Condensation Index Explains How Plants Perceive Fall Temperature Changes


Credit: John Innes Center

As the weather cools in the fall, you may notice the condensation process, with water droplets forming on the windows.

Researchers have found that a similar process, biophysical condensation, occurs inside plants and allows them to detect temperature fluctuations.

The ability to detect seasonal changes is crucial for plants to grow and reproduce at the right time of year.

The first author of the research, Dr Pan Zhu, said: “Our results are useful in understanding how plants perceive fluctuating temperature signals – and it is the fluctuation in temperature that is expected to become more extreme with climate change. . “

One gene in particular is important for how plants remember seasonal changes: the flower C locus (FLC). It acts as a brake on flowering which is lifted in the spring, so the plant is ready to flower.

While much is known about how FLC is epigenetically extinct and remains off through winter, ready for spring, less is known about the initial process known as “transcriptional shutdown” when the FLC DNA ceases to be used by the cell.

Now, researchers have discovered how, at low temperatures, a protein of a known FLC activator forms liquid bubbles, called condensates, inside the nuclei of plant cells. The protein is called FRIGIDA. By forming condensates at low temperature, FRIGIDA is kept away from activation of the FLC.

When temperatures are warm, the FRIGIDA protein is free to revert to FLC DNA and ensure that the flowering brake persists. This prevents the plant from flowering too early if it is very hot in the fall.

Researchers in Professor Dame Caroline Dean’s group at the John Innes Center discovered the biophysical mechanism using the model plant Arabidopsis thaliana.

This research which appears in Nature provides new insight into how plants perceive temperature fluctuations at a time when this knowledge is important for crop improvement in the face of climate change.

This newly discovered role of biological condensation in regulating plant genetics suggests that the process can be used in other ways in plants, to enable them to respond to other changes in the environment.

Professor Dean explains: “Dynamic molecular partitioning involving transcription regulators and non-coding RNA interactions is likely to be generally relevant for abiotic interactions in plants – and therefore for crop productivity.”

Experiences and discoveries in brief

The research team found that high levels of FRIGIDA build up in the cold. Upon closer inspection using microscopy, they saw that it accumulates in the nuclei of plant cells, where DNA is lodged, and forms biomolecular condensates. Biomolecular condensates are micron-scale compartments of concentrated proteins.

Other biochemical and visualization techniques, including the use of a temperature-controlled timelapse microscope, revealed that protein condensates disappear within five hours of warm temperatures, but return after a six-hour period of cold. . Experiments have shown how the condensation of FRIGIDA is responsible for stopping transcription at FLC.

The study also found how condensates from FRIGIDA fit into the larger picture of FLC regulation, as Dr Zhu explains: “Another interesting finding was that a specific isoform of non-RNA. encoding the long COOLAIR, the antisense transcripts of the FLC locus, contributes to the induced cold. Formation of nuclear condensate from FRIGIDA. This reveals a type of mechanism explaining how the cessation of COOLAIR-mediated FLC occurs at the onset of vernalization.

The first frost is the deepest

More information:
Caroline Dean, Cold Induced Arabidopsis FRIGIDA Nuclear Condensates for FLC Suppression, Nature (2021). DOI: 10.1038 / s41586-021-04062-5.

Provided by the John Innes Center

Quote: Condensation Index Explains How Plants Perceive Fall Temperature Change (2021, November 3) retrieved November 3, 2021 from temperature.html

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