GoKawiilResearchers 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.