Scientists Have Edited Plant Mitochondrial DNA for the First Time

July 11, 2019

Nuclear DNA was first edited in the early 1970s, chloroplast DNA was first edited in 1988, and animal mitochondrial DNA was edited in 2008. However, no tool previously successfully edited plant mitochondrial DNA.

Low mitochondrial diversity in plants leaves whole species vulnerable to diseases. If all plants are genetically similar, very few individuals will have resistance to certain diseases, which will give a low survival rate. Manipulating plant mitochondrial DNA could promote food security, and provide scientists with a mechanism to improve genetic diversity in crops.

To find a way to manipulate the complex plant mitochondrial genome, scientists turned to collaborators familiar with the CMS systems in rice and rapeseed (canola). The scientists aimed to delete the CMS gene, which causes male infertility in plants. This gene is found in plant mitochondrion, so is unable to be removed by editing genes in the nucleus. Infertile plants pose huge problems for farmers, as they harm genetic diversity and mean they must pay agricultural companies every year for new seeds.

The scientists used a technique called mitoTALENs, which has successfully edited mitochondrial genes in animal cells. This technique uses a single protein to locate the mitochondrial genome, cut the DNA at the desired gene, and delete it. The fully fertile four new lines of rice and three new lines of rapeseed (canola) that scientists created are a proof of concept that the mitoTALENs system can successfully manipulate even the complex plant mitochondrial genome.

This advancement could lead to crops that are more resistant to both diseases and environmental pressures, and could enable a more secure food supply for the future.