D., Nagarajan, Nithya, Uhse, Simon, Giannini, Caterina, Djamei, Armin
• Format: Journal Article
• Language: English
• Published: Frontiers Media S.A 19.10.2022
• Subjects: Bax1; Fungal Biology; smut disease; TetON; tetracycline; transcriptional inducible system; Ustilago maydis
• ISSN: 2673-6128; 2673-6128
• DOI: 10.3389/ffunb.2022.1029114

Ustilago maydis is a biotrophic phytopathogenic fungus that causes corn smut disease. As a well-established model system, U. maydis is genetically fully accessible with large omics datasets available and subject to various biological questions ranging from DNA-repair, RNA-transport, and protein secretion to disease biology. For many genetic approaches, tight control of transgene regulation is important. Here we established an optimised version of the Tetracycline-ON (TetON) system for U. maydis . We demonstrate the Tetracycline concentration-dependent expression of fluorescent protein transgenes and the system’s suitability for the induced expression of the toxic protein BCL2 Associated X-1 (Bax1) . The Golden Gate compatible vector system contains a native minimal promoter from the mating factor a-1 encoding gene, mfa with ten copies of the tet-regulated operator (tetO) and a codon optimised Tet-repressor (tetR*) which is translationally fused to the native transcriptional corepressor Mql1 (UMAG_05501). The metabolism-independent transcriptional regulator system is functional both, in liquid culture as well as on solid media in the presence of the inducer and can become a useful tool for toxin-antitoxin studies, identification of antifungal proteins, and to study functions of toxic gene products in Ustilago maydis .