Amplification of substoichiometric recombinant mitochondrial DNA sequences in a nuclear, male sterile mutant regenerated from protoplast culture in Nicotiana sylvestris

Mol Gen Genet. 1992 May;233(1-2):193-200. doi: 10.1007/BF00587579.


A Nicotiana sylvestris plant regenerated from protoplast culture was found to be mutated in both the mitochondrial (mt) and nuclear genomes. The novel mt DNA organization, called U, is due to the amplification of recombinant substoichiometric DNA sequences that preexist in the parent line. The recombination event involves two 404 bp repeats, which hybridize to a 2.1 kb transcript. Although the sequence of both repeats was not altered by the recombination, an additional transcript of 2.5 kb was detected in U mitochondria. In addition to this mitochondrial reorganization, the protoclone carried a recessive nuclear mutation conferring male sterility (ms4). A possible role of ms4 in the appearance of the U mt DNA organization was investigated by introducing this gene into normal N. sylvestris cytoplasm. No mt DNA change could be found in homozygous ms4/ms4 plants of the F2 generation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Chloroplasts
  • Cloning, Molecular
  • Cosmids
  • DNA, Mitochondrial / genetics*
  • DNA, Recombinant / genetics
  • Gene Amplification*
  • Homozygote
  • Molecular Sequence Data
  • Mutation*
  • Plants, Toxic*
  • Protoplasts*
  • RNA / genetics
  • Repetitive Sequences, Nucleic Acid
  • Reproduction
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Tobacco / genetics*


  • DNA, Mitochondrial
  • DNA, Recombinant
  • RNA