Researchers report cell-to-cell movement of mitochondria through a graft junction

A team of researchers with Rutgers University has found an example via experimentation, of cell-to-cell movement of mitochondria through a graft junction of two tobacco species.

In their paper published in PNAS, the team describes their experiments with grafting tobacco plants and what they learned about cells swapping mitochondria during the aftermath.

Human beings have been grafting plants for centuries, cutting a branch from one plant and pressing it against an exposed part of another has resulted in fruit trees that bear more than one type of fruit, for example. But, what has not been clear is what else happens during grafting—to the human eye it appears a grafted branch produces the type of fruit it originally would have, but not much else.

But genetic research over the past decade has shown that chloroplasts can be exchanged between cells on either side of a graft, and in some cases an entire cell nucleus can be exchanged as well. In this new effort, the researchers have found that cells can exchange mitochondria also which means that plants mix their DNA together when grafting takes place.

This new evidence blurs the line between genetically modified plants, or crops that come about due to man-made processes and those that occur naturally, because natural grafting sometimes occurs when two plants grow close to one another. Those who insist that GMOs are harmless will now have another argument to back them up because it now appears that plants have been swapping DNA naturally all along.