Researchers from the University of Tokyo were able to edit the mitochondrial
DNA of the plant for the first time. The scientists turned their attention
to the cytoplasmic male sterility (CMS) of the plant, which is a type of
rare plant male infertility caused by genes in the mitochondria. CMS is
attributed to certain mitochondrial genes.
Using rice and rapeseed (anola), the research team used the technique called
mitoTALENs, or the mitochondria localization signals transcription
activator-like effector nucleases. This technique was previously used to
edit mitochondrial genomes of animal cells. To sum up, the technique uses a
single protein to locate the mitochondrial genome, then cut the DNA at the
desired gene to delete it. By deleting the CMS gene, the plants became
fertile again. The Japanese scientists likened the plants used in the
experiment as "more polite," noting how the plants bowed deeply under the
weight of heavy seeds.
Further investigation through sequencing showed that double-strand breaks
induced by mitoTALENs were repaired by homologous recombination. This proved
that the target genes and surrounding sequences were deleted, showing that
mitoTALENs can be used to stably and heritably modify the mitochondrial
genome in plants. This is the first time that the editing of a mitochondrial
plant DNA was documented.
The mitochondria is the powerhouse of the cell. Plants get a significant
portion of their energy through the mitochondria. Quoting the scientists,
"without it, there is no life." Currently, there is a lack of mitochondrial
genetic diversity in crops, which is a weak point in the global food
production. The result of this study is an important first step towards
plant mitochondrial research that could lead to a more secure food supply.