15 May 2020

How do plants forget?

An international group of researchers found the answer to the question: how do plants forget? The study now published in Nature Cell Biology reveals more information on the capacity of plants, identified as “epigenetic memory”, which allows recording important information to, for example, remember prolonged cold in the Winter to ensure they flower at the right time during the Spring. As soon as they produce seeds, this information is “erased” from memory so they don’t bloom too early the following winter.

Jörg Becker, principal investigator at the Instituto Gulbenkian de Ciência, involved in the international team led by researcher Frédéric Berger, of the Gregor Mendel Institute of the Austrian Academy of Sciences, says that researchers set out to analyse histones in pollen, hypothesizing that the process of forgetting would most likely occur in the embedded sperm.   According to Jörg Becker, “the study led us to identify a phenomenon, the so-called “epigenetic resetting”, akin to erasing and reformatting data on a hard drive”.

Although they do it differently from humans, plants also have memories. “Epigenetic memory” occurs when specialized proteins, histones, are modified, which play an important role in indexing and defining the cell’s DNA. One of these modified histones, H3K27me3, tends to mark genes that are disabled. In the case of flowering, in cold conditions, H3K27me3, accumulates in the genes that control flowering. The researchers found that H3K27me3 completely disappears in the sperm and “this ensures that the” memory “is erased from hundreds of genes, not only those that prevent flowering, but also those that control a wide range of important functions in the seeds” reinforces Jörg. 

 

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