Natures wonders: plant response to heat stress (Introduction)

by David Turell , Sunday, June 27, 2021, 17:44 (1243 days ago) @ David Turell

A small group of proteins protect against heat shock:

https://www.sciencedaily.com/releases/2021/06/210610091025.htm

"Researchers have found that plants adapt to heat stress via a specific 'memory' mechanism. The JUMONJI family of proteins can control small heat shock genes, allowing plants to become heat tolerant for better adaptation to future heat stress.

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"Heat stress is often repeating and changing," says lead author of the study Nobutoshi Yamaguchi. "Once plants have undergone mild heat stress, they become tolerant and can adapt to further heat stress. This is referred to as heat stress 'memory' and has been reported to be correlated to epigenetic modifications." Epigenetic modifications are inheritable changes in the way genes are expressed, and do not involve changes in the underlying DNA sequences.

"'We wanted to discover how plants retain a memory of environmental changes," explains Toshiro Ito, senior author. "We examined the role of JUMONJI (JMJ) proteins in acquired temperature tolerance in response to recurring heat within a few days."

"JUMONJI proteins are histone demethylases. Demethylases are enzymes that remove methyl groups from molecules such as proteins, particularly histones, which provide structural support to chromosomes. The team revealed that plants are able to maintain heat memory because of lowered H3K27me3 (histone H3 lysine 27 trimethylation) on small heat shock genes.

"'We found that these proteins are necessary for heat acclimation in Arabidopsis thaliana. These results, along with future studies, will further clarify the mechanisms of plant memory and adaptation," says Yamaguchi.

Comment: These plans are not thinking. Climbing heat makes them demethylate DNA and tolerate the heat. JUMONJ2 is an enzyme, which means a giant specialized molecule that must have been designed for the task.