SRM1 phosphorylation coordinates plant immunity and growth in Arabidopsis

Plants mount an array of immune responses to combat pathogen invasion, which is often accompanied by growth inhibition. How plants coordinate immunity and growth is of great agricultural significance. Here, we report an MYB-related transcription factor, SRM1, that positively regulates both plant immunity and growth in Arabidopsis thaliana. SRM1 enhances disease resistance by directly binding to the promoters and activating expression of the core immune factor EDS1 and the anthocyanin synthesis gene DFR. Notably, SRM1 also promotes plant growth by directly activating PORA expression for chlorophyll synthesis. Under normal conditions, low SRM1 levels are maintained by ubiquitination and degradation by the 26S proteasome. Upon infection, SRM1 is phosphorylated by MPK3/6, which increases its stability and accumulation to enhance plant resistance. Ultimately, SRM1 coordinates plant growth and defense through post-translational modifications. Targeting SRM1 phosphorylation motifs may enable breeding of disease-resistant crops without yield penalty. The evolutionary conservation of SRM1 in plants provides clues for breeding crops with balanced disease resistance and yield.