Plants build an “isolation wall” when infected... Korea University (KU) identifies immune switch

[Financial News] Researchers in South Korea have identified a key immune mechanism by which plants build a “physical barrier” around an infected area to trap pathogens when bacteria invade. The finding is expected to be an important key to developing crops resistant to pests and diseases.
KU said on the 4th that a research team led by Professor Kim Ok-mae of its Department of Life Sciences had identified the key signaling system that instructs plants to build a defense barrier of lignin, a component of the cell wall, when infected by pathogens. The results were recently published online in Nature Plants, an international journal in the field of plant science.
Unlike animals, plants cannot move, so when bacteria enter, they kill infected cells themselves to prevent pathogens from spreading. But this has limits when it comes to stopping bacteria that spread through tiny gaps between cells. The research team confirmed that plants build a fortress by accumulating lignin, which strengthens cell walls, around infected areas. Until now, however, it had remained unclear how the instruction to build this wall is transmitted inside the cell.
The research team found that plants activate a kind of “relay signal” the moment they detect a pathogen. When a pathogen invades, sensing mechanisms on the cell surface detect it and activate proteins that transmit signals inside the cell in sequence. The activated proteins then switch on the production of materials for the defense barrier, enabling a sturdy wall to form around the infected area.
The signaling system was initially known for its role in forming boundary walls as plant roots grow. The study also found that in leaves, it transforms into an immune switch that stops pathogens. In effect, plants were efficiently using the same tool for “growth” in their roots and “defense” in their leaves.
Professor Kim Ok-mae of KU said, “We were the first to confirm that a signaling pathway that helps roots grow plays a key role in immune responses that fend off pathogens in leaves,” and added, “This will serve as important foundational data for developing robust crops that can better withstand disease in the future.”  

[email protected] Kim Man-gi Reporter