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Crops and other plants are often attacked by bacteria, viruses and other pathogens. Unlike animals, plants do not have specialized immune cells that can be delivered through the bloodstream to the site of infection. Therefore, each cell of the plant should be able to protect itself by quickly switching to "combat mode".

When plants are attacked, they switch their priorities from growth to defense, so cells begin to synthesize new proteins and suppress the production of others. Then, as scientists note, within two to three hours everything returns to normal.

Tens of thousands of proteins formed in cells perform many functions: they catalyze reactions, serve as chemical intermediaries, recognize foreign substances, move materials in and out. To build a specific protein, the genetic instructions in the DNA packed inside the cell nucleus are transcribed into a messenger molecule - mRNA. This mRNA strand is then sent to the cytoplasm, where the ribosome "reads" the message and translates it into a protein.

Previously, the team found that when a plant is infected, some mRNA molecules are translated into proteins faster than others. It turned out that these mRNA molecules have a common region at the front end of the RNA chain with repeated letters in its genetic code, where the nucleotide bases adenine and guanine are repeated over and over again.

In a new study, scientists show how this region interacts with other structures inside the cell to activate protein production in the face of an impending threat.

When plants detect a pathogen attack, the molecular pointers that signal the usual starting point for ribosomes to read mRNA are turned off. And this prevents the cell from producing its typical "peacetime" proteins.

Instead, ribosomes bypass the usual starting point of translation, using the region of repeated adenine and guanine inside the RNA molecule for docking, and instead begin to "read" from there.

At the same time, the more forces a plant throws at protecting itself from infection, the fewer resources are left for photosynthesis and other vital matters. The production of too many protective proteins can lead to a side effect: plants with an overly active immune system suffer from growth retardation. By understanding how plants maintain this balance, scientists hope to find new ways to create disease-resistant crops without compromising yields.

The team conducted most of their experiments on a plant called rhesus Talia (Arabidopsis thaliana). But similar mRNA sequences have been found in other organisms, including fruit flies, mice, and humans, so they may play a broader role in controlling protein synthesis in both plants and animals.

The article was published in the journal Cell
The information is taken from the portal "Scientific Russia" (https://scientificrussia.ru /)

PHOTO © Guoyong Xu

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