Induction of Mitochondrial Rearrangements for Cytoplasmic Male Sterility in Crop Plants

Cytoplasmic male sterility (CMS) is usually manifested by the inability of an otherwise normal plant to shed viable pollen. This trait is valuable to the hybrid seed industry, as a means of generating cross-pollinated seed, and it is also viewed as a possible means of preventing pollen escape in transgenic crops.

A method of inducing CMS through mitochondrial DNA (mtDNA) rearrangements was described by researchers at the University of Nebraska. The group of Sally Mackenzie examined a nuclear gene called Msh1 in tobacco and tomato. Msh1 is believed to be involved in the suppression of mtDNA rearrangements during plant development. By disrupting the gene expression through RNA interference (RNAi), the researchers observed that CMS is induced in the transgenic plants.

Mackenzie and colleagues found out that even when the transgene segregates, it did not reverse the male sterile phenotype, producing stable, nontransgenic male sterility. Their method may help provide a means to develop novel cytoplasmic male sterile lines for release as non-GMO or transgenic materials.

The paper published by the Proceedings of the National Academy of Sciences (USA), is available for subscribers at http://www.pnas.org/cgi/content/abstract/104/6/1766