Salicylic Acid - GoKawiil

Study reveals how salicylic acid switches on plant immune genes via NPR1-Mediator complex

Researchers used structural biology techniques, including crystallography and molecular cloning of Arabidopsis proteins such as NPR1, NPR3, NPR4, MED15 subunits and TGA3, to map how the hormone salicylic acid triggers plant defense gene transcription. The work details the physical interactions between the NPR1 receptor and Mediator complex components that turn on immune responses in plants.

nature.com · 2026-09-16

Researchers map how salicylic acid switches plant defense genes on and off

Scientists studying Arabidopsis have uncovered how the plant hormone salicylic acid controls immune gene expression through two receptor systems, NPR1 and NPR3/NPR4. They found that salicylic acid prompts NPR1 to bind a protein called MED15A, linking it to the cell's transcription machinery to activate defense genes, while simultaneously blocking NPR3/NPR4 from partnering with NIMIN1 and repressive complexes that would otherwise silence those genes.

nature.com · 2026-09-16