title: A set of isogenic auxotrophic strains for constructing multiple gene deletion mutants and parasexual crossings in Aspergillus niger.
abstract: To construct a set of isogenic auxotrophic strains in Aspergillus niger suited for creating multiple gene deletion mutants and executing parasexual crossings, we have combined mutations in genes involved in colour pigmentation (fwnA and olvA) with well-selectable auxotrophic markers (pyrG, nicB, argB, and adeA). All markers, except for the pyrG marker, were introduced by targeted deletion, omitting UV mutagenesis of the strains. Aspergillus oryzae orthologous genes of the argB, nicB, and adeA markers were used as heterologous selection markers, and all markers were shown to complement to respective auxotrophic A. niger mutants. A quadruple auxotrophic marker was further constructed suitable for multiple gene deletions. Genome sequencing of two auxotrophic colour mutants JN3.2 (olvA::pyrG, argB::hygB) and JN6.2 (olvA::pyrG, nicB::hygB) revealed four SNPs between them in non-coding regions, indicating a high level of isogenicity between both strains. The availability of near-isogenic complementary auxotrophic colour mutants facilitates the selection of diploids and the isolation of haploid segregants from the diploid using the parasexual cycle.
authors.affiliation: Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
authors.forename: Jing
authors.initials: J
authors.lastname: Niu
authors.affiliation: Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Arentshorst
authors.affiliation: Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.
authors.forename: Felix
authors.initials: F
authors.lastname: Seelinger
authors.affiliation: Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands. a.f.j.ram@biology.leidenuniv.nl.
authors.forename: Arthur F J
authors.initials: AF
authors.lastname: Ram
authors.affiliation: Molecular Microbiology and Biotechnology, Institute of Biology Leiden, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands.|Centre for Structural and Functional Genomics, Concordia University, 7141 Sherbrooke St. W., Montreal, QC, H4B 1R6, Canada.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Ouedraogo
mesh_terms: D001234:Aspergillus niger / Q000235:genetics*; D002874:Chromosome Mapping; D004171:Diploidy; D017353:Gene Deletion; D016296:Mutagenesis; D014169:Transformation, Bacterial / Q000235:genetics*
keywords: Auxotrophy; Isogenic strains; Multiple markers; Parasexual crossing