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Plants swap chloroplasts via grafts

Energy-converting cellular organs can pass through garden-variety connections

Plants of different species can swap chloroplasts, the little cellular factories that capture energy from sunlight, when stems graft together. The surprising discovery may explain why evolutionary histories based on chloroplasts sometimes disagree with those based on other sources of DNA.

“If you had asked me before I did this work, I would have said, ‘This isn’t happening,’” says plant geneticist Pal Maliga of Rutgers University in Piscataway, N.J.

Chloroplasts contain their own genetic material, which is typically passed to offspring as mother plants form seed. Now it appears that two plants of different species can exchange chloroplast DNA nonreproductively, by swapping the whole cellular organs through a graft, Maliga’s team and an independent group in Germany report online January 30 in the Proceedings of the National Academy of Sciences.

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