A study conducted by scientists from the University of Nottingham and the
University of Birmingham, in collaboration with researchers from the
Universities of Oxford and Utrecht uncovered the mechanism that allows
plants to remember changes in their environment.

To figure out how plants sense and 'remember' changes in their environment,
the scientists focused on the polycomb repressive complex 2 (PRC2) protein,
which is known to play a key role in cell identity, developmental
transitions, and the establishment of environmental memory. Plants have
different versions of this PRC2 protein that are responsible for different
functions. For example, VRN2-PRC2 regulates vernalization in which certain
genes are silenced upon long-term exposure to cold thereby encoding a memory
of cold.

The research team discovered that the VRN2 protein directly senses and
responds to signals from the environment, but the protein is extremely
unstable and broken down when it is not required, therefore, the PRC2 also
remains inactive until required. However, the protein accummulates under
suitable conditions. The VRN2 protein was previously identified as a
positive regulator of vernalization, but scientists have now explained the
"proteolytic mechanism" behind the environmentally-induced accumulation of
VRN2 in response to cold temperatures specific to flowering plants.

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