(B) PHR1 negatively regulates FLS2-BAK1 complex formation under Pi-starvation conditions. Col-0, phr1 mutant seedlings were grown in either HP or LP media for 5 days, then lysing roots into protoplasts, transformed with water or PHR1-Myc plasmid and treated with flg22 for 6 hours. The amount of immunoprecipitated FLS2 and coimmunoprecipitated BAK1 were determined using anti-FLS2 and anti-BAK1 antibodies, respectively. Preimmune serum (IgG) was used as negative control. Data information: All experiments were repeated three times with similar results. 