Sequencing DNA collected from leaves on different branches of a 234-year-old oak tree on the University of Lausanne campus in Switzerland, plant biologist Philippe Reymond and colleagues found far fewer single base-pair substitutions than expected based on known plant mutations rates and the number of cell divisions that presumed to have occurred between an old branch near the tree’s base and a younger branch 40 meters higher up. The team, which did not analyze other types of genetic mutations such as deletions, published its results last week (June 13) on the preprint server bioRxiv.
“It’s a tantalizing study,” Daniel Schoen, a plant evolutionary biologist at McGill University in Montreal, Canada, tells Nature. “It touches on something that was simmering always, in the back of the minds of plant biologists.”
Specifically, the findings support the idea that plants somehow protect their stem cells from accumulating mutations. Last year, for example, scientists from the University of Bern found evidence in Arabidopsis thaliana and tomato that plants limit the number of cell divisions in the meristem tissues that house the stem cells that support plant growth. “Plants seem to set aside some cells in such a way as to minimize the number of mutations they accumulate,” Rob Lanfear of Macquarie University in Australia wrote in an email to The Scientist following the study’s publication.