Gene expression in isolated plant mitochondria: high fidelity of transcription, splicing and editing of a transgene product in electroporated organelles

Mitochondrial gene expression was studied using an electrotransformation pr otocol to introduce foreign DNA into purified wheat mitochondria. Optimal c onditions for DNA uptake and transient gene expression were determined. We show here that a DNA plasmid containing either a cognate or a noncognate ge ne under the control of a plant mitochondrial promoter is incorporated into the organelle and faithfully recognized by the transcription machinery, Tr anscripts generated by a plasmid bearing the intron-containing cox II gene were correctly spliced. Moreover, the transcripts were edited at the expect ed target C residues. The expression and maturation process of the transgen e is dependent on the integrity of functional elements such as the promotor or the presence of structural domains necessary for splicing. The mitochon drial transformation described in this report is an important tool to study the multiple steps involved in plant mitochondrial gene expression at cond itions closer to those found in vivo.