Recombination of mitochondrial DNAs following transmission of mitochondria among incompatible strains of black Aspergilli

F. Kevei, B. Tóth, A. Coenen, Z. Hamari, J. Varga, J. H. Croft

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Successful intra- and interspecific mitochondrial transfers were performed by polyethylene glycol (PEG)-induced protoplast fusion among incompatible strains belonging to the Aspergillus niger species aggregate. The mitochondrial DNAs (mtDNAs) of the strains examined were of three main types based on their restriction fragment length polymorphism (RFLP) profiles. mtDNA types 1 and 2 correspond to A. niger and A. tubingensis species, respectively, while type 3 is represented by some Brazilian wild-type isolates (possibly a distinct species or subspecies). mtDNA types 1 and 2 could be further divided into several subgroups (1a-1e and 2a-2f). All these strains, representing different RFLP groups or subgroups, were fully incompatible with respect to nuclear complementation. The transfer experiments were carried out under selection pressure, using a mitochondrial oligomycin-resistant mutant of mtDNA type 2a as donor. Following fusion mitochondrial oligomycin-resistant progenies were recovered in the presence of oligomycin by selecting for the nuclear phenotypes of the oligomycin-sensitive recipient strains. All attempted transfers were successful, and resulted in different varieties of resistant recombinant mitochondrial progenies at various frequencies. Within the group of strains of mtDNA type 1, the transfer of oligomycin-resistant mitochondria resulted in the appearance of a single recombinant type of RFLP profile in each case. The recombination events were more complex when the transfer of oligomycin resistance occurred between strains representing different species (mtDNA groups 1a→2 and 1a→3). A great variety of recombinant mtDNA RFLP profiles appeared. Explanation for this phenomenon are discussed on the basis of preliminary physical mapping data.

Original languageEnglish
Pages (from-to)379-388
Number of pages10
JournalMolecular and General Genetics
Volume254
Issue number4
DOIs
Publication statusPublished - Jun 14 1997

Keywords

  • Aspergillus niger
  • Incompatibility
  • Mitochondrial transfer
  • mtDNA recombination

ASJC Scopus subject areas

  • Genetics

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