A comparison of cytoplasmic revertants to fertility from different CMS-S maize sources.
The mitochondrial genome organizations of a number of independent culture-derived fertile CMS-S revertants with the nuclear genotype W182BN were compared to spontaneous field revertants with the genotypes WF9, M825/Oh07 and 38-11. Regions of the genome around sequences homologous to the terminal repeats of the linear S1 and S2 episomes characteristic of CMS-S mitochondria were used as hybridization probes on Southern blots of BamHI and SalI digested mitochondrial DNA. The results obtained suggest that the nuclear, not the cytoplasmic, genotype of the parent plant affects the type of novel mitochondrial DNA organization found in the revertant. The DNA reorganization during reversion from CMS-S in tissue culture appears to be similar to that observed in spontaneous revertants obtained during the normal plant life-cycle. Unlike the situation for reversion from CMS-T, no common DNA sequence or reading frame appeared to be lost or disrupted in revertants.
Department of Botany, University of Edinburgh, The King's Buildings, Mayfield Road, EH9 3JH, Edinburgh, UK.
I D
ID
Small
E D
ED
Earle
L J
LJ
Escote-Carlson
S
S
Gabay-Laughnan
J R
JR
Laughnan
C J
CJ
Leaver