Extensive nuclear influence on mitochondrial transcription and genome structure in male-fertile and male-sterile alloplasmic Nicotiana materials.

Nuclear influences on mitochondrial transcription and genome organization were analysed in six different male-fertile and male-sterile alloplasmic Nicotiana cultivars. The alloplasmic materials were compared with the corresponding nuclear species (N. tabacum) and cytoplasmic donor species (N. debneyi, N. rapanda or N. suaveolens) in Northern and Southern analyses using twelve different mitochondrial genes as probes. The investigation revealed that the nucleus exerts extensive influence on the expression and structure of the mitochondrial genome. For the majority of the probes, changes in both mitochondrial transcription and DNA patterns in alloplasmic cultivars were detected. Even though changes in transcription patterns, which correlated with male sterility, were detected for three of the probes (atpA, orf25 and coxII), the changes were not consistent for all the male-sterile materials. Likewise, no consistent association between mtDNA restriction patterns and cytoplasmic male sterility (CMS) was detected.