Monday, August 07, 2006
Plants under stress not only activate their own defences, but also manage to pass on a possible protective strategy to their descendants. That's the surprising conclusion of a study published online today by Nature: "Transgeneration memory of stress in plants" (Abstract).
Stresses such as pathogen infection or ultraviolet radiation can trigger increased rates of genetic mutation in some plant cells, occasionally even scrambling regions of their DNA. Some scientists hypothesize that by augmenting their genomic flexibility, plants boost their ability to produce genetic changes that could allow them to adapt to stressful environments. Now it seems that plants can also pass this genetic pliability on to their offspring.
Researchers in Barbara Hohn's lab at the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland, study a process in which one piece of DNA within the genome replaces another fragment of similar sequence. This process, called 'homologous recombination', occurs more frequently in stressed plants. Plants grown near the site of the Chernobyl nuclear-reactor accident, for example, were found to have rates of homologous recombination that increased with the dose of radiation they received.